@article{boone_kulkarni_cortes_gaghan_mohammed_villalobos_esandi_gimeno_2024, title={Evaluation of Adjuvant Effect of Cytosine-Guanosine-Oligodeoxynucleotide in Meat-Type Chickens Coadministered <i>In Ovo</i> with Herpesvirus of Turkey Vaccine}, volume={2}, ISSN={["1557-8976"]}, url={https://doi.org/10.1089/vim.2023.0125}, DOI={10.1089/vim.2023.0125}, abstractNote={Herpesvirus of turkey (HVT) increases activation of T cells in 1-day-old chickens when administered in ovo. This study evaluated whether adding cytosine-guanosine oligodeoxynucleotides (CpG ODNs) to the HVT vaccine could enhance the adjuvant effect of HVT. We used a CpG ODN dose of 10 μg per egg. The experimental groups were (1) diluent-only control (sham), (2) HVT, (3) HVT+CpG ODN, (4) HVT+non-CpG ODN, (5) CpG ODN, and (6) non-CpG ODN control. Cellular response evaluation included measuring the frequencies of macrophages (KUL01+MHC-II+), gamma delta T cells (γδTCR+MHC-II+), CD4+, and CD8+ T cell subsets, including double-positive (DP) cells. In addition, CD4+ and CD8+ T cell activation was evaluated by measuring the cellular expression of major histocompatibility complex class II (MHC-II), CD44 or CD28 costimulatory molecules. An adjuvant effect was considered when HVT+CpG ODN, but not HVT+non CpG ODN, or CpG ODN, or non-CpG ODN, induced significantly increased effects on any of the immune parameters examined when compared with HVT. The findings showed that (1) HVT vaccination induced significantly higher frequencies of γδ+MHC-II+ and CD4+CD28+ T cells when compared with sham chickens. Frequencies of DP and CD4+CD28+ T cells in HVT-administered birds were significantly higher than those observed in the non-CpG ODN group. (2) Groups receiving HVT+CpG ODN or CpG ODN alone were found to have significantly increased frequencies of activated CD4+ and CD8+ T cells, when compared with HVT. Our results show that CpG ODN administration in ovo with or without HVT significantly increased frequencies of activated CD4+ and CD8+ T cells.}, journal={VIRAL IMMUNOLOGY}, author={Boone, Allison C. and Kulkarni, Raveendra R. and Cortes, Aneg L. and Gaghan, Carissa and Mohammed, Javid and Villalobos, Tarsicio and Esandi, Javier and Gimeno, Isabel M.}, year={2024}, month={Feb} }
 @article{faiz_cortes_phang_gimeno_2024, title={Optimizing protocols for monitoring <i>in vivo</i> replication of a novel chimeric Marek's disease vaccine with an insertion of the long terminal repeat of reticuloendotheliosis virus in the CVI988 strain genome (CVI-LTR)}, volume={3}, ISSN={["1465-3338"]}, DOI={10.1080/03079457.2024.2324930}, abstractNote={Monitoring Marek's disease (MD) vaccination is routinely done by evaluating the load of MD vaccine in the feather pulp (FP) between 7 and 10 days of age. However, attempts in our laboratory to detect a novel CVI-LTR vaccine in the FP samples from commercial flocks failed. The objective of this study was to evaluate the most suitable tissue and age to monitor CVI-LTR vaccination. We used two different commercial CVI988 vaccines as controls. One hundred and sixty 1-day-old commercial brown layers were vaccinated with either CVI-LTR, CVI988-A, CVI988-B or remained unvaccinated. Samples of the spleen, thymus, and bursa were collected at 3, 4, 5, and 6 days of age and samples of FP were collected at 7 and 21 days for DNA isolation. Our results showed that CVI-LTR replicated earlier than CVI988 vaccines in the lymphoid organs but was not detected in the FP at either 7 or at 21 days of age. We also confirmed that either the spleen or thymus collected at 4–6 days was a suitable sample to monitor CVI-LTR vaccination in commercial flocks. Finally, we evaluated the load of oncogenic MDV DNA in five commercial flocks that were vaccinated with either CVI-LTR + rHVT or CVI988-A + rHVT. The load of oncogenic MDV DNA was evaluated at 21 days in the FP in 20 chickens per group. Our results demonstrated that CVI-LTR was more successful in reducing oncogenic MDV DNA at 21 days of age than the CVI988-A strain.}, journal={AVIAN PATHOLOGY}, author={Faiz, Nik M. and Cortes, Aneg L. and Phang, Yuen-fun and Gimeno, Isabel M.}, year={2024}, month={Mar} }
 @article{gaghan_browning_cortes_gimeno_kulkarni_2023, title={Effect of CpG-Oligonucleotide in Enhancing Recombinant Herpes Virus of Turkey-Laryngotracheitis Vaccine-Induced Immune Responses in One-Day-Old Broiler Chickens}, volume={11}, ISSN={["2076-393X"]}, url={https://doi.org/10.3390/vaccines11020294}, DOI={10.3390/vaccines11020294}, abstractNote={Infectious laryngotracheitis (ILT) is an economically important disease of chickens. While the recombinant vaccines can reduce clinical disease severity, the associated drawbacks are poor immunogenicity and delayed onset of immunity. Here, we used CpG-oligonucleotides (ODN) as an in ovo adjuvant in boosting recombinant herpesvirus of turkey-laryngotracheitis (rHVT-LT) vaccine-induced responses in one-day-old broiler chickens. Two CpG-ODN doses (5 and 10 μg/egg) with no adverse effect on the vaccine-virus replication or chick hatchability were selected for immune-response evaluation. Results showed that while CpG-ODN adjuvantation induced an increased transcription of splenic IFNγ and IL-1β, and lung IFNγ genes, the IL-1β gene expression in the lung was significantly downregulated compared to the control. Additionally, the transcription of toll-like receptor (TLR)21 in the spleen and lung and inducible nitric oxide synthase (iNOS) in the spleen of all vaccinated groups was significantly reduced. Furthermore, splenic cellular immunophenotyping showed that the CpG-ODN-10μg adjuvanted vaccination induced a significantly higher number of macrophages, TCRγδ+, and CD4+ T cells as well as a higher frequency of activated T cells (CD4+CD44+) when compared to the control. Collectively, the findings suggested that CpG-ODN can boost rHVT-LT-induced immune responses in day-old chicks, which may help in anti-ILT defense during their later stages of life.}, number={2}, journal={VACCINES}, author={Gaghan, Carissa and Browning, Matthew and Cortes, Aneg L. and Gimeno, Isabel M. and Kulkarni, Raveendra R.}, year={2023}, month={Feb} }
 @article{boone_kulkarni_cortes_villalobos_esandi_gimeno_2023, title={In ovo HVT vaccination enhances cellular responses at hatch and addition of poly I:C offers minimal adjuvant effects}, volume={41}, ISSN={["1873-2518"]}, url={https://doi.org/10.1016/j.vaccine.2023.02.076}, DOI={10.1016/j.vaccine.2023.02.076}, abstractNote={In ovo vaccination with herpesvirus of turkey (HVT) hastens immunocompetence in chickens and the recommended dose (RD) of 6080 plaque-forming-units (PFU) offers the most optimal effects. In previous studies conducted in egg-type chickens, in ovo vaccination with HVT enhanced lymphoproliferation, wing-web thickness with phytohemagglutinin-L (PHA-L), and increased spleen and lung interferon-gamma(IFN-γ) andToll-like receptor 3 (TLR3) transcripts. Here, we evaluated the cellular mechanisms by which HVT-RD can hasten immunocompetence in one-day-old meat-type chickens, and also determined if HVT adjuvantation with a TLR3 agonist, polyinosinic-polycytidylic acid (poly(I:C)), could enhance vaccine-induced responses and provide dose-sparing effects. Compared to sham-inoculated chickens, HVT-RD significantly increased transcription of splenic TLR3 and IFN γ receptor 2 (R2), and lung IFN γ R2, while the splenic IL-13 transcription was found decreased. Additionally, these birds showed increased wing-web thickness following PHA-L inoculation. The thickness was due to an innate inflammatory cell population, CD3+ T cells, and edema. In another experiment, HVT-1/2 (3040 PFU) supplemented with 50 μg poly(I:C) [HVT-1/2 + poly(I:C)] was administered in ovo and immune responses were compared with those produced by HVT-RD, HVT-1/2, 50 μg poly(I:C), and sham-inoculated. Immunophenotyping of splenocytes showed HVT-RD induced a significantly higher frequency of CD4+, CD4+MHC-II+, CD8+CD44+, and CD4+CD28+ T cells compared to sham-inoculated chickens, and CD8+MHC-II+, CD4+CD8+, CD4+CD8+CD28+, and CD4+CD8+CD44+ T cells compared to all groups. Treatment groups, except HVT-1/2 + poly(I:C), had significantly higher frequencies of γδ T cells and all groups induced significantly higher frequencies of activated monocytes/macrophages, compared to sham-inoculated chickens. Poly(I:C)-induced dose-sparing effect was only observed in the frequency of activated monocytes/macrophages. No differences in the humoral responses were observed. Collectively, HVT-RD downregulated IL-13 transcripts (Th2 immune response) and had strong immunopotentiation effects on innate immune responses and the activation of T cells. However addition of poly(I:C) offered a minimal adjuvant/dose-sparing effect.}, number={15}, journal={VACCINE}, author={Boone, Allison C. and Kulkarni, Raveendra R. and Cortes, Aneg L. and Villalobos, Tarsicio and Esandi, Javier and Gimeno, Isabel M.}, year={2023}, month={Apr}, pages={2514–2523} }
 @article{ellington_cortes_faiz_mays_fadly_silva_gimeno_2021, title={Characterization of Md5-BAC-REV-LTR virus as Marek's disease vaccine in commercial meat-type chickens: protection and immunosuppression}, volume={10}, ISSN={["1465-3338"]}, DOI={10.1080/03079457.2021.1970108}, abstractNote={ABSTRACT Md5-BAC-REV-LTR is a recombinant Marek’s disease virus (MDV), with an insertion of the long terminal repeat (LTR) of reticuloendotheliosis virus (REV) into the genome of the highly virulent MDV strain rMd5. It has been shown that Md5-BAC-REV-LTR does not induce tumours and confers high protection against challenge with MDV in 15 × 7 chickens. The objective of the present study was to evaluate the protection and safety (in terms of oncogenicity and immunosuppression) of Md5-BAC-REV-LTR in commercial meat-type chickens bearing maternal antibodies against MDV. Our results show that sub-cutaneous administration of Md5-BAC-REV-LTR at 1 day of age conferred high protection (protection index PI = 84.2) against an early challenge (1 day) by contact exposure to shedder birds infected with the vv+ MDV 648A strain. In such stringent challenge conditions, Md5-BAC-REV-LTR was more protective than a commercial CVI988 (PI = 12.4) and similar to the experimental vaccine Md5-BACΔmeq (PI = 92.4). Furthermore, Md5-BAC-REV-LTR did not induce either tumours or immunosuppression in this study. Immunosuppression was evaluated by the relative lymphoid organ weights and also by the ability of the vaccine to induce late-MDV-induced immunosuppression associated with reactivation of the virus. This study shows that Md5-BAC-REV-LTR has the potential to be used as a MD vaccine and is highly protective against early challenge with vv+ MDV. RESEARCH HIGHLIGHTS Md5-BAC-REV-LTR is highly protective against early challenge with vv+ MDV in commercial meat-type chickens. Md5-BAC-REV-LTR does not cause early immunosuppression. Md5-BAC-REV-LTR does not cause late immunosuppression. Unlike other serotype 1 vaccines, Md5-BAC-REV-LTR is not detected in feather pulp at 7 days post vaccination.}, journal={AVIAN PATHOLOGY}, author={Ellington, C. and Cortes, A. L. and Faiz, N. M. and Mays, J. K. and Fadly, Aly and Silva, Robert F. and Gimeno, I. M.}, year={2021}, month={Oct} }
 @article{salvador_cortes_pandiri_gimeno_2021, title={Cytokine expression in the eye and brain of chickens following infection with a very virulent plus Marek's disease virus strain}, volume={237}, ISSN={["1873-2534"]}, url={https://doi.org/10.1016/j.vetimm.2021.110277}, DOI={10.1016/j.vetimm.2021.110277}, abstractNote={Cytokine transcripts were evaluated chronologically in the brain and in the eye of chickens infected with the very virulent plus Marek’s disease virus (vv + MDV) strain 648A. Brain and eye samples were collected from chickens that were either suffering from transient paralysis (TP) (11 days post inoculation, dpi) or had completely recovered from TP but started developing clinical signs of persistent neurological disease (PND) (18−31 dpi). Results obtained from samples collected at 11 dpi are referred as EL (early lesions) and results obtained from samples collected at later times (18−31 dpi) are referred as LL (late lesions). Marked differences were found in the cytokine transcripts in brain and eye. While proinflammatory cytokines (IL-1β, IL-8, IL-18), iNOS, IFN-α, IFN-γ, and IL-15 were upregulated in the brain during EL and LL, only IL-8 and IFN-γ were upregulated in the eye at both times (EL and LL). The two evaluated viral transcripts (gB and meq) were found in both eye and brain during EL and LL. Levels of the two viral transcripts evaluated were higher at LL than at EL in both brain and eye. No differences were found in any of the viral transcripts between eye and brain during EL. However, during the LL, the levels of meq transcripts were higher in the eye than in the brain. Our results suggest that MDV elicits different immune responses in the brain and in the eye of infected chickens. Because immune responses in the eye of chickens have been poorly studied, further studies on the pathogenesis of MDV in the eye could greatly contribute to our knowledge on the chicken eye immunity.}, journal={VETERINARY IMMUNOLOGY AND IMMUNOPATHOLOGY}, publisher={Elsevier BV}, author={Salvador, Coral and Cortes, Aneg L. and Pandiri, Arun R. and Gimeno, Isabel M.}, year={2021}, month={Jul} }
 @article{gimeno_shaw_turner_bremen_cortes_faiz_gonder_robbins_2021, title={Replication of Marek's disease vaccines in turkey embryos and their effect on TLR-3 and IFN-gamma transcripts}, volume={50}, ISSN={["1465-3338"]}, DOI={10.1080/03079457.2021.1882937}, abstractNote={ABSTRACT Understanding the pathogenesis of herpesvirus of turkeys (HVT) in its natural host is necessary before recombinant HVT (rHVT) can be used efficiently in turkey flocks. The objectives of this study were to evaluate when commercial turkey flocks get infected with wild type HVT, to study replication of HVT (conventional and recombinant rHVT-Newcastle disease, rHVT-ND) and other Marek’s disease (MD) vaccines (SB-1 and CVI988) in turkey embryonic tissues, and to evaluate the expression of TLR-3 and IFN-γ in the lung and spleen of one-day-old turkeys after in ovo vaccination with MD vaccines. Our results demonstrated that commercial turkeys got exposed to wild type HVT within the first days of life; therefore, there is a potential of interaction between wild type HVT and rHVT when administered at day of age. On the other hand, all evaluated vaccines (especially HVT and rHVT-ND) replicated very well in turkey embryonic tissues. In ovo vaccination with HVT and CVI988 increased transcription of TLR-3 in the spleen of one-day-old turkeys. However, no effect on the transcription of TLR-3 or IFN-γ in the lungs and IFN-γ in the spleen in newly hatched turkeys was detected in the present study. Because of the limitations of evaluated genes, timepoints, and studied tissues, future studies are warranted to better understand the effect of MD vaccines on the turkey embryo immune responses. RESEARCH HIGHLIGHTS Commercial turkey flocks get infected with wild type HVT within the first days of life. HVT and rHVT replicates readily in turkey embryonic tissues. SB-1 and CVI988 also replicate in turkey embryonic tissues, but at lower rates than HVT and rHVT. HVT and CVI988 increase transcription of TLR-3 in the spleen.}, number={3}, journal={AVIAN PATHOLOGY}, author={Gimeno, I. M. and Shaw, W. N. and Turner, A. and Bremen, J. and Cortes, A. L. and Faiz, N. M. and Gonder, E. and Robbins, K.}, year={2021}, month={May}, pages={227–233} }
 @article{boone_kaser_cortes_kulkarni_abad_villalobos_esandi_perozo_lemiere_gimeno_2020, title={In ovo vaccination with herpesvirus of turkey enhances innate and cellular responses in meat-type chickens: Effect of vaccine dose and strain}, volume={38}, ISSN={["1873-2518"]}, DOI={10.1016/j.vaccine.2020.05.050}, abstractNote={In ovo vaccination with herpesvirus of turkey (HVT) or recombinant HVT (rHVT) is commonly used in meat-type chickens. Previous studies showed that in ovo vaccination with HVT enhances innate, cellular, and humoral immune responses in egg-type chicken embryos. This study evaluated if in ovo vaccination with HVT hastens immunocompetence of commercial meat-type chickens and optimized vaccination variables (dose and strain of HVT) to accelerate immunocompetence. A conventional HVT vaccine was given at recommended dose (RD), HVT-RD = 6080 plaque forming units (PFU), double-dose (2x), half-dose (1/2), or quarter-dose (1/4). Two rHVTs were given at RD: rHVT-A = 7380 PFU, rHVT-B = 8993 PFU. Most, if not all, treatments enhanced splenic lymphoproliferation with Concanavalin A and increased the percentage of granulocytes at day of age. Dose had an effect and HVT-RD was ideal. An increase of wing-web thickness after exposure to phytohemagglutinin-L was only detected after vaccination with HVT-RD. Furthermore, compared to sham-inoculated chickens, chickens in the HVT-RD had an increased percentage of CD3+ T cells and CD4+ T-helper cells, and increased expression of major histocompatibility complex (MHC)-II on most cell subsets (CD45+ cells, non-T leukocytes, T cells and the CD8+ and T cell receptor γδ T-cell subsets). Other treatments (HVT-1/2 and rHVT-B) share some of these features but differences were not as remarkable as in the HVT-RD group. Expression of MHC-I was reduced, compared to sham-inoculated chickens, in most of the cell phenotypes evaluated in the HVT-RD, HVT-2x and rHVT-A groups, while no effect was observed in other treatments. The effect of in ovo HVT on humoral immune responses (antibody responses to keyhole limpet hemocyanin and to a live infectious bronchitis/Newcastle disease vaccine) was minimal. Our study demonstrates in ovo vaccination with HVT in meat-type chickens can accelerate innate and adaptive immunity and we could optimize such effect by modifying the vaccine dose.}, number={31}, journal={VACCINE}, author={Boone, Allison C. and Kaser, Tobias and Cortes, Aneg L. and Kulkarni, Raveendra R. and Abad, Blanca A. Lopez de Juan and Villalobos, Tarsicio and Esandi, Javier and Perozo, Francisco and Lemiere, Stephane and Gimeno, Isabel M.}, year={2020}, month={Jun}, pages={4837–4845} }
 @article{gimeno_cortes_reddy_abad_kaser_limsatanun_2019, title={Highly virulent Marek's disease virus strains affect T lymphocyte function and viability of splenocytes in commercial meat-type chickens}, volume={48}, ISSN={["1465-3338"]}, DOI={10.1080/03079457.2019.1643451}, abstractNote={ABSTRACT In previous studies, we have demonstrated that very virulent plus Marek’s disease viruses (vv+MDV) are highly immunosuppressive in commercial meat-type chickens. The specific objectives of this work were to evaluate if vv+MDV immunosuppression (MDV-IS) is induced by reduction of lymphocyte responsiveness and/or viability. Three experiments were conducted to (i) compare vv+MDV 686 with a partially attenuated 686-BAC; (ii) compare vv+MDV strains (648A and 686) with vMDV (GA) and vvMDV (Md5); and (iii) compare chickens vaccinated with Md5-BACΔMEQ and with CVI988 + HVT. In each experiment, spleens were collected at 28–30 days post infection and lymphocytes were isolated and investigated in three ways: their proliferative response to Concanavalin A (ConA) was analysed by MTT proliferation assay; cell death, and expression of CD45 and MHC-I was studied by flow cytometry; and MHC-IA and β-2 microglobulin (B2M) expression was evaluated by real time RT-PCR. Splenocytes of chickens inoculated with vv+MDV were severely impaired to proliferate when exposed to ConA. Furthermore, vv+MDV induced severe splenocyte death that did not occur after infection with v or vvMDV strains. Vaccination with CVI988 + HVT, and at less level with Md5-BACΔMEQ reduced these negative effects. This is in contrast to our previous results in which Md5-BACΔMEQ but not CVI988 + HVT protected against MDV-IS suggesting that although cell death and decrease lymphocyte function seem to be related to MDV virulence and certainly will be associated with immunosuppression, they might not fully explain the previously reported MDV-IS. RESEARCH HIGHLIGHTS vv+MDV induces extensive death in splenocytes in meat-type chickens 28–30 dpi. vv+MDV impairs lymphocyte function in meat-type chickens 28–30 dpi. Vaccination protects against splenocyte death and reduced lymphocyte function. Cell lysis and reduced lymphocyte function do not fully explain MDV-IS.}, number={6}, journal={AVIAN PATHOLOGY}, author={Gimeno, I. M. and Cortes, A. L. and Reddy, S. M. and Abad, B. Lopez de Juan and Kaser, T. and Limsatanun, A.}, year={2019}, month={Nov}, pages={564–572} }
 @article{gimeno_cortes_reilley_barbosa_alvarado_koopman_martinez_2019, title={Study of Efficacy and Replication of Recombinant Vector Vaccines by Using Turkey Herpesvirus Combined with Other Marek's Disease Vaccines}, volume={63}, ISSN={["1938-4351"]}, DOI={10.1637/11987-103018-Reg.1}, abstractNote={SUMMARY. Several recombinant turkey herpesviruses (rHVTs) have been developed within the past decades, and they are now used commercially worldwide. In broiler chickens, rHVTs are usually administered alone, but in long-living birds they are used in combination with Marek's disease (MD) vaccines of other serotypes (i.e., CVI988). The objectives of this work were to 1) evaluate protection against MD conferred by HVT and two rHVTs when combined with CVI988 and 2) optimize the use of rHVT in combination with CVI988 to maximize replication of rHVT without compromising MD protection. Various vaccine protocols, all using rHVT or HVT at the recommended dose (RD), were evaluated. Protocols evaluated included in ovo vaccination with HVT+CVI988 or rHVT+CVI988 (using either the double dose [DD] or the RD of CVI988), day of age vaccination of rHVT+CVI988 at DD, and revaccination protocols using rHVT in ovo followed by CVI988 at DD at day of age. Our results show that, when combined with CVI988, HVT and rHVTs confer a similar level of protection against MD (>90%) regardless of whether CVI988 was used at RD or at DD. However, the combination of rHVT with CVI988 at DD resulted in reduced replication rates of rHVT (60%–76% vs. 95%–100%). Our results show that such a negative effect could be avoided without jeopardizing MD protection by administering CVI988 at RD (if combined in ovo with rHVT) or administered rHVT first in ovo followed by CVI988 at DD at day of age.}, number={2}, journal={AVIAN DISEASES}, author={Gimeno, I. M. and Cortes, A. L. and Reilley, A. and Barbosa, T. and Alvarado, I and Koopman, R. and Martinez, A.}, year={2019}, month={Jun}, pages={335–341} }
 @article{faiz_cortes_guy_reddy_gimeno_2018, title={Differential attenuation of Marek's disease virus-induced tumours and late-Marek's disease virus-induced immunosuppression}, volume={99}, ISSN={["1465-2099"]}, DOI={10.1099/jgv.0.001076}, abstractNote={Marek's disease virus (MDV) is a herpesvirus that induces lymphoma and a variety of non-neoplastic syndromes in chickens. Furthermore, very virulent plus (vv+) MDVs induce a form of immunosuppression (late-MDV-IS) that might involve both neoplastic and non-neoplastic mechanisms. The objective of this study was to evaluate whether the attenuation of MDV-induced tumours and late-MDV-IS occurs simultaneously or can be dissociated. The immunosuppressive ability of three viruses derived from vv+ MDV strain 686 (wild-type 686, the somewhat attenuated molecular clone 686-BAC, and the nononcogenic molecular clone lacking the two copies of the oncogene meq 686-BACΔMEQ) was evaluated. Late-MDV-IS was evaluated indirectly by assessing the negative effect of MDV strains on the protection conferred by infectious laryngotracheitis (ILT) vaccines. Our results showed that the ability to induce late-MDV-IS was attenuated before the ability to induce tumours. Strain 686 induced both tumours and late-MDV-IS, 686-BAC induced tumours but did not induce late-MDV-IS and 686-BACΔMEQ did not induce either tumours or late-MDV-IS. Further comparison of strains 686 and 686-BAC revealed that strain 686 reduced the humoral immune responses to ILTV (1132 vs 2167) more severely, showed higher levels of meq transcripts (2.1E+09 vs 4.98E+8) and higher expression of MDV microRNAs (mdv1-miR-M4-5p and mdv1-miR-M2-3p) in the spleen, and further reduced the percentage of CD45+-MHC-I+splenocytes (13 vs32 %) compared to molecular clone 686-BAC. This study suggests that the immunosuppressive ability of MDV might follow a continuous spectrum and only the most virulent MDVs can overcome a certain threshold level and induce clinical MDV-IS in the ILT model.}, number={7}, journal={JOURNAL OF GENERAL VIROLOGY}, author={Faiz, Nik M. and Cortes, Aneg L. and Guy, James S. and Reddy, Sanjay M. and Gimeno, Isabel M.}, year={2018}, month={Jul}, pages={927–936} }
 @article{gall_korosi_cortes_delvecchio_prandini_mitsch_gimeno_2018, title={Use of real-time PCR to rule out Marek's disease in the diagnosis of peripheral neuropathy}, volume={47}, ISSN={["1465-3338"]}, DOI={10.1080/03079457.2018.1473555}, abstractNote={ABSTRACT This article reports nine cases of neurological disease in brown layer pullets that occured in various European countries between 2015 and 2018. In all cases, the onset of neurological clinical signs was at 4–8 weeks of age and they lasted up to 22 weeks of age. Enlargement of peripheral nerves was the main lesion observed in all cases. Histopathological evaluation of nerves revealed oedema with moderate to severe infiltration of plasma cells. Marek’s disease (MD) was ruled out by real-time PCR as none of the evaluated tissues had a high load of oncogenic MD virus (MDV) DNA, characteristics of MD. Based on the epidemiological data (layers with clinical signs starting at 5–8 weeks of age), gross lesions (peripheral nerve enlargement with a lack of tumours in other organs), histopathological lesions (oedema and infiltration of plasma cells), and no evidence of high load of MDV DNA, we concluded that those cases were due to peripheral neuropathy (PN). PN is an autoimmune disease easily misdiagnosed as MD, leading to a costly enforcement of the vaccination protocol. Additional vaccination against MD does not protect against PN and could worsen the clinical signs by over-stimulating the immune system. Differential diagnosis between PN and MD should always be considered in cases of neurological disease with enlargement of peripheral nerves as the only gross lesion. This case report shows for the first time how real-time PCR to detect oncogenic MDV is a very valuable tool in the differential diagnosis of PN and MD.}, number={4}, journal={AVIAN PATHOLOGY}, author={Gall, Sesny and Korosi, Laszlo and Cortes, Aneg L. and Delvecchio, Andrea and Prandini, Francesco and Mitsch, Peter and Gimeno, Isabel M.}, year={2018}, pages={427–433} }
 @article{faiz_cortes_guy_fletcher_cimino_gimeno_2017, title={Evaluation of factors influencing the development of late Marek's disease virus-induced immunosuppression: virus pathotype and host sex}, volume={46}, ISSN={["1465-3338"]}, DOI={10.1080/03079457.2017.1290214}, abstractNote={ABSTRACT Marek’s disease virus (MDV) is a herpesvirus that induces lymphoma and immunosuppression in chickens. MDV-induced immunosuppression (MDV-IS) is complex and can be divided into two phases: early-MDV-IS associated with cytolytic infection in the lymphoid organs in chickens lacking maternal antibodies against MDV (MAbs) and late-MDV-IS that appears later in the pathogenesis and occurs even in chickens bearing MAbs. We have recently developed a model to reproduce late-MDV-IS under laboratory conditions. This model evaluates late-MDV-IS indirectly by assessing the effect of MDV infection on the efficacy of infectious laryngotracheitis (ILT) vaccines against challenge with ILT virus. In the present study, we have used this model to investigate the role of two factors (MDV pathotype and host sex) on the development of late-MDV-IS. Five MDV strains representing three different pathotypes: virulent (vMDV; 617A, GA), very virulent (vvMDV; Md5), and very virulent plus (vv+MDV; 648A, 686), were evaluated. Only vv+ strains were able to induce late-MDV-IS. An immunosuppression rank (IS-rank) was established based on the ability of MDV to reduce the efficacy of chicken embryo origin vaccine (values go from 0 to 100, with 100 being the highest immunosuppressive ability). The IS-rank of the evaluated MDV strains ranged from 5.97 (GA) to 20.8 (617A) in the vMDV strains, 5.97 to 16.24 in the vvMDV strain Md5, and 39.08 to 68.2 in the vv+ strains 648A and 686. In this study both male and female chickens were equally susceptible to MDV-IS by vv+MDV 686. Our findings suggest that late-MDV-IS is a unique feature of vv+ strains.}, number={4}, journal={AVIAN PATHOLOGY}, author={Faiz, Nik M. and Cortes, Aneg L. and Guy, James S. and Fletcher, Oscar J. and Cimino, Thomas and Gimeno, Isabel M.}, year={2017}, pages={376–385} }
 @article{faiz_cortes_guy_fletcher_west_montiel_gimeno_2016, title={Early infection with Marek's disease virus can jeopardize protection conferred by laryngotracheitis vaccines: a method to study MDV-induced immunosuppression}, volume={45}, ISSN={["1465-3338"]}, DOI={10.1080/03079457.2016.1191618}, abstractNote={ABSTRACT Marek’s disease virus (MDV) is a herpesvirus that induces lymphomas and immunosuppression in chickens. MDV-induced immunosuppression (MDV-IS) is divided into two phases: early-MDV-IS occurring mainly in chickens lacking maternal antibodies (MAb) against MDV and associated with lymphoid organ atrophy; and late-MDV-IS occurring once MDV enters latency and during tumour development. Our objectives were to document the impact of late-MDV-IS on commercial poultry (meat-type chickens bearing MAb against MDV and that were vaccinated or unvaccinated against MD) and to optimize a model to study late-MDV-IS under laboratory conditions. The impact of late-MDV-IS was evaluated by assessing the effect of early infection (day of age) with a very virulent plus MDV (vv+MDV) on the efficacy of chicken-embryo-origin (CEO) infectious laryngotracheitis (ILT) virus vaccine against ILT challenge. The CEO ILT vaccine was administered in water at 14 days of age and ILT virus (ILTV) challenge was done intratracheally at 30 days of age. Development of ILT was monitored by daily evaluation of clinical signs, development of gross and histological lesions in trachea, and quantification of ILTV transcripts in trachea. Infection with vv+MDV strain 648A resulted in total abrogation of protection conferred by the CEO vaccine against ILTV challenge even in chickens vaccinated at 1 day of age with either HVT, HVT+SB-1, or CVI988. Chickens exposed to vv+MDV prior to vaccination with CEO ILTV vaccine had similar (P < 0.05) clinical scores, gross lesions, histopathologic lesion scores, and load of ILTV transcripts in trachea after ILTV challenge, as chickens that were not vaccinated with CEO ILTV vaccine.}, number={6}, journal={AVIAN PATHOLOGY}, author={Faiz, Nik M. and Cortes, Aneg L. and Guy, James S. and Fletcher, Oscar J. and West, Melissa and Montiel, Enrique and Gimeno, Isabel M.}, year={2016}, pages={606–615} }
 @article{gimeno_cortes_faiz_villalobos_badillo_barbosa_2016, title={Efficacy of Various HVT Vaccines (Conventional and Recombinant) Against Marek's Disease in Broiler Chickens: Effect of Dose and Age of Vaccination}, volume={60}, ISSN={["1938-4351"]}, DOI={10.1637/11415-040116-reg.1}, abstractNote={SUMMARY Herpesvirus of turkeys (HVT) has been successfully used as a Marek's disease (MD) vaccine for more than 40 yr. Either alone (broiler chickens) or in combination with vaccines of other serotypes (broilers, broiler breeders, and layers), HVT is used worldwide. In recent years, several vector vaccines based on HVT (rHVT) have been developed. At present, there are both conventional HVT and rHVTs in the market, and it is unknown if all of them confer the same level of protection against MD. The objective of this study was to further characterize the protection conferred by two conventional HVTs (HVT-A and HVT-B) and three recombinant HVTs (rHVT-B, rHVT-C, and rHVT-D) against MD in broiler chickens. In a first study we evaluated the efficacy of two conventional HVTs (HVT-A and HVT-B) administered at different doses (475, 1500, and 4000 PFU) at day of age on the ability to protect against an early challenge with very virulent plus strain 645. In a second experiment we evaluated the protection ability of several HVTs (both conventional and recombinant) when administered in ovo at a dose of 1500 PFU using the same challenge model. Our results show that each HVT product is unique, regardless of being conventional or recombinant, in their ability to protect against MD and might require different PFUs to achieve its maximum efficacy. In Experiment 1, HVT-A at 4000 PFU conferred higher protection (protection index [PI] = 63) than any of the other vaccine protocols (PI ranging from 36 to 47). In Experiment 2, significant differences were found among vaccine protocols with PI varying from 66 (HVT-A) to 15 (rHVT-D). Our results show that each HVT is unique and age at vaccination and vaccine dose greatly affected vaccine efficacy. Furthermore, they highlight the need of following manufacturer's recommendations.}, number={3}, journal={AVIAN DISEASES}, author={Gimeno, I. M. and Cortes, A. L. and Faiz, N. and Villalobos, T. and Badillo, H. and Barbosa, T.}, year={2016}, month={Sep}, pages={662–668} }
 @article{faiz_cortes_guy_fogle_gimeno_2016, title={Efficacy of various Marek's disease vaccines protocols for prevention of Marek's disease virus-induced immunosuppression}, volume={34}, ISSN={["1873-2518"]}, DOI={10.1016/j.vaccine.2016.06.061}, abstractNote={Marek’s disease virus (MDV) induces tumors and severe immunosuppression in chickens. MDV-induced immunosuppression (MDV-IS) is very complex and difficult to study. In particular, the late MDV-IS (late-MDV-IS) is of great concern since it can occur in the absence of lymphoid organ atrophy or gross tumors. We have recently developed a model to reproduce late-MDV-IS under laboratory conditions. This model measures MDV-IS indirectly by assessing the effect of MDV infection on the efficacy of infectious laryngotracheitis (ILT) vaccination; hence the name late-MDV-IS ILT model. In this study, we have used the late-MDV-IS ILT model to evaluate if MD vaccination can protect against late-MDV-IS. One experiment was conducted to determine whether serotype 1 MD vaccines (CVI988 and Md5ΔMEQ) could induce late-MDV-IS by themselves. Three additional experiments were conducted to evaluate efficacy of different MD vaccines (HVT, HVT+SB-1, CVI988, and Md5ΔMEQ) and different vaccine protocols (day-old vaccination, in ovo vaccination, and double vaccination) against late-MDV-IS. Our results show that none of the currently used vaccine protocols (HVT, HVT+SB-1, or CVI988 administered at day of age, in ovo, or in double vaccination protocols) protected against late-MDV-IS induced by vv+MDV strains 648A and 686. Experimental vaccine Md5ΔMEQ administered subcutaneously at one day of age was the only vaccine protocol that significantly reduced late-MDV-IS induced by vv+MDV strain 686. This study demonstrates that currently used vaccine protocols confer high levels of protection against MDV-induced tumors (protection index = 100), but do not protect against late-MDV-IS; thus, commercial poultry flocks could suffer late-MDV-IS even in complete absence of tumors. Our results suggest that MDV-IS might not be related to the development of tumors and novel control methods are needed. Further evaluation of the experimental vaccine Md5ΔMEQ might shed light on protective mechanisms against late-MDV-IS.}, number={35}, journal={VACCINE}, author={Faiz, Nik M. and Cortes, Aneg L. and Guy, James S. and Fogle, Jonathan E. and Gimeno, Isabel M.}, year={2016}, month={Jul}, pages={4180–4187} }
 @article{gimeno_cortes_faiz_barbosa_villalobos_2015, title={Evaluation of Factors Influencing Efficacy of Vaccine Strain CVI988 Against Marek's Disease in Meat-Type Chickens}, volume={59}, ISSN={["1938-4351"]}, DOI={10.1637/11085-040915-reg.1}, abstractNote={SUMMARY Marek’s disease (MD) strain CVI988 is the most-protective commercially available vaccine against very virulent plus (vv+) Marek’s disease virus (MDV). However, its use in meat-type chickens has been controversial. While several countries have been using CVI988 for more than 40 yr, others do not authorize its use or it is restricted mainly to layers. The use of CVI988 in meat-type chickens will be necessary in the future in areas where other vaccine protocols fail. The objective of this study was to evaluate factors (vaccine dose, vaccine origin, chicken genetics, age and route of vaccination, and combination with other MD vaccines) influencing the efficacy of CVI988 against MD in meat-type chickens. Three animal experiments were conducted in which various vaccine protocols using CVI988 were tested for their protection against challenge with vv+ strain 648A by contact at day of age. Experiments 1 and 2 were to compare the efficacy of CVI988 vaccines from three different origins (CVI988-A, CVI988-B, and CVI988-C) and evaluate the effect of vaccine dose and chicken genetics. Experiment 3 was to evaluate the effect of adding CVI988 vaccine to various vaccine protocols using other MD vaccines of serotypes 2 (SB-1) and 3 (rHVT). Our results show that, regardless of the origin of the vaccine, protection against early challenge with 648A was good when vaccines were administered at a high dose (>3000 plaque-forming units [PFU]). Differences among vaccines, however, were detected even when using a high dose in experiment 2 (vaccine CVI988-B conferred higher protection than did CVI988-C) but not in Experiment 1 (CVI988-B was compared to CVI988-A). The use of a fixed low dose (2000 PFU) of vaccine resulted in reduction in protection, and such reduction was more remarkable when using CVI988-A. No statistically significant differences were found when we compared the efficacy of CVI988 in two different genetic lines of broiler chickens (G1 and G2). Vaccination protocols that included CVI988 had better protection than protocols that only included MD vaccines of serotypes 2 and 3. This was true regardless of the vaccine protocol used (CVI988/rHVT+SB-1; CVI988+rHVT+SB-1/None; rHVT+SB-1/CVI988; wherein the vaccine before the slash (/) was administered in ovo at embryonation day 18 and the vaccine after the slash was administered at day of age, subcutaneously). When only vaccines of serotypes 2 and 3 were used, protection against early challenge with vv+MDV was higher when vaccines were administered in ovo (rHVT+SB-1/None) than if vaccines were administered at hatch (None/rHVT+SB-1). Monitoring vaccine DNA load in feather pulp (FP) samples at 1 wk was used to monitor vaccination, and results showed that differences in vaccine replication exist among vaccines but such differences were not necessarily related to protection (r  =  0.41, P  > 0.05). Monitoring load of challenge MDV DNA in FP at 21 days was conducted, and results correlated (r  =  0.85, P  < 0.05) with the percentage of chickens with MD lesions at the termination of the study, confirming that early diagnosis is a very powerful tool with which to evaluate protection.}, number={3}, journal={AVIAN DISEASES}, author={Gimeno, Isabel M. and Cortes, Aneg L. and Faiz, Nik M. and Barbosa, Taylor and Villalobos, Tarsicio}, year={2015}, month={Sep}, pages={400–409} }
 @article{gimeno_cortes_faiz_hernandez-ortiz_guy_hunt_silva_2015, title={Evaluation of the Protection Efficacy of a Serotype 1 Marek's Disease Virus-Vectored Bivalent Vaccine Against Infectious Laryngotracheitis and Marek's Disease}, volume={59}, ISSN={0005-2086 1938-4351}, url={http://dx.doi.org/10.1637/10966-103014-reg}, DOI={10.1637/10966-103014-reg}, abstractNote={SUMMARY Laryngotracheitis (LT) is a highly contagious respiratory disease of chickens that produces significant economic losses to the poultry industry. Traditionally, LT has been controlled by administration of modified live vaccines. In recent years, the use of recombinant DNA-derived vaccines using turkey herpesvirus (HVT) and fowlpox virus has expanded, as they protect not only against the vector used but also against LT. However, HVT-based vaccines confer limited protection against challenge, with emergent very virulent plus Marek's disease virus (vv+MDV). Serotype 1 vaccines have been proven to be the most efficient against vv+MDV. In particular, deletion of oncogene MEQ from the oncogenic vvMDV strain Md5 (BAC&dgr;MEQ) resulted in a very efficient vaccine against vv+MDV. In this work, we have developed two recombinant vaccines against MD and LT by using BAC&dgr;MEQ as a vector that carries either the LT virus (LTV) gene glycoprotein B (gB; BAC&Dgr;MEQ-gB) or LTV gene glycoprotein J (gJ; BAC&dgr;MEQ-gJ). We have evaluated the protection that these recombinant vaccines confer against MD and LT challenge when administered alone or in combination. Our results demonstrated that both bivalent vaccines (BAC&Dgr;MEQ-gB and BAC&dgr;MEQ-gJ) replicated in chickens and were safe to use in commercial meat-type chickens bearing maternal antibodies against MDV. BAC&Dgr;MEQ-gB protected as well as a commercial recombinant (r)HVT-LT vaccine against challenge with LTV. However, BAC&dgr;MEQ-gJ did not protect adequately against LT challenge or increase protection conferred by BAC&Dgr;MEQ-gB when administered in combination. On the other hand, both BAC&Dgr;MEQ-gB and BAC&dgr;MEQ-gJ, administered alone or in combination, protected better against an early challenge with vv+MDV strain 648A than commercial strains of rHVT-LT or CVI988. Our results open a new avenue in the development of recombinant vaccines by using serotype 1 MDV as vectors.}, number={2}, journal={Avian Diseases}, publisher={American Association of Avian Pathologists (AAAP)}, author={Gimeno, Isabel M. and Cortes, Aneg L. and Faiz, Nik M. and Hernandez-Ortiz, Byron A. and Guy, James S. and Hunt, Henry D. and Silva, Robert F.}, year={2015}, month={Jun}, pages={255–262} }
 @article{gimeno_faiz_cortes_barbosa_villalobos_pandiri_2015, title={In Ovo Vaccination with Turkey Herpesvirus Hastens Maturation of Chicken Embryo Immune Responses in Specific-Pathogen-Free Chickens}, volume={59}, ISSN={["1938-4351"]}, DOI={10.1637/11060-031115-reg.1}, abstractNote={SUMMARY Administration of Marek’s disease (MD) vaccines in ovo has become a common practice for the poultry industry. Efficacy of MD vaccines is very high, even though they are administered to chicken embryos that are immunologically immature. We have recently demonstrated that in ovo vaccination with turkey herpesvirus (HVT) results in increased activation of T cells at hatch. Our previous results suggested that in ovo vaccination with HVT might have a positive impact not only on MD protection but also on the overall maturity of the developing immune system of the chicken (Gallus gallus domesticus). The objective of this study was to evaluate the effect of administration of HVT at 18 days of embryonation (ED) on the maturation of the embryo immune system. Four experiments were conducted in Specific-Pathogen-Free Avian Supplies (SPAFAS) chickens to evaluate the effect of administration of HVT at 18 ED on the splenic cell phenotypes at day of age (experiment 1) and on the ability of 1-day-old chickens to respond to various antigens compared with older birds (experiments 2 and 3). In addition, a fourth experiment was conducted to elucidate whether administration of other serotype’s MD vaccines (CVI988 and SB-1) at 18 ED had the same effect as HVT on the spleen cell phenotypes at day of age. Our results demonstrated that 1-day-old chickens that had received HVT in ovo (1-day HVT) had higher percentages of CD45+, MHC-I+, CD45+MHC-I+, CD3+, MHC-II+, CD3+MHC-II+, CD4+, CD8+, and CD4+CD8+ cells in the spleen than 1-day-old sham-inoculated chickens (1-day sham). Moreover, spleens of 1-day HVT chickens had greater percentages of CD45+MHC-I+ cells and equal or greater numbers of CD4+CD8− and CD4−CD8+ cells than older unvaccinated chickens. In addition, administration of HVT at 18 ED rendered chicks at hatch more responsive to unrelated antigens such as concavalin A, phytohemagglutinin-L, and keyhole limpet hemocyanin. Administration of MD vaccines of other serotypes had an effect, although less remarkable than HVT, on the spleen cell phenotypes at hatch. Vaccines of all three serotypes resulted in an increased percentage of MHC-I+, CD45−MHC-I+, CD4−CD8+, and CD8+ cells, but only HVT resulted in a higher percentage of CD45+, CD45+MHC-I+, CD3+MHC-II+, and CD4+CD8− cells. Results of this study show that it is possible to hasten maturation of the chicken embryo immune system by administering HVT in ovo and open new avenues to optimize the procedure to improve and strengthen the immunocompetency of commercial chickens at hatch.}, number={3}, journal={AVIAN DISEASES}, author={Gimeno, Isabel M. and Faiz, Nik M. and Cortes, Aneg L. and Barbosa, Taylor and Villalobos, Tarsicio and Pandiri, Arun R.}, year={2015}, month={Sep}, pages={375–383} }
 @article{gimeno_dunn_cortes_el-gohary_silva_2014, title={Detection and Differentiation of CVI988 (Rispens Vaccine) from Other Serotype 1 Marek's Disease Viruses}, volume={58}, ISSN={["1938-4351"]}, DOI={10.1637/10666-091713-reg.1}, abstractNote={SUMMARY The serotype 1 Marek's disease virus (MDV) is the causative agent for Marek's disease (MD), a lymphoproliferative disease of chickens of great concern to the poultry industry. CVI988 (Rispens vaccine), an attenuated serotype 1 MDV, is currently the most efficacious commercially available vaccine for preventing MD. However, it is difficult to detect and differentiate CVI988 when other serotype 1 MDVs are present. To facilitate the detection of CVI988, we developed two sets of primers for a mismatch amplification mutation assay (MAMA) PCR that targeted the single nulceotide polymorphism associated with the H19 epitope of the phosphorylated protein 38 gene. The PCR was very specific. One primer set (oncogenic primers) amplified DNA from 15 different serotype 1 MDVs except CVI988. The other primer set (CVI988 primers) amplified DNA from CVI988 but not from any of the other 15 serotype 1 MDVs. A real-time PCR assay was developed using MAMA primers, and specificity and sensitivity was evaluated in vitro and in vivo. Mixtures of plasmids (CVI988 plasmid and oncogenic plasmid) at various concentrations were used to evaluate the sensitivity/specificity of MAMA primers in vitro. Both primer sets were able to amplify as little as one copy of their respective plasmid. Oncogenic primers were highly specific and only amplified CVI988 plasmid when the concentration of oncogenic plasmid was very low (1 × 101) and CVI988 plasmid was very high (1 × 106). Specificity of CVI988 primers was not as high because they could amplify oncogenic plasmids when the concentration of CVI988 plasmid was 1 × 103 and the concentration of oncogenic 1 × 102. Validation of MAMA primers in in vivo samples demonstrated that oncogenic primers can be used for both early diagnosis of MD in feather pulp (FP) samples collected at 3 wk of age and confirmation of MD diagnosis in tumors. CVI988 primers could be used to monitor CVI988 vaccination in samples with a low load of oncogenic MDV DNA (latently infected samples or negative) but not in samples with a high load of oncogenic MDV DNA (tumors). Our results suggest that monitoring CVI988 vaccination in FP samples collected at 1 wk of age ensures the specificity of the CVI988 primers. RESUMEN Detección y diferenciación de la cepa CVI988 (Rispens Vacuna) de otras cepas del virus de la enfermedad de Marek pertenecientes al serotipo 1. El serotipo 1 del virus de la enfermedad de Marek (MDV) es el agente causal de la enfermedad de Marek (MD), que es una enfermedad linfoproliferativa de los pollos de gran importancia para la industria avícola. La cepa CVI988 (vacuna Rispens), una vacuna atenuada del serotipo 1 del virus de Marek, es actualmente la vacuna más eficaz disponible comercialmente para prevenir la enfermedad de Marek. Sin embargo, es difícil de detectar y diferenciar la cepa CVI988 cuando otros virus de Marek del serotipo 1 están presentes. Para facilitar la detección de la cepa CVI988, se desarrollaron dos conjuntos de iniciadores para un ensayo de PCR para la amplificación de mutaciones por discrepancia de nucleótidos (con las siglas en inglés MAMA), dirigido al polimorfismo de nucleótido simple asociado con el gene del epítope H19 de la proteína fosforilada (PP) 38. El método de PCR fue muy específico. Un conjunto de iniciadores (primers oncogénicos) amplificó el ADN de 15 virus diferentes pertenecientes al serotipo 1 excepto la cepa CVI988. El otro conjunto de iniciadores (primers CVI988) amplificó el ADN de la cepa CVI988 pero ninguno de los otros 15 virus incluidos en el serotipo 1. Un ensayo de PCR en tiempo real fue desarrollado usando los iniciadores del ensayo MAMA y se evaluó la especificidad y sensibilidad in vitro e in vivo. Se usaron mezclas de plásmidos (plásmido CVI988 y el plásmido oncogénico) con varias concentraciones para evaluar la sensibilidad/especificidad de los iniciadores MAMA in vitro. Ambos conjuntos de iniciadores fueron capaces de amplificar hasta una copia de su respectivo plásmido. Los iniciadores oncogénicos fueron altamente específicos y solo amplificaron al plásmido CVI988 cuando la concentración del plásmido oncogénico fue muy baja (1 × 101) y la concentración del plásmido CVI988 era muy alta (1 × 106). La especificidad de los iniciadores para la cepa CVI988 no fue muy alta, ya que pudieron amplificar plásmidos oncogénicos cuando la concentración de plásmido CVI988 fue de 1 × 103 y la concentración de los plásmidos oncogénico fue de 1 × 102. La validación de los iniciadores MAMA en muestras in vivo demostró que los iniciadores oncogénicos se pueden utilizar tanto para el diagnóstico precoz de la enfermedad de Marek en muestras de pulpa de la pluma (FP) recolectadas a las tres semanas de edad y para el diagnóstico confirmatorio de la enfermedad de Marek en tumores. Los iniciadores CVI988 podrían utilizarse para el seguimiento de la vacunación CVI988 en muestras con una baja carga de ADN del virus oncogénico del virus de Marek (muestras infectadas de forma latente o negativas), pero no en las muestras con una alta carga de ADN del virus oncogénico de Marek (tumores). Estos resultados sugieren que el seguimiento de la vacunación con la cepa CVI988 en muestras de pulpa de la pluma recolectadas en la primera semana de edad asegura la especificidad de los iniciadores CVI988.}, number={2}, journal={AVIAN DISEASES}, author={Gimeno, Isabel M. and Dunn, John R. and Cortes, Aneg L. and El-Gohary, Abd El-Galil and Silva, Robert F.}, year={2014}, month={Jun}, pages={232–243} }
 @article{gimeno_cortes_witter_pandiri_2012, title={Optimization of the Protocols for Double Vaccination Against Marek's Disease by Using Commercially Available Vaccines: Evaluation of Protection, Vaccine Replication, and Activation of T Cells}, volume={56}, ISSN={["0005-2086"]}, DOI={10.1637/9930-091311-reg.1}, abstractNote={SUMMARY. Revaccination against Marek's disease is a widespread practice in some countries. The rationale of this practice is unknown, and there is no consensus in the protocols. Recently, we have demonstrated that administration of the first vaccine at 18 days of embryonation followed by a more protective second vaccine at hatch (18ED/1d) reproduced systematically the benefits of revaccination under laboratory conditions. Here, we have used the same model to optimize the revaccination protocols by using currently available vaccines and to determine whether two features associated with Marek's disease vaccine-induced protection (activation of T cells and replication of vaccine virus) are involved in the revaccination protocols. Protection conferred by three revaccination protocols (turkey herpesvirus [HVT] 18ED/HVT+SB-1 1d, HVT 18ED/CVI988 1d, and HVT+SB-1 18ED/CVI988 1d) was evaluated. Revaccination protocols also were compared with single vaccination protocols (HVT 18ED, HVT+SB-1 18ED, HVT+SB-1 1d, CVI988 18ED, and CVI988 1d). Our results demonstrated that it is possible to improve efficacy of the currently available vaccines by using them in revaccination programs. Administration of HVT 18ED/CVI988 1d and HVT+SB-1 18ED/CVI988 1d were the two protocols that conferred the highest protection against a very early challenge (2 days of age) with very virulent plus Marek's disease virus strain 648A. In a separate experiment, we evaluated vaccine replication and activation of T cells in single and revaccination protocols. Our results demonstrated that replication of the second vaccine, although decreased compared with single vaccination, could be detected at 3 days (HVT, CVI988) or at 6 days (SB-1). Administration of the first vaccine (HVT) at 18ED resulted in a high percentage of activated T cells. Administration of a second vaccine (either HVT-SB-1 or CVI988) at 1d resulted in increased intensity of MHC-II stain in activated T cells. RESUMEN. Optimización de los protocolos de vacunación doble contra la enfermedad de Marek mediante el uso de vacunas comercialmente disponibles: Evaluación de la protección, replicación de la vacuna y activación de células T. La revacunación contra la enfermedad de Marek es una práctica muy extendida en algunos países. La justificación de esta práctica es desconocida, y no hay un consenso en los protocolos. Recientemente, se demostró que la administración de la primera vacuna a los 18 días de desarrollo embrionario (DE) seguido por la aplicación de una segunda vacuna más protectora a la eclosión (18DE/1d), reproduce de manera sistemática los beneficios de la revacunación bajo condiciones de laboratorio. En este trabajo, se utilizó el mismo modelo para optimizar los protocolos de la revacunación con las vacunas actualmente disponibles y para determinar si dos aspectos asociados con protección inducida por la vacuna contra la enfermedad de Marek (la activación de las células T y la replicación de virus vacunal) están involucrados en los protocolos de la revacunación. La protección conferida por tres protocolos de la revacunación (virus herpes de pavo [HVT] a los18DE/HVT + SB-1 al día 1; HVT 18DE/CVI988 al día 1; y HVT + SB-1 18DE/CVI988 al día 1) se evaluaron. Los protocolos de revacunación también se compararon con los protocolos de vacunación individuales (HVT 18ED, HVT + SB-1 18ED, HVT + SB-1 día 1, CVI988 18ED, y CVI988 día 1). Los resultados observados demostraron que es posible mejorar la eficacia de las vacunas actualmente disponibles mediante su aplicación dentro de programas de revacunación. La administración de HVT 18ED/CVI988 día 1 y HVT + SB-1 18ED/CVI988 día 1, fueron los dos protocolos que le confirieron la máxima protección contra a un desafío muy temprano (dos días de edad) con una cepa muy virulenta del virus de la enfermedad de Marek, la cepa 648A. En un experimento por separado, se evaluaron la replicación del virus vacunal y la activación de células T en los protocolos individuales y de revacunación. Los resultados demuestran que la replicación de la segunda vacuna, aunque disminuida en comparación con una sola vacunación, se pudo detectar a los tres días (HVT, CVI988) o a los seis días (SB-1). La administración de la primera vacuna (HVT) a los 18 días de desarrollo embrionario, resultó en un alto porcentaje de células T activadas. La administración de una segunda vacuna (ya sea HVT-SB-1 o CVI988) al primer día de edad resultó en un aumento de la intensidad de la detección de moléculas MHC-II en las células T activadas.}, number={2}, journal={AVIAN DISEASES}, author={Gimeno, Isabel M. and Cortes, Aneg L. and Witter, Richard L. and Pandiri, Arun R.}, year={2012}, month={Jun}, pages={295–305} }
 @article{gimeno_cortes_2011, title={Chronological study of cytokine transcription in the spleen and lung of chickens after vaccination with serotype 1 Marek's disease vaccines}, volume={29}, ISSN={["1873-2518"]}, DOI={10.1016/j.vaccine.2010.12.079}, abstractNote={Transcription of cytokine genes was evaluated in the lung and spleen of chickens vaccinated with various serotype 1 Marek's disease (MD) vaccines. Three vaccine pairs/series, each consisting of one or two high protective (HP) and one low protective (LP) vaccine, were used. Vaccinated chickens had increased transcripts of IFN-γ in the lung and spleen at 3, 5, and 10 days post vaccination (dpv) compared to unvaccinated control chickens. In addition, transient increase of cytokine transcripts (iNOS, IL-1β, IL-18, IL-8, and IL-6 in the lung and iNOS, IL-18, and IL-6 in the spleen) was detected. Compared to chickens vaccinated with LP vaccines, HP vaccinated chickens had increased transcripts of iNOS at 5 dpv but decreased transcripts of IL-6, IL-8, and IL-18 at 10 dpv in the lung. HP vaccinated chickens had increased IFN-γ in the spleen at 3 and at 10 dpv. This study demonstrated that MD vaccines administered subcutaneously elicit a pulmonary immune response and identified differences in the cytokine gene expression between HP and LP vaccinated chickens.}, number={8}, journal={VACCINE}, author={Gimeno, Isabel M. and Cortes, Aneg L.}, year={2011}, month={Feb}, pages={1583–1594} }
 @article{cortes_montiel_lemiere_gimeno_2011, title={Comparison of Blood and Feather Pulp Samples for the Diagnosis of Marek's Disease and for Monitoring Marek's Disease Vaccination by Real Time-PCR}, volume={55}, ISSN={["1938-4351"]}, DOI={10.1637/9578-101510-resnote.1}, abstractNote={Abstract Comparison of blood and feather pulp (FP) samples for the diagnosis of Marek's disease (MD) and for monitoring Marek's diseases vaccination in chickens (serotypes 2 and 3 vaccines) by real time-PCR was evaluated. For diagnosis of MD, quantification of serotype 1 Marek's disease virus (MDV) DNA load was evaluated in 21 chickens suffering from MD. For each chicken, samples of blood and FP were collected and MDV DNA load was quantified. Solid tumors are the sample of choice for MD diagnosis by real time-PCR and, hence, 14 solid tumors were included in the study as positive controls. Load of MDV DNA in FP was equivalent to that detected in solid tumors (threshold cycle [Ct] ratio above 1.7). MDV DNA load in blood samples was lower than in solid tumors and FP samples. Nonetheless, there was a statistically significant correlation of the results obtained from FP and blood (r  =  0.92). Results of the Pearson correlation test showed that Ct ratio values of 1.7 in FP correspond to Ct ratio values of 1.2 in peripheral blood. For monitoring vaccines, serotypes 2 and 3 MDV DNA load was evaluated in blood and FP samples of vaccinated chickens. Serotype 2 MDV DNA load was evaluated in samples of blood and FP from 34 chickens vaccinated with SB-1 strain. Serotype 3 MDV DNA load was evaluated in blood and FP samples from 53 chickens vaccinated with HVT strain. For both serotypes, frequency of positive samples and load of vaccine DNA was higher in FP than in blood samples. There was not a statistically significant correlation between the load of SB-1 DNA (r  =  0.17) or HVT DNA (r  =  −0.04) in FP and blood. Our results show that the load of serotypes 1, 2, and 3 DNA is higher in FP than in blood. Diagnosis of MD could be done using both FP and blood samples. Monitoring of MD vaccination by real time-PCR required the use of FP samples. There were a high percentage of false negative samples when using blood to detect serotypes 2 and 3 MDV by real time-PCR.}, number={2}, journal={AVIAN DISEASES}, author={Cortes, Aneg L. and Montiel, Enrique R. and Lemiere, Stephane and Gimeno, Isabel M.}, year={2011}, month={Jun}, pages={302–310} }
 @article{gimeno_cortes_montiel_lemiere_pandiri_2011, title={Effect of Diluting Marek's Disease Vaccines on the Outcomes of Marek's Disease Virus Infection When Challenged with Highly Virulent Marek's Disease Viruses}, volume={55}, ISSN={["1938-4351"]}, DOI={10.1637/9579-101510-reg.1}, abstractNote={Abstract Dilution of Marek's disease (MD) vaccines is a common practice in the field to reduce the cost associated with vaccination. In this study we have evaluated the effect of diluting MD vaccines on the protection against MD, vaccine and challenge MD virus (MDV) kinetics, and body weight when challenged with strains Md5 (very virulent MDV) and 648A (very virulent plus MDV) by contact at day of age. The following four vaccination protocols were evaluated in meat-type chickens: turkey herpesvirus (HVT) at manufacturer-recommended full dose; HVT diluted 1∶10; HVT + SB-1 at the manufacturer-recommended full dose; and HVT + SB-1 diluted 1∶10 for HVT and 1∶5 for SB-1. Vaccine was administered at hatch subcutaneously. One-day-old chickens were placed in floor pens and housed together with ten 15-day-old chickens that had been previously inoculated with 500 PFU of either Md5 or 648A MDV strains. Chickens were individually identified with wing bands, and for each chicken samples of feather pulp and blood were collected at 1, 3, and 8 wk posthatch. Body weights were recorded at 8 wk for every chicken. Viral DNA load of wild-type MDV, SB-1, and HVT were evaluated by real time-PCR. Our results showed that dilution of MD vaccines can lead to reduced MD protection, reduced relative body weights, reduced vaccine DNA during the first 3 wk, and increased MDV DNA load. The detrimental effect of vaccine dilution was more evident in females than in males and was more evident when the challenge virus was 648A. However, lower relative body weights and higher MDV DNA load could be detected in chickens challenged with strain Md5, even in the absence of obvious differences in protection.}, number={2}, journal={AVIAN DISEASES}, author={Gimeno, Isabel M. and Cortes, Aneg L. and Montiel, Enrique R. and Lemiere, Stephane and Pandiri, Arun K. R.}, year={2011}, month={Jun}, pages={263–272} }
 @article{gimeno_witter_cortes_reed_2011, title={Replication ability of three highly protective Marek's disease vaccines: implications in lymphoid organ atrophy and protection}, volume={40}, ISSN={["0307-9457"]}, DOI={10.1080/03079457.2011.617725}, abstractNote={The present work is a chronological study of the pathogenesis of three attenuated serotype 1 Marek's disease (MD) virus strains (RM1, CVI988 and 648A80) that provide high protection against MD but have been attenuated by different procedures and induce different degrees of lymphoid organ atrophy. All studied strains replicated in the lymphoid organs (bursa,x thymus and spleen) and a peak of replication was detected at 6 days post inoculation (d.p.i.). Differences, however, were observed among vaccine strains. RM1 strain replicates more in all lymphoid organs compared with CVI988 and 648A80 strains. In addition, replication of RM1 in the thymus did not decrease after 6 d.p.i. but continued at high levels at 14 d.p.i. and until the thymus was completely destroyed. Lung infection occurred very early after infection with all of the three vaccines and the level of replication was similar to that found in the lymphoid organs. Infected cells were very large and appeared scattered in the lung parenchyma and in the parabronchial lining. The study of the target cells for the early infection in cell suspensions of blood and spleen showed that both non-adherent cell populations (enriched in lymphoid cells) and adherent cells (enriched in monocytes/macrophages) supported MD virus infection. Infection in adherent cells was especially high at very early stages of the infection (3 to 6 d.p.i.). Atrophy of lymphoid organs is a major drawback in the production of highly protective vaccines against MD. A better understanding of the mechanisms associated with lymphoid organ atrophy will aid in overcoming this problem.}, number={6}, journal={AVIAN PATHOLOGY}, author={Gimeno, Isabel M. and Witter, Richard L. and Cortes, Aneg L. and Reed, Willie M.}, year={2011}, pages={573–579} }
 @article{gimeno_cortes_guy_turpin_williams_2011, title={Replication of recombinant herpesvirus of turkey expressing genes of infectious laryngotracheitis virus in specific pathogen free and broiler chickens following in ovo and subcutaneous vaccination}, volume={40}, ISSN={["0307-9457"]}, DOI={10.1080/03079457.2011.588196}, abstractNote={Replication of a recombinant herpesvirus of turkey vaccine expressing infectious laryngotracheitis virus genes (rHVT-LT) was evaluated in specific pathogen free (SPF) and commercial broiler chickens after various vaccination protocols (amniotic route at embryonation day [ED] 18; intra-embryonic route at ED 19; and subcutaneous at 1 day of age [s.c.]). Three experiments were conducted: in the first experiment, replication of rHVT-LT vaccine was chronologically evaluated and compared with the replication of herpesvirus of turkey (HVT) in SPF chickens; in the second experiment, the effect of different in ovo vaccination procedures on rHVT-LT vaccine replication was evaluated in SPF chickens; and in the third experiment, the effect of different in ovo vaccination procedures on rHVT-LT vaccine replication was evaluated in commercial broiler chickens with maternal antibodies against HVT and infectious laryngotracheitis virus (LTV). rHVT-LT vaccine replicated in chickens after in ovo (ED 18 and ED 19) or s.c. administration at a similar level. In vivo replication of rHVT-LT vaccine was slower than HVT vaccine. However, in vivo both rHVT-LT and HVT vaccines replicated at similar levels. Both vaccines were consistently detected in the spleen and feather pulp and at lower frequency in the lung. The frequency of samples with detectable levels of rHVT-LT DNA was lower in broiler chickens than in SPF chickens, probably due to interactions with maternal antibodies. Differences between SPF chickens and broiler chickens were found also in the transcription of the LTV glycoprotein I gene (gI). In SPF chickens, in ovo inoculation resulted in a higher number of spleen samples with detectable gI transcripts than s.c. inoculation. In broiler chickens, however, no differences in the level of gI transcripts in spleen samples were found between chickens vaccinated in ovo and those vaccinated by the s.c. route. Transcription of LTV gI gene in lung samples was very low in both SPF and broiler chickens. Further studies to evaluate the mucosal immune response elicited by rHVT-LT in chicken with and without maternal antibodies are warranted.}, number={4}, journal={AVIAN PATHOLOGY}, author={Gimeno, Isabel M. and Cortes, Aneg L. and Guy, James S. and Turpin, Elizabeth and Williams, Christopher}, year={2011}, pages={395–403} }
 @article{gimeno_cortes_2010, title={Evaluation of factors influencing replication of serotype 1 Marek's disease vaccines in the chicken lung}, volume={39}, ISSN={["1465-3338"]}, DOI={10.1080/03079451003599250}, abstractNote={Factors influencing replication of serotype 1 Marek's disease vaccines in the lung of chickens within the first 10 days of age (doa) were evaluated. In particular, the effect of vaccine efficacy, age/route of vaccination, and vaccine dose were examined in three experiments. In the first experiment, three vaccine pairs, each pair consisting of a high protective (HP) and a low protective (LP) vaccine (CVI988/BP5 and CVI988-Clone C, 648A80 and 648A100, R2 and R2/23) were used to inoculate chickens subcutaneously (s.c.) with 2000 plaque-forming units (PFU) at hatch. DNA load in the lung was significantly higher in the HP vaccine group than the LP vaccine group at 5 and 10 doa in two of the three vaccine pairs. In the lung, at 5 doa, early MDV gene transcripts (ICP4 and pp38) were detected in most vaccine groups, whereas late MDV gene transcripts (gB and gI) were detected only in the HP vaccine group. In the second experiment, chickens were vaccinated in ovo or s.c. at hatch with 2000 PFU R2, R2/23, or CVI988/BP5. Compared with s.c. vaccination, in ovo vaccination resulted in higher MDV DNA load in the lung at 3 doa, lower or equal MDV DNA load at 5 doa, and lower MDV DNA load at 10 doa. In the third experiment, chickens were vaccinated s.c. at hatch with either 2000 or 10,000 PFU strain R2. There were no statistically significant differences in the load of MDV DNA in the lung after vaccination with R2 between the two doses. Our results showed that HP vaccines tend to replicate better than LP vaccines in the lung; and vaccine replication in the lung within the first 10 days of age was affected by the age/route of inoculation (in ovo versus s.c.) but not by the dose of vaccine administered.}, number={2}, journal={AVIAN PATHOLOGY}, author={Gimeno, Isabel M. and Cortes, Aneg L.}, year={2010}, pages={71–79} }
 @article{cortes_montiel_gimeno_2009, title={Validation of Marek's Disease Diagnosis and Monitoring of Marek's Disease Vaccines from Samples Collected in FTA (R) Cards}, volume={53}, ISSN={["1938-4351"]}, DOI={10.1637/8871-041009-Reg.1}, abstractNote={Abstract The use of Flinders Technology Associates (FTA®) filter cards to quantify Marek's disease virus (MDV) DNA for the diagnosis of Marek's disease (MD) and to monitor MD vaccines was evaluated. Samples of blood (43), solid tumors (14), and feather pulp (FP; 36) collected fresh and in FTA cards were analyzed. MDV DNA load was quantified by real-time PCR. Threshold cycle (Ct) ratios were calculated for each sample by dividing the Ct value of the internal control gene (glyceraldehyde-3-phosphate dehydrogenase) by the Ct value of the MDV gene. Statistically significant correlation (P < 0.05) within Ct ratios was detected between samples collected fresh and in FTA cards by using Pearson's correlation test. Load of serotype 1 MDV DNA was quantified in 24 FP, 14 solid tumor, and 43 blood samples. There was a statistically significant correlation between FP (r  =  0.95), solid tumor (r  =  0.94), and blood (r  =  0.9) samples collected fresh and in FTA cards. Load of serotype 2 MDV DNA was quantified in 17 FP samples, and the correlation between samples collected fresh and in FTA cards was also statistically significant (Pearson's coefficient, r  =  0.96); load of serotype 3 MDV DNA was quantified in 36 FP samples, and correlation between samples taken fresh and in FTA cards was also statistically significant (r  =  0.84). MDV DNA samples extracted 3 days (t0) and 8 months after collection (t1) were used to evaluate the stability of MDV DNA in archived samples collected in FTA cards. A statistically significant correlation was found for serotype 1 (r  =  0.96), serotype 2 (r  =  1), and serotype 3 (r  =  0.9). The results show that FTA cards are an excellent media to collect, transport, and archive samples for MD diagnosis and to monitor MD vaccines. In addition, FTA cards are widely available, inexpensive, and adequate for the shipment of samples nationally and internationally.}, number={4}, journal={AVIAN DISEASES}, author={Cortes, Aneg L. and Montiel, Enrique R. and Gimeno, Isabel M.}, year={2009}, month={Dec}, pages={510–516} }
 @article{gimeno_cortes_silva_2008, title={Load of Challenge Marek's Disease Virus DNA in Blood as a Criterion for Early Diagnosis of Marek's Disease Tumors}, volume={52}, ISSN={["0005-2086"]}, DOI={10.1637/8089-081407-Reg.1}, abstractNote={Abstract Outbreaks of Marek's disease (MD) in vaccinated flocks still occur sporadically and lead to economic losses. Unfortunately, adequate methods to predict MD outbreaks are lacking. In the present study, we have evaluated whether high load of challenge MD virus (MDV) DNA in peripheral blood could aid in the early diagnosis of MD and in monitoring efficacy of vaccines against MD. One experiment was conducted to simulate field conditions by combining various vaccines (turkey herpesvirus [HVT] and HVT + MDV serotype 2 [SB1]) and challenge viruses (GA, Md5, and 648A). Vaccine efficacy among our experimental groups ranged from 13.3% to 94.2%. Each chicken was sampled three times during the length of the experiment (3, 5, and 15 wk postchallenge [wpc]), and gross lesions were evaluated in chickens that died and at termination of the experiment. DNA was extracted from whole blood and buffy coats from each sample, and the load of challenge MDV DNA and HVT DNA were quantified by real-time polymerase chain reaction. Chickens that developed MD by the end of the experiment had higher load of challenge MDV DNA (threshold cycle [Ct] glyceraldehyde-3-phosphate dehydrogenase [GAPDH]/Ct glycoprotein B [gB] ratios of 1.0, 1.04, and 1.05 at 3, 5, and 15 wpc, respectively) than those that did not develop MD (Ct GAPDH/Ct gB ratios of 0.7, 0.69, and 0.46 at 3, 5, and 15 wpc, respectively). However, load of HVT DNA in blood was not correlated with the development of tumors (Ct GAPDH/Ct HVT ratios from 0.04 to 0.10 in both groups). Vaccinated groups with >75% protection had statistically significant less challenge DNA virus (Ct GAPDH/Ct gB ratios of 0.76, 0.70, and 0.45 at 3, 5, and 15 wpc, respectively) than less protected groups (Ct GAPDH/Ct gB ratios of 0.92, 0.97, and 0.85 at 3, 5, and 15 wpc, respectively). No differences in the load of HVT DNA could be found between protected and nonprotected groups at any time point of the study (Ct GAPDH/Ct HVT from 0.05 to 0.09 in both groups). Our results showed that load of challenge MDV DNA but not load of HVT DNA in blood can be used as criterion for early diagnosis of MD.}, number={2}, journal={AVIAN DISEASES}, author={Gimeno, Isabel M. and Cortes, Aneg L. and Silva, R. F.}, year={2008}, month={Jun}, pages={203–208} }
 @article{pandiri_cortes_lee_gimeno_2008, title={Marek's Disease Virus Infection in the Eye: Chronological Study of the Lesions, Virus Replication, and Vaccine-Induced Protection}, volume={52}, ISSN={["1938-4351"]}, DOI={10.1637/8284-031308-Reg.1}, abstractNote={Abstract Marek's disease virus (MDV) infection in the eye was studied chronologically after inoculating 1-day-old chickens with a very virulent MDV strain, Md5. The ocular lesions could be classified as early lesions (6–11 days postinoculation [dpi]) and late lesions (26 and 56 dpi), based upon the location and severity of the lesions. The early lesions involved iris, ciliary body, and choroid layer, and were characterized by endothelial cell hypertrophy, vasculitis, and infiltration of lymphocytes (mainly CD8+), plasma cells, macrophages, and heterophils. Expression of early MDV-antigen pp38 in the cells infiltrating choroid layer was detected as early as 11 dpi. Late lesions consisted of severe lymphohistiocytic uveitis, keratitis, pectenitis, vitreitis, retinitis, and segmental to diffuse retinal necrosis. Cell infiltration included macrophages, granulocytes, plasma cells, and both CD4+ and CD8+ cells of various sizes. Expression of early MDV-antigen pp38 was readily found within the retina, uveal tract, and corneal epithelium. No expression of late-antigen gB or oncoprotein meq was detected in any of the eyes examined. A second experiment was conducted to study the effect of vaccination on the development of ocular lesions. Both HVT and CVI988 were able to protect against the development of early ocular lesions in chickens infected with very virulent plus strain MDV 648A. However, only CVI988 conferred complete protection against the development of late ocular lesions. HVT conferred partial protection, as it reduced the frequency and severity of the late ocular lesions. These results enhance our understanding of the nature and pattern of MDV infection in the eye. Abbreviations: ABC = avidin-biotin-peroxidase complex; CEF = chicken embryo fibroblasts; DEF = duck embryo fibroblasts; dpi = days postinoculation; H&E = hematoxylin and eosin; HSV = herpes simplex virus; HVT = herpesvirus of turkeys; MAb = monoclonal antibodies; MD = Marek's disease; MDV = Marek's disease virus; MHC = major histocompatibility complex; OCT = optimal cutting temperature; PN = peripheral neuropathy; S/C = subcutaneous route; SPAFAS = specific pathogen free; VZV = varicella-zoster virus Infección en el ojo con el virus de la enfermedad de Marek: Estudio cronológico de lesiones, replicación viral y protección inducida mediante la vacunación. La infección por el virus de la enfermedad de Marek se estudió cronológicamente luego de la inoculación de pollitos de un día de edad con una cepa muy virulenta del virus de la enfermedad de Marek denominada Md5. Basándose en la localización y severidad de las lesiones oculares estas pudieron ser clasificadas como lesiones tempranas (de seis a 11 días posteriores a la inoculación) y lesiones tardías (de 26 a 56 días posteriores a la inoculación). Las lesiones tempranas infectaron el iris, el cuerpo ciliar y la capa coroidea y se caracterizaron por hipertrofia de las células endoteliales, vasculitis e infiltración linfocitaria (principalmente linfocitos T CD8+), células plasmáticas, macrófagos y heterófilos. La expresión del antígeno temprano pp38 del virus de la enfermedad de Marek en las células infiltrando la capa coroidea se detectó desde el día 11 posterior a la inoculación,. Las lesiones tardías consistían en uveítis linfohistiocítica severa, queratitis, pectenitis, vitreítis, retinitis y necrosis retinal que varió de segmentada a difusa. La infiltración celular incluía macrófagos, granulocitos, células plasmáticas y células CD4+ y CD8+ de varios tamaños. La expresión del antígeno temprano pp38 del virus de la enfermedad de Marek fue muy evidente en la retina, tracto uveal y epitelio de la córnea. En ninguno de los ojos examinados se detectó la expresión del antígeno tardío gB o de la oncoproteína meq. Se realizó un segundo experimento para estudiar el efecto de la vacunación en el desarrollo de las lesiones oculares. Tanto el virus Herpes de pavo como el virus CVI988 fueron capaces de proteger contra el desarrollo de las lesiones oculares tempranas en pollos infectados con la cepa muy virulenta “plus” del virus de la enfermedad de Marek 648A. Sin embargo, solo el virus CVI988 confirió protección completa contra el desarrollo de las lesiones oculares tardías. El virus Herpes de pavo confirió protección parcial reduciendo la frecuencia y severidad de las lesiones oculares tardías. Estos resultados aumentan el conocimiento de la naturaleza y patrón de la infección en el ojo con el virus de la enfermedad de Marek.}, number={4}, journal={AVIAN DISEASES}, author={Pandiri, Arun K. R. and Cortes, Aneg L. and Lee, Lucy F. and Gimeno, I. M.}, year={2008}, month={Dec}, pages={572–580} }