@article{simoes_lavoy_dean_2019, title={Effects of Regulatory T Cell Depletion on NK Cell Responses against Listeria monocytogenes in Feline Immunodeficiency Virus Infected Cats}, volume={11}, ISSN={["1999-4915"]}, DOI={10.3390/v11110984}, abstractNote={Regulatory T cells (Treg) are key players in the maintenance of peripheral tolerance, preventing autoimmune diseases and restraining chronic inflammatory diseases. Evidence suggests Treg cells and NK cells have important roles in feline immunodeficiency virus (FIV) pathogenesis; however, in vivo studies investigating the interplay between these two cell populations are lacking. We previously described innate immune defects in FIV-infected cats characterized by cytokine deficits and impaired natural killer cell (NK) and NK T cell (NKT) functions. In this study, we investigated whether in vivo Treg depletion by treatment with an anti-feline CD25 monoclonal antibody would improve the innate immune response against subcutaneous challenge with Listeria monocytogenes (Lm). Treg depletion resulted in an increased overall number of cells in Lm-draining lymph nodes and increased proliferation of NK and NKT cells in FIV-infected cats. Treg depletion did not normalize expression of perforin or granzyme A by NK and NKT cells, nor did Treg depletion result in improved clearance of Lm. Thus, despite the quantitative improvements in the NK and NKT cell responses to Lm, there was no functional improvement in the early control of Lm. CD1a+ dendritic cell percentages in the lymph nodes of FIV-infected cats were lower than in specific-pathogen-free control cats and failed to upregulate CD80 even when Treg were depleted. Taken together, Treg depletion failed to improve the innate immune response of FIV-infected cats against Lm and this may be due to dendritic cell dysfunction.}, number={11}, journal={VIRUSES-BASEL}, author={Simoes, Rita D. and LaVoy, Alora and Dean, Gregg A.}, year={2019}, month={Nov} }
 @article{stoeker_nordone_gunderson_zhang_kajikawa_lavoy_miller_klaenhammer_dean_2011, title={Assessment of Lactobacillus gasseri as a Candidate Oral Vaccine Vector}, volume={18}, ISSN={["1556-6811"]}, DOI={10.1128/cvi.05277-11}, abstractNote={ABSTRACT Lactobacillus species are commensal bacteria that have long been recognized as probiotic microbes and are generally regarded as safe (GRAS) for human consumption. We have investigated the use of L. gasseri as a vaccine vector for oral immunization against mucosal pathogens. Recent research has shown that the immune response to different lactobacilli can vary widely depending on the species or subspecies of Lactobacillus being studied. While some lactobacilli seem to induce oral tolerance, others induce an adaptive immune response. This study characterized the systemic and mucosal immune response to wild-type and genetically modified L. gasseri. L. gasseri primarily activates TLR2/6, with additional activation through the TLR2 homodimer. To expand the Toll-like receptor (TLR) activation profile of L. gasseri and the immunogenicity of the vector, a plasmid containing fliC, the gene encoding bacterial flagellin, was introduced which resulted in the strong activation of TLR5. The treatment of human myeloid dendritic cells with recombinant lactobacilli expressing flagellin triggered phenotypic maturation and the release of proinflammatory cytokines. In contrast, bacterial treatment also resulted in a statistically significant increase in IL-10 production. In vivo studies established that treatment with L. gasseri led to a diversification of B-cell populations in the lamina propria of the murine colon. Furthermore, treatment with genetically modified L. gasseri led to a significant decrease in the percentage of FoxP3+ colonic lymphocytes. Taken together, these data clarify the interaction of L. gasseri with the host immune system and support further investigation of the in vivo immunogenicity of L. gasseri expressing both flagellin and candidate vaccine antigens.}, number={11}, journal={CLINICAL AND VACCINE IMMUNOLOGY}, author={Stoeker, Laura and Nordone, Shila and Gunderson, Sara and Zhang, Lin and Kajikawa, Akinobu and LaVoy, Alora and Miller, Michael and Klaenhammer, Todd R. and Dean, Gregg A.}, year={2011}, month={Nov}, pages={1834–1844} }
 @article{kajikawa_nordone_zhang_stoeker_lavoy_klaenhammer_dean_2011, title={Dissimilar Properties of Two Recombinant Lactobacillus acidophilus Strains Displaying Salmonella FliC with Different Anchoring Motifs}, volume={77}, ISSN={["0099-2240"]}, DOI={10.1128/aem.05153-11}, abstractNote={ABSTRACT Display of heterologous antigens on the cell surface is considered a useful technique for vaccine delivery by recombinant lactobacilli. In this study, two recombinant Lactobacillus acidophilus derivatives displaying Salmonella flagellin (FliC) were constructed using different anchor motifs. In one instance, the FliC protein was fused to the C-terminal region of a cell envelope proteinase (PrtP) and was bound to the cell wall by electrostatic bonds. In the other case, the same antigen was conjugated to the anchor region of mucus binding protein (Mub) and was covalently associated with the cell wall by an LPXTG motif. These two recombinant L. acidophilus cell surface displays resulted in dissimilar maturation and cytokine production by human myeloid dendritic cells. The surface-associated antigen was highly sensitive to simulated gastric and small intestinal juices. By supplementation with bicarbonate buffer and soybean trypsin inhibitor, the cell surface antigen was protected from proteolytic enzymes during gastric challenge in vitro. The protective reagents also increased the viability of the L. acidophilus cells upon challenge with simulated digestive juices. These results demonstrate the importance of protecting cells and their surface-associated antigens during oral immunization.}, number={18}, journal={APPLIED AND ENVIRONMENTAL MICROBIOLOGY}, author={Kajikawa, Akinobu and Nordone, Shila K. and Zhang, Lin and Stoeker, Laura L. and LaVoy, Alora S. and Klaenhammer, Todd R. and Dean, Gregg A.}, year={2011}, month={Sep}, pages={6587–6596} }
 @article{gunderson_nordone_lavoy_zhang_klaenhammer_dean_2009, title={Immunogenicity of Lactobacillus gasseri-FliC as an oral mucosal vaccine adjuvant for HIV}, volume={6}, ISSN={["1742-4690"]}, DOI={10.1186/1742-4690-6-s3-p163}, abstractNote={Background Transmission of HIV-1 across mucosal surfaces is the most prevalent mode of viral infection. Therefore, a successful vaccine must induce broad anti-viral immunity at the mucosal surface. In the present study, we investigated the immunogenicity of a novel Lactobacillus gasseri mucosal vaccine vector for use in oral delivery of HIV antigens. L. gasseri was genetically engineered to express Salmonella spp. flagellin (L. gasseri-FliC) – the agonist for Toll-like receptor 5 (TLR5) and a potent activator of innate immune cells.}, journal={RETROVIROLOGY}, author={Gunderson, S. and Nordone, S. and LaVoy, A. and Zhang, L. and Klaenhammer, T. and Dean, G.}, year={2009} }
 @article{stoeker_nordone_lavoy_tallon_klaenhammer_dean_2009, title={Toll-like receptor activation profiles of wild-type, recombinant, and mutant Lactobacillus: implications for vaccine design}, volume={6}, ISSN={["1742-4690"]}, DOI={10.1186/1742-4690-6-s3-p133}, journal={RETROVIROLOGY}, author={Stoeker, L. and Nordone, S. and LaVoy, A. and Tallon, R. and Klaenhammer, T. and Dean, G.}, year={2009} }
 @article{lankford_petty_la voy_reckling_tompkins_dean_2008, title={Cloning of feline FOXP3 and detection of expression in CD4+CD25+ regulatory T cells}, volume={122}, ISSN={["1873-2534"]}, DOI={10.1016/j.vetimm.2007.11.007}, abstractNote={Regulatory T cells (Treg) are increased and directly infected by feline immunodeficiency virus (FIV) and likely play a role in other feline autoimmune, neoplastic, and infectious diseases. Phenotypically, Treg are best characterized by surface expression of CD4 and CD25 and intranuclear expression of the forkhead transcription factor Foxp3. Our objective was to clone and sequence feline FOXP3 for the purpose of developing assays to enhance studies of feline Treg. We determined the feline FOXP3 is 1293 nucleotides in length and codes for a protein that shares high homology to other species. A splice variant devoid of exon 2 was also identified. A real-time PCR assay was developed and used to show Foxp3 mRNA expression occurs primarily in CD4+CD25+ T cells. Two cross-reacting antibodies were identified by immunocytochemical staining of HEK293 cells transfected with feline FOXP3. The antibody labeling confirmed the nuclear localization of the protein. A flow cytometric assay was also validated and used to correlate the phenotypic and functional characteristics of feline Treg induced by treatment of lymph node lymphocytes with flagellin or LPS in combination with mitogen or IL2. Together, these studies provide useful tools to further investigate Foxp3 and Tregs in cats.}, number={1-2}, journal={VETERINARY IMMUNOLOGY AND IMMUNOPATHOLOGY}, author={Lankford, Susan and Petty, Christopher and La Voy, Alora and Reckling, Stacie and Tompkins, Wayne and Dean, Gregg A.}, year={2008}, month={Mar}, pages={159–166} }
 @article{dean_lavoy_yearley_stanton_2006, title={Cytokine modulation of the innate immune response in feline immunodeficiency virus - Infected cats}, volume={193}, ISSN={["0022-1899"]}, DOI={10.1086/503873}, abstractNote={BACKGROUND
In vitro data suggest that innate immune function in human immunodeficiency virus type 1-infected patients is compromised; however, in vivo studies are lacking. Feline immunodeficiency virus (FIV) infection in cats provides an excellent model to explore innate immune function in vivo. The innate response against Listeria monocytogenes is well understood, making it a useful immune probe.


METHODS
Recombinant L. monocytogenes carrying eukaryotic expression plasmids for feline tumor necrosis factor (TNF)- alpha , interleukin (IL)-10, interferon (IFN)- gamma , and IL-15 were created to determine whether specific cytokines would modulate innate immune function. L. monocytogenes was delivered subcutaneously, and local lymph nodes were evaluated for size, cell subpopulations, and L. monocytogenes burden. Two months later, memory responses were evaluated by IFN- gamma enzyme-linked immunospot assay.


RESULTS
FIV-positive cats had significantly less lymph-node enlargement and a greater L. monocytogenes burden than FIV-negative control cats. TNF- alpha improved listericidal activity in FIV-negative control cats but not in FIV-positive cats, whereas IL-10 modestly reduced function in FIV-negative control cats. IFN- gamma improved memory responses but not clearance of L. monocytogenes. IL-15 improved innate function in FIV-positive cats and increased the percentage of natural killer cells.


CONCLUSIONS
Lentivirus infection impairs innate immune function in vivo, and IL-15 can significantly restore function. We hypothesize that altered dendritic-cell function and increased regulatory T cell activity may underlie the innate immune defect in HIV infection.}, number={11}, journal={JOURNAL OF INFECTIOUS DISEASES}, author={Dean, GA and Lavoy, A and Yearley, J and Stanton, C}, year={2006}, month={Jun}, pages={1520–1527} }
 @article{olivry_lavoy_dunston_brown_lennon_warren_prisayanh_müller_suter_dean_et al._2006, title={Desmoglein-1 is a minor autoantigen in dogs with pemphigus foliaceus}, volume={110}, ISSN={["0165-2427"]}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-33644524373&partnerID=MN8TOARS}, DOI={10.1016/j.vetimm.2005.10.002}, abstractNote={The majority of human patients with pemphigus foliaceus (PF) have circulating IgG autoantibodies that target conformational epitopes on the desmosomal cadherin desmoglein-1 (dsg1). Limited studies using immunoblot techniques suggested that the principal autoantigen in dogs with PF might also be dsg1. It was the objective of this study to test this hypothesis. A comprehensive survey of canine PF sera was conducted using a novel screening strategy that detects conformational epitopes. This method consists of the ectopic expression of canine dsg1 at the surface of human 293T epithelial kidney cells and their live screening, i.e. prior to fixation. Out of seven control human PF sera that bound to canine epidermis, three (57%) contained IgG autoantibodies that recognized ectopically expressed canine dsg1 with a membrane and punctate pattern. Out of 83 canine PF sera only five (6%) contained IgG that recognized canine dsg1. Consistent with findings for human PF sera obtained in this study, autoantibody binding was conformation- and glycosylation-dependent as demonstrated by calcium chelation with EDTA and tunicamycin or wheat germ agglutinin treatment, respectively. In conclusion, these studies establish canine dsg1 as a minor autoantigen for canine PF. Antigenic epitopes appear to be conformation- and glycosylation-dependent.}, number={3-4}, journal={VETERINARY IMMUNOLOGY AND IMMUNOPATHOLOGY}, author={Olivry, T. and LaVoy, A. and Dunston, S.M. and Brown, R.S. and Lennon, E.M. and Warren, S.J. and Prisayanh, P. and Müller, E.J. and Suter, M.M. and Dean, G.A. and et al.}, year={2006}, month={Apr}, pages={245–255} }
 @article{dean_barger_lavoy_2005, title={Cloning and expression of feline interleukin 15}, volume={29}, ISSN={["1096-0023"]}, DOI={10.1016/j.cyto.2004.09.012}, abstractNote={A cDNA encoding feline interleukin 15 (IL15) was cloned from the lymph node of a cat infected with feline infectious peritonitis virus. The cDNA is 486 bp in length and encodes a protein of 162 amino acids. Recombinant protein was readily expressed as a GST fusion in Escherichia coli and purified by glutathione affinity chromatography. Expression of recombinant protein in mammalian cells was only accomplished by eliminating the 5′ and 3′ UTR, replacing the IL15 signal peptide with the tissue plasminogen activator signal peptide, and adding 3′ sequence to disrupt presumptive secondary structure of the mRNA. Biologically active feline IL15 was expressed in HEK293T cells and was shown to sustain primary feline lymphocytes, a feline T cell line, and mouse CTLL-2 cells. Proliferation of CTLL-2 cells was induced by the recombinant protein in a dose-dependent manner. Monoclonal and polyclonal antibodies against human IL15 recognized feline IL15 in immunofluorescence and Western blot assays. Additionally, feline IL15 was detectable using a commercially available human IL15 ELISA kit.}, number={2}, journal={CYTOKINE}, author={Dean, GA and Barger, A and LaVoy, A}, year={2005}, month={Jan}, pages={77–83} }
 @article{stevens_lavoy_nordone_burkhard_dean_2005, title={Pre-existing immunity to pathogenic Listeria monocytogenes does not prevent induction of immune responses to feline immunodeficiency virus by a novel recombinant Listeria monocytogenes vaccine}, volume={23}, ISSN={["1873-2518"]}, DOI={10.1016/j.vaccine.2004.09.033}, abstractNote={Listeria monocytogenes is an attractive biologic vaccine vector against HIV because it induces a strong cell mediated immune response, can be delivered by mucosal routes, can be readily manipulated to express viral antigens, and is easy and inexpensive to produce. Proof of concept studies have been performed using HIV Gag expressing recombinant L. monocytogenes in the mouse. Here we report the development and validation of recombinant L. monocytogenes to be evaluated in the FIV/cat model of HIV. Using a simplified approach to introduce individual and polyprotein FIV gag genes, we show that recombinant L. monocytogenes containing the entire gag expresses the full-length Gag polyprotein in a soluble secreted form. A DNA vaccine plasmid (pND14-Lc-env) that replicates in Gram positive bacteria and contains the FIV SU (gp100) and the ectodomain of TM (gp40) in a eukaryotic expression cassette was transfected into LM-gag to create LM-gag/pND14-Lc-env. After infection of target cells with LM-gag/pND14-Lc-env in vitro, both FIV Gag and Env proteins were detected in soluble cell lysates. Whether previous exposure to L. monocytogenes affects the immunogenicity of LM-gag/pND14-Lc-env was determined in cats infected with wild-type L. monocytogenes orally and/or subcutaneously. After a single oral dose of LM-gag/pND14-Lc-env, cats with existing anti-L. monocytogenes immune responses developed anti-FIV Gag IgA titers in vaginal secretions, saliva, and feces. Similarly, FIV Gag and Env specific IFN-γ ELISPOT responses were measurable in spleen and lymph node but at a statistically higher frequency in cats exposed to a single subcutaneous dose of wild-type L. monocytogenes versus cats exposed both subcutaneously and orally. The FIV/cat model will provide a useful challenge system to determine whether recombinant L. monocytogenes can protect against a lentivirus in its natural host after challenge by the routes common to HIV transmission.}, number={12}, journal={VACCINE}, author={Stevens, R and LaVoy, A and Nordone, S and Burkhard, M and Dean, GA}, year={2005}, month={Feb}, pages={1479–1490} }
 @article{sirriyah_dean_lavoy_burkhard_2004, title={Assessment of CD4+ and CD8+ IFN-gamma producing cells by ELISPOT in naive and FIV-infected cats}, volume={102}, ISSN={["1873-2534"]}, DOI={10.1016/j.vetimm.2004.06.011}, abstractNote={IFN-gamma is critical for the development of antiviral cell-mediated immunity in HIV infected humans and FIV infected cats. The ELISPOT has proven to be a technically straightforward assay to quantify the number of IFN-gamma producing cells and offers a reasonable alternative for the quantitative measurement of T-cell function in cats. We used a feline-specific ELISPOT to identify constitutive as well as Con A stimulated IFN-gamma production in T-cell subsets and determine if there were differences between purified (positively sorted) and negatively depleted populations from naïve and FIV infected cats. We found no difference in the total number of PBMC constitutively producing IFN-gamma in naïve and FIV+ cats. Con A exposure was associated with increased numbers of IFN-gamma producing PBMC in naïve, but not FIV+, cats. Equivalent numbers of CD4+ and CD8+ T cells constitutively expressed IFN-gamma in naïve cats. However, in FIV+ cats, the number of IFN-gamma producing CD8+ T-cells was approximately two-fold over that seen for CD4+ T-cells. We found minimal differences between purified (e.g. CD4+ or CD8+) and corresponding depleted (e.g. CD8- or CD4-) populations in samples from FIV+ cats. In contrast, depleted populations from naïve cats showed greater response to Con A than did purified populations. Thus, while determination of the number of IFN-gamma producing cells by feline-specific ELISPOT is a useful tool for the evaluation of the feline immune response, determination of the initial sample population and T-cell subset is critical for optimal interpretation of the IFN-gamma ELISPOT.}, number={1-2}, journal={VETERINARY IMMUNOLOGY AND IMMUNOPATHOLOGY}, author={Sirriyah, J and Dean, GA and LaVoy, A and Burkhard, MJ}, year={2004}, month={Nov}, pages={77–84} }
 @article{dean_lavoy_burkhard_2004, title={Peptide mapping of feline immunodeficiency virus by IFN-gamma elispot}, volume={100}, ISSN={["1873-2534"]}, DOI={10.1016/j.vetimm.2004.03.001}, abstractNote={Interferon-gamma (IFN-γ) enzyme-linked immunospot (ELISPOT) has become an important tool in studying antigen-specific T lymphocyte responses. Soluble peptides can be used to map T-cell epitopes, providing information that is useful in the design and evaluation of vaccines as well as studies of immunopathogenesis. To date, this assay has not been widely utilized in feline immunodeficiency virus (FIV) research. We have developed a feline IFN-γ ELISPOT assay and used it to determine FIV-specific T-cell epitopes recognized by infected cats. A panel of 331 peptides, 15 amino acids in length and overlapping by 10 residues was synthesized. The peptide library spanned the FIV structural (Gag), envelope (Env), reverse transcriptase (RT), and open-reading-frame A (OrfA) proteins. Initially, 34 pools, containing 7–10 peptides each were screened by IFN-γ ELISPOT against peripheral blood mononuclear cells (PBMC) from eight cats chronically infected with the NCSU1 molecular clone of FIV and four uninfected control cats. Individual peptides from pools recognized by FIV+ cats were then evaluated and optimal peptides were combined into pools representing Gag, Env, RT, and OrfA. A higher percentage of FIV infected cats were identified as responders against the peptide pools when using fresh PBMC as compared to cryopreserved PBMC. In vitro restimulation of cryopreserved PBMC with the peptide pools improved the sensitivity of the assay to similar levels as observed from fresh samples. Individual peptides used in the pools were generally found to stimulate CD8+ T-cells more efficiently than CD4+ T-cells. Comparison of the peptide sequences to representative FIV sequences from clades A–D showed conservation was high among Gag and RT peptides, variable among Env peptides and low for OrfA peptides. The IFN-γ ELISPOT assay and FIV-specific peptide pools we describe here will be useful in assessing cell-mediated responses to experimental FIV vaccines.}, number={1-2}, journal={VETERINARY IMMUNOLOGY AND IMMUNOPATHOLOGY}, author={Dean, GA and LaVoy, A and Burkhard, MJ}, year={2004}, month={Jul}, pages={49–59} }
 @article{woo_dean_lavoy_clark_moore_1999, title={Investigation of recombinant human insulin-like growth factor type I in thymus regeneration in the acute stage of experimental FIV infection in juvenile cats}, volume={15}, ISSN={["1931-8405"]}, DOI={10.1089/088922299310089}, abstractNote={Thymus involvement and the development of thymic lesions in HIV-1 infection is hypothesized to suppress thymus function and limit T cell maturation and replenishment of the peripheral lymphoid pool. Therapeutic modulation to protect or enhance thymus function may therefore ameliorate peripheral lymphocytopenia and retard disease progression. Thymotrophic agents, such as insulin-like growth factor type I (IGF-I), may therefore represent adjunctive but important methods of treatment to protect or promote thymus function. The assessment of rhIGF-I in lentiviral infection and its impact on the thymus was performed using the feline immunodeficiency virus (FIV) model. Regeneration of the thymus in juvenile cats and amelioration of the thymic lesion after FIV infection was assessed by multiple measurements including thymic weight, stereologic analysis of the thymus cortex and medulla, histologic and immunohistologic analysis, quantitation of thymocyte and peripheral lymphocyte subsets, and quantitative competitive RT-PCR. Evidence of thymic cortical regeneration was observed in FIV-inoculated cats after 12 and 20 weeks of rhIGF-I treatment. Inflammation in the thymus was reduced during this period of treatment in this group of rhIGF-I/FIV-inoculated cats as evidenced by the reduced numbers of B cells detected. Viral replication rates in peripheral lymph nodes were not altered by rhIGF-I treatment and were decreased by 1 log in the thymus after 20 weeks of treatment. Peripheral blood CD4+ T cell counts also increased after 14 weeks of treatment. This suggests that rhIGF-I treatment can enhance thymus function and replenishment of the peripheral T cell pool.}, number={15}, journal={AIDS RESEARCH AND HUMAN RETROVIRUSES}, author={Woo, JC and Dean, GA and Lavoy, A and Clark, R and Moore, PF}, year={1999}, month={Oct}, pages={1377–1388} }