@article{schuchman_vancini_piper_breuer_ribeiro_farreira_magliocca_emmerich_hernandez_brown_2016, title={The role of the vacuolar ATPase in alphavirus replication.}, volume={27}, journal={Molecular Biology of the Cell}, author={Schuchman, R. and Vancini, R. and Piper, A. and Breuer, D. and Ribeiro, M. and Farreira, D. and Magliocca, J. and Emmerich, V. and Hernandez, R. and Brown, D.}, year={2016} }
 @article{briggs_smith_piper_huitt_spears_quiles_ribeiro_thomas_brown_hernandez_2014, title={Live Attenuated Tetravalent Dengue Virus Host Range Vaccine Is Immunogenic in African Green Monkeys following a Single Vaccination}, volume={88}, ISSN={["1098-5514"]}, DOI={10.1128/jvi.00541-14}, abstractNote={ABSTRACT
          
            The causative agent of dengue fever, dengue virus (DENV), is transmitted by mosquitoes, and as distribution of these insects has expanded, so has dengue-related disease. DENV is a member of the
            Flaviviridae
            family and has 4 distinct serotypes (DENV-1, -2, -3, and -4). No lasting cross protection is afforded to heterologous serotypes following infection by any one of the individual serotypes. The presence of nonneutralizing antibodies to one serotype can facilitate the occurrence of more-severe dengue hemorrhagic fever through immune enhancement upon infection with a second serotype. For this reason, the development of a safe, tetravalent vaccine to produce a balanced immune response to all four serotypes is critical. We have developed a novel approach to produce safe and effective live-attenuated vaccines for DENV and other insect-borne viruses. Host range (HR) mutants of each DENV serotype were created by truncating transmembrane domain 1 of the E protein and selecting for strains of DENV that replicated well in insect cells but not mammalian cells. These vaccine strains were tested for immunogenicity in African green monkeys (AGMs). No vaccine-related adverse events occurred. The vaccine strains were confirmed to be attenuated
            in vivo
            by infectious center assay (ICA). Analysis by 50% plaque reduction neutralization test (PRNT
            50
            ) established that by day 62 postvaccination, 100% of animals seroconverted to DENV-1, -2, -3, and -4. Additionally, the DENV HR tetravalent vaccine (HR-Tet) showed a tetravalent anamnestic immune response in 100% (16/16) of AGMs after challenge with wild-type (WT) DENV strains.
          
          
            IMPORTANCE
            We have generated a live attenuated viral (LAV) vaccine capable of eliciting a strong immune response in African green monkeys (AGMs) in a single dose. This vaccine is delivered by injecting one of four attenuated serotypes into each limb of the animal. 100% of animals given the vaccine generated antibodies against all 4 serotypes, and this response was found to be balanced in nature. This is also one of the first studies of dengue in AGMs, and our study suggests that viremia and antibody response in AGMs may be similar to those seen in DENV infection in humans.
          }, number={12}, journal={JOURNAL OF VIROLOGY}, author={Briggs, Caitlin M. and Smith, Katherine M. and Piper, Amanda and Huitt, Emerson and Spears, Carla J. and Quiles, Michelle and Ribeiro, Mariana and Thomas, Malcolm E. and Brown, Dennis T. and Hernandez, Raquel}, year={2014}, month={Jun}, pages={6729–6742} }
 @article{piper_ribeiro_smith_briggs_huitt_nanda_spears_quiles_cullen_thomas_et al._2013, title={Chikungunya Virus Host Range E2 Transmembrane Deletion Mutants Induce Protective Immunity against Challenge in C57BL/6J Mice}, volume={87}, ISSN={["1098-5514"]}, DOI={10.1128/jvi.03357-12}, abstractNote={ABSTRACT
          
            A vaccine against Chikungunya virus (ChikV), a reemerging pathogenic arbovirus, has been made by attenuating wild-type (WT) virus via truncation of the transmembrane domain (TMD) of E2 and selecting for host range (HR) mutants. Mice are a standard model system for ChikV disease and display the same symptoms of the disease seen in humans. Groups of mice were inoculated with one of three ChikV HR mutants to determine the ability of each mutant strain to elicit neutralizing antibody and protective immunity upon virus challenge. One mutant, ChikV TM17-2, fulfilled the criteria for a good vaccine candidate. It displayed no reactogenicity at the site of injection, no tissue disease in the foot/ankle and quadriceps, and no evidence of viral persistence in foot/ankle tissues 21 days after infection. Upon challenge with a highly pathogenic strain of ChikV, the mutant blocked viral replication in all tissues tested. This study identified a ChikV HR mutant that grows to high levels in insect cells but was restricted in the ability to assemble virus in mammalian cells
            in vitro
            . The study demonstrates that these HR strains are attenuated in the mammalian host and warrant further development as live-attenuated vaccine strains.
          }, number={12}, journal={JOURNAL OF VIROLOGY}, author={Piper, Amanda and Ribeiro, Mariana and Smith, Katherine M. and Briggs, Caitlin M. and Huitt, Emerson and Nanda, Kavita and Spears, Carla J. and Quiles, Michelle and Cullen, John and Thomas, Malcolm E. and et al.}, year={2013}, month={Jun}, pages={6748–6757} }
 @article{he_piper_meilleur_hernandez_heller_brown_2012, title={Conformational Changes in Sindbis Virus Induced by Decreased pH Are Revealed by Small-Angle Neutron Scattering}, volume={86}, ISSN={["0022-538X"]}, url={http://europepmc.org/abstract/med/22156534}, DOI={10.1128/jvi.06569-11}, abstractNote={ABSTRACT
          Alphaviruses, such as Sindbis virus, undergo dramatic changes in three-dimensional structure upon exposure to low pH, and such exposure can establish conditions allowing fusion of the virus membrane with a cell plasma membrane upon return to neutral pH. While exposure to low pH is not required for entry of Sindbis virus into vertebrate or invertebrate cells, the conformational changes occurring at low pH may mimic those occurring upon virus-receptor interaction. Here, we employed small-angle neutron scattering with contrast variation to probe how the structure of a mammalian-grown Sindbis virus responds to moderately acidic pH. Several changes took place throughout the virion structure when the pH decreased from 7.2 to 6.4. Specifically, the RNA in the virion core underwent a conformational change. Additionally, the protein was redistributed. A significant amount of protein moved from the layer containing the lipid bilayer to the exterior of the virion. The results improve our understanding of the pH-driven alteration of Sindbis virus structure.}, number={4}, journal={JOURNAL OF VIROLOGY}, author={He, Lilin and Piper, Amanda and Meilleur, Flora and Hernandez, Raquel and Heller, William T. and Brown, Dennis T.}, year={2012}, month={Feb}, pages={1982–1987} }
 @article{stowe_tucker_thompson_piper_richards_rogers_mathies_melander_cavanagh_2012, title={Evaluation of the toxicity of 2-aminoimidazole antibiofilm agents using both cellular and model organism systems}, volume={35}, ISSN={["1525-6014"]}, DOI={10.3109/01480545.2011.614620}, abstractNote={Biofilm formation is a ubiquitous bacterial defense mechanism and has been shown to be a primary element in the antibiotic resistance of many human diseases, especially in the case of nosocomial infections. Recently, we have developed several compound libraries that are extremely effective at both dispersing preexisting biofilms and also inhibiting their initial formation. In addition to their antibiofilm properties, some of these molecules are able to resensitize resistant bacterial strains to previously ineffective antibiotics and are being assessed as adjuvants. In this study, we evaluated the toxic effects of three of our most effective 2-aminoimidazole compounds (dihydrosventrin, RA, and SPAR) using a rapid pipeline that combines a series of assays. A methylthiazolyldiphenyl-tetrazolium assay, using the HaCaT keratinocyte cell line was used to determine epidermal irritants and was combined with Caenorhabditis elegans fecundity assays that demonstrated the effects of environmental exposure to various concentrations of these molecules. In each case, the assays showed that the compounds did not exhibit toxicity until they reached well above their current biofilm dispersion/inhibition concentrations. The most effective antibiofilm compound also had significant effects when used in conjunction with several standard antibiotics against resistant bacteria. Consequently, it was further investigated using the C. elegans assay in combination with different antibiotics and was found to maintain the same low level of toxicity as when acting alone, bolstering its candidacy for further testing as an adjuvant.}, number={3}, journal={DRUG AND CHEMICAL TOXICOLOGY}, author={Stowe, Sean D. and Tucker, Ashley T. and Thompson, Richele and Piper, Amanda and Richards, Justin J. and Rogers, Steven A. and Mathies, Laura D. and Melander, Christian and Cavanagh, John}, year={2012}, month={Jul}, pages={310–315} }
 @article{smith_nanda_mccarl_spears_piper_ribeiro_quiles_briggs_thomas_thomas_et al._2012, title={Testing of Novel Dengue Virus 2 Vaccines in African Green Monkeys: Safety, Immunogenicity, and Efficacy}, volume={87}, ISSN={["1476-1645"]}, DOI={10.4269/ajtmh.2012.12-0004}, abstractNote={The immunogenicity and safety of three novel host-range vaccines containing deletions in the transmembrane domain of dengue virus serotype 2 (DV2) E glycoprotein were evaluated in African green monkeys. The shorter transmembrane domains are capable of functionally spanning an insect but not a mammalian cell membrane, resulting in production of viral mutants that have reduced infectivity in mammalian hosts but efficient growth in insect cells. Groups of four monkeys received one dose each of test vaccine candidate with no booster immunization. After immunization, levels of viremia produced by each vaccine were determined by infectious center assay. Vaccine recipient immune response to wild-type DV2 challenge was measured on Day 57 by enzyme-linked immunosorbent assay and plaque reduction neutralization test. Two vaccines, DV2ΔGVII and DV2G460P, generated neutralizing antibody in the range of 700–900 50% plaque reduction neutralization test units. All three vaccine strains decreased the length of viremia by at least two days. No safety concerns were identified.}, number={4}, journal={AMERICAN JOURNAL OF TROPICAL MEDICINE AND HYGIENE}, author={Smith, Katherine M. and Nanda, Kavita and McCarl, Victoria and Spears, Carla J. and Piper, Amanda and Ribeiro, Mariana and Quiles, Michelle and Briggs, Caitlin M. and Thomas, Gwynneth S. and Thomas, Malcolm E. and et al.}, year={2012}, month={Oct}, pages={743–753} }
 @article{smith_nanda_spears_ribeiro_vancini_piper_thomas_thomas_brown_hernandez_2011, title={Structural mutants of dengue virus 2 transmembrane domains exhibit host-range phenotype}, volume={8}, ISSN={["1743-422X"]}, DOI={10.1186/1743-422x-8-289}, abstractNote={There are over 700 known arboviruses and at least 80 immunologically distinct types that cause disease in humans. Arboviruses are transmitted among vertebrates by biting insects, chiefly mosquitoes and ticks. These viruses are widely distributed throughout the world, depending on the presence of appropriate hosts (birds, horses, domestic animals, humans) and vectors. Mosquito-borne arboviruses present some of the most important examples of emerging and resurgent diseases of global significance. A strategy has been developed by which host-range mutants of Dengue virus can be constructed by generating deletions in the transmembrane domain (TMD) of the E glycoprotein. The host-range mutants produced and selected favored growth in the insect hosts. Mouse trials were conducted to determine if these mutants could initiate an immune response in an in vivo system. The DV2 E protein TMD defined as amino acids 452SWTMKILIGVIITWIG467 was found to contain specific residues which were required for the production of this host-range phenotype. Deletion mutants were found to be stable in vitro for 4 sequential passages in both host cell lines. The host-range mutants elicited neutralizing antibody above that seen for wild-type virus in mice and warrant further testing in primates as potential vaccine candidates. Novel host-range mutants of DV2 were created that have preferential growth in insect cells and impaired infectivity in mammalian cells. This method for creating live, attenuated viral mutants that generate safe and effective immunity may be applied to many other insect-borne viral diseases for which no current effective therapies exist.}, journal={VIROLOGY JOURNAL}, author={Smith, Katherine M. and Nanda, Kavita and Spears, Carla J. and Ribeiro, Mariana and Vancini, Ricardo and Piper, Amanda and Thomas, Gwynneth S. and Thomas, Malcolm E. and Brown, Dennis T. and Hernandez, Raquel}, year={2011}, month={Jun} }
 @article{he_piper_meilleur_myles_hernandez_brown_heller_2010, title={The Structure of Sindbis Virus Produced from Vertebrate and Invertebrate Hosts as Determined by Small-Angle Neutron Scattering}, volume={84}, ISSN={["1098-5514"]}, url={http://europepmc.org/abstract/med/20219936}, DOI={10.1128/jvi.00044-10}, abstractNote={ABSTRACT
          The complex natural cycle of vectored viruses that transition between host species, such as between insects and mammals, makes understanding the full life cycle of the virus an incredibly complex problem. Sindbis virus, an arbovirus and prototypic alphavirus having an inner protein shell and an outer glycoprotein coat separated by a lipid membrane, is one example of a vectored virus that transitions between vertebrate and insect hosts. While evidence of host-specific differences in Sindbis virus has been observed, no work has been performed to characterize the impact of the host species on the structure of the virus. Here, we report the first study of the structural differences between Sindbis viruses grown in mammalian and insect cells, which were determined by small-angle neutron scattering (SANS), a nondestructive technique that did not decrease the infectivity of the Sindbis virus particles studied. The scattering data and modeling showed that, while the radial position of the lipid bilayer did not change significantly, it was possible to conclude that it did have significantly more cholesterol when the virus was grown in mammalian cells. Additionally, the outer protein coat was found to be more extended in the mammalian Sindbis virus. The SANS data also demonstrated that the RNA and nucleocapsid protein share a closer interaction in the mammalian-cell-grown virus than in the virus from insect cells.}, number={10}, journal={JOURNAL OF VIROLOGY}, author={He, Lilin and Piper, Amanda and Meilleur, Flora and Myles, Dean A. A. and Hernandez, Raquel and Brown, Dennis T. and Heller, William T.}, year={2010}, month={May}, pages={5270–5276} }