Yersinia pestis is a Category A pathogen and the causative agent of pneumonic plague. A type III secretion system (T3SS) that is essential for virulence is used by Y. pestis to export a set of proteins known as Yops. Yop effectors (e.g. YopE) are delivered into host cells to disrupt intracellular signaling pathways. Yop effectors are delivered across the host cell plasma membrane by the translocators YopD and YopB. The LcrV protein, localized to the tip of the T3SS, is required to insert YopD and YopB into the plasma membrane and is a well-characterized protective antigen. Y. pestis also assembles protein fibers on its surface that are composed of the F1 protein. F1 is a protective antigen and is being developed together with LcrV as a subunit vaccine. Murine IgG MAbs specific for LcrV or F1 have been shown to confer passive protection against plague in mice. However, it is possible to genetically modify Y. pestis to make it resistant to LcrVand F1-based vaccines or immunotherapeutics, because F1- mutants remain fully virulent, and protective epitopes within LcrV can be altered. Therefore, additional protective antigens need to be identified and developed into targets for vaccines or immunotherapeutics to counteract the threat of genetically modified Y. pestis. This research will identify and characterize protective IgG MAbs specific for YopD and YopB that could be used to passively immunize humans against genetically modified plague.
In Aim 1, we will demonstrate passive protection of mice against F1- Y. pestis with MAbs specific for Yop translocator proteins. These experiments will establish a proof-of-principle that pneumonic plague caused by genetically modified Y. pestis can be prevented by MAb immunotherapy.
In Aim 2, we will identify epitopes in Yop translocators proteins recognized by protective MAbs. These studies will provide information on the nature of the protective epitopes, and allow for development of a MAb cocktail as an optimized immunotherapy.
In Aim 3, we will determine role of constant heavy (CH) regions in protective MAb function. F(ab')2 fragments of protective anti-YopB and anti-YopD MAbs will be generated and tested for protective activity. Chimeric (ch) MAbs containing variable regions of protective MAbs and human CH regions of different isotypes will be constructed, characterized for affinity and specificity, and assayed for protective function. Mice expressing human Fc receptor will be used to measure protective activity of murine-human ch MAbs. Results will increase the usefulness of these MAbs as immunotherapeutics in humans, as well as provide knowledge on the role of constant region in MAb function.
Plague is a highly virulent disease in humans and is considered a major threat as a biological weapon. Current strategies to prevent pneumonic plague, such as the use of vaccines or antibiotics, are non-effective or could be bypassed by intentional genetic manipulation of the pathogen. The studies proposed here will lead to the development of new immunotherapeutics to prevent or treat plague caused by genetically modified Y. pestis in the human population.
|Zhou, Yijun; Li, Xiao-Ping; Chen, Brian Y et al. (2017) Ricin uses arginine 235 as an anchor residue to bind to P-proteins of the ribosomal stalk. Sci Rep 7:42912|
|Aguilar, Jorge L; Varshney, Avanish K; Pechuan, Ximo et al. (2017) Monoclonal antibodies protect from Staphylococcal Enterotoxin K (SEK) induced toxic shock and sepsis by USA300 Staphylococcus aureus. Virulence 8:741-750|
|Chen, Han; Coseno, Molly; Ficarro, Scott B et al. (2017) A Small Covalent Allosteric Inhibitor of Human Cytomegalovirus DNA Polymerase Subunit Interactions. ACS Infect Dis 3:112-118|
|Pham, Alissa M; Santa Maria, Felicia Gilfoy; Lahiri, Tanaya et al. (2016) PKR Transduces MDA5-Dependent Signals for Type I IFN Induction. PLoS Pathog 12:e1005489|
|Basu, Debaleena; Kahn, Jennifer N; Li, Xiao-Ping et al. (2016) Conserved Arginines at the P-Protein Stalk Binding Site and the Active Site Are Critical for Ribosome Interactions of Shiga Toxins but Do Not Contribute to Differences in the Affinity of the A1 Subunits for the Ribosome. Infect Immun 84:3290-3301|
|Li, Melody M H; Bozzacco, Leonia; Hoffmann, Hans-Heinrich et al. (2016) Interferon regulatory factor 2 protects mice from lethal viral neuroinvasion. J Exp Med 213:2931-2947|
|Torres, AnnMarie; Luke, Joanna D; Kullas, Amy L et al. (2016) Asparagine deprivation mediated by Salmonella asparaginase causes suppression of activation-induced T cell metabolic reprogramming. J Leukoc Biol 99:387-98|
|Charles, Jermilia; Firth, Andrew E; Loroño-Pino, Maria A et al. (2016) Merida virus, a putative novel rhabdovirus discovered in Culex and Ochlerotatus spp. mosquitoes in the Yucatan Peninsula of Mexico. J Gen Virol 97:977-87|
|Taylor, Travis J; Diaz, Fernando; Colgrove, Robert C et al. (2016) Production of immunogenic West Nile virus-like particles using a herpes simplex virus 1 recombinant vector. Virology 496:186-193|
|Song, Jeongmin; Wilhelm, Cara L; Wangdi, Tamding et al. (2016) Absence of TLR11 in Mice Does Not Confer Susceptibility to Salmonella Typhi. Cell 164:827-8|
Showing the most recent 10 out of 649 publications