Defining Molecular Epitopes of Protective Antibodies to Flaviviruses

Project Summary/Abstract: The objective of this K08 Mentored Clinical Scientist Career Award Application is to provide Dr. Alena Markmann with a strong foundation in human immunology and the latest methods for studying human immune cells before launching her independent research career on the human immune response to RNA viruses. Dr. Markmann is an Assistant Professor of Medicine, tenure track, at the University of North Carolina -Chapel Hill (UNC) School of Medicine with a joint appointment in the Department of Microbiology and Immunology. The candidate has expertise in and a strong track record of publications on antibody structure, antibody-antigen interactions and antibody neutralization of viruses. By strengthening her knowledge of adaptive immunity to RNA viruses and mastering the latest methods for analyzing antigen specific B cells, Dr. Markmann will study how the human immune response to emerging flaviviruses like dengue and Zika can suppress viral infection and disease or enhance viral replication and exacerbate disease. The candidate and her mentor Dr. Aravinda de Silva have designed a training plan that includes a rigorous research component along with didactic instruction, networking and presentation opportunities, team management skills as well as manuscript writing and grantsmanship. Together these skills will establish the methods and principles necessary for successful career development. Flaviviruses are enveloped positive stranded RNA viruses that pose a growing threat to the human population and cause millions of infections annually. They are vector-borne, transmitted by ticks and mosquitoes, and cause a spectrum of disease manifestations including febrile illness, encephalitides that can cause lifelong complications, Congenital Zika Syndrome and dengue hemorrhagic fever and shock syndromes. For the most part, flaviviral infection result in a neutralizing protective antibody response against the infecting virus, that can last for years after infection. The four dengue viruses however are very similar antigenically and in many cases, result in generating a broad cross-neutralizing antibody responseto dengue virus serotypes that individuals have not yet been exposed to. Thus far, no one has identified the viral target site of these broadly neutralizing dengue antibodies that exist in the serum. Furthermore, though we know of a few major targets of the Zika protective antibody response from studying memory B cells, we do not know what the serum targets are. Preliminary results suggest that in the case of Zika serum antibody responses, binding targets are correlated with known strongly neutralizing memory B cell-derived antibody targets. Thus, we hypothesize in Aim 1, that serum antibody responses will mirror memory B cell responses, but will likely come from a smaller number of B cell clones and be less cross-reactive with other flaviviruses. In Aim 2 we will identify the viral binding targets of broadly cross- neutralizing dengue antibodies from the serum. These studies will result in the ident ification of critical protective viral targets to both dengue and Zika viruses from the serum antibody compartment in order to inform successful vaccine design.