Priyanka Dutta Gupta Microbiology and Immunology Graduate Program B.S., Devi Ahilya University, Indore, M.P. India, 2003 M.S., Microbiology, Barkatullah University, Bhopal, M.P. India, 2005 Email: priyanka.dutta.gupta@drexel.edu Advisor: Dr. Peter Katsikis

 Thesis Research Summary:

Dendritic cells are an intriguing subset of antigen presenting cells, which regulate tolerance to self antigens and immunity to pathogens. These cells are the first responders to any microbe that enters the host. On uptake and processing of antigen these cells migrate to the lymphoid organs to alarm effector cells such as lymphocytes, thereby mediating immediate host immune response. The lines above highlight some commonly known facts about dendritic cells, however there are a few important questions that require answers from an immunological standpoint that my research focuses around. To begin with, there are a large number of dendritic cell subsets that have different locations and possibly different functions. It is largely unknown how the different subsets work together to ensure efficient antigen presentation. One can also ask whether there are specific dendritic cell subsets that process and present different viral bacterial and fungal antigens. It is already known that dendritic cells activate the T cells via two signals: the antigen +MHC-II complex and costimulation. How important are these two signals at different stages of the T cell lifecycle? Could one signal do without the other after the first batch of T cell activation has taken place? In the world of antigen presenting cells (APC), dendritic cells are considered the numero uno APC. Often we tend to overlook the other APCs such as B cells and macrophages, which are equally important. One wonders if the concept of division of labour exists among these APCs, and if so, how does it work? Or is one sufficient (in terms of Tcell activation) without the other? I believe that answering these questions could also shed light on pathogen invasion and evasion of host immune responses. It is quite possible that pathogens may modify this important process of antigen presentation and processing to escape the host response.