Research in the Bhattacharya lab focuses on molecular approaches to direct B cell differentiation to establish immunity to infectious disease, and stem cell differentiation for regenerative medicine. Current projects in the lab include: 1) Understanding the cellular basis of antibody-mediated immunity to variable viruses. After infection or vaccination, B cells that recognize the pathogen proliferate and undergo a massive level of expansion. Upon clearance of the infection a small fraction of the "best" B cells are retained to become memory B cells or long-lived plasma cells. Our recent work has established that memory B cells are excellent at recognizing not only the original pathogen, but also mutant escape variants of the pathogen. In contrast, long-lived plasma cells are highly specific only for the original pathogen. We are studying the transcription factors that regulate the memory B cell vs. long-lived plasma cell fate, and are studying mechanisms to alter this fate to provide effective immunity against mutable viruses such as influenza and Dengue. 2) Identifying molecular regulators of the duration of immunity. Most clinically used vaccines rely on the production of antibodies to confer immunity. The duration of immunity can vary greatly between different vaccines, yet the molecular basis of this remains unknown. Current efforts are focused on the identification of genes that regulate plasma cell lifespan and on the features of the vaccine that confer durable antibody immunity. 3) Engineering human pluripotent stem cells to generate antibody-mediated immunity. A small fraction of patients infected with HIV or dengue virus, or vaccinated against influenza develop remarkable antibodies that neutralize nearly all clinical isolates of these viruses. Yet it is unclear how to induce these types of antibodies in the broader population through standard vaccination. Using novel targeted nuclease technologies, we are engineering human embryonic stem cells to express these antibodies and differentiating them into transplantable long-lived plasma cells. The long-term goal of this project is to provide permanent immunity to recipients of these engineered plasma cells.