Joshy Jacob, PhD
Professor
Emory Vaccine Center
Professor
Department of Microbiology and Immunology
Emory University School of Medicine
Researcher
Emory National Primate Research Center
Investigator
Emory Center for AIDS Research
ARTDTP Research Discipline:
Plasma cells are the terminally differentiated effector cells of the humoral arm of adaptive immunity. They can be short-lived with a half-life of two weeks or long-lived and persist for a lifetime. The mechanisms involved in the regulation of plasma cell function are not fully understood. Our studies have shown that CD28/B7 pathway is crucial for regulating plasma cell function. CD28, which is constitutively expressed on T cells, interacts with B7.1/B7.2 expressed on antigen-presenting cells is critical for T cell activation. CD28 is also expressed on murine and human plasma cells but its function on these cells remains unclear. We have demonstrated that CD28-deficieny in murine short- and long-lived plasma cells leads to increased survival and antibody production than their wildtype counterparts. Interestingly, plasma cells also express the ligand for CD28, B7.1/2. Surprisingly, deficiency of B7.1 and B7.2 in B cells also led to higher antibody levels, analogous to CD28-/- plasma cells. Collectively, our results suggest that the CD28-B7 interaction operates as a key modulator of plasma cell function. Our current research is focused on understanding the mechanistic aspects of how CD28/B7 signals regulate plasma cell function.