Joshy Jacob, PhD
Emory Vaccine Center
Department of Microbiology and Immunology, Emory University School of Medicine
Yerkes National Primate Research Center
Emory Center for AIDS Research
Dr. Jacob is a Professor in the Emory School of Medicine Department of Microbiology and Immunology. He received his Ph.D. in immunology from the University of Maryland School of Medicine at Baltimore, and did his post-doctoral training at the Rockefeller University and the Massachusetts Institute of Technology.
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.
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