IL16 Promotes Plasma Cell Differentiation.

The regulation of terminal differentiation of B cells into plasma cells is influenced by transcription factors, epigenetics, and cytokines. Both human and murine B cells possess the capacity to produce interleukin 16 (IL16), a pleiotropic cytokine that serves as a chemoattractant. Despite its production, the precise role of IL16 in B cells has remained elusive. In this study, we showed that IL16 overexpression promoted primary B cell differentiation into B220lowCD138+ plasma cells. This effect was independent of the secreted form of IL16. The overexpression of IL16 resulted in an increase in the expression of plasma transcription factors Blimp-1, IRF4, and Xbp-1, as well as the expression of immunoglobulin genes. Consistently, upon the inoculation of mice with influenza A virus, the absence of IL16 led to a decrease in the number of plasma cells and the production of virus-specific antibodies. Our data demonstrate that IL16 contributes to the terminal differentiation of B cells to plasma cells.