Dendritic cells, BAFF, and APRIL: innate players in adaptive antibody responses.

The first antibody produced in bacterial or viral infection results from B cell growth as plasmablasts. Dendritic cell-derived TNF-family ligands APRIL and/or BAFF enhance plasmablast survival and differentiation to plasma cells. Expression of these ligands by dendritic cells is promoted by innate immune signals that can convert subliminal B cell activation to a productive response. While this may be lifesaving in the face of infection, it can predispose to autoantibody production.