Analysis of CD40-CD40 ligand interactions in the regulation of human B cell function.

CD40-CD40 ligand interactions play an essential role in T cell/B cell collaboration. The data presented in this review have served to widen the scope of CD40-CD40 ligand interactions to include initial activation, proliferation, differentiation, and isotype switching of B cells, as well as subsequent downregulation of B cell function. Moreover, CD40 ligand expression by activated B cells is likely to play an essential role in facilitating ongoing responses of stimulated B cells maturing in germinal centers. Finally, CD40 expression by activated T cells may also play an important role in regulating the function of helper T cells within germinal centers. In summary, emerging data have expanded the role of CD40-CD40 ligand interaction during T cell/B cell collaboration and have emphasized its potential to regulate many of the functions of both partners in this essential interaction involved in antibody production.