Interleukin-10-producing CD5+ B cells inhibit mast cells during immunoglobulin E-mediated allergic responses.

Subsets of B cells inhibit various immune responses through their production of the cytokine interleukin-10 (IL-10). We found that IL-10-producing CD5(+) B cells suppressed the immunoglobulin E (IgE)- and antigen-mediated activation of mast cells in vitro as well as allergic responses in mice in an IL-10-dependent manner. Furthermore, the suppressive effect of these B cells on mast cells in vitro and in vivo depended on direct cell-to-cell contact through the costimulatory receptor CD40 on CD5(+) B cells and the CD40 ligand on mast cells.

The scaffold protein prohibitin is required for antigen-stimulated signaling in mast cells.

The protein prohibitin (PHB) is implicated in diverse cellular processes, including cell signaling, transcriptional control, and mitochondrial function. We found that PHB was abundant in the intracellular granules of mast cells, which are critical for allergic responses to antigens. Thus, we investigated whether PHB played a role in signaling mediated by the high-affinity receptor for antigen-bound immunoglobulin E (IgE), FcεRI.