Mucosal Immunity

The subepithelial dome (SED) area of intestinal Peyer’s patches is a major hub for serial interactions between B cells and DCs that play a critical role in the induction of secretory IgA. Reboldi et al. report in the May 13 issue of Science that pre-germinal center B cells require the CCR6 chemokine receptor to follow a CCL20 gradient and efficiently enter the SED “workspace”. Once they reach the SED, CCR6+ B cells undergo a series of intimate interactions with αvβ8 integrin-expressing DCs. The DC αvβ8 converts latent TGF-β to active TGF-β, which is the key cytokine driving IgA class switching by the B cells. http://science.sciencemag.org/content/352/6287/aaf4822.full