B cell development in GALT: role of bacterial superantigen-like molecules

Intestinal bacteria drive the formation of lymphoid tissues, and in rabbit, bacteria also promote development of the pre-immune Ab repertoire and positive selection of B cells in GALT. Previous studies indicated that Bacillus subtilis promotes B cell follicle formation in GALT, and this study investigated the mechanism by which B. subtilis stimulates B cells. The researchers found that spores of B. subtilis and other Bacillus species, including Bacillus anthracis, bound rabbit IgM through an unconventional, superantigen-like binding site, and in vivo, surface molecules of B. anthracis spores promoted GALT development. The study provides direct evidence that B cell development in GALT may be driven by superantigen-like molecules, and furthermore, that bacterial spores modulate host immunity. J Immunol. 2010;184(12):6782-9. Epub 2010 May 7.