Gut bacteria exert a dramatic, systemic effect on the development of the immune system's B-lymphocytes, according to a new mouse study by researchers at Boston Children's Hospital. While influences of gut bacteria on T-lymphocytes have been noted before, this is the first time that researchers have documented early B-cell development in the gut and that microbes influence this process.
The study team—led by Duane Wesemann, MD, PhD, and Frederick Alt, PhD, of Boston Children's Hospital's Program in Cellular and Molecular Medicine (PCMM)—reported their findings online Aug. 21 in Nature.
Starting at birth, the immune system programs immature B-cells to produce antibodies against a wide array of potentially pathogenic antigens by shuffling genes for different antibody components. This shuffling process, called V(D)J recombination, depends on a factor called RAG, which results in an immense number of B-cells that collectively are able to respond to a diverse repertoire of antigens that the immune system has yet to encounter.