Small metabolites have big effects on the intestinal immune response

Normal gut bacteria are instrumental in inducing an immune response in the presence of invading pathogens. However, exactly how commensal bacteria cause CX3CR1+ macrophages in the intestine to protrude their tentacle-like dendrites to capture antigens, triggering the immune response, was unclear. Now, a research team has shown that common bacterial metabolites pyruvate and lactate interact with the GPR31 receptor on CX3CR1+ cells, enhancing the immune response and protecting against gut pathogen...