Gut microbes shape our antibodies before we are infected by pathogens

Colonization with intestinal microbes is known to shape many body systems, especially the white blood cells that produce antibodies. Because the microbiota is so complex, containing hundreds of different bacterial species, it is not known how the presence of microbes in the intestine shaped the antibodies that are present even before we are challenged by an infection. Researchers at the Department for BioMedical Research (DBMR) of the University of Bern and the Inselspital, University Hospital Bern, have now shown how these beneficial microbes reprogram the repertoire of white blood B cells that produce antibodies and how this helps counter infections. B cells are white blood cells that develop to produce antibodies. These antibodies, or immunoglobulins, can bind to harmful foreign particles (such as viruses or disease-causing bacteria) to stop them invading and infecting the body's cells. Each B cell carries an individual B cell receptor (BCR) which determines which particles it can bind, rather like each lock accepts a different key. There are many millions of B cells with different receptors in the body.