Researchers from the University of British Columbia revealed that IgA antibodies in breastmilk specifically inhibit the gut bacterium Erysipelatoclostridium ramosum, which is implicated in promoting allergic responses in infants. Their findings, published in PNAS, showed that IgA prevents bacterial adhesion to intestinal cells, shaping the maturation of infant gut microbiota and potentially lowering allergy risk. This insight supports the therapeutic prospective of incorporating IgA into infant formulas to mimic breastmilk’s immunological benefits.