LAUSR

Immunology The germinal centers (GCs) of intestinal Peyer's patches form in response to microbiota- and food-derived antigens. Within the GCs, B cells differentiate into antibody (immunoglobulin A)–secreting plasma cells after trafficking from microanatomical Peyer's patch structures called subepithelial domes, where they first encounter antigen. Using light-sheet fluorescent microscopy, Biram et al. found that dome colonization and expansion, as well as translocation to the GC, depended on T cell help. B cell trafficking from domes to the GCs, where B cell clonal expansion and diversification takes place, was regulated by B cell receptor affinity. These findings could be valuable in the development of oral vaccines against enteric pathogens. Nat. Immunol. 20 , 482 (2019).