Immunology
IgA Changes the Rules of Memory
Andrea Cerutti1,2
The human intestinal mucosa is exposed to a complex ecosystem of harmless bacteria (commensals) that are excluded from the sterile environment of the body by an antibody isotype called immunoglobulin A (IgA) (
1). Characterizing the dynamics of this immune response has been problematic because of constant immune stimulation by such bacteria. On page 1705 of this issue, Hapfelmeier
et al. (
2) use a reversible system of gut bacterial colonization in mice to show that responses to commensals lack cardinal features of systemic (extramucosal) IgG responses to pathogenic bacteria.
1 Catalan Institute for Research and Advanced Studies, IMIM–Hospital del Mar, Barcelona Biomedical Research Park, 08003 Barcelona, Spain.
2 The Immunology Institute, Department of Medicine, Mount Sinai School of Medicine, New York, NY 10029, USA.
E-mail acerutti{at}imim.es; andrea.cerutti{at}mssm.edu