Surveillance B lymphocytes and mucosal immunoregulation.
Mucosal lymphocyte homeostasis involves the dynamic interaction of enteric microbiota, the intestinal host epithelium, and the mucosal immune system. Dysregulation of mucosal lymphocyte homeostasis results in a variety of intestinal disorders, notably inflammatory bowel diseases like ulcerative colitis and Crohn's disease. One key cellular component regulating homeostasis are B lymphocytes that reside in gut-associated lymphoid tissue. This compartment includes Peyer's patches, isolated lymphoid follicles, lamina propria, and mesenteric lymph nodes. Recent data have pointed to two new and exciting aspects of B cells in the gut. First, there has been progress on identification and functional analysis of abundant isolated lymphoid follicle B cells that are key mediators of IgA genesis. Second, several groups have now clarified the functional identification and characterization of immunoregulatory B cells in the gut. This review examines the novel aspects of these B cells, and examines how each plays a role in mediating mucosal homeostasis in this bacteria-laden compartment.
Velázquez
Peter
P
Department of Pathology and Laboratory Medicine, University of California, Los Angeles, 650 Charles E. Young Drive South, Los Angeles, CA 90095, USA.
Wei
Bo
B
Braun
Jonathan
J
D000818:Animals; D000917:Antibody Formation; D016175:B-Lymphocyte Subsets / Q000276:immunology*; D006706:Homeostasis; D006801:Humans; D018928:Immunity, Mucosal; D007413:Intestinal Mucosa / Q000166:cytology / Q000276:immunology; D051379:Mice; D010641:Phenotype; D015398:Signal Transduction; D013601:T-Lymphocytes / Q000276:immunology