Researchers from Brigham and Women’s Hospital, (Harvard Medical School) have demonstrated that exposure to microbes during early childhood is associated with protection from immune-mediated diseases such as inflammatory bowel disease (IBD) and asthma. In their article researchers show that, in germ-free mice (GF), invariant natural killer T cells (iNKT) accumulate in the colonic lamina propria and lung, resulting in increased morbidity in models of IBD and allergic asthma compared to specific pathogen-free (SPF) mice. This was associated with increased intestinal and pulmonary expression of the chemokine ligand CXCL16, which was associated with increased mucosal iNKT cells. Colonization of neonatal—but not adult—GF mice with a conventional microbiota protected the animals from mucosal iNKT accumulation and related pathology. These results indicate that age-sensitive contact with commensal microbes is critical for establishing mucosal iNKT cell tolerance to later environmental exposures.
Adapted from: Original source