Ontogeny of the mucosal immune response

Abstract

In the 8-week period from 11 weeks to 19–20 weeks gestation human fetal intestine develops organised Peyer's patches and mucosal T cells in the lamina propria and epithelium (Table 2). T cell numbers are, however, low compared to post-natal intestine, and the Peyer's patches only contain primary B cell follicles. There is little information on changes which occur between 20 weeks gestation and birth. However, there is little further development of human gut-associated lymphoid tissue until the gut is exposed to food and bacterial antigens. Thus, there are no plasma cells in newborn human intestine. It would, therefore, appear that the mucosal immune system is functionally mature by 20 weeks gestation, but remains quiescent until birth.