The Neonatal Development of Intraepithelial and LaminaPropria Lymphocytes in the Murine Small Intestine

摘要

During early neonatal life, important changes occur in the gut. The intestine is challenged byboth milk and a microbial flora. Later on, at weaning, the diet of mice changes from milk topelleted food leading to changes in microbial contents. This period seems essential for a completedevelopment of the mucosal immune system. We investigated the development of bothintraepithelial (IEL) and lamina propria lymphocytes (LPL), from day 5, and every 5 days, upto day 30 after birth. IEL and LPL were isolated from the small intestine and the phenotypewas assessed by FACS analyses, using antibodies for detection of T-cell markers CD3,TCRαβ, TCRγδ, CD4, CD8α, CD8β, CD5, CD18, CD54, and CD49d. Our data show a clearincrease in the number of LPL just before weaning, while the number of IEL increased afterday 15. A more mature pattern of membrane antigen expression of both IEL and LPL was observedat weaning. The adhesion molecules CD18, CD54, and CD49d, essential for cellularcommunication of lymphocytes, showed an expression peak at weaning. In conclusion, themouse mucosal immune system develops during the first 3 weeks of neonatal life leading tothe formation of a more mature immune system at weaning.