Intestinal intraepithelial NK and NKT cell ontogeny in Lewis rats

Natural killer T (NKT) cells have been described in the liver and spleen of adult rats, but their presence and function in other tissues and in early life remains uncertain. This study was designed to determine the proportion of NK cells and NKT cells among small intestine intraepithelial (IE) lymphocytes in suckling rats and adult animals by flow cytometry. Very few intestinal IE-NKT cells (NKR-P1A+ TCR alpha beta+) were present in adult rats (similar to 1%), but a high proportion of this population was found during early life (similar to 40% of IE lymphocytes in 9-dayold rats), with a marked age-decreasing pattern. Most of these cells presented the CD8 alpha beta+ Phenotype. Intestinal IE-NK cells (NKR-P1A+ TCR alpha beta-) were also present in a relatively high proportion during the suckling period (similar to 30% of IE lymphocytes). Thus, a predominance of both NK and NKT cell subpopulations in small intestine epithelium is characteristic in the early life of rats and may have a protective rote during the suckling period. (C) 2008 Elsevier Ltd. All rights reserved.