Regional variations in the distributions of small intestinal intraepithelial lymphocytes (IELs) in BALB/c+/+, nu/+, and nu/nu mice

Regional variations in intraepithelial lymphocytes (IELs) in the small inte stine were examined in BALB/c +/+, nu/+, and nu/nu mice. The small intestin e was obtained from 11- to 12-week-old mice and divided equally into three (proximal, middle, and distal) parts. The IELs were isolated from each part of the intestine, and the total numbers of IELs in nu/+ and nu/nu mice wer e about a fifth of those in +/+ mice. Regional variations in the distributi on of the IEL alpha beta, but not the gamma delta T-cell subset were found by use of flow cytometry in +/+ and nu/+ mice. On the other hand, such diff erences were not found in nu/nu mice, suggesting that thymus-independent de velopment of T cells is not different among regions. Different local expans ion of thymus-dependent alpha beta T cells may cause the regional variation s seen in the distribution of alpha beta T cell IELs in +/+ and nu/+ mice.