DISTRIBUTION OF DOMINANT T-CELL RECEPTOR-BETA CHAINS IN HUMAN INTESTINAL-MUCOSA

The majority of human intestinal intraepithelial lymphocytes (iIELs) a re CD8(+) T cells that use the T cell receptor (TCR)-alpha/beta. Previ ous studies have shown that iIELs isolated from segments of small inte stine or colon contain one or several dominant alpha/beta T cell clone s. It is not known whether these clones expand only locally in respons e to a particular antigen or whether they are widely distributed throu ghout the intestine. To address this question, iIELs were purified fro m near the proximal and distal margins in a series of intestinal resec tions for noninflammatory diseases. TCR-beta expression was then asses sed by semiquantitative polymerase chain reaction amplification, analy sis of N-region length, and DNA sequencing. The previously described o ligoclonal expansion of iIELs was confirmed in each sample. Identical dominant clones were identified in the proximal and distal samples fro m most cases, including samples taken from sites as distant as the tra nsverse and sigmoid colon or rectum. Distinct clones were found in onl y one case with samples from the terminal ileum and transverse colon. These results demonstrate that a relatively small number of widely dis persed T cell clones comprise the majority of cells in the human intes tinal mucosa.