THE V-DELTA-1 T-CELL RECEPTOR REPERTOIRE IN HUMAN SMALL-INTESTINE ANDCOLON

V delta 1 bearing T cells comprise the major population of gamma/delta T cells in the human intestinal tract. To gain insight into mechanism s involved in the generation of these cells and the diversity of their repertoire, we have characterized the junctional sequences of V delta 1 T cell receptor transcripts in the human small intestine and colon. Mucosal biopsies obtained from defined regions along the length of th e small intestine or colon contained a high frequency of either one or a few identical in frame V delta 1 sequences. Less abundant sequences were also detected repeatedly throughout the length of small intestin e or colon. Moreover, the intestinal V delta 1 repertoire in the small intestine and colon appeared compartmentalized and showed no overlap with the V delta 1 repertoire in peripheral blood. Dominant V delta 1 transcripts in each subject differed between the small intestine and c olon, and the dominant transcripts within these sites differed among i ndividuals. Analysis of small intestinal transcripts obtained at a 1-y r interval revealed that the V delta 1 repertoire was stable over time . The fact that the majority of V delta 1 transcripts, both dominant a nd rare, are distributed throughout a several meter length of the adul t intestinal tract and are stable over time suggests they are not gene rated by an ongoing process of in situ VDJ gene rearrangement. Our res ults favor a model in which the repertoire of V delta 1 T cells in the intestinal tract is shaped by positive selection in response to a lim ited array of ligands before the migration of V delta 1 cells througho ut the small intestine or colon.