Regional Variation in the Lamina Propria T Cell Receptor Vβ Repertoire in Normal Human Colon

Lamina propria (LP) T cell populations in the normal human colon contain oligoclonal expansions, but their distribution has not been well studied. We analyzed T cell receptor (TCR) β-chain (Vβ) variable region expression in CD4+and CD8+peripheral blood T cells and LP T cells from separated colonic segments in 13 subjects. CD4+and CD8+Vβ subset expansions were found in the LP of most individuals, and remarkable differences in CD4+and CD8+TCR repertoires were apparent between colon and blood as well as between colon segments within each individual. The presence of such T cell expansions in colon therefore cannot be used to infer immunopathology. In addition, CD8+Vβ expansions seen in peripheral blood T cells, which have been previously shown to be clonal in origin, were also often expanded in LP T cells of the same subject. These results suggest that LP CD8+T cell stimulation may contribute to CD8+peripheral blood T cell expansions.