GAMMA-DELTA-T-CELLS IN THE HUMAN INTESTINE EXPRESS SURFACE-MARKERS OF ACTIVATION AND ARE PREFERENTIALLY LOCATED IN THE EPITHELIUM

We have investigated the expression of the αβ and the γδ T cell receptor (TCR) in the human intestine. By immunohistology we found that 39% of CD3+ intraepithelial lymphocytes (IEL) expressed the γδ TCR compared to 3% of CD3+ lamina propria lymphocytes (LPL). Cytofluorometric analysis of isolated cells revealed a significantly higher proportion of γδ T cells among CD3+ IEL compared to LPL and peripheral blood lymphocytes. This was due to an increase in both CD8+ (low density) and CD4-CD8- γδ T cells in IEL. Most αβ IEL expressed high-density CD8. About 30% of both IEL and LPL expressed CD25 (α-chain of the IL-2 receptor). HML-1 expression was detected on nearly all IEL and on 27% of LPL. CD25 and HML-1 were preferentially expressed on intestinal αβ and γδ T cells, respectively. Thus, human γδ T cells are located preferentially in the gut epithelium and are phenotypically different from αβ T cells, which constitute the majority of both LPL and IEL. © 1990.