BACKGROUND AND AIM Indirect evidence suggests that CD4⁺ T cells have a pathogenic while γδ T cells have a protective role in the initiation and perpetuation of inflammatory bowel disease. To define the role of T cell subsets in a rat colitis model (2,4,6-trinitrobenzene sulphonic acid (TNBS)) we analysed colitis severity after effective depletion of T helper cells, αβ Τ cells, or γδ T cells.

RESULTS Surprisingly, depletion of T helper cells or αβ T cells had no influence on survival, macroscopic or microscopic scores, or myeloperoxidase activity following colitis induction. In contrast, depletion of γδ T cells resulted in significantly increased mortality (V65: 73%, n=15) compared with controls (30%, n=13; p<0.03). In addition, colitis was histologically more severe in the γδ T cell depleted group compared with controls (p<0.05).

CONCLUSIONS T helper cells or αβ T cells did not influence the initiation or perpetuation of rat TNBS colitis. In contrast, γδ T cells had a protective role in rat TNBS colitis as depletion caused increased mortality.