PHENOTYPIC AND FUNCTIONAL STUDY OF CD4+, CD8+ AND DN GD T CELLS IN COLON CANCER

Abstract

Intraepithelial lymphocytes (IELs) expressing the gammadelta TCR (gammadelta IELs) play an important role in maintaining the intestinal epithelium. In this project, we studied the frequency and the production of several cytokines by gammadelta T cells from 15 colon cancer patients and 5 APC mice. We found that CD4+ gammadelta T cells frequency was higher in the tumour microenvironment and expressed higher levels of PD-1, IL-17 and TNF-α. CD4+ gammadelta T cells produced less IFN-gamma and granzyme B compared to CD8+ gammadelta T cells in the tumour tissue. They had the lowest killing capacity and the highest expression of exhaustion markers compared to CD8+ and DN gammadelta T cells. CD4+gammadeltaT cells may suppress anti-tumour immune responses in the colon tumour microenvironment. We need future studies to define the functional capacity of both CD4+ and CD8+ gammadelta T cells infiltrating tumour and in normal tissues during colorectal cancer development.