Localization of T cell receptor (TCR)- γδ+ T cells into human colorectal cancer: flow cytometric analysis of TCR-γδ expression in tumour-infiltrating lymphocytes

Abstract

We analysed TCR‐γδ expression in tumour‐infiltrating lymphocytes (TIL) obtained from 13 patients with colorectal cancer and simultaneously isolated the T lymphocytes from normal intestinal tissue (IL) to compare the frequencies of TCR‐γδ expression in TIL, IL. and peripheral blood lymphocytes (PBL) in the same patient. Flow cytometric analysis showed that the frequency of TCR‐γδ expression in TIL (275 ± 1·84%) was significantly lower than that in IL (15·28 ± 9·45%, P < 001). However, a larger quantity of TIL was separated than IL per unit weight of specimen, so the total number of γδ T cells obtained per unit weight was not different between tumour tissue and normal intestine. In addition, phenotypic analysis revealed that about half of the TCR‐γδ TIL were CD8+ (CD4⁺, 3·0 ± 3·1%; CD8⁺, 54·7 ± 19·9%, mean ± s.d. of five patients), and a very similar result was obtained in TCR‐γδ⁺ IL (CD4⁺ 2·7 ± 2·4%; CD8⁺, 53·1 ± 17·4%). In contrast, most TCR‐γδ+ PBL were double‐negative (CD4⁺. 3·2 ± 3·0%; CD8⁺ 20·6 ±7·4%). These results indicated that TCR‐γδ+ CD8⁺ T cells selectively and consistently localized in colorectal tumour tissue, similarly to normal intestinal epithelium.