Lymphocytes infiltrating normal human lung and lung carcinomas rarely express γδ T cell antigen receptors

Abstract

SUMMARY It has been suggested that T lymphocytes expressing γδ T cell receptors (TCR) could play an important role in the defence of epithelia against infection and neoplastic transformation, but the potential for γδ T lymphocytes to serve these functions in human respiratory epithelium has received little attention. In this study, we used immunohistochemical techniques and specific monoclonal antibodies to characterize the number and distribution of T lymphocytes expressing αβ und γδ TCR in normal human lung and in lung carcinomas. T lymphocytes present in normal bronchi and alveolar parenchyma were predominantly of the αβ TCR phenotype. whereas γδ T lymphocytes represented only 1·1 ±0·7% and 1·3±0·5% of total CD3+ lymphocytes respectively. An important lymphocytic infiltration was noted in the stroma of all primary lung carcinomas examined, and some T lymphocytes were also present infiltrating between tumour cells. These T lymphocytes were almost entirely αβ T cells and only rare γδ T ceils were found, regardless of the histologic type of carcinoma (0·8±0·1% of CD3+ T cells). This study demonstrates that T cells present in normal bronchi and lung parenchyma and those infiltrating primary lung carcinomas express predominantly αβ TCR. These findings do not support the conclusion that γδ T lymphocytes play an important role cither in the defence of human lung epithelia or in immune responses directed against primary lung carcinomas.