Suppression by sorted CD8+CD11b− cells from T-cell growth factor-activated peripheral blood lymphocytes on cytolytic activity against tumour in patients with gastric carcinoma

Abstract

To confirm the phenotypic characteristics of lymphokine-activated suppressor (LAS)effector cells, we isolated CD8⁺CD11b⁻ and CD8⁻CD11b⁻ cells from T-cell growth factor (TCGF)-activated peripheral blood lymphocytes (PBL) in 7 patients with gastric carcinoma (4 non-resectable and 3 resectable carcinoma) and 3 healthy controls. Sorted CD8⁺CD11b⁻ cells from 3 of the patients with non-resectable carcinoma and from 1 of the patients with resectable carcinoma showed LAS cell activity. However, the LAS cell activity could not be observed in CD8⁺CD11b⁻ cells from healthy controls. In addition, a sorted CD8⁻CD11b⁻ subset of cells from both cancer patients and control did not express any suppressive activity. These facts clearly show that the cell populations responsible for suppression of cell-mediated antitumour immunity reside within CD8⁺CD11b⁻ T-cells, at least in patients with advanced carcinoma.