The generation of interleukin-2-dependent suppressor T-cells from patients with systemic metastasis of gastric carcinoma and the phenotypic characterization of the cells defined by monoclonal antibodies.

Suppressor cells, which might be activated in patients with gastric carcinoma, were successfully enriched by the use of interleukin-2 (IL-2) prepared from human tonsils and spleens. That is, peripheral blood lymphocytes cultured for 3 or 4 weeks with IL-2 strongly inhibited the patient's own lymphocyte-proliferative responses to alloantigen or phytohemagglutinin (PHA). Quantitative fluorescence measurement for immunologic analysis of phenotypic characterization of the cells was made on FACS-IV with monoclonal antibodies anti-Leu-1 anti-Leu-2a, anti-Leu-3a, anti-Leu-4, anti Leu-5, anti-Leu-7, and anti-HLA-DR and goat anti-human immunoglobulin (Ig). Functional suppressor T-cells expanded with IL-2 showed the following phenotype: Leu-1+ Leu-2a+, Leu-3a-, Leu-4+, Leu-5+, Leu-7-, HLA-DR+, human Ig-. The IL-2-dependent suppressor T-cells could be obtained only when the cells were derived from patients with systemic metastasis of gastric carcinoma. These findings suggest that generation of IL-2-dependent suppressor T-cells is the result of large tumor burdens; this may exert negative cellular control in the immune responses, thus inducing the status of the lower cell-mediated antitumor immunity, and may promote cancer progression in gastric cancer patients.