CYTOTOXIC ACTIVITY OF TUMOR INFILTRATING LYMPHOCYTES AND MACROPHAGES IN GASTRIC CANCER

Abstract

In order to study the defence mechanism against cancer cells in patients with malignancy, tumor-infiltrated lymphocytes (TIL) and macrophages isolated from 18 operated stomachs with gastric cancer were tested for natural killing (NK) or natural cytotoxic (NC) activity and antibody dependent cellmediated cytotoxic (ADCC) activity against two target cells: K562 cells and antibody coated-P815 cells. The resected stomachs were deviled into 3 parts: cancerous, surrounding and normal area, and lymphocytes and macrophages were isolated. The obtained results were as follows: (1) TIL showed higher NK activity in the surrounding area than in other areas. There was no significant difference in the ADCC activities of TIL in each areas. (2) T cells were predominant over B cells in TIL, and null cells and Tγ cells showed higher percent. Especially, Tγ cell percent was higher in the surrounding area. (3) Tumor infiltrated macrophages showed relatively high NC and ADCC ativities, but there was no significant difference among the areas. (4) NK activity of TIL in patients with favorable prognosis was significantly higher than that in patients with unfavorable prognosis. NC activity of the tumor infiltrated macrophages showed the similar tendency.