Lymphokine-activated Killer (LAK) Activity Against Autologous Malignant Tumors of the Skin

Abstract

When peripheral blood mononuclear cells (PBMC) cultured with interleukin 2 (IL-2) develop the ability to lyse fresh tumor cells, such activity is referred to as lymphokine-activated killer (LAK) activity. In this paper, we examined LAK activity against the autologous skin tumors, malignant melanoma (MM), squamous cell carcinoma (SCC), and basal cell epithelioma (BCE), which have distinct clinical characteristics. Similar levels of LAK activity against Daudi 1A4, an NK resistant cell line were significantly obtained from all cancer patients. However, different levels of LAK activity against autologous tumor cells were found from three kinds of cancer patients using mixtures of autologous tumors and LAK. The levels of cytotoxicity were 29.8 +/- 7.0% in five MM, 15.9 +/- 4.9% in seven SCC, and 4.0 +/- 2.3% in five BCE patients at an effector/target ratio of 50/1. Allogeneic MM targets were lysed by LAK from all three types of cancer patients at similar levels, implying that LAK is not restricted to major histocompatibility complex (MHC) antigens. These results indicate that the levels of autologous LAK activity were significantly associated with the magnitude of clinical malignancy of the tumor targets, and suggested the selective lysis of tumor targets by LAK. NK activity of cancer patients bearing tumors was also examined prior to therapy. The levels of NK activity observed in MM patients were considerably lower than those in two other cancer patients.