Lymphokine-activated killer (LAK) cell phenomenon. IV. Lysis by LAK cell clones of fresh human tumor cells from autologous and multiple allogeneic tumors

Activated killer cells are generated by the incubation of peripheral blood mononuclear leukocytes (PBL) in the lymphokine interleukin 2 (IL-2). Unseparated populations of these lymphokine-activated killer (LAK) cells lyse a variety of fresh noncultured human tumor targets, but they do not kill normal PBL. This study analyzed the generation and lytic specificity of LAK cell clones. Of 49 (84%) clones isolated by limiting-dilution techniques from a whole population of LAK cells, 41 manifested significant LAK cell activity. LAK cell clones had varied cell surface phenotypes. Clones with high and intermediate LAK cell activity were Leu 2⁺3^-4⁺7^-DR⁺Tac⁺ and Leu 2^-3⁺4⁺7^-DR⁺Tac⁺, respectively. Single LAK cell clones lysed multiple fresh human tumor targets including autologous sarcoma, 5 allogeneic sarcomas, and a colon cancer in addition to the cultured cell line K562. Autologous PBL were not lysed. Tumor targets were each lysed by multiple LAK cell clones. Sixteen subclones were derived from 5 of these LAK cell clones. These subclones had 99% or greater probability of being derived from a single cell. These subclones also exhibited lysis of multiple tumor targets. These findings suggest the existence of a shared determinant, expressed by multiple human tumors, which is recognized in common by multiple LAK cell clones.