ABSTRACT
We previously demonstrated the cytotoxicity of human LAK cells to solid tumors in vitro. The work we reported here investigated the mechanisms involved in killing of solid tumor cells by LAK cells. It was shown that the cytotoxicity of LAK cells was mediated by some factors secreted by LAK cells and effects of direct contact with targets. Following lysis, the nucli of targets were destroyed and fragments of DNA were released into the medium. The cytotoxicity of LAK cells, under some circumtances, was of a positive correlation to the proliferation of themselves.
ABSTRACT
We have investigated, in both cases of normal individuals and tumor- bearing patients, the cytotoxic activity of lymphokine- activated killer (LAK) cells to cultured cell lines or fresh solid tumor cells with a 4- hour chromium 51 (~(51)Cr) - release assay. The LAK cells were generated by incubating peripheral blood mononuclear (PBM) cells in vitro with recombinant interleukin 2 (rIL- 2)or partially purified interleukin2(PPIL- 2). Our results indicated that these two sources of L \K cells were cytotoxic to either K562, NK- sensitive or Daudi, NK resistant tumor cell lines. These two kinds of LAK cells could also kill a broad rang of fresh solid tumor cells, suggesting that these cells be indeed LAK cells. Furthermore, the results demonstreated that some fresh solid tumor cells were resistant to LAK cell killing to some extent as they showed different sensitivities to LAK cytotoxicity.