Generation of lymphokine-activated killer cells in long-term cultures.

The induction of lymphokine-activated killer (LAK) cells with low levels of interleukin-2 (IL-2) was studied in long-term cultures with regard to the relationship between cytotoxicity and proliferation. Proliferation of LAK cells reduced their cytolytic activity, which was restored when proliferation stagnated. In order to explain this phenomenon, a competition between receptors of intermediate and high affinity for IL-2 is suggested. Whereas the former type of receptor mediates cytotoxicity, the second one seems to be responsible exclusively for proliferation of LAK cells.