Down-regulation of LAK cell-mediated cytotoxicity: cancer and ageing

A comparative study was made of the generation of lymphokine-activated killer (LAK) cells in patients with melanoma and healthy donors of different age groups. Significant reduction of effector cell cytotoxicity in patients following 72 h culture with 1,000 U/ml or recombinant IL-2 (rIL-2) as well as a decreased ability to generate LAK cells in elderly individuals were shown to be correlated with suppressor cell activation in rIL-2 stimulated cell population. Suppressor effect depends on monocytes and T-lymphocytes: partial abolition of suppression in LAK cells was observed following removal of adherent cells or treatment with OKT8 monoclonal antibodies and complement.