The anti-tumor effect of in vitro tumor-stimulated autologous peripheral blood lymphocytes measured by the subrenal capsule assay.

Lymphokine-activated killer cells (LAK) are able to kill natural killer (NK)-resistant fresh bioptic tumor cells. We have tried to increase the antitumor activity of peripheral blood lymphocytes by the simultaneous stimulation with interleukin-2 and autologous tumor extract (TE). The influence of LAK cells and LAK cells stimulated with TE was compared in the subrenal capsule assay in nude mice. Experiments were performed with eight head and neck tumors following their surgical extirpation. The tumors were first grown in the renal capsule space while lymphocytes were being stimulated in vitro. Following this, the lymphocytes were injected into the growing tumors. The autologous TE-stimulated LAK cells were more effective in treating tumors than were the LAK cells. Tumors regressed in some cases so treated, a finding which was never observed with LAK cells alone.