The possible use of spleen cells for the adoptive immunotherapy of cancer patients.

The possible use of spleen-derived mononuclear cells (SPMC) for the intentional and economical adoptive immunotherapy of cancer patients was studied. SPMC were obtained from spleens resected surgically from patients with gastric cancer or idiopathic thrombocytopenic purpura (ITP). When SPMC were cultured in recombinant interleukin 2 (rIL2), SPMC, in the form of interleukin-activated killer spleen cells (IL-SP) proliferated in six of eight cases. CD8+ lymphocytes were the major expanding cell population in most SPMC cultures and IL-SP showed a significant cytolytic activity against cultured tumor cells during cell proliferation. When cultured with a streptococcal preparation, OK-432, for 24 to 48 h, SPMC showed cytotoxic activity against tumor cells and were expressed as OK-432 activated killer spleen cells (OK-SP). The effects of supernatants from IL-SP and OK-SP on tumor cell growth were also examined. The supernatants from IL-SP and OK-SP significantly inhibited cell growth in 3 and 10 out of 11 cases, respectively, while those from OK-SP showed higher growth inhibitory activity than those from IL-SP. The results of this study indicate the potential of SPMC as effector cells for the adoptive immunotherapy of cancer patients.