Human T cells specifically activated against autologous malignant melanoma

Lymphocytes from ten patients with melanoma were specifically stimulated in vitro with autologous melanoma cells and expanded in interleukin 2. Significant lysis of autologous melanoma cells was demonstrated in T cells derived from six of these patients. The mean percent of lysis of autologous tumor cells at an effector-target ratio of 20:1 was 46% among these six patients. The T cells derived from two patients developed specificity in lysing autologous melanoma cells. In both cases, specificity was enhanced by the in vitro stimulation with autologous tumor cells. Restimulation with autologous melanoma cells was associated with increasing specificity over time. Whether derived from peripheral blood lymphocytes or from lymph node cells, T cells from one patient lysed fresh autologous melanoma cells more potently than K562, allogeneic melanoma cells, and nonmelanoma cells. On day 38, at an effector-target ratio of 10:1, cell lysis of K562, an osteosarcoma, a pancreatic cancer, and three allogeneic melanomas was 3%, 4%, 7%, 8%, 7%, and 2%, respectively, while lysis of autologous melanoma cells was 47%. Specificity was maintained beyond day 60. The T cells could be expanded over 50-fold within one month.