A simple and effective method for cancer immunotherapy by inactivated allogeneic leukocytes infusion

Allogeneic mixed leukocytes reaction has been reported to activate vast numbers of T lymphocytes and produce large amounts of type 1 cytokines that are linked to an initiation of antitumor immunity. Using poor immunogeneic B16-F10 and Lewis lung carcinoma (LLC) tumor model, we evaluated the effects of inactivated allogeneic leukocytes infusion (ALI) on the generation of antitumor immune response, as well as its effect on the primary and metastatic tumor. Allogeneic response promoted the generation of both specific and nonspecific antitumor immunity in an in vitro mixed lymphocytes-tumor cell culture system. Introveinous infusion of mitotically inactivated allogeneic leukocytes resulted in increased type-1 cytokines (including IL-2 and IFN-gamma) release, proliferation of various lymphocyte subsets, and generation of both specific and nonspecific antitumor immune response. As a result of such immune response, ALI caused a delayed tumor growth and a prolonged survival in established B16-F10 melanoma model. In LLC pulmonary spontaneous metastases model, ALI treatment significantly reduced postoperative tumor metastasis as the lung weights were far smaller than control group (0.16 vs. 0.34 g). Furthermore, after primary tumor resection and ALI treatment, 62.5% mice obtained long-term survival (>120 days) and there were no tumor growths in these mice when they were rechallenged with the same tumor. These experiments demonstrate that inactivated ALI could activate innate and adoptive antitumor immune response. It would be a simple, effective and secured method for cancer immunotherapy.