Abstract
A considerable amount of research has been reported on LAK adoptive immunotherapy (LAK AIT). In order to evaluate the effect of LAK cells and interleukin-2 (IL-2), most investigators have been using highly-immunogenic tumors and showed therapeutic benefit in the treatment of these tumors.
But many of human neoplasms are usually said to be nonimmunogenic. So both highly-immunogenic tumors and nonimmunogenic tumors were used, and the difference of the effect of IL-2 between these tumors were studied in our in vitro and in vivo experiments. The effects of IL-2 against highly-immunogenic and nonimmunogenic tumors were checked by in vitro cytotoxicity assays, and it was shown that IL-2 increased the cytolytic activity against both of these tumors. These activations are thought to be due to elevation of nonspecific immunity by IL-2.
Against highly-immunogenic tumors, if spleen cells immunized with highly-immunogenic tumors were used for induction of LAK cells, the cytolytic capacity was higher than that of not immunized spleen cells. In the case of LAK AIT models against highly-immunogenic tumor bearing mice, the most effective group was the group using LAK cells induced from immunized spleen cells. This fact showed that IL-2 elevated LAK activity and CTL, so using immunized cells was the most effective case.
In the case of nonimmunogenic tumor, activated specific immunity was unable to be detected. But nonspecific immunity was increased and therapeutic benefit was also signi-ficantly obtained against nonimmunogenic tumors in both in vitro and in vivo assays.
According to these results, LAK AIT is considered to be useful against human cancer which is thought to be nonimmunogenic.
