Enhanced induction of tumor-specific Lyt-1+2- T cell-mediated protective immunity by in vivo administration of interleukin 1.

The present study deals with the effect of in vivo administration of interleukin 1 (IL 1) on the induction of tumor-specific immunity. Culture fluid supernatant (CFS) containing IL 1 was obtained by stimulating J774.1 cells with lipopolysaccharide. C3H/HeN mice were inoculated intradermally with viable syngeneic X5563 tumor cells, followed by five consecutive subcutaneous or intraperitoneal inoculations of IL 1-containing CFS. Lymph node and spleen cells from IL 1-CFS-treated or -untreated C3H/HeN mice 8 days after the tumor inoculation were tested for 1) cytotoxic T lymphocyte (CTL) responses as measured by subsequent in vitro sensitization with X5563 cells, 2) delayed-type hypersensitivity (DTH) responses as measured by utilizing a local adoptive transfer, and 3) tumor-neutralizing activity in a Winn assay. Lymph node cells or spleen cells from IL 1-CFS-treated X5563 tumor-bearing mice not only exhibited enhanced CTL and DTH responses, but also produced complete tumor neutralization, in contrast with cells from IL 1-CFS-untreated X5563 tumor-bearing mice. In vivo protective immunity augmented by IL 1-CFS was tumor-specific and Lyt-1+2- T cell-mediated. The molecules responsible for enhanced induction of tumor-specific immunity co-migrated with IL 1 activity on gel filtration. These results indicate that IL 1 has the potential to augment tumor-specific Lyt-1+2- T cell-mediated in vivo protective immunity in tumor-bearing hosts.