The effects of syngeneic soluble tumor membrane extract on concomitant spleen cell immunity and spontaneous metastases

Abstract

The effects of a soluble tumor KCl extract, containing membrane antigen on spontaneous metastases and spleen cell immunity were studied in a syngeneic C57BL/6J murine sarcoma model. The extract was shown to be antigenically distinct from normal tissue by tumor immunization rejection experiments. Tumor soluble extract (SE) was administered daily during the growth of a murine sarcoma. The afferent and efferent arc of immunity were monitored by proliferative index (PI) and in vitro cytotoxicity of spleen cells, as well as the incidence of metastases. PI was significantly activated in the group receiving sarcoma SE as compared to the two control groups receiving muscle SE or saline P < 0.05. However, in vitro cytotoxicity was significantly depressed on Days 7 and 14 ( P < 0.05) of tumor growth in the mice receiving sarcoma SE. The incidence of metastases was significantly increased to 70% in the sarcoma SE group as compared to the incidence in the control groups of 50% P < 0.05. This data supports the hypothesis that release of soluble antigen membrane components by growing tumor facilitates the growth of metastases in this model.