Studies on the Cellular Immunity and Enhancing Factors in MCA-induced Sarcoma in CsH/HeN Mice

Abstract

Colony inhibition assay in-vitro using the peritoneal cells as the effector cells and in-vivo transplantation method were adopted to demonstrate cellular and humoral immunity to MCAinduced sarcoma in tumor-bearing and in mice immunized with various doses of MCA tumor antigen. Transplantation of:;MCA sarcoma III normal immune strain of tumor origin and III allogeneic mice revealed that some imrnunolocgial surveillance mechanism is operating normally. Peritoneal cells from immune mice consistently inhibited colony formation of plated target tumor cells in-vitro, and the confrontation of the peritoneal cells with tumor antigen or sera from mice carrying advanced tumors, before the treated peritoneal cells being added to plated target tumor cells, abrogated the antitumor activities of those cells. Peritoneal cells from mice bearing advanced tumors were found inactive in the inhibition of colony formation in-vitro and although the sera from the same mice enhanced dramatically the tumor ~graft establishment in-vivo, it was destructive on the plated tumor cells in-vitro. The doses of killed tumor cells on which the immunoprotection of the host against the same viable tumor cells was dependent were investigated with in-vivo challenge method and a narrow zone of tumor antigen dose for efficient protection was found to exist in the 5-weeks' schedule of immunization with one-week interval and via I.P. injections.