Further studies on cross-immunity among syngeneic tumors of mice.

Cross-immunity among allogeneic tumors in rats immunized with gamma-irradiated ascites tumors.

“…On the other hand, in a study employing the solid type of tumors, it was difficult to demonstrate the common antigenicity in animals pretreated with gammairradiated solid tumors (Usubuchi et al 1975). As compared with the present study, the solid tumors seem to have a low resistance to irradiation, and, therefore, their common antigenicity may be destroyed easily.…”

Cross-immunity between syngeneic tumors in mice immunized with gamma-irradiated ascites tumors.

“…This comment, however, may be excluded because of our previous observation in the experiment in which cross-immunity among nonviral MAC-induced sarcomas in C3H/He mice could be detected by using viable tumor cells (Usubuchi et al 1975). And so, there may be no basis of viral interac tion by which cross-immunity is expressed.…”

“…In comparative experiments on the immunizing effect of non-irradiated and irradiated tumor cells using MCA-induced solid sarcomas in C3H/He mice, Usubuchi et al (1975) stated that common antigenicity was revealed by using nonirradiated viable tumor cells whereas irradiated tumor cells did not show it. Those findings indicated that the irradiation extinguished common antigen(s) leaving only unique antigen(s), so that the growth of challenge tumors was not inhibited in animals pretreated with the other irradiated tumor, while the growth of challenge tumors was inhibited in animals pretreated with the same irradiated tumor.…”

“…On the other hand, other investigators usually used irradiated tumor cells alone as immunogen. On these occasions, the effect of immunogenicity of nonirradiated and irradiated tumor cells was compared by using solid MCA-induced sarcomas in C3H/He mice (Usubuchi et al 1975). The data revealed crossimmunity among tumors when non-irradiated tumor cells were used as immunizing cells, but did not show it when irradiated tumor cells were employed.…”

Effect of Immunization with an Allogeneic Tumor on the Growth of Primary Methylcholanthrene-Induced Sarcomas in Rats

“…Sato and Mitsui (1975) described the risk of transplantation in the case of active im munotherapy using intact tumor cells. In the experiments of syngeneic transplantation of MCA-induced sarcomas in OH/He mice, Usubuchi et al (1975) were able to inhibit tumor growth by using living tumor cells following repeated immunization with 6OCo-irradiated tumor cells. As the transplantation of allogeneic tumor is far more curable than that of syngeneic tumor, the immunotherapy can be applied without danger to the patient by using intact living tumor cells following repeated immunization with irradiated allogeneic human cancer cells.…”