Abstract
Host resistance against the transplantation of allogeneic tumors, such as Yoshida sarcoma, Hirosaki sarcoma, Takeda sarcoma or Ascites Hepatoma 7974, occurs in rats immunized with allogeneic Usubuchi sarcoma. It is considered that allogeneic tumors of rats have common antigens and this antigenicity causes cross-immunity among various allogeneic tumors. The cross-immunity induced by the common antigens was usually weak as compared with the immunity demonstrated in the re-transplantation of the same tumor. In such a state, the antigenicity peculiar to the host, in which each tumor originated, acts effectively in addition to the common antigens.
