Alien H-2 allospecificities in murine chemically-induced tumors.

Sera from C3H/HeHa mice immunized with syngeneic methylcholanthrene-induced sarcoma react with allogeneic thymus, lymphoma and leukemia cells. The presence on leukemia and lymphoma cells of H-2 specificities expressed on normal cells of other H-2 haplotypes from the one in which the tumor originates is described. It was observed that the reaction of antisera to H-2 specificities with lymphoma cells was blocked by anti-MCA sarcoma sera. The cross-reactivity between MC sarcomas, thymus, leukemia and lymphoma cells is considered to be due to antibodies against these "alien" allospecificities.