Lymphomas and immunological tolerance in the rat induced by murine leukemia viruses.

Several lines of Friend, Gross, and Rauscher virus-induced rat tumors were able to grow only in Friend, Gross, and Rauscher virus-tolerant rats that had received injections of each of these viruses at birth. When the tumors were transplanted into the virus-tolerant rats that had received injections of the other types of murine leukemia virus (MuLV), they grew initially and then regressed. Tumors did not grow in normal rats. The same is true in the methylcholanthrene-induced tumors that had been infected with MuLVs. It was deduced from these results that the transplantation antigen of tumor cells that were induced by infection with Friend, Gross, and Rauscher viruses may contain an antigen common to all three viruses and also an antigen that is individually specific, and that the host's immunological tolerance (induced by the neonatal injection of either Friend, Gross, or Rauscher virus) may consist of the tolerance common to all three viruses and, also, of the tolerance that is individually specific.