Abstract
The autologous transplantation of methylcholanthrene (MCA)-induced sarcomas in non-inbred rats, which had been immunized intensively with various allogeneic tumors, was inhibited in 33 out of 65 cases tested. The differ-ence of tissues from which allogeneic tumors originated did not influence the inhibitory effect on autotransplantation. In 10 out of 69 non-immunized controls, the autotransplantation of MCA-induced sarcomas proved to be negative. In addition, remarkable lymphoid cell infiltration was demonstrated in most of tumors induced by MCA in non-inbred rats which were immunized intensively with allogeneic tumors. The autologous transplantation was more markedly inhibited in the tumor infiltrated with massive lymphoid cells than in that not infiltrated.
