Studies on Specific Transplantation Resistance to Polyoma-Virus-Induced Tumors. III. Transplantation Resistance to Genetically Compatible Polyoma Tumors Induced by Polyoma Tumor Homografts<xref ref-type="fn" rid="FN2">2</xref>

Abstract

Homografts of 16 different polyoma tumors induced resistance to subsequent isografting of 12 different polyoma tumors. No resistance was detected in animals similarly pretreated with 16 nonpolyoma tumors. One exceptional methylcholanthrene-induced sarcoma, previously shown to be susceptible to the polyoma-virus-induced resistance, was weakly susceptible also to the resistance induced by polyoma homografts and itself induced a weak resistance to polyoma tumor isografts. Seven other nonpolyoma tumors tested grew equally well in all recipient categories. Only a resistance demonstrated in mice developing no antiviral antibodies was regarded as an indication of immunity induced by the tumor cells. Polyoma tumor cells X-irradiated with 8000 r failed to induce the resistance. Eight polyoma tumor lines grew out in preirradiated recipients after inoculation of 2 to 50 times lower cell doses than in irradiated animals, while 3 spontaneous mammary carcinomas grew equally well in the 2 groups.