Mammary tumor virus oncogenesis and tumor immunogenicity in three sublines of the C3H mouse

Mammary tumorigenesis and mammary tumor transplantation immunogenicity have been studied and compared in three sublines of the C3H strain: in standard mammary tumor virus (MTV-S)-infected C3H/He mice; in MTV-S-infected C3H/Ki mice; and in MTV-S-free C3Hf/He mice. The age at the appearance of the first tumor, the growth rate of the tumors in their first transplant generation, and the immunogenicity of each tumor in syngeneic female recipients have been determined for the first tumor to appear in each of 25 breeding females from each of the three sublines. Two statistically significant trends were evident among the tumor characteristics compared in the three sublines: (a) an early appearance of tumors was related to the presence of the MTV-S. The genetically dissimilar sublines, C3H/He and C3H/Ki, both infected with the MTV-S, developed mammary tumors at an average age of about 10 months, 11 months before MTV-S-free C3Hf/He mice; (b) the tumor characteristics of immunogenicity and growth stimulation were related to host genetic factors. The genetically similar sublines, C3H/He and C3Hf/He, developed similar proportions of immunogenic and growth-stimulating mammary tumors; the genetically divergent C3H/Ki subline developed tumors that were not immunogenic and tended to be strongly growth stimulating.