Mouse strain-related differences in the biologic and immunologic responses to a murine sarcoma virus

Important differences were present in the biologic and immunologic responses of 4-week-old BALB/c, C3H, and (NZW X NZB)Fi (B/W) mice to a murine sarcoma virus (Gz-MSV) isolated from a B/Wmouse. Although the 3 strains rapidly developed large soft-tissue tumors at the virus inoculation site, thetumors regressed in C3H mice but grew progressively in BALB/c mice. These 2 strains showed excellentcorrelation among tumor regression, virus titers, and plasma levels of virus-neutralizing and cytotoxic antibodies. The biologic responses of B/W mice to the virus were complex and were not correlated with thehumoral immune responses. Tumors in B/W mice persisted for long periods, despite histologic evidence ofrejection and high levels of cytotoxic antibodies. Cellular immune responses to the tumor were relativelyweak in all 3 strains. B/W mice developed massive splenomegaly, with extensive inflammatory fibrosis andvascular proliferation replacing the normal architecture. The biologic responses of NZB and B/W mice toGz-MSV were similar. Splenectomy did not prevent the death of virus-inoculated BALB/c, NZB, andB/W mice but it prolonged the survival time of B/W mice.—J Natl Cancer Inst 50: 971-978, 1973.