Interferon and host resistance to Rauscher virus-induced leukemia.

A random bred strain of mice (CD-1) was shown to develop resistance to Rauscher leukemia virus (RLV) as the animals matured. Resistant adult mice developed relatively high-serum levels of interferon (150 to 2,000 units per ml) in contrast to susceptible 21-day-old animals in which interferon levels were undetectable or low (less than 20 to 200 units per ml). A similar correlation between resistance and interferon levels was observed in comparisons between resistant CD-1 and susceptible BALB/c mice. The F(1) hybrids of CD-1 x BALB/c and BALB/c x CD-1 matings manifested an intermediate degree of susceptibility and interferon production. The difference in interferon production by CD-1 and BALB/c mice was specific for the RLV-host interaction, since both strains produced equal serum levels of interferon in response to Sindbis and Newcastle disease viruses. The mortality of CD-1 suckling mice infected with Rauscher leukemia virus was decreased by treatment with interferon. These data demonstrate an association between interferon production by the host and the observed relative resistance of the CD-1 strain of adult mice to the subsequent malignant transformation. This virus-host relationship provides an excellent model for further study of factors affecting the development of virus-induced leukemia.