Relationship of interferon synthesis and the resistance of mice infected with street rabies virus.

Genetically homogeneous and heterogeneous mouse populations were tested for resistance to experimental street rabies virus infection and their ability to synthesize interferon (IFN) during the infection. The genetically heterogenous HI mouse population was highly resistant (12% mortality), and the genetically homogeneous BALB/c and C3H mice as well as the genetically heterogeneous Sw and LI mouse populations were susceptible (60 to 71% mortality). The genetically homogeneous A/J mice were highly susceptible (85% mortality) to experimental street rabies infection. The ability of these mice to synthesize IFN as measured in serum 4 days after the infection was directly related to the degree of resistance, with the highly resistant HI mice showing large amounts of IFN (850 U/ml), and the susceptible mice showing low amounts of IFN (50 to 280 U/ml). IFN induced within the central nervous system and measured in brain homogenates during infection was not correlated with resistance. The present data suggest that high levels of IFN occurring in serum early during infection with street rabies virus contribute to the resistance of these mice.