Acute necrotizing inflammatory disease after intracerebral injection of LCM virus is largely dependent on the host immune response to the virus and is controlled, in part, by a dominant gene which is closely linked to the H-2 locus. The F(1) hybrid (H-2(q/k)) from mating a susceptible SWR/J mouse (H-2(q/q)) to a resistant C3H/HeJ mouse (H-2(k/k)) is susceptible to LCM virus disease. When such hybrids (H-2(q/k)) are backcrossed to susceptible parents (H-2(q/q)), all F(2) offspring (H-2(q/q), H-2(q/k)) are highly susceptible. In contrast, hybrid (H-2(q/k)) backcross to resistant parents (H-2(k/k)) results in half of the F(2) offspring being susceptible (H-2(q/k)) while the other half are resistant (H-2(k/k)). Similarly, in congenic H-2(q/q) and H-2(k/k) mice, H-2(q/q) mice are relatively susceptible to acute LCM disease, whereas H-2(k/k) are resistant.