Acute and subacute demyelination induced by mouse hepatitis virus strain A59 in C3H mice.

Mouse hepatitis virus (MHV, strain A-59), a coronavirus, induced acute and subacute demyelinating disease in the central nervous system of weanling C3H mice that were reported to be genetically resistant to MHV. Subtle clinical signs developed in greater than 90% of animals 5-7 days after intracerebral inoculation of 25 PFU, and foci of demyelination were detected from 1 to 4 weeks postinoculation (p.i.) by histopathology and immunolabeling with antibody directed against myelin basic protein. Infectious virus could be isolated only during the first 10 days p.i., but viral antigens persisted in the cytoplasm of oligodendrocytes in the demyelinating lesions for up to 4 weeks p.i. Serum antibody titers against MHV-A59 rose by 2 weeks p.i. and persisted at high levels for months. This infection of genetically "resistant" animals by a normally hepatotropic strain of MHV can serve as a highly reproducible model for the study of acute and subacute demyelination by a coronavirus.