Partial suppression of Theiler's virus-induced demyelination in vivo by administration of monoclonal antibodies to immune-response gene products (Ia antigens).

In vivo administration of monoclonal antibody reactive with major histocompatibility complex-encoded Ia molecules (I-As) partially suppressed inflammation and demyelination in the spinal cord of SJL/J (H-2s) mice persistently infected with Theiler's murine encephalomyelitis virus. Demyelination was decreased if antibody was given at the time of virus inoculation or after inflammation had been established in the spinal cord. The decrease in demyelination was independent of isolation of infectious virus from the CNS or of serum titers of immunoglobulin to purified viral antigen. Thus, Theiler's virus-induced demyelination is mediated, in part, by immune cells that carry Ia class II molecules.