Enhancement of encephalomyeloradiculitis in mice sensitized with spinal cord tissue and infected with lactate dehydrogenase-elevating virus.

C57BR/cdJ mice develop encephalomyeloradiculitis following peripheral inoculation of the C strain of lactate dehydrogenase-elevating virus (LDV-C). We investigated the effect of subcutaneous administration of syngeneic spinal cord homogenate mixed with phosphate buffered saline or emulsified in complete or incomplete Freund's adjuvant 1 week before or after inoculation of LDV-C on the incidence and severity of central nervous system lesions. C57BR/cdJ mice developed an acute histological allergic encephalomyelitis when given 2 weekly sensitizing injections of homogenate in complete Freund's adjuvant. When peripheral inoculation of LDV-C was substituted for one of the two sensitizing injections, a higher percentage of mice developed lesions, and the lesions were more severe and persisted for much longer periods of time. This same lesion-enhancing effect was not observed if the mice were sensitized with homogenate suspended in buffer or emulsified in incomplete Freund's adjuvant. Interestingly, mice sensitized with complete Freund's adjuvant alone before or after infection with LDV-C also developed intense central nervous system lesions, suggesting that the mycobacterial component of the adjuvant was the critical element in enhancing the lesions.