Histopathology of Immune Polioencephalomyelitis in C58 Mice

Abstract

Immune polioencephalomyelitis (IPE) in C58 mice was induced by immunization with syngeneic malignant lymphocytes. Signs of disease occurred 9 to 15 days after immunization —impaired spreading reflex of the hind limbs, impaired grasp reflex of the hind legs, flaccid paralysis, and death in some animals. Histopathologic studies showed that no lesions occurred before day 6, were most severe by day 8, but did not intensify thereafter. Disease was confined to the gray matter of the cord and brain stem; demyelination was absent. The principal changes were infiltration with chronic inflammatory cells, microglial proliferation, and neuron destruction. The histopathologic features of IPE were compared with experimental allergic encephalomyelitis and the nonmetastatic central nervous system diseases associated with malignancy in man. Since multiple lines of evidence indicate that IPE is not viral in origin, possible pathogenetic immune mechanisms were discussed.