Adoptively transferred chronic relapsing experimental autoimmune encephalomyelitis in the mouse. Neuropathologic analysis.

The fine structure is described of a new model of chronic relapsing experimental allergic encephalomyelitis in the SJL/J mouse induced by the single adoptive transfer of myelin basic protein-sensitized lymph node cells. The neuropathology of the condition compared favorably with that seen in other species, and unlike a similar disease in the same strain of mouse induced by active sensitization with a central nervous system emulsion, there was little axonal pathology. Typical of mouse experimental allergic encephalomyelitis was the consistent involvement of polymorphonuclear leukocytes and extravasated material in central nervous system lesions. Remissions showed remyelination to be the major feature in the central nervous system, and clinical relapses were matched pathologically by fresh waves of inflammation and demyelination. Unusually large, apparently organized, sinusoidal collections of lymphoid cells (some of them displaying evidence of proliferation) were seen in the periventricular areas of the brain. The ability to induce chronic relapsing demyelination by passive means indicates that an antigen depot is not necessary for the perpetuation of the disease which is possibly transferred by memory cells in the inoculum. This model has virtue in its applicability to the pathogenesis and therapy of multiple sclerosis.