In vivo demyelination induced by intraneural injection of anti-galactocerebroside serum: a morphologic study

Intraneural injection of rabbit anti-galactocerebroside (anti-GC) serum produced focaldemyelinative lesions in rat sciatic nerves. Recipient rats developed a sensory motordeficit of the toes and feet on the side injected with anti-GC serum. Schwann cellabnormalities in recipient nerves were apparent by 20 minutes, followed by myelinsplitting and vesiculation over the next 8 hours. Macrophages first appeared in moder-ate numbers by 15 hours, and degraded myelin was completely phagocvtized by 5 days.An acute inflammatory reaction consisting of endoneurial edema, polymorphonuclearcell infiltration, and fibrin extravasation also was prominent. In vivo demyelinativeactivity of rabbit anti-GC serums was removed by pre-incubation with GC or central orperipheral nervous system myelin and was also lost when the serums were heated at 56C for 30 minutes and injected into nerves of rats previously injected with cobra venomfactor. Anti-GC antibodies are present in the serum of rabbits with experimentalallergic neuritis (WNV-EAN) and encephalomyelitis (WM-EAE) produced, respectively,by immunization with whole peripheral nerve or brain white matter and may play arole in the pathogenesis of demyelination in GC-induced EAN, WN-EAN, or WM-EAE.