An immunohistological study of autoimmune encephalomyelitis and neuritis in the rabbit. Observations in the dorsal root ganglion using the freeze-dried paraffin-embedded tissue technique

Spontaneous chemiluminescence activity of peripheral blood cells during experimental allergic neuritis (EAN)

In 30 Lewis rats the time course of spontaneous monocyte and granulocyte chemiluminescence activity (CLA) during myelin-induced experimental allergic neuritis (EAN) was studied. CLA of blood and peritoneal cells, and clinical, histopathological and electrophysiological findings were compared with data from 14 animals immunized with complete Freund's adjuvant and ten normal Lewis rats. About 12 days post-immunization there was a significant (p less than 0.003) rise in monocyte, but not in granulocyte CLA in EAN animals. CLA correlated significantly (p less than 0.02) with infiltrate formation in nerve roots, preceding clinical or electrophysiological signs of disease by 1-2 days. There was no increase in peritoneal monocyte CLA, which was consistently higher than blood monocyte CLA (p less than 0.002).

Methysergide, a serotonin antagonist, does not inhibit the expression of autoimmune encephalomyelitis in the rabbit

In view of recent interest in the potential role of vasoactive amines in the expression of experimental autoimmune encephalomyelitis (EAE) and neuritis (EAN), we set out to determine the effect of slow-release methysergide, a serotonin antagonist, on the effector phase of EAE/EAN in rabbits immunized with homologous spinal cord in Freund's adjuvant. On day 6 post-immunization (p.i.), slow-release pellets of methysergide maleate were implanted subcutaneously in graded doses 0-400 mg. At the highest dose, blood concentrations of methysergide were approximately 90 ng/ml on day 8 p.i. falling to 20 ng/ml by day 16 p.i. However, even at the highest dose of methysergide, rabbits developed typical clinical and histological signs of EAE/EAN. It is concluded that serotonergic mechanisms do not play a critical role in the effector phase of EAE/EAN in the rabbit.

Role of endoneural cells in experimental allergic neuritis and characterisation of a resident phagocytic cell

Electrophysiological, clinical and histological techniques were used to monitor the time course of events related to experimental allergic neuritis (EAN) in 48 Lewis rats. The primary lesion was found to be paranodal demyelination without cellular infiltration. Endoneural phagocytes derive from hematogenous ED1+ED2- monocytes and possibly from resident ED1-ED2+ monocytic cells, not from Schwann cells and fibroblasts. We demonstrate a population of monocytic Ia-bearing, ED1-ED2+ spindle-shaped cells residing in normal peripheral nerve and provide evidence for their transformation into macrophages in the course of EAN.