COMPLEMENT DEPLETION AFFECTS DEMYELINATION AND INFLAMMATION IN EXPERIMENTAL ALLERGIC NEURITIS

The effect of systemic complement depletion by cobra venom factor (CVF ) on experimental allergic neuritis (EAN) was studied in rats immunize d with variable amounts of bovine peripheral nerve myelin. Low-dose my elin EAN rats treated with CVF i.p. (n = 10) had lower clinical scores (0.3 +/- 0.7 vs. 1.1 +/- 1.1), less demyelination (0.4 +/- 0.8 vs. 1. 9 +/- 1.1) and inflammation (0.6 +/- 1.2 vs. 2 +/- 1) than EAN animals treated with i.p. saline (n = 10). Endoneurial infiltrates had fewer ED1-positive (phagocytic) macrophages (0.4 +/- 0.5 vs. 1.6 +/- 1.1) an d CD11bc-positive (expressing iC3b receptor or CR3) cells (1 +/- 0.8 v s. 2.5 +/- 0.8) (mean +/- S.D.) detected by immunocytochemistry. This effect was partially abrogated by immunizing animals with a higher dos e of myelin. Our studies suggest that complement may play a role in th e recruitment of macrophages into the endoneurium and in opsonizing my elin for phagocytosis.