Identification of an encephalitogenic determinant of myelin proteolipid protein for the rabbit.

A late onset, demyelinating form of experimental allergic encephalomyelitis (EAE) was induced in New Zealand White rabbits following immunisation with a synthetic peptide representing the amino acid sequence 91-110 of bovine myelin proteolipid protein (PLP). Histologically, disease was associated with varying degrees of central nervous system (CNS) inflammation, which in six of seven animals was accompanied by axonal degeneration and secondary demyelination. Primary demyelination with axonal sparing was generally absent in this model of EAE. Immunohistochemical and immunoelectron microscopic analysis of CNS tissue indicate that B cell epitopes within this encephalitogenic PLP sequence are not exposed at the surface of the myelin sheath, but are sequestered within compact multilamellar myelin. Furthermore, no correlation was observed between the anti-PLP antibody titer induced by the peptide and either the clinical severity or histopathology of the disease. These observations suggest that the B cell response to epitopes within the PLP sequence 91-110 does not play a primary role in the immunopathogenesis of PLP-induced EAE.