Inhibition of Binding of Hamster Antibody to Myelin Basic Protein by a Synthetic Triproline-Containing Peptide from JC Virus T-Antigen

Abstract

Antisera raised against porcine myelin basic protein (MBP) in Syrian hamsters were assayed by an ELISA method. The specificity of a hightitered antiserum was probed with synthetic peptides representing (a) a hexapeptide and a decapeptide of the JC virus (JCV) large T-antigen C-terminus which is homologous to the MBP triproline region, (b) a decapeptide from MBP which is encephalitogenic in guinea pigs, and (c) peptides unrelated to MBP, i.e, substance P and poly-L-lysine. In an ELISA inhibition assay, preincubation of the hamster antiserum to MBP with either the JCV T-antigen C-terminal decapeptide or the encephalitogenic determinant inhibited binding activity in a dose-dependent manner. In contrast, the T-antigen C-terminal hexapeptide, substance P, and poly-L-lysine were not inhibitory. These results suggest that the triproline region of MBP can be immunogenic in hamsters, and support the concept that a conformation of the MBP triproline region is shared with certain of its viral homologues. In an effort to detect similar cross-reactive specificities in hamster antisera to JCV T-antigen, sera of 50 hamsters bearing subcutaneous tumors induced by JCV-transformed glial cells were tested for ability to bind to MBP in the ELISA assay. While significant increases in response compared to prebleed levels were observed in about one-fourth of the sera, some of them showed similar increases in binding to other basic proteins such as histones, and the binding to MBP was not inhibited by the triproline-containing decapeptide.