An immunochemical analysis of a myelin basic protein serum factor: cross reactivity with residues 69-71 of the rabbit encephalitogenic sequence 65-74 of myelin basic protein.
A partially purified myelin basic protein serum factor (MBP-SF), cross-reactive with residues 65-74 (TTHYGSLPQK) of myelin basic protein, has been employed in an immunochemical study to identify the nature of the cross-reacting determinant more precisely. To probe the structural requirements of this determinant, Scatchard inhibition analyses and competitive peptide inhibition radioimmunoassays were employed with a series of peptide analogs of the 65-74 region and with three different reagent antisera: a rabbit anti-rat myelin antiserum (#My05) and two antisera, one rabbit (#162) and one chicken (#66), raised against synthetic peptide S24 (TTHYGSLPQKG). Scatchard inhibition analyses with MBP-SF revealed specific inhibition of binding of 125I-S24 to #162 and #My05, but not to #66. Further delineation of the structural requirements of the cross-reactive determinant, employing a liquid-phase radioimmunoassay, revealed a unique reactivity pattern for the chicken anti-S24 antiserum which, unlike #162 and #My05, did not cross-react under high-affinity conditions with synthetic peptide S20 (GSLPQK, representing the C-terminal half of S24). This, in concert with the Scatchard data, is suggestive of the presence of a cross-reactive determinant centered around residues 69-71 of MBP.
D000818:Animals; D001667:Binding, Competitive; D002645:Chickens; D003429:Cross Reactions; D000939:Epitopes / Q000032:analysis*; D007106:Immune Sera; D007700:Kinetics; D004676:Myelin Basic Protein / Q000097:blood* / Q000276:immunology; D010446:Peptide Fragments / Q000097:blood* / Q000276:immunology; D011817:Rabbits; D011863:Radioimmunoassay; D051381:Rats
D000939:Epitopes; D007106:Immune Sera; D004676:Myelin Basic Protein; D010446:Peptide Fragments; C041031:myelin basic protein 45-89