ANALYSIS OF MULTIPLE ANTIGENIC DETERMINANTS OF THE BOVINE CONGLUTININMOLECULE USING DIFFERENT SYNTHETIC PEPTIDES

Twenty-three overlapping peptides corresponding to the complete amino acid sequence of the bovine conglutinin molecule were synthesized on t he basis of the sequence data to analyze antigenic determinants. Of th e synthetic peptides tested, peptides 31-50, 166-185, and 241-260 were highly reactive with rabbit antibodies against native conglutinin, wh ereas peptides 1-20, 16-35, 31-50, 76-95, 136-155, 151-170, 181-200, 2 71-290, 301-320, and 316-335 were less reactive with the antibodies. P eptides 16-35, 31-50, 46-65, 76-95, 91-110, 106-125, 151-170, 166-185, 211-230, 226-245, and 286-305 inhibited the binding of native conglut inin to mannan. On the other hand, all of these synthetic peptides eli cited rabbit antibodies reactive with native conglutinin. Antibodies t o peptide 241-260 showed the highest reactivity with native conglutini n. Of these anti-peptide antibodies, however, only antibodies to synth etic peptide 46-65 inhibited effectively the binding of conglutinin to mannan. Antibodies to the remaining peptides failed to block the bind ing at the highest concentrations tested. These results suggest that t he multiple antigenic determinants associated with both ligand binding and immunogenicity may be located on the conglutinin molecule and tha t the predominant antigenic determinant responsible for binding saccha rides may be located in the vicinity of the region 46-65.