Analysis of multiple antigenic determinants of the bovine conglutinin molecule using different synthetic peptides.

Twenty-three overlapping peptides corresponding to the complete amino acid sequence of the bovine conglutinin molecule were synthesized on the basis of the sequence data to analyze antigenic determinants. Of the synthetic peptides tested, peptides 31-50, 166-185, and 241-260 were highly reactive with rabbit antibodies against native conglutinin, whereas peptides 1-20, 16-35, 31-50, 76-95, 136-155, 151-170, 181-200, 271-290, 301-320, and 316-335 were less reactive with the antibodies. Peptides 16-35, 31-50, 46-65, 76-95, 136-155, 151-170, 181-200, 271-290, 301-320, and 316-335 were less reactive with the antibodies. Peptides 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 conglutinin to mannan. On the other hand, all of these synthetic peptides elicited rabbit antibodies reactive with native conglutinin. Antibodies to peptide 241-260 showed the highest reactivity with native conglutinin. Of these anti-peptide antibodies, however, only antibodies to synthetic peptide 46-65 inhibited effectively the binding of conglutinin to mannan. Antibodies to the remaining peptides failed to block the binding at the highest concentrations tested. These results suggest that the multiple antigenic determinants associated with both ligand binding and immunogenicity may be located on the conglutinin molecule and that the predominant antigenic determinant responsible for binding saccharides may be located in the vicinity of the region 46-65.