Antigenic properties of peptidic mimics for epitopes of the lipopolysaccharide from Brucella

The lipopolysaccharide (LPS) is up to now the only identified major virulen ce determinant of Brucella. This bacterium is responsible for brucellosis i n animals and for Malta fever in humans. Several monoclonal antibodies (mAb s) directed against various LPS epitopes have been characterized. Two mAbs, named A15-6B3 and B66-2C8, directed against distinct LPS epitopes have bee n used to select peptides from 11 phage display libraries. The sequences of the selected peptides contain an overrepresentation of either proline or t ryptophan residues when selected with either A15-6B3 or B66-2C8 mAbs, respe ctively. For the best binding peptides, competition with LPS for the bindin g to the mAb is detected, which suggests that the peptides bind to the para tope of the mAb. The phages selected from the libraries were used to immuni se mice, and a weak antibody response directed against LPS has been observe d. These data suggest that a subset of the selected peptides are mimotopes of the LPS epitopes. (C) 1999 Academic Press.