Analysis of peptide mimotopes ofBurkholderia pseudomalleiexopolysaccharide

Previously two capsule-specific monoclonal antibodies (4VA5 and 3VIE5) were identified as protective againstBurkholderia pseudomalleiin passive transfer experiments. Panning these antibodies against evolutionary phage libraries identified reactive peptides capable of inhibiting its parent monoclonal from binding toB. pseudomallei. Mice immunized with peptide conjugated to thyroglobulin developed serum antibodies capable of recognizing the immunizing peptide of which a subset recognized exopolysaccharide in the context of wholeB. pseudomalleicells. These serum antibodies recognized protease treatedB. pseudomalleibut notB. thailandensissuggesting that these peptides are mimotopes of theB. pseudomalleicapsular exopolysaccharide. In a murine model of acute melioidosis, immunization with the mimotope of the 4VA5 binding site extended the mean time to death to 8.00 days over the 2.18 days afforded by immunization with thyroglobulin alone. This mimotope may be of use in developing an antibody response againstB. pseudomalleiexopolysaccharide.