Study of the association of an O-specific polysaccharide from Pseudomonas fluorescens with antibodies

The O-specific polysaccharide has been isolated from the lipopolysaccharide-protein complex of Pseudomonas fluorescens by mild acid hydrolysis followed by gel chromatography of the carbohydrate fraction of Sephadex G-50. According to 13C NMR spectroscopy, the polysaccharide is constructed of regularly repeating trisaccharide units including three 6-deoxyhexose residues two of which are amino sugars. An investigation has been performed of the interaction of the polysaccharide with specific antibodies and univalent Fab fragments of the antibodies. For the isolation of the antibodies and Fab fragments and their fractionation with respect to affinity we used an immunosorbent based on the polysaccharide bound to Sepharose 4B. It was established that antibodies to the polysaccharide were heterogeneous to some extent in relation to their affinity, and their interaction with polysaccharide had a cooperative nature