Structural features of polysaccharides that induce intra-abdominal abscesses.

The capsular polysaccharide complex from Bacteroides fragilis promotes the formation of intra-abdominal abscesses--a pathologic host response to infecting microorganisms. This complex consists of two distinct polysaccharides, each with repeating units that have positively charged amino groups and negatively charged carboxyl or phosphate groups. Analysis of these polysaccharides as well as other charged carbohydrates before and after chemical modification revealed that these oppositely charged groups are required for the induction of intra-abdominal abscesses in a rat model.