Bacterial surface polysaccharides are versatile structures that provide specificity to the behavior and interactions of a given bacterial strain. One surface polysaccharide displayed on the organism Bacteroides fragilis, Capsular Polysaccharide A, has been implicated as a potential therapeutic for autoimmune disorders. This polymer is composed of repeating units of the tetrasaccharide 2-acetamido-4-amino-2,4,6-trideoxygalactopyranose (AATGal), 4,6-O-pyruvate-galactopyranose (PyrGal