Pasteurella piscicida grown in a glucose-rich medium produces a capsul
e that can be see under light and electron microscopy. The capsular po
lysaccharide was purified and characterized by chemical and HPLC analy
sis. The polymer has the composition glucose/mannose/N-acetylgalactosa
mine/galacturonic acid/acetic acid in the molar ratios of approximatel
y 2.5:1.3:0.5:0.4:2.5. The polysaccharide was immunogenic in rabbits a
nd did not cross-react with antibodies against the O-antigen lipopolys
accharide.