LPS Profiles Research Articles

Electrophoretic and immunochemical analysis of surface antigens of the fish pathogens Vibrio salmonicida and Vibrio anguillarum

Abstract. Outer membranes and lipopolysaccharides of the marine fish pathogens Vibrio salmonicida and Vibrio anguillarum were isolated. SDS‐PAGE profiles of purified LPS preparations from V. salmonicida revealed a broad low molecular weight band, whereas V. anguillarum LPS profiles demonstrated both a low‐molecular band and several weaker high‐molecular weight bands. Hydrolysis of V, salmonicida and V. anguillarum LPS separating the polysaccharide chain from the lipid A part and subsequent gel‐chromatography suggests a polysaccharide molecular weight of ca. 1000 (‘rough type’ LPS) and ca. 6000 ('smooth type’ LPS), respectively. Western blot of V. salmonicida outer membrane preparations and purified lipopolysaccharides and subsequent immunostaining with mouse monoclonal antibodies was performed. Eleven out of 15 monoclonal antibodies made against V. salmonicida cells reacted with one broad antigen‐band in the low molecular weight region of both outer membrane and LPS profiles, corresponding to the LPS region. The previously reported outer surface antigen, VS‐P1 from V. salmonicida, was observed to carry LPS epitopes as revealed by binding of monoclonal antibodies to VS‐P1 as well as purified LPS preparations. These results strongly suggest that the VS‐P1 antigen is a complex of both protein and LPS molecules.