Antibodies against Vibrio cholerae lipopolysaccharide, cell-bound haemagglutinin and toxin in the intestinal fluid during convalescence.

Specific antibodies to V. cholerae lipopolysaccharide (LPS), cell-bound haemagglutinin (CHA) and toxin (CT) in the intestinal lavages of healthy Thais and Thai cholera patients during the convalescence period were determined by enzyme-linked immunosorbent assay. Only IgM and IgA specific antibodies were detectable in the specimens. All of the persons who were just recovered from cholera had IgA anti-CT and IgA anti-LPS and 82.4% had IgA anti-CHA. The IgA anti-CT, anti-LPS and anti-CHA were detected also in the gut fluids of 70.6%, 94.1% and 88.2%, respectively, of the healthy controls. The mean levels of the IgA antibodies of all specificities between the two groups of individuals were not different. However, the IgM anti-CT and IgM anti-LPS of the cholera patients increased during the convalescence period. The levels, therefore, were significantly higher than those of the controls. The ratios of IgA anti-CT: IgM anti-CT and IgA anti-LPS: IgM anti-LPS among the patients were 2.93:1 and 2.02:1, respectively while those of the controls were 10:1 and 34:1, respectively. IgA antibodies predominated in the lavages of both groups of the individuals.