Weak serum and intestinal antibody responses to Vibrio cholerae soluble hemagglutinin in cholera patients.

A soluble hemagglutinin/protease from Vibrio cholerae has been suggested to be a putative virulence factor and protective antigen. However, clinical cholera infection gave rise to detectable serum antibody responses to soluble hemagglutinin in only 2 of 10 Bangladeshi patients or 1 of 17 cholera-infected North American volunteers. A gut mucosal immunoglobulin A antibody response to soluble hemagglutinin was seen in 4 of 8 Bangladeshi patients, but in 0 of 10 North American volunteers. These responses were much weaker than those to cholera toxin or lipopolysaccharide.