Sensitivity of agglutinating and vibriocidal antibodies to 2-mercaptoethanol in human cholera

Agglutinating antibodies against Vibrio cholera were measured before and after treatment of serum with 0.1 M 2-mercaptoethanol (2-ME). Acute and convalescent sera were obtained from 23 cholera patients and from 11 patients with noncholera diarrheas. Two types of response were observed in the cholera patients. The majority (14 of 23) produced mainly 2-ME-resistant antibody, and were thus considered to have a secondary pattern of immune response. The remaining 9 cholera patients produced only small amounts of antibody, all of which was 2ME- sensitive, thus demonstrating a primary type of immune response. Vibriocidal antibody titers done on a smaller number of these patients showed the same patterns of antibody response. The finding that 2-ME-resistant antibody titers were low in the acute sera of cholera patients is compatible with findings from experiments in animals that have suggested that 7S antibody may be more important than 19S antibody in protection against cholera.