Enterotoxin-specific immunoglobulin E responses in humans after infection or vaccination with diarrhea-causing enteropathogens

Cholera toxin (CT)-specific antibody responses of the immunoglobulin E (IgE ) isotype in the sera of adult patients suffering from infection with eithe r Vibrio cholerae O1, V. cholerae O139, or enterotoxigenic Escherichia coli (ETEC) were analyzed and compared with those in the sera of volunteers imm unized with a bivalent B subunit O1/O139 whole-cell cholera vaccine. A sign ificant IgE response to CT was observed in 90% of the patients with V. chol erae O1 infection (18 of 20; P = <0.001) and 95% of the patients with V. ch olerae O139 infection (19 of 20; P = <0.001). Similarly, the majority of th e patients with ETEC diarrhea (83%; 13 of 15) showed a positive IgE respons e to CT. Eight of 10 North American volunteers (80%) orally challenged with V : cholerae O1 showed CT-specific IgE responses (P = 0.004). In contrast, Swedish volunteers immunized with the oral cholera vaccine showed no IgE r esponses to CT (P value not significant). During the study period, total Ig E levels in the sera of the diarrheal patients, the North American voluntee rs, and the Swedish cholera vaccinees alike remained unchanged. However, th e total IgE levels in the sera of patients and healthy Bangladeshi controls were on average 89-fold higher than those in the sera of the healthy Swedi sh volunteers and 34-fold higher than those in the sera of the North Americ an volunteers.