Protective Immunity to Human Cholera in Bangladesh

Diarrheal diseases are some of the most common causes of morbidity and mortality in the world today. Unfortunately, effective vaccines for most of the infectious causes of diarrhea are not yet available. Vibrio cholerae (V cholerae) is an important infectious cause of severe secretory diarrhea in humans. The purpose of this study is to assess the duration of immune responses in a group of 250 individuals, aged 2-60 years, presenting to the International Centre for Diarrheal Diseases Research, Bangladesh (ICDDR,B) hospital who are admitted with acute cholera. Fifty of these participants will be enrolled in a substudy of mucosal immunity involving duodenal biopsy. This protocol focuses exclusively on the subset of 50 study participants (healthy 18-45 year old non pregnant subjects) enrolled in the substudy of mucosal immunity involving duodenal biopsy. This study is linked to DMID protocol 06-0045. The remainder of the study is observational, involving collection of stool, vomit, and blood samples only (DMID protocol 06-0045). A duodenal biopsy will be performed on enrollment or the next day and at Day 30. Twenty five subjects will undergo a third duodenal biopsy after 6 months of follow-up and 25 subjects will undergo a third duodenal biopsy after 12 months follow-up. The objectives of this study are as follows: to measure immune responses directed against Vibrio cholerae antigens and evaluate the development of anti-V cholerae memory B cells in study participants with cholera; to assess the duration of the immune responses following an episode of cholera; and to correlate the duration of antigen-specific, antibody-secreting cells for various cholera antigens in duodenal tissue with measurements of the duration of immunity based on antibody responses in serum, as well as circulating antigen-specific memory B cells. This is a single site study with a 5 year duration requiring three years of patient participation.