Clinical Trial: Immunity to Human Cholera in Bangladesh

Study Status: Completed
Recruit Status: Unknown status
Study Type: Observational

Official Title: Protective Immunity to Human Cholera in Bangladesh

Brief Summary: Cholera is a severe diarrhea illness caused by bacteria. The purpose of this study is to better understand how the immune systems of people in Dhaka, Bangladesh, fight infection with cholera. Understanding immune responses that influence the outcome of infection with cholera can assist in the development of more effective cholera vaccines. The International Center for Diarrheal Diseases Research, Bangladesh (ICDDR,B) will enroll in this study 75 patients with acute cholera and 250 of their household contacts. Individuals ages 2-60 years are eligible. Study participation will last 1 year for cholera patients and 30 days for household contacts. Participants will come to the ICDDR,B for 3 (household contacts) or 4 (cholera patients) study visits, and field workers will visit them at home at other times. For all participants, blood samples will be taken at each of the ICDDR,B visits. Household contacts will have rectal swabs taken at 2 ICDDR visits and during field worker visits.

Detailed Summary: The purpose of this study is to investigate protective immunity to human cholera in Dhaka, Bangladesh. Immune responses to Vibrio cholerae are poorly understood and have not been extensively studied in an endemic setting such as Bangladesh. Understanding systemic and mucosal immune responses that influence the outcome of infection with V cholerae can assist in the development of more effective cholera vaccines. Identifying host factors, such as human genetic variations or nutritional status, that affect the outcome of infection with V cholerae can lead to an improved understanding of disease pathogenesis and better treatment modalities. One of the likely key determinants of protection following either natural cholera or vaccination is the duration of immune responses to key antigens, particularly at the mucosal surface. This study proposes to assess the duration of immune responses in a group of 75 cholera study participants over the course of 1 year of follow-up and to correlate baseline immune responses in 250 household contacts of the index patients, with protection from disease over the subsequent 30 days. The researchers will assess the duration of immunity in serum to known cholera virulence factors, including the serum vibriocidal antibody and antibodies specific for LPS, cholera toxin, B subunit (CtxB), and TcpA. The researchers will also measure antigen-specific memory B cells circulating in human blood, which has previously been used to examine the longevity of B cell immunologic memory following various infections and vaccinations. The objectives of this study are to determine genes and proteins expressed by V. cholerae during human infection; determine which V. cholerae proteins are immunogenic during human cholera infection in Bangladesh; assess the duration of immune responses to V. cholerae antigens following an episode of cholera; determine which anti-V. cholerae immune responses are protective on exposure to cholera in household contacts; and evalua
Sponsor: National Institute of Allergy and Infectious Diseases (NIAID)

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Information By: National Institute of Allergy and Infectious Diseases (NIAID)

Dates:
Date Received: November 17, 2006
Date Started: November 2006
Date Completion:
Last Updated: August 26, 2010
Last Verified: July 2007