Study of Enteric Infection in Volunteers Support of Laboratory Studies.
Abstract
Enterotoxigenic Escherichia coli (ETEC) represent the most frequent etiologic agent of Travelers' Diarrhea. Studies of immunity to ETEC were undertaken in volunteers in order to evaluate the feasibility of immunoprophylaxis against ETEC. Seventeen students and other community volunteers were give 10 to the 6th power or 10 to the 8th power organisms of E. coli B7A (0148:H28) which produces heat-labile (LT) and heat-stable (ST) enterotoxins. Ten individuals developed diarrheal illness closely resembling natural Travelers' Diarrhea; of these ten, rises in titer of circulating antitoxin and antisomatic antibody occurred in eight (80%). Eight B7A veterans and 12 controls were challenged nine weeks later with 10 to the 8th power B7A organisms. Only one of eight veterans developed diarrhea vs. seven of 12 controls (p=0.05). Despite clinical protection, all veterans excreted B7A after rechallenge. Four controls who developed diarrhea during the homologous B7A rechallenge were rechallenged nine weeks later with 10 to the 9th power organisms of E. coli strain E2528-C1 (025:NM) which produces only LT and which shares no other common antigens with B7A. Three of four veterans and two of six controls developed comparable diarrhea. These studies demonstrate that prior illness due to ETEC can confer significant homologous immunity against subsequent challenge and the operative mechanism apparently is not bactericidal. Heterologous protection was not confered where the only common antigen was LT, indicating that LT antitoxin also is not protective.
Document Details
- Document Type
- Technical Report
- Publication Date
- Aug 01, 1978
- Accession Number
- ADA062313
Entities
People
- Myron M. Levine
- Richard B. Hornick
Organizations
- University of Maryland School of Medicine