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Immunity to enterotoxigenic Escherichia coli.
Infection and Immunity
|March 1, 1979
Summary
Prior enterotoxigenic Escherichia coli infection provides homologous immunity against traveler's diarrhea. This protection is not bactericidal and not mediated by anti-O antibodies, with no heterologous protection observed.
Area of Science:
- Microbiology
- Immunology
- Infectious Diseases
Background:
- Enterotoxigenic Escherichia coli (ETEC) is a primary cause of traveler's diarrhea.
- Understanding immunity to ETEC is crucial for developing effective prevention and treatment strategies.
Purpose of the Study:
- To investigate the mechanisms of immunity induced by ETEC infection.
- To evaluate the protective effects of prior ETEC disease against subsequent homologous and heterologous challenges.
Main Methods:
- Volunteer challenge studies using E. coli B7A (O148:H28) and E. coli E2528-C1 (O25:H-).
- Monitoring for diarrheal illness, antibody titers (serum antitoxin and anti-O antibody), and bacterial excretion.
- Homologous and heterologous rechallenge experiments were conducted.
Main Results:
- Prior ETEC disease (traveler's diarrhea) conferred significant homologous protection against subsequent ETEC challenge (1 of 8 "veterans" vs. 7 of 12 controls, P=0.05).
- Clinical protection did not prevent bacterial excretion in "veterans".
- No heterologous protection was observed when the only common antigen was heat-labile enterotoxin, suggesting antitoxin immunity is not protective.
Conclusions:
- Prior ETEC infection induces homologous immunity, but the mechanism is not bactericidal or mediated by serum anti-O antibodies.
- Immunity to heat-labile enterotoxin alone does not confer protection against subsequent ETEC challenge.