Serologic correlates of protection against enterotoxigenic Escherichia coli diarrhea

J Infect Dis. 2005 Feb 15;191(4):562-70. doi: 10.1086/427662. Epub 2005 Jan 14.


Background: We conducted a nested case-control study in 397 rural Egyptian children <36 months of age to assess the correlation between serum levels of antibodies against toxin and colonization factors (CFs) and the risk of homologous enterotoxigenic Escherichia coli (ETEC) diarrhea.

Methods: Active case detection was performed via semiweekly home visits, and blood was obtained at 3-month intervals. After each serosurvey, case subjects were selected from children experiencing a CF antigen (CFA)/I-, CFA/II-, CFA/IV-, or heat-labile enterotoxin (LT)-ETEC diarrheal episode during the subsequent 3 months. Up to 5 control subjects per case subject were selected from children who did not experience an ETEC diarrheal episode during the corresponding interval. Serum titers of immunoglobulin G antibodies against CFA/I, coli surface antigen (CS) 3, CS6, and LT were measured by enzyme-linked immunosorbant assay.

Results: The distribution of serum titers of LT, CS3, and CS6 antibodies did not differ between the case and control subjects. For children <18 months of age, serum titers of CFA/I antibody were inversely related to the risk of CFA/I-ETEC diarrhea; reciprocal serum titers of CFA/I antibody > or =76 were associated with a 77% reduction in the odds of CFA/I-ETEC diarrhea.

Conclusion: Induction of reciprocal serum titers of antibodies against CFA/I within or above the 76-186 range should be further evaluated as a predictor for assessment of the ability of candidate vaccines to protect against CFA/I-ETEC diarrhea.

MeSH terms

  • Antibodies, Bacterial / blood*
  • Bacterial Proteins / analysis
  • Bacterial Proteins / immunology
  • Bacterial Toxins / analysis
  • Bacterial Toxins / immunology*
  • Case-Control Studies
  • Child, Preschool
  • Diarrhea / microbiology*
  • Diarrhea / prevention & control*
  • Egypt
  • Enterotoxins / analysis
  • Enterotoxins / immunology*
  • Enzyme-Linked Immunosorbent Assay
  • Escherichia coli / immunology*
  • Escherichia coli / pathogenicity
  • Escherichia coli Infections / immunology*
  • Escherichia coli Infections / microbiology
  • Escherichia coli Proteins / analysis
  • Escherichia coli Proteins / immunology*
  • Female
  • Fimbriae Proteins / analysis
  • Fimbriae Proteins / immunology
  • Humans
  • Immunoglobulin G / blood
  • Infant
  • Male
  • Virulence Factors / analysis
  • Virulence Factors / immunology


  • Antibodies, Bacterial
  • Bacterial Proteins
  • Bacterial Toxins
  • Enterotoxins
  • Escherichia coli Proteins
  • Immunoglobulin G
  • Virulence Factors
  • colonization factor antigens
  • Fimbriae Proteins
  • heat-labile enterotoxin, E coli