The frequency of Vero cytotoxin 1 (VT1)-neutralizing antibody (NAb) in serum specimens from 790 age-stratified (0 to 70 years) control individuals from Toronto was 61 of 790 (7.7%), with a peak of 19% in the 20- to 30-year-old age group and a second peak of 16.7% in the 60- to 70-year-old age group. A total of 568 serum specimens, including 538 from the 790 Toronto control subjects, 21 from patients from three outbreaks of VT-producing Escherichia coli (VTEC) infection, and 9 known VT1-NAb-positive serum specimens from patients with hemolytic-uremic syndrome (HUS), were then tested for the presence of anti-VT1 immunoglobulin G (IgG) by an enzyme-linked immunosorbent assay (ELISA). The mean ELISA values of 522 VT1-NAb-negative serum specimens and 46 VT1-NAb-positive serum specimens were 0.09 +/- 0.06 (range, 0 to 0.56) and 0.78 +/- 0.66 (range, 0.16 to 2.91), respectively (P < 0.001; Student's t test). With a breakpoint of 0.21 (mean ELISA value of the VT1-NAb-negative sera + 2 standard deviations), the sensitivity, specificity, positive predictive value, and negative predictive value of the VT1 IgG ELISA compared with those of the VT1-NAb assay were, respectively, 95.7, 98.7, 86.3, and 99.6%. There were nine discrepant serum specimens, of which seven were anti-VT1 IgG positive and VT1-NAb negative and two were anti-VT1 IgG negative and VT1-NAb positive. The ELISA was also used for testing 238 control serum specimens from The Netherlands, Japan, and India and acute- and convalescent-phase serum specimens from 42 Toronto patients with HUS. The frequencies of anti-VT1 IgG (with VT1-NAb frequencies in parantheses) in control sera from the Netherlands, Japan, and India were 6% (3%), 1.1% (0%), and 12% (10%), respectively, with no age clustering. The frequencies of anti-VT1 IgG seropositivity in HUS patients were 5 of 14 (35.7%) in patients with unknown toxin exposure, 2 of 22 (9.1%) in individuals with known exposure to VT1 plus VT2 or VT1 alone, and 0 of 6 (0%) in patients exposed to only VT2. Development of serum anti-VT1 IgG response appears to be the exception rather than the rule in sporadic HUS patients infected with VTEC expressing VT1. However, in two family outbreaks associated with VTEC strains expressing VT1 alone and VT1 plus VT2, respectively, the presence of anti-VT1 IgG in virtually all exposed individuals who remained symptom free suggests that the presence of antibody was associated with protection.

• MeSH
• Bacterial Toxins * immunology   MeSH
• Child MeSH
• Adult MeSH
• Enzyme-Linked Immunosorbent Assay * MeSH
• Disease Outbreaks MeSH
• Escherichia coli * immunology   MeSH
• Hemolytic-Uremic Syndrome immunology   blood   microbiology   MeSH
• Immunoglobulin G immunology   blood   MeSH
• Incidence MeSH
• Escherichia coli Infections epidemiology   immunology   blood   MeSH
• Infant MeSH
• Middle Aged MeSH
• Humans MeSH
• Adolescent MeSH
• Milk microbiology   MeSH
• Foodborne Diseases epidemiology   microbiology   MeSH
• Neutralization Tests MeSH
• Infant, Newborn MeSH
• Predictive Value of Tests MeSH
• Child, Preschool MeSH
• Antibodies, Bacterial * immunology   blood   MeSH
• Diarrhea epidemiology   microbiology   MeSH
• Aged MeSH
• Sensitivity and Specificity MeSH
• Shiga Toxin 1 MeSH
• Animals MeSH
• Check Tag
• Child MeSH
• Adult MeSH
• Infant MeSH
• Middle Aged MeSH
• Humans MeSH
• Adolescent MeSH
• Male MeSH
• Infant, Newborn MeSH
• Child, Preschool MeSH
• Aged MeSH
• Female MeSH
• Animals MeSH
• Geographicals
• India MeSH
• Japan MeSH
• Canada MeSH
• Netherlands MeSH