Human antibody responses to R3-core epitopes on the lipopolysaccharide of Escherichia coli O157.
OBJECTIVE
To establish the incidence of serum antibodies binding to the R3-core lipopolysaccharide (LPS) of verocytotoxin-producing Escherichia coli (VTEC) O157, in patients with serum antibodies to E. coli O157 LPS, and to characterize the class(es) of antibodies binding to epitopes on the R3-core.


RESULTS
SDS-PAGE profiles of LPS prepared from VTEC O157 were used in combination with immunoblotting to detect and characterize serum antibodies binding to the R3-core LPS of VTEC O157. Of 417 sera, referred to the Laboratory of Enteric Pathogens (LEP) for routine O157 serology and found to have serum antibodies to long-chain VTEC O157 LPS, 31 had antibodies binding to the R3-core of VTEC O157 LPS. The majority of the 31 sera contained IgA-class antibodies to both long-chain and R3-core LPS epitopes. Patients who did not develop haemolytic uraemic syndrome (HUS) produced antibodies of the IgM class to R3-core and IgG-class antibodies to long-chain LPS more frequently than patients with HUS.


CONCLUSIONS
Only 7.4% of sera received by the LEP, and shown to have antibodies to VTEC O157 LPS, contained antibodies binding to the R3-core of VTEC LPS. Most sera contained IgA-class antibodies to both long-chain and R3-core LPS epitopes.


CONCLUSIONS
Patients infected with VTEC O157 produced antibodies binding to the R3-core epitopes of VTEC O157 LPS only rarely, and these antibodies are unlikely to interfere with the serodiagnosis of infections caused by these organisms.
Dalwai
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Division of Gastrointestinal Infections, Central Public Health Laboratory, London, UK.
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D000907:Antibodies, Bacterial / Q000097:blood* / Q000145:classification; D000942:Antigens, Bacterial / Q000737:chemistry / Q000276:immunology; D004591:Electrophoresis, Polyacrylamide Gel; D000939:Epitopes / Q000276:immunology; D004927:Escherichia coli Infections / Q000276:immunology* / Q000382:microbiology; D019453:Escherichia coli O157 / Q000737:chemistry / Q000201:enzymology / Q000276:immunology*; D005260:Female; D006463:Hemolytic-Uremic Syndrome / Q000276:immunology / Q000382:microbiology; D006801:Humans; D015151:Immunoblotting; D007070:Immunoglobulin A / Q000097:blood; D007074:Immunoglobulin G / Q000097:blood; D007075:Immunoglobulin M / Q000097:blood; D008070:Lipopolysaccharides / Q000276:immunology*; D008297:Male; D012698:Serologic Tests; D022603:Shiga Toxins / Q000096:biosynthesis
D000907:Antibodies, Bacterial; D000942:Antigens, Bacterial; D000939:Epitopes; D007070:Immunoglobulin A; D007074:Immunoglobulin G; D007075:Immunoglobulin M; D008070:Lipopolysaccharides; D022603:Shiga Toxins