Human antibody response to Campylobacter jejuni flagellin protein and a synthetic N-terminal flagellin peptide.
We measured isotype-specific human antibodies directed against Campylobacter jejuni native flagellin and a synthetic peptide derived from the N-terminal amino acid sequence of the protein by using a microdilution enzyme-linked immunosorbent assay (ELISA). Serum samples from patients with gastrointestinal infection caused by C. jejuni (n = 20) and control samples (number from normal subjects = 20; number from patients with diarrhea other than campylobacter = 20) were tested in this assay. Serum specimens from patients with campylobacter infection showed statistically significant higher isotype-specific antiflagellin antibody titers than control samples did. Detection of immunoglobulin G (IgG) antibodies was less specific (70%) than detection of either IgA or IgM antibodies in infected patients (95%). The sensitivity of testing for any of the isotypes ranged from 64 to 100% in acute-phase serum specimens and 85 to 95% in convalescent-phase serum specimens. An ELISA with an N-terminal synthetic peptide derived from the flagellin protein as antigen was not sensitive (60%) for detecting campylobacter infection but was very specific (97.5%). In conclusion, detection of serum IgA or IgM against C. jejuni flagellin may be a useful marker of infection. Although the N-terminal synthetic peptide was antigenic in a few patients with infection and showed good specificity in the ELISA, additional amino acid sequences with better sensitivity for detecting infection need to be identified.
Nachamkin
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Department of Pathology and Laboratory Medicine, University of Pennsylvania School of Medicine, Philadelphia 19104-4283.
Yang
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XH
D000595:Amino Acid Sequence; D000907:Antibodies, Bacterial / Q000096:biosynthesis*; D000942:Antigens, Bacterial; D001426:Bacterial Proteins / Q000276:immunology*; D001667:Binding, Competitive; D002168:Campylobacter fetus / Q000276:immunology*; D005408:Flagellin / Q000276:immunology*; D006801:Humans; D007070:Immunoglobulin A / Q000096:biosynthesis; D007074:Immunoglobulin G / Q000096:biosynthesis; D007075:Immunoglobulin M / Q000096:biosynthesis; D008969:Molecular Sequence Data; D010455:Peptides / Q000276:immunology
D000907:Antibodies, Bacterial; D000942:Antigens, Bacterial; D001426:Bacterial Proteins; D007070:Immunoglobulin A; D007074:Immunoglobulin G; D007075:Immunoglobulin M; D010455:Peptides; D005408:Flagellin