title: Persistent elevation of immunoglobulin G titer against the C region of recombinant group A streptococcal M protein in patients with rheumatic fever.
abstract: To analyze the immune response to the C region of group A streptococcal M protein in patients with rheumatic fever (RF), we cloned the structural gene for the C region of type 12 M protein and produced recombinant C region of M protein. IgG titers against the C region of M protein were measured by ELISA from sera of patients with RF (n = 10), uncomplicated streptococcal pharyngitis (n = 26), and age-matched controls (n = 49). IgG titers against the C region were significantly higher in patients with RF than in controls or patients with uncomplicated streptococcal pharyngitis (43 versus 1.5 or 1.8 micrograms/mL, p < 0.01). Studies using overlapping synthetic peptides of the C region demonstrated that increased IgG reactivity was observed against the amino-terminal halves of the C repeat blocks (C1, C2) in RF, indicating that these domains are the main immunodominant epitopes in the C region.
authors.affiliation: Department of Pediatrics, University of Tokushima, Japan.
authors.forename: K
authors.initials: K
authors.lastname: Mori
authors.forename: N
authors.initials: N
authors.lastname: Kamikawaji
authors.forename: T
authors.initials: T
authors.lastname: Sasazuki
mesh_terms: D000595:Amino Acid Sequence; D000907:Antibodies, Bacterial / Q000276:immunology*; D000942:Antigens, Bacterial; D001425:Bacterial Outer Membrane Proteins; D001426:Bacterial Proteins / Q000235:genetics / Q000276:immunology*; D001483:Base Sequence; D002352:Carrier Proteins; D002648:Child; D004269:DNA, Bacterial / Q000235:genetics; D018604:Epitope Mapping; D005260:Female; D015964:Gene Expression Regulation, Bacterial; D006801:Humans; D007074:Immunoglobulin G / Q000276:immunology*; D008297:Male; D008969:Molecular Sequence Data; D011993:Recombinant Fusion Proteins / Q000276:immunology; D012213:Rheumatic Fever / Q000276:immunology*
chemical_list: D000907:Antibodies, Bacterial; D000942:Antigens, Bacterial; D001425:Bacterial Outer Membrane Proteins; D001426:Bacterial Proteins; D002352:Carrier Proteins; D004269:DNA, Bacterial; D007074:Immunoglobulin G; D011993:Recombinant Fusion Proteins; C014689:streptococcal M protein