Elevated IgG titer against the C region of streptococcal M protein and its immunodeterminants in patients with poststreptococcal acute glomerulonephritis.

Mori, K; Ito, Y; Kamikawaji, N; Sasazuki, T

Mori, K; Ito, Y; Kamikawaji, N; Sasazuki, T.

Afiliação

Mori K; Department of Pediatrics, Kouchi Red-Cross Hospital, Japan.

J Pediatr ; 131(2): 293-9, 1997 Aug.

Article em En | MEDLINE | ID: mdl-9290619

RESUMO

OBJECTIVE: To determine the immune responses to the streptococcal M protein in patients with poststreptococcal acute glomerulonephritis (PSAGN). STUDY DESIGN: The gene coding type 12 M protein of group A streptococcus (M12), a known PSAGN-associated serotype, was cloned and expressed in Escherichia coli to investigate the specific immune responses to the M12 protein in patients with PSAGN. Recombinant M proteins for the variable N-terminal half (AB region) and conserved C-terminal half (C region) were produced separately. IgG titers against each region were measured by enzyme-linked immunosorbent assay in patients with PSAGN (n = 51), uncomplicated streptococcal pharyngitis (n = 26), chronic glomerulonephritis (n = 10), and in healthy control subjects (n = 51). Immunodominant domains within the M protein in PSAGN were further investigated by use of overlapping synthetic peptides. RESULTS: IgG titers against the C region, but not the AB region, were markedly higher in the PSAGN group than in other groups (p < 0.01), and these titers were maintained for at least several months after antistreptolysin O or antistreptokinase levels had returned to normal. Studies with overlapping synthetic peptides demonstrated that increased IgG reactivity was observed against the C repeat blocks. CONCLUSION: IgG titers against the C region are significantly elevated in patients with PSAGN, and it may be a diagnostic marker for PSAGN.

Assuntos

Anticorpos Antibacterianos/análise; Antígenos de Bactérias/imunologia; Antígenos de Superfície/imunologia; Proteínas da Membrana Bacteriana Externa; Proteínas de Bactérias/imunologia; Proteínas de Transporte; Glomerulonefrite/microbiologia; Imunoglobulina G/análise; Infecções Estreptocócicas/imunologia; Streptococcus pyogenes/imunologia; Doença Aguda; Antígenos de Bactérias/genética; Antígenos de Superfície/genética; Antiestreptolisina/análise; Proteínas de Bactérias/genética; Biomarcadores/análise; Estudos de Casos e Controles; Criança; Doença Crônica; Ensaio de Imunoadsorção Enzimática; Escherichia coli/genética; Feminino; Expressão Gênica; Glomerulonefrite/imunologia; Humanos; Epitopos Imunodominantes/genética; Epitopos Imunodominantes/imunologia; Masculino; Peptídeos; Faringite/imunologia; Faringite/microbiologia; Reação em Cadeia da Polimerase; Proteínas Recombinantes; Sequências Repetitivas de Ácido Nucleico; Análise de Sequência de DNA; Streptococcus pyogenes/genética; Estreptoquinase/análise

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Coleções: 01-internacional Base de dados: MEDLINE Assunto principal: Infecções Estreptocócicas / Streptococcus pyogenes / Proteínas da Membrana Bacteriana Externa / Proteínas de Bactérias / Imunoglobulina G / Proteínas de Transporte / Glomerulonefrite / Anticorpos Antibacterianos / Antígenos de Bactérias / Antígenos de Superfície Tipo de estudo: Observational_studies / Risk_factors_studies Limite: Child / Female / Humans / Male Idioma: En Revista: J Pediatr Ano de publicação: 1997 Tipo de documento: Article País de afiliação: Japão País de publicação: Estados Unidos

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