Determining antibody-binding site of streptococcal pyrogenic exotoxin B to protect mice from group a streptococcus infection.
PLoS One
; 8(1): e55028, 2013.
Article
em En
| MEDLINE
| ID: mdl-23383045
ABSTRACT
Streptococcal pyrogenic exotoxin B (SPE B), a cysteine protease, is an important virulence factor in group A streptococcal (GAS) infection. SPE B binds and cleaves antibody isotypes and further impairs the immune system by inhibiting complement activation. In this study, we examined the antibody-binding site of SPE B and used it to block SPE B actions during GAS infection. We constructed different segments of the spe B gene and induced them to express different recombinant fragments of SPE B. Using an enzyme-linked immunosorbent assay (ELISA), we found that residues 345-398 of the C-terminal domain of SPE B (rSPE B(345-398)), but not the N-terminal domain, was the major binding site for antibody isotypes. Using a competitive ELISA, we also found that rSPE B(345-398) bound to the Fc portion of IgG. The in vitro functional assays indicate that rSPE B(345-398) not only interfered with cleavage of antibody isotypes but also interfered with SPE B-induced inhibition of complement activation. Immunization of BALB/c mice using rSPE B(345-398) was able to induce production of a high titer of anti-rSPE B(345-398) antibodies and efficiently protected mice from GAS-induced death. These findings suggest that SPE B uses its C-terminal domain to bind the Fc portion of IgG and that immunization of mice with this binding domain (rSPE B(345-398)) could protect mice from GAS infection.
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Infecções Estreptocócicas
/
Streptococcus pyogenes
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Proteínas de Bactérias
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Exotoxinas
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Anticorpos Antibacterianos
Limite:
Animals
/
Humans
/
Male
Idioma:
En
Revista:
PLoS One
Assunto da revista:
CIENCIA
/
MEDICINA
Ano de publicação:
2013
Tipo de documento:
Article
País de afiliação:
Taiwan