Functional and immunological characterization of a natural polymorphic variant of a heat-labile toxin (LT-I) produced by enterotoxigenic Escherichia coli (ETEC).
FEMS Immunol Med Microbiol
; 55(1): 93-9, 2009 Jan.
Article
em En
| MEDLINE
| ID: mdl-19076225
Heat-labile toxins (LT) encompass at least 16 natural polymorphic toxin variants expressed by wild-type enterotoxigenic Escherichia coli (ETEC) strains isolated from human beings, but only one specific form, produced by the reference ETEC H10407 strain (LT1), has been intensively studied either as a virulence-associated factor or as a mucosal/transcutaneous adjuvant. In the present study, we carried out a biological/immunological characterization of a natural LT variant (LT2) with four polymorphic sites at the A subunit (S190L, G196D, K213E, and S224T) and one at the B subunit (T75A). The results indicated that purified LT2, in comparison with LT1, displayed similar in vitro toxic activities (adenosine 3',5'-cyclic monophosphate accumulation) on mammalian cells and in vivo immunogenicity following delivery via the oral route. Nonetheless, the LT2 variant showed increased adjuvant action to ovalbumin when delivered to mice via the transcutaneous route while antibodies raised in mice immunized with LT2 displayed enhanced affinity and neutralization activity to LT1 and LT2. Taken together, the results indicate that the two most frequent LT polymorphic forms expressed by wild ETEC strains share similar biological features, but differ with regard to their immunological properties.
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Polimorfismo Genético
/
Toxinas Bacterianas
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Proteínas de Escherichia coli
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Enterotoxinas
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Escherichia coli Enterotoxigênica
Limite:
Animals
Idioma:
En
Revista:
FEMS Immunol Med Microbiol
Assunto da revista:
ALERGIA E IMUNOLOGIA
/
DOENCAS TRANSMISSIVEIS
/
MICROBIOLOGIA
Ano de publicação:
2009
Tipo de documento:
Article
País de afiliação:
Brasil
País de publicação:
Reino Unido