Development of sandwich chemiluminescent immunoassay based on an anti-staphylococcal enterotoxin B Nanobody-Alkaline phosphatase fusion protein for detection of staphylococcal enterotoxin B.
Anal Chim Acta
; 1108: 28-36, 2020 Apr 29.
Article
em En
| MEDLINE
| ID: mdl-32222241
ABSTRACT
In this study, sandwich chemiluminescent immunoassay (CLIA) for the detection of Staphylococcal enterotoxin B (SEB) was developed using nanobody-alkaline phosphatase (Nb-ALP) fusion protein. The SEB-binding nanobodies were obtained from a naïve phage-display library and the Nb-ALP fusion protein was constructed and obtained as a thermally stable and potentially effective substance for detecting antibodies in CLIA. The working range of the sandwich CLIA based on anti-SEB monoclonal antibodies (mAbs) and our fusion protein, Nb37-ALP, was 3.12-50.0 ng mL-1 with SC50 = 8.59 ± 0.37 ng mL-1. The limit of detection was 1.44 ng mL-1 according to the blank value plus 3 standard deviations. In order to understand the interaction of SEB and Nb37 in depth, the 3D structure of the SEB-Nb37 complex was constructed and verified by molecular modeling and the docking method. The results showed that the complementary-determining region 3 (CDR3) of Nb37 embedded itself in the opening generated by the major histocompatibility complex (MHC) and T-cell receptor- (TcR) binding sites of SEB, indicating that Nb37 may affect the recognition of SEB by MHC class â
¡ molecules and the TcR. The arginine residue (Arg) 101, Arg102 and phenylalanine residue (Phe)103 of CDR3 in Nb37 may have contributed to specific binding to form six salt-bridges between these and SEB. In conclusion, in terms of their specificity and sensitivity, the obtained anti-SEB Nb-ALP appears to have the potential to replace chemically labeled probes for the detection of SEB.
Palavras-chave
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Proteínas Recombinantes de Fusão
/
Imunoensaio
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Enterotoxinas
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Anticorpos de Domínio Único
Tipo de estudo:
Diagnostic_studies
Limite:
Animals
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Humans
Idioma:
En
Revista:
Anal Chim Acta
Ano de publicação:
2020
Tipo de documento:
Article
País de afiliação:
China