Application of Assisted Design of Antibody and Protein Therapeutics (ADAPT) improves efficacy of a Clostridium difficile toxin A single-domain antibody.
Sci Rep
; 8(1): 2260, 2018 02 02.
Article
en En
| MEDLINE
| ID: mdl-29396522
ABSTRACT
Assisted Design of Antibody and Protein Therapeutics (ADAPT) is an affinity maturation platform interleaving predictions and testing that was previously validated on monoclonal antibodies (mAbs). This study expands the applicability of ADAPT to single-domain antibodies (sdAbs), a promising class of recombinant antibody-based biologics. As a test case, we used the camelid sdAb A26.8, a VHH that binds Clostridium difficile toxin A (TcdA) relatively weakly but displays a reasonable level of TcdA neutralization. ADAPT-guided A26.8 affinity maturation resulted in an improvement of one order of magnitude by point mutations only, reaching an equilibrium dissociation constant (KD) of 2 nM, with the best binding mutants having similar or improved stabilities relative to the parent sdAb. This affinity improvement generated a 6-fold enhancement of efficacy at the cellular level; the A26.8 double-mutant T56R,T103R neutralizes TcdA cytotoxicity with an IC50 of 12 nM. The designed mutants with increased affinities are predicted to establish novel electrostatic interactions with the antigen. Almost full additivity of mutation effects is observed, except for positively charged residues introduced at adjacent positions. Furthermore, analysis of false-positive predictions points to general directions for improving the ADAPT platform. ADAPT guided the efficacy enhancement of an anti-toxin sdAb, an alternative therapeutic modality for C. difficile.
Texto completo:
1
Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Toxinas Bacterianas
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Productos Biológicos
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Diseño de Fármacos
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Enterotoxinas
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Anticuerpos Neutralizantes
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Anticuerpos de Dominio Único
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Factores Inmunológicos
Tipo de estudio:
Prognostic_studies
Límite:
Animals
Idioma:
En
Revista:
Sci Rep
Año:
2018
Tipo del documento:
Article
País de afiliación:
Canadá
Pais de publicación:
ENGLAND
/
ESCOCIA
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GB
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GREAT BRITAIN
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INGLATERRA
/
REINO UNIDO
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SCOTLAND
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UK
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UNITED KINGDOM