Recombinant HSA-CMG2 Is a Promising Anthrax Toxin Inhibitor

Anthrax toxin is the major virulence factor produced by Bacillus anthracis. Protective antigen (PA) is the key component of the toxin and has been confirmed as the main target for the development of toxin inhibitors. The inhibition of the binding of PA to its receptor, capillary morphogenesis protei...

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Main Authors: Liangliang Li, Qiang Guo, Ju Liu, Jun Zhang, Ying Yin, Dayong Dong, Ling Fu, Junjie Xu, Wei Chen
Format: Article
Language:English
Published: MDPI AG 2016-01-01
Series:Toxins
Subjects:
Online Access:http://www.mdpi.com/2072-6651/8/1/28
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author Liangliang Li
Qiang Guo
Ju Liu
Jun Zhang
Ying Yin
Dayong Dong
Ling Fu
Junjie Xu
Wei Chen
author_facet Liangliang Li
Qiang Guo
Ju Liu
Jun Zhang
Ying Yin
Dayong Dong
Ling Fu
Junjie Xu
Wei Chen
author_sort Liangliang Li
collection DOAJ
description Anthrax toxin is the major virulence factor produced by Bacillus anthracis. Protective antigen (PA) is the key component of the toxin and has been confirmed as the main target for the development of toxin inhibitors. The inhibition of the binding of PA to its receptor, capillary morphogenesis protein-2 (CMG2), can effectively block anthrax intoxication. The recombinant, soluble von Willebrand factor type A (vWA) domain of CMG2 (sCMG2) has demonstrated potency against anthrax toxin. However, the short half-life of sCMG2 in vivo is a disadvantage for its development as a new anthrax drug. In the present study, we report that HSA-CMG2, a protein combining human serum albumin (HSA) and sCMG2, produced in the Pichia pastoris expression system prolonged the half-life of sCMG2 while maintaining PA binding ability. The IC50 of HSA-CMG2 is similar to those of sCMG2 and CMG2-Fc in in vitro toxin neutralization assays, and HSA-CMG2 completely protects rats from lethal doses of anthrax toxin challenge; these same challenge doses exceed sCMG2 at a sub-equivalent dose ratio and overwhelm CMG2-Fc. Our results suggest that HSA-CMG2 is a promising inhibitor of anthrax toxin and may contribute to the development of novel anthrax drugs.
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spelling doaj.art-58b06bcc27e14989b1f032651e27eb722022-12-22T01:57:27ZengMDPI AGToxins2072-66512016-01-01812810.3390/toxins8010028toxins8010028Recombinant HSA-CMG2 Is a Promising Anthrax Toxin InhibitorLiangliang Li0Qiang Guo1Ju Liu2Jun Zhang3Ying Yin4Dayong Dong5Ling Fu6Junjie Xu7Wei Chen8Laboratory of Vaccine and Antibody Engineering, Beijing Institute of Biotechnology, Beijing 100071, ChinaLaboratory of Vaccine and Antibody Engineering, Beijing Institute of Biotechnology, Beijing 100071, ChinaLaboratory of Vaccine and Antibody Engineering, Beijing Institute of Biotechnology, Beijing 100071, ChinaLaboratory of Vaccine and Antibody Engineering, Beijing Institute of Biotechnology, Beijing 100071, ChinaLaboratory of Vaccine and Antibody Engineering, Beijing Institute of Biotechnology, Beijing 100071, ChinaLaboratory of Vaccine and Antibody Engineering, Beijing Institute of Biotechnology, Beijing 100071, ChinaLaboratory of Vaccine and Antibody Engineering, Beijing Institute of Biotechnology, Beijing 100071, ChinaLaboratory of Vaccine and Antibody Engineering, Beijing Institute of Biotechnology, Beijing 100071, ChinaLaboratory of Vaccine and Antibody Engineering, Beijing Institute of Biotechnology, Beijing 100071, ChinaAnthrax toxin is the major virulence factor produced by Bacillus anthracis. Protective antigen (PA) is the key component of the toxin and has been confirmed as the main target for the development of toxin inhibitors. The inhibition of the binding of PA to its receptor, capillary morphogenesis protein-2 (CMG2), can effectively block anthrax intoxication. The recombinant, soluble von Willebrand factor type A (vWA) domain of CMG2 (sCMG2) has demonstrated potency against anthrax toxin. However, the short half-life of sCMG2 in vivo is a disadvantage for its development as a new anthrax drug. In the present study, we report that HSA-CMG2, a protein combining human serum albumin (HSA) and sCMG2, produced in the Pichia pastoris expression system prolonged the half-life of sCMG2 while maintaining PA binding ability. The IC50 of HSA-CMG2 is similar to those of sCMG2 and CMG2-Fc in in vitro toxin neutralization assays, and HSA-CMG2 completely protects rats from lethal doses of anthrax toxin challenge; these same challenge doses exceed sCMG2 at a sub-equivalent dose ratio and overwhelm CMG2-Fc. Our results suggest that HSA-CMG2 is a promising inhibitor of anthrax toxin and may contribute to the development of novel anthrax drugs.http://www.mdpi.com/2072-6651/8/1/28Bacillus anthracisprotective antigenanthrax toxin inhibitorCMG2HSA
spellingShingle Liangliang Li
Qiang Guo
Ju Liu
Jun Zhang
Ying Yin
Dayong Dong
Ling Fu
Junjie Xu
Wei Chen
Recombinant HSA-CMG2 Is a Promising Anthrax Toxin Inhibitor
Toxins
Bacillus anthracis
protective antigen
anthrax toxin inhibitor
CMG2
HSA
title Recombinant HSA-CMG2 Is a Promising Anthrax Toxin Inhibitor
title_full Recombinant HSA-CMG2 Is a Promising Anthrax Toxin Inhibitor
title_fullStr Recombinant HSA-CMG2 Is a Promising Anthrax Toxin Inhibitor
title_full_unstemmed Recombinant HSA-CMG2 Is a Promising Anthrax Toxin Inhibitor
title_short Recombinant HSA-CMG2 Is a Promising Anthrax Toxin Inhibitor
title_sort recombinant hsa cmg2 is a promising anthrax toxin inhibitor
topic Bacillus anthracis
protective antigen
anthrax toxin inhibitor
CMG2
HSA
url http://www.mdpi.com/2072-6651/8/1/28
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