A Heterodimer of a VHH (Variable Domains of Camelid Heavy Chain-only) Antibody That Inhibits Anthrax Toxin Cell Binding Linked to a VHH Antibody That Blocks Oligomer Formation Is Highly Protective in an Anthrax Spore Challenge Model

Moayeri, Mahtab; Leysath, Clinton E.; Tremblay, Jacqueline M.; Vrentas, Catherine E.; Crown, Devorah; Leppla, Stephen H.; Shoemaker, Charles B.

doi:10.1074/jbc.m114.627943

Cited by 35 publications

(52 citation statements)

References 43 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…VHH-based neutralizing agents consisting of two or more different VHHs covalently linked to each other via a peptide spacer have proven to be extremely effective in mouse (and in one case piglet) models at inactivating an array of different plant-and microbe-derived protein toxins, including botulinum neurotoxin (6), C. difficile toxins TcdA and TcdB (7-9), Shiga toxins (10,29), ricin (11,12), and anthrax toxin (13). However, with the exception of anthrax toxin, the mechanisms by which these VNAs function in vitro and in vivo remains poorly understood.…”

Section: Discussionmentioning

confidence: 99%

“…Although a number of promising toxinneutralizing murine and humanized monoclonal antibodies (mAbs) are in the pipeline, the emergence of technologies surrounding the generation and expression of toxin-specific camelid heavy chain-only VH domains (VHHs) 3 has opened up new avenues for the rational design and delivery of antitoxin agents (5). VHHs with toxin-neutralizing activity have been described against botulinum neurotoxin (6), Clostridium difficile toxins TcdA and TcdB (7)(8)(9), Shiga toxins (10), ricin (11,12), and anthrax toxin (13). X-ray crystallography of toxin-VHH complexes has provided novel insights into the mechanisms of toxin neutralization (7,14) and single chain antibodies have been successfully delivered into the intracellular compartment of mammalian cells where they can effectively inactivate their targets (15).…”

mentioning

confidence: 99%

See 1 more Smart Citation

Mechanisms of Ricin Toxin Neutralization Revealed through Engineered Homodimeric and Heterodimeric Camelid Antibodies

Herrera

Tremblay

Shoemaker

et al. 2015

Journal of Biological Chemistry

Self Cite

View full text Add to dashboard Cite

Background: Bispecific heterodimeric camelid heavy chain-only antibodies (VHHs) have been shown to neutralize ricin toxin in vivo. Results: Heterodimeric VHHs promote ricin aggregation in solution and block toxin attachment to cell surfaces. Conclusion:The bispecific nature of the heterodimeric VHHs may be important for toxin neutralization in vivo. Significance: Understanding mechanisms of toxin neutralization will lead to the development of new antitoxin agents.

show abstract

Section: Discussionmentioning

confidence: 99%

mentioning

confidence: 99%

Mechanisms of Ricin Toxin Neutralization Revealed through Engineered Homodimeric and Heterodimeric Camelid Antibodies

Herrera

Tremblay

Shoemaker

et al. 2015

Journal of Biological Chemistry

Self Cite

View full text Add to dashboard Cite

show abstract

“…Anthrax is caused by a toxin consisting of protective antigen (PA), lethal factor (LF), and edema factor (EF). Several VHHs directed against the three components of the toxin have been shown to be efficient against Anthrax disease [53,54]. Gene therapy with an adenoviral vector expressing a bispecific VHH, consisting of two linked VHHs targeting different PA-neutralizing epitopes, was tested in mice, and found to protect them from anthrax toxin challenge and anthrax spore infection [55].…”

Section: Anthraxmentioning

confidence: 99%

Use of camel single-domain antibodies for the diagnosis and treatment of zoonotic diseases

Lafaye

2018

Comparative Immunology, Microbiology and Infectious Diseases

View full text Add to dashboard Cite

A B S T R A C TCamelids produce both conventional heterotetrameric antibodies and homodimeric heavy-chain only antibodies. The antigen-binding region of such homodimeric heavy-chain only antibodies consists of one single domain, called VHH. VHHs provide many advantages over conventional full-sized antibodies and currently used antibody-based fragments (Fab, scFv), including high specificity, stability and solubility, and small size, allowing them to recognize unusual antigenic sites and deeply penetrate tissues. Since their discovery, VHHs have been used extensively in diagnostics and therapy. In recent decades, the number of outbreaks of diseases transmissible from animals to humans has been on the rise. In this review, we evaluate the status of VHHs as diagnostic and therapeutic biomolecular agents for the detection and treatment of zoonotic diseases, such as bacterial, parasitic, and viral zoonosis. VHHs show great adaptability to inhibit or neutralize pathogenic agents for the creation of multifunctional VHH-based diagnostic and therapeutic molecules against zoonotic diseases.

show abstract

“…The generation of recombinant replication-incompetent Ad5-based vectors was previously described (20). Briefly, in a modification from the method of Mukherjee et al (7), pShCMV-JGf7 shuttle plasmid was used for subcloning the VNA2-PA-coding sequence (6), under the control of the mammalian cytomegalovirus (CMV) promoter and followed by the bovine growth hormone poly(A) signal. A control vector, Ad/VNA-RT, was created in a similar manner with the sequence from two VHHs against ricin A chain (21).…”

Section: Ethics Statementmentioning

confidence: 99%

“…We previously characterized a potent VNA for the treatment of anthrax (VNA2-PA), made as a heterodimer of two VHHs that neutralize PA by different mechanisms. One VHH, JKH-C7, inhibits the translocation of the cell surface-generated PA63 oligomer, while the other, JIK-B8, is a potent receptor blocker with a subnanomolar binding affinity for PA (6).…”

mentioning

confidence: 99%

Adenoviral Expression of a Bispecific VHH-Based Neutralizing Agent That Targets Protective Antigen Provides Prophylactic Protection from Anthrax in Mice

Moayeri

Tremblay

Debatis

et al. 2016

Clin Vaccine Immunol

Self Cite

View full text Add to dashboard Cite

dBacillus anthracis, the causative agent of anthrax, secretes three polypeptides, which form the bipartite lethal and edema toxins (LT and ET, respectively). The common component in these toxins, protective antigen (PA), is responsible for binding to cellular receptors and translocating the lethal factor (LF) and edema factor (EF) enzymatic moieties to the cytosol. Antibodies against PA protect against anthrax. We previously isolated toxin-neutralizing variable domains of camelid heavy-chain-only antibodies (VHHs) and demonstrated their in vivo efficacy. In this work, gene therapy with an adenoviral (Ad) vector (Ad/VNA2-PA) (VNA, VHH-based neutralizing agents) promoting the expression of a bispecific VHH-based neutralizing agent (VNA2-PA), consisting of two linked VHHs targeting different PA-neutralizing epitopes, was tested in two inbred mouse strains, BALB/cJ and C57BL/6J, and found to protect mice against anthrax toxin challenge and anthrax spore infection. Two weeks after a single treatment with Ad/VNA2-PA, serum VNA2-PA levels remained above 1 g/ml, with some as high as 10 mg/ml. The levels were 10-to 100-fold higher and persisted longer in C57BL/6J than in BALB/cJ mice. Mice were challenged with a lethal dose of LT or spores at various times after Ad/VNA2-PA administration. The majority of BALB/cJ mice having serum VNA2-PA levels of >0.1 g/ml survived LT challenge, and 9 of 10 C57BL/6J mice with serum levels of >1 g/ml survived spore challenge. Our findings demonstrate the potential for genetic delivery of VNAs as an effective method for providing prophylactic protection from anthrax. We also extend prior findings of mouse strain-based differences in transgene expression and persistence by adenoviral vectors. Bacillus anthracis produces two toxins, which are responsible for allowing the bacterium to establish disease and induce lethality in the host. Lethal toxin (LT) and edema toxin (ET) are composed of three proteins: protective antigen (PA), lethal factor (LF), and edema factor (EF). PA is a receptor-binding component that transports LF (a protease) or EF (an adenylate cyclase) into cells where they can manifest their catalytic activities through the targeting of ubiquitous substrates. EF targets ATP and converts it to cyclic AMP (cAMP), resulting in cellular dysfunction and vascular events that can lead to lethality. LF cleaves the mitogen-activated protein kinase (MEK) family and rodent nucleotide-binding domain and leucine-rich repeat containing a pyrin domain 1 (NLRP1) inflammasome sensors. LF plays an important role in both early and late anthrax infection. Early in infection, inactivation of the MEK proteins by cleavage leads to the inhibition of a wide variety of innate immune cell responses, which allows the bacterium to evade the immune system, divide, and disseminate. The cleavage of NLRP1 early in infection in certain inbred rodents results in the activation of the inflammasome, macrophage pyroptosis, and induction of proinflammatory cytokines, which induce a protective immune response. Thus,...

show abstract

A Heterodimer of a VHH (Variable Domains of Camelid Heavy Chain-only) Antibody That Inhibits Anthrax Toxin Cell Binding Linked to a VHH Antibody That Blocks Oligomer Formation Is Highly Protective in an Anthrax Spore Challenge Model

Cited by 35 publications

References 43 publications

Mechanisms of Ricin Toxin Neutralization Revealed through Engineered Homodimeric and Heterodimeric Camelid Antibodies

Mechanisms of Ricin Toxin Neutralization Revealed through Engineered Homodimeric and Heterodimeric Camelid Antibodies

Use of camel single-domain antibodies for the diagnosis and treatment of zoonotic diseases

Adenoviral Expression of a Bispecific VHH-Based Neutralizing Agent That Targets Protective Antigen Provides Prophylactic Protection from Anthrax in Mice

Contact Info

Product

Resources

About