Anthrax prevention through vaccine and post-exposure therapy

ABSTRACT

Introduction

Vaccines and therapeutic antibodies are the most crucial components of anthrax prophylaxis (pre- and post-exposure) and treatment. The improvement in the availability and safety profile of vaccines and the therapeutic antibodies has helped immensely in reducing the worldwide burden of anthrax.

Areas covered

Current recommendations for anthrax prophylaxis and control, vaccines and therapeutic antibodies, the recent endeavors, particularly, made after 2010 toward making them safer and more efficacious along with our opinion on its future course. Primarily, PubMed and Europe PMC were searched to cover the recent developments in the above-indicated areas.

Expert opinion

Some key existing lacunae in our understanding of the working of biologicals-based anthrax-control measures, i.e., vaccines and therapeutic antibodies, should be addressed to improve their overall stability, safety profile, and efficacy. The identification of novel inhibitors targeting different key-molecules and vital-steps contributing to the overall anthrax pathophysiology could make a difference in anthrax control.

KEYWORDS:

• Anthrax
• anthrax toxin
• Bacillus anthracis
• bioterrorism
• protective antigen
• therapeutic antibodies
• vaccines

Article highlights

• Anthrax pathogenicity is primarily the result of the interplay of anthrax toxins – Lethal Toxin (LT) and Edema Toxin (ET) produced by Bacillus anthracis, and their combined effect on tissues and overall physiology of the host.

• Pre-Exposure Prophylaxis involves the administration of Vaccines [Live: Sterne strain and derivatives for livestock; A16R and STI-1 for humans; Acellular: Anthrax Vaccine Adsorbed (AVA) and Anthrax Vaccine Precipitated (AVP)].

• Post-Exposure Prophylaxis involves Antibiotics, Immunotherapy (Therapeutic antibodies: Polyclonal plasmapheresed horse serum, Polyclonal human IgG - ‘Anthrasil’ and Monoclonals - Raxibacumab and obiltoxaximab/ Anthim®/ ETI-204) and acellular vaccines.

• Endeavors are being made to generate the next generation improved live attenuated, non-living spore-based, plant-based, subunit, DNA, peptide-based/multiepitope, chimeric antigen, virus, and virus-like nanoparticle vaccines. Considering limitations of anthrax immunotherapy (hyperimmune polyclonal serum, monoclonal antibodies) various efforts are underway to make it safer and more useful (P-mAb, nanobodies, immunoadhesins).

• Dependence of protective immunity generation on host genetic makeup along with differential tissue and organ toxicity from different virulence factors secreted by B. anthracis, including the anthrax toxins and their interaction with the host, needs to be understood to develop better next-generation vaccines and therapeutic antibody cocktails.

• Discovery of small-molecule inhibitors that could interfere with host colonization, virulence factors interaction with target molecules both outside and inside the cell along with the improvement in supportive hemodynamic and ventilator support for critically ill could help improve the overall survival from B. anthracis infection.

Declaration of interest

Funders had no role in the decision to publish the work. No writing assistance was utilized in the drafting and production of this manuscript. The authors have no other relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript apart from those disclosed.

Reviewer disclosures

Peer reviewers on this manuscript have no relevant financial relationships or otherwise to disclose.

Correction Statement

This article has been republished with minor changes. These changes do not impact the academic content of the article.

Additional information

Funding

Financial support from the Department of Biotechnology (DBT) & Department of Science and Technology (DST), India is acknowledged. SS is a Ramalingaswami Fellow, supported by DBT, India (No. BT/RLF/Re-entry/50/2011).