Characterization of the adaptive immune response of donors receiving live anthrax vaccine.

Victoria V Firstova,Igor G Shemyakin,Yana O Romanenko,Methun M Rogozin,Maksim A Marin,Anastasia S Shakhova,Alena K Riabko,Natalia A Zeninskaya,Marina V Silkina,Ivan A Dyatlov,Alena S Kartseva,Samer Singh

doi:10.1371/journal.pone.0260202

Abstract

Live anthrax vaccine containing spores from attenuated strains STI-1 of Bacillus anthracis is used in Russia and former CIS (Commonwealth of Independent States) to prevent anthrax. In this paper we studied the duration of circulation of antibodies specific to spore antigens, the protective antigen (PA), the lethal factor (LF) and their domains (D) in donors’ blood at different times after their immunization with live anthrax vaccine. The relationship between the toxin neutralization activity level and the level of antibodies to PA, LF and their domains was tested. The effect of age, gender and number of vaccinations on the level of adaptive post-vaccination immune response has been studied. It was shown that antibodies against PA-D1 circulate in the blood of donors for 1 year or more after immunization with live anthrax vaccine. Antibodies against all domains of LF and PA-D4 were detected in 11 months after vaccination. Antibodies against the spores were detected in 8 months after vaccination. A moderate positive correlation was found between the titers of antibodies to PA, LF, or their domains, and the TNA of the samples of blood serum from the donors.

Highlights

Vaccination against Bacillus anthracis is considered one of the most effective preventive measures against anthrax
We examined the samples of blood serum from 67 donors who had previously been vaccinated with live anthrax vaccine (LAV) and the samples of blood serum from 21 healthy donors who had never been vaccinated with LAV
The number of samples of the blood serum seropositive to protective antigen (PA) and lethal factor (LF) decreased in 4–8 months or more after immunization with LAV

Summary

Introduction

Vaccination against Bacillus anthracis is considered one of the most effective preventive measures against anthrax. Two types of anthrax vaccines are used in the world—live attenuated vaccines and subunit vaccines. Live anthrax vaccine contains live spores of the vaccine strain Bacillus anthracis STI that produces the anthrax toxin. Subunit cell-free vaccines BioThraxTM (i.e., Anthrax Vaccine Adsorbed (AVA)) and NuThraxTM manufactured by Emergent BioSolutions Inc., USA (that is at the 3rd stage of clinical trials) as well as Anthrax Vaccine Precipitated (AVP) manufactured by Porton Biopharma Ltd, UK, are all in the form of a sterile filtrate adsorbed on a carrier of the anthrax toxin obtained from a culture of vaccine anthrax strains. The above-mentioned vaccines do not contain live microorganisms.

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Conclusion