Anthrax vaccine absorbed: genomic assessment of markers of protective immunity

Abstract

Bacillus anthacis is a nonmotile sporulating Gram-positive rod that can exist in normal soil flora. Inhalational anthrax has a high fatality rate if not detected and treated very rapidly, but early clinical diagnosis is difficult with nonspecific flu-like symptoms that can rapidly progress over a few days to respiratory distress and circulatory collapse. Antibiotic treatment at this later point is ineffective, so protection from anthrax using vaccines is a mainstay of dealing with potential anthrax infection. Anthrax Vaccine Adsorbed (AVA) was FDA approved 1970, based on limited data on mill workers (1950s). To predict the level of protection, antibody titers to protective antigen are used, but that antibody response takes weeks to occur, and immunity conferred prior to this elevation in anti-PA is unclear. Global gene analysis, in correlation with a classical immune function studies, can predict the protection conferred or impending adverse reaction. In this study, volunteers were vaccinated with 4 iterations of AVA and 2 months after the last dose, cells were obtained by leukopheresis, purified and exposed to B. anthracis in vitro. Global host gene expression responses were determined for comparisons with unvaccinated volunteers whose leukocytes were also exposed to B.anthracis. Bioinformatics mining tools have identified key factors showing unique responses between the vaccinated vs naïve volunteers