title: In vitro correlate of immunity in a rabbit model of inhalational anthrax.
abstract: A serological correlate of vaccine-induced immunity was identified in the rabbit model of inhalational anthrax. Animals were inoculated intramuscularly at 0 and 4 weeks with varying doses of Anthrax Vaccine Adsorbed (AVA) ranging from a human dose to a 1:256 dilution in phosphate-buffered saline (PBS). At 6 and 10 weeks, both the quantitative anti-protective antigen (PA) IgG ELISA and the toxin-neutralizing antibody (TNA) assays were used to measure antibody levels to PA. Rabbits were aerosol-challenged at 10 weeks with a lethal dose (84-133 LD(50)) of Bacillus anthracis spores. All the rabbits that received the undiluted and 1:4 dilution of vaccine survived, whereas those receiving the higher dilutions of vaccine (1:16, 1:64 and 1:256) had deaths in their groups. Results showed that antibody levels to PA at both 6 and 10 weeks were significant (P<0.0001) predictors of survival.
authors.affiliation: United States Army Medical Research Institute of Infectious Diseases, Fort Detrick, Frederick, MD 21702-5011, USA. louise.pitt@amedd.army.mil
authors.forename: M L
authors.initials: ML
authors.lastname: Pitt
authors.forename: S F
authors.initials: SF
authors.lastname: Little
authors.forename: B E
authors.initials: BE
authors.lastname: Ivins
authors.forename: P
authors.initials: P
authors.lastname: Fellows
authors.forename: J
authors.initials: J
authors.lastname: Barth
authors.forename: J
authors.initials: J
authors.lastname: Hewetson
authors.forename: P
authors.initials: P
authors.lastname: Gibbs
authors.forename: M
authors.initials: M
authors.lastname: Dertzbaugh
authors.forename: A M
authors.initials: AM
authors.lastname: Friedlander
mesh_terms: D000280:Administration, Inhalation; D000336:Aerosols; D000818:Animals; D000881:Anthrax / Q000276:immunology* / Q000517:prevention & control / Q000635:transmission; D022122:Anthrax Vaccines / Q000276:immunology*; D000907:Antibodies, Bacterial / Q000096:biosynthesis / Q000276:immunology*; D000942:Antigens, Bacterial / Q000276:immunology; D001408:Bacillus anthracis / Q000276:immunology*; D016667:Bacterial Capsules / Q000276:immunology; D001427:Bacterial Toxins / Q000276:immunology; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D007074:Immunoglobulin G / Q000096:biosynthesis / Q000276:immunology; D007273:Injections, Intramuscular; D008297:Male; D008322:Mammals; D023421:Models, Animal; D009500:Neutralization Tests; D011817:Rabbits; D013045:Species Specificity; D013047:Specific Pathogen-Free Organisms; D013171:Spores, Bacterial; D014774:Virulence
chemical_list: D000336:Aerosols; D022122:Anthrax Vaccines; D000907:Antibodies, Bacterial; D000942:Antigens, Bacterial; D001427:Bacterial Toxins; D007074:Immunoglobulin G; C030325:anthrax toxin