Showing papers on "Anthrax vaccines published in 1998"

Fermentation, Purification, and Characterization of Protective Antigen from a Recombinant, Avirulent Strain of Bacillus anthracis

Abstract: Bacillus anthracis, the etiologic agent for anthrax, produces two bipartite, AB-type exotoxins, edema toxin and lethal toxin. The B subunit of both exotoxins is an Mr 83,000 protein termed protective antigen (PA). The human anthrax vaccine currently licensed for use in the United States consists primarily of this protein adsorbed onto aluminum oxyhydroxide. This report describes the production of PA from a recombinant, asporogenic, nontoxigenic, and nonencapsulated host strain of B. anthracis and the subsequent purification and characterization of the protein product. Fermentation in a high-tryptone, high-yeast-extract medium under nonlimiting aeration produced 20 to 30 mg of secreted PA per liter. Secreted protease activity under these fermentation conditions was low and was inhibited more than 95% by the addition of EDTA. A purity of 88 to 93% was achieved for PA by diafiltration and anion-exchange chromatography, while greater than 95% final purity was achieved with an additional hydrophobic interaction chromatography step. The purity of the PA product was characterized by reversed-phase high-pressure liquid chromatography, sodium dodecyl sulfate (SDS)-capillary electrophoresis, capillary isoelectric focusing, native gel electrophoresis, and SDS-polyacrylamide gel electrophoresis. The biological activity of the PA, when combined with excess lethal factor in the macrophage cell lysis assay, was comparable to previously reported values.

Study of Immunization against Anthrax with the Purified Recombinant Protective Antigen of Bacillus anthracis

Abstract: Protective antigen (PA) of anthrax toxin is the major component of human anthrax vaccine. Currently available human vaccines in the United States and Europe consist of alum-precipitated supernatant material from cultures of toxigenic, nonencapsulated strains of Bacillus anthracis. Immunization with these vaccines requires several boosters and occasionally causes local pain and edema. We previously described the biological activity of a nontoxic mutant of PA expressed in Bacillus subtilis. In the present study, we evaluated the efficacy of the purified mutant PA protein alone or in combination with the lethal factor and edema factor components of anthrax toxin to protect against anthrax. Both mutant and native PA preparations elicited high anti-PA titers in Hartley guinea pigs. Mutant PA alone and in combination with lethal factor and edema factor completely protected the guinea pigs from B. anthracis spore challenge. The results suggest that the mutant PA protein may be used to develop an effective recombinant vaccine against anthrax.

Vaccines for preventing anthrax

Abstract: BACKGROUND Anthrax is an acute bacterial skin disease which may be fatal. Three anthrax vaccines are commercially available but their comparative effectiveness and safety is not clear. OBJECTIVES The objective of this review was to assess the effects of human anthrax vaccines in healthy adults and children. SEARCH STRATEGY We searched the Cochrane Controlled Trials Register, Medline, Embase and the reference lists of articles. We handsearched the journal Vaccine and contacted researchers in the field. SELECTION CRITERIA Randomised and quasi-randomised trials comparing anthrax vaccines with placebo, vaccines for other diseases or no intervention. DATA COLLECTION AND ANALYSIS Trial quality assessment and data extraction was conducted independently by the six authors. MAIN RESULTS Two trials involving 16,052 people were included. Both trials had methodological limitations. Compared to placebo, vaccination was associated with a reduced risk of contracting anthrax (relative risk 0.16, 95% confidence interval 0.07 to 0.35). Compared to placebo, the killed vaccine was associated with a higher incidence and severity of adverse effects (odds ratio 5.15, 95% confidence interval 2.28 to 11.61). Just over 5% of participants in the vaccine group reported adverse effects. The effectiveness of the vaccine does not appear to be influenced by the route of inoculation. REVIEWER'S CONCLUSIONS Killed anthrax vaccines appear to be effective in reducing the risk of contracting anthrax with a relatively low rate of adverse effects. Further research should be restricted to testing new vaccines only.

Mixed anthrax vaccine

Abstract: FIELD: medicine. SUBSTANCE: vaccine has living spores of noncapsule strain of Bac. anthracis aeAEe and protective antigen of Bac. anthracis. A single dose of commercial variant of vaccine has: living spores of strain Bac. anthracis aeAEe - 40-60 mln; protective antigen of Bac. anthracis - 30-40 ea 50 and aluminium hydroxide gel 2.5 mg, not above, where ea 50 - mean effective immunizing unit for albino mice. Vaccination is carried out one time per a year, expressing immunity is formed in 7-10 days. Immunization at antibiotic therapy background is possible. EFFECT: improved quality of vaccine. 5 tblt

Method of selection of anthrax vaccine strain cultures and vaccines prepared of thereof

Abstract: FIELD: microbiology. SUBSTANCE: anthrax strain cultures are tested preliminary in vitro with respect to their capability to produce toxin in medium of capsule formation. Selected cultures at relative content of Tox + KOE 95-98% are subjected for selection on bilayer agar. Hemolysis zone-forming colonies (size is 2-8 mm) are isolated in 18-24 h. Selected cultures are tested and evaluated with respect to their culture-morpholigical properties, harmless and immunogenicity in vivo. Invention can be used for quality control of living anthrax vaccines. EFFECT: decreased time and cost for vaccine strains, subcultures and ready vaccines testing. 6 tbl, 6 exc