• Vaccine Name: Anthrax Spore Vaccine
• Target Pathogen: Bacillus anthracis
• Target Disease: Anthrax
• Product Name: B. anthracis Sterne strain spore vaccine
• Manufacturer: Colorado Serum Company
• Vaccine Ontology ID: VO_0000874
• Type: Live, attenuated vaccine
• Status: Licensed
• PagA from B. anthracis str. 'Ames Ancestor' gene engineering:
  • Type: Protein
  • Description:
  • Detailed Gene Information: Click Here.
• Preparation: Anthrax Spore Vaccine is prepared with a relatively nonpathogenic, noncapsulated variant strain of B. anthracis, originally developed at the Onderstepoort Laboratory, Pretoria, South Africa. Further work was conducted in England, India and in many other countries. Vaccine Strain is Sterne 34F2. The vaccine is a suspension of viable Bacillus anthracis spores in saponin (Spore vaccine).

Guinea pig Response

• Host Strain: Female Hartley guinea pigs
• Vaccination Protocol: Three 0.5-ml doses of the PA vaccine were administered at 2-week intervals. The commercial live veterinary Sterne strain spore vaccine was administered in three doses: 0.2, 0.3, and 0.5 ml i.m. at 2-week intervals. The stock spore vaccine contained 5 x 10^6 to 6 x 10^6 spores per ml (Little et al., 1986).
• Immune Response: A high ELISA titer was obtained after immunization, as demonstrated by immunization with Sterne strain spores or PA vaccine + LF. However, it did not reflect the level of expected protection. This was demonstrated after challenge with a vaccine-resistant isolate. Comparison of the vaccine-resistant isolates with the Vollum cultures suggested that it is not the difference in the LD50s of the isolates that determines vaccine resistance but some other factors (Little et al., 1986).
• Challenge Protocol: The animals were then challenged i.m. with 2,500 spores of Vollum 1B 2 weeks after immunization.
• Efficacy: With Vollum and Vollum 1B, strains of B. anthracis killed 50% or more of the PA-immunized animals. The data confirm earlier findings: although guinea pigs were immunized effectively against a Vollum challenge, they were not protected against challenge with some isolates of B. anthracis. The study tested 4 of the10 strains used from the earlier study challenging their guinea pigs. In total 9 of 27 isolates tested were found to be resistant to immunization with the PA vaccine. Vaccination of guinea pigs with Sterne strain spores appears to provide broad protection against i.m. challenge with various anthrax isolates. A dose-response curve of the Sterne spore vaccine was obtained by injecting guinea pigs with 0.5 ml i.m. in a single dose or as two doses 14 days apart. The data indicate that excellent protection and antibody response to PA antigen can be achieved with two immunization doses of 10^6 Sterne spores (Little et al., 1986).
• Description: Although various antigen preparations appear to provide a substantial degree of protection when immunized animals are challenged with the standard Vollum strain, earlier studies demonstrated that certain B. anthracis isolates were able to override this immunity in guinea pigs. This current study seeks an overall effort to evaluate and improve the PA vaccine presently used for humans and to confirm and expand upon those earlier studies (Little et al., 1986).