• Vaccine Name: DNA vaccine encoding PA (PA63)
• Target Pathogen: Bacillus anthracis
• Target Disease: Anthrax
• Vaccine Ontology ID: VO_0000518
• Type: DNA vaccine
• Antigen: B. anthracis PA (Gu et al., 1999)
• PagA from B. anthracis str. 'Ames Ancestor' gene engineering:
  • Type: Protein
  • Description:
  • Detailed Gene Information: Click Here.
• DNA vaccine plasmid:
  • DNA vaccine plasmid name:
  • DNA vaccine plasmid VO ID: VO_0000276
• Preparation: The gene fragment encoding AAs 173–764 of PA was PCR amplified. The PCR product was digested with NheI and BamHI and ligated into the pJW4303 vector, which was cut with the same two restriction enzymes. Both PA plasmid and control DNA were purified from E. coli DH5a using Endo-free plasmid preparation kits (Qiagen) and resuspended in PBS before use (Gu et al., 1999).
• Virulence: Virulent strains of B. anthracis are characterized by their expression of a polyglutamic acid capsule and the production of a protein toxin. In vivo studies to determine whether cell mediated immunity provided protection against virulent B. anthracis could not be performed, since such studies require BL3 con-tainment facilities (Gu et al., 1999).
• Storage: Not virulent.
• Description: There have been many attempts to improve the safety and immunogenicity of the current licensed anthrax vaccine, including the formulation of PA in different adjuvants, the use of recombinant, mutant PA, expression of PA by attenuated salmonellae, and the generation of attenuated B. anthracis strains lacking one or more toxin components. Current studies have examined the possibility of inducing protection against anthrax toxin by immunizing with a DNA vaccine encoding PA. Studies in other model systems indicate that antigen-encoding DNA plasmids can stimulate strong cellular and humoral immune responses against proteins from pathogens (Gu et al., 1999).

Mouse Response

• Host Strain: BALB/c
• Vaccination Protocol: BALB/c mice were immunized at 6–8 weeks of age by bilateral injection into the gastrocnemius muscle three times at 3-week intervals with 50 μg of purified plasmid in 50 μl of saline. Mice were bled two weeks after each vaccination. Some mice were challenged by tail vein injection of PA (60 μg/mouse) and LF (25–30 μg/mouse), a combination equivalent to approximately five LD50 (Gu et al., 1999).
• Persistence: (Gu et al., 1999)
• Side Effects: none (Gu et al., 1999)
• Efficacy: The PA DNA vaccine protects against lethal challenge with a combination of anthrax PA + LF (Gu et al., 1999).
• Description: Splenocytes from immunized BALB/c mice were stimulated to secrete IFNγ and IL-4 when exposed to PA in vitro. Immunized mice also mounted a humoral immune response dominated by IgG1 anti-PA antibody production. A 1:100 dilution of serum from these animals protected cells in vitro against cytotoxic concentrations of PA. Moreover, 7/8 mice immunized three times with the PA DNA vaccine were protected against lethal challenge with a combination of anthrax PA plus LF (Gu et al., 1999).