• Vaccine Name: T. gondii DNA vaccine pcDNA3.1-HisGRA6
• Target Pathogen: Toxoplasma gondii
• Target Disease: Toxoplasmosis
• Type: DNA vaccine
• Status: Research
• Host Species for Licensed Use: Human
• Antigen: GRA6 (Sun et al., 2011)
• GRA6 gene engineering:
  • Type: Recombinant protein preparation
  • Description: GRA6 ORF was PCR amplified and the PCR product was ligated into the pcDNA3.1 vectors to construct recombinant plasmid pcDNA3.1-HisGRA6. (Sun et al., 2011)
  • Detailed Gene Information: Click Here.
• Immunization Route: Intramuscular injection (i.m.)
• Description: T. gondii DNA vaccine encoding GRA6 using pcDNA3.1 vector. (Sun et al., 2011)

Mouse Response

• Host Strain: BALB/c mice carrying H-2Ld gene and Kunming mice without H-2Ld gene. (Sun et al., 2011)
• Host age: Six- to eight-week-old (Sun et al., 2011)
• Host gender: female (Sun et al., 2011)
• Vaccination Protocol: BALB/c mice received three injections of 100 μg of pcDNA3.1-HisGRA6 DNA at 2-week intervals in both tibialis anterior muscles. Kunming mice were immunized with pcDNA3.1-HisGRA6 and BALB/c with empty pcDNA3.1 as controls. One group of BALB/c mice was immunized with pcDNA3.1-HisGRA6 formulated in 1% LMS as the adjuvant. (Sun et al., 2011)
• Challenge Protocol: The immunized mice were challenged intraperitoneally with 1, 000 tachyzoites of T. gondii RH strain (Type I). One week after the challenge, brain, liver and spleen were removed and fixed in 10% formalin for histological examination. Two weeks after the last immunization, the animals were observed daily for mortality. (Sun et al., 2011)
• Efficacy: Immunization of BALB/c mice with pcDNA3.1-HisGRA6 significantly increased the survival rate of these mice (40% survival) (P < 0.05) in comparison with BALB/c immunized with the control vector or Kunming mice immunized with pcDNA3.1-HisGRA6 (0% survival) (P < 0.05). Survival was further increased in mice immunized with pcDNA3.1-HisGRA6 plus LMS (53.3% survival cf. 40% without LMS; P < 0.05). Mice alive at week 12 stayed alive for at least 2 months.
  No parasite was detected in the brain, liver or spleen of BALB/c mice immunized with pcDNA3.1-HisGRA6 alone or pcDNA3.1-HisGRA6 plus LMS. Parasites were clearly visible in the tissues of the control groups.
  (Sun et al., 2011)