• Vaccine Name: T. gondii DNA vaccine pVitro-SAG1-GRA7
• Target Pathogen: Toxoplasma gondii
• Target Disease: Toxoplasmosis
• Type: DNA vaccine
• Status: Research
• Host Species for Licensed Use: Human
• Antigen: SAG1 (Mavi et al., 2019); GRA7 (Mavi et al., 2019)
• SAG1 gene engineering:
  • Type: DNA vaccine construction
  • Description: Full-length coding region of SAG1 were PCR amplified and were cloned into pTZ57R/T vectors. The recombinant construct pTZ-SAG1 was digested with BglII and NheI, and the ligations were subcloned into empty pVitro2-neo-mcs vectors, previously digested by corresponding restriction enzymes. (Mavi et al., 2019)
  • Detailed Gene Information: Click Here.
• GRA7 gene engineering:
  • Type: DNA vaccine construction
  • Description: Full-length coding region of GRA7 were PCR amplified and were cloned into pTZ57R/T vectors. The recombinant construct pTZ-GRA7 was digested with BamHI and ClaI, and the ligations were subcloned into empty pVitro2-neo-mcs vectors, previously digested by corresponding restriction enzymes. (Mavi et al., 2019)
  • Detailed Gene Information: Click Here.
• Immunization Route: Intramuscular injection (i.m.)
• Description: T. gondii DNA vaccine encoding SAG1 and GRA7 as antigens using pVitro2-neo-mcs vector (Mavi et al., 2019)

Mouse Response

• Host Strain: BALB/c (Mavi et al., 2019)
• Vaccination Protocol: 84 BALB/c mice were divided randomly into seven groups of 12 mice. Negative control groups, including Groups I to III, received 100 µL of PBS, 100 µg of empty pVitro2-neo-mcs vector in 100 µL of PBS and 30 µg of CpG-ODN in 100 µL of PBS, respectively. Experimental groups of IV to VII were injected with 100 µg of pVitro-SAG1 plasmid in 100 µL of PBS, 100 µg of pVitro-GRA7 plasmid in 100 µL of PBS, 100 µg of pVitro-SAG1-GRA7 plasmid in 100 µL of PBS and 100 µg of pVitro-SAG1-GRA7 plasmid with 30 µg of CpG-ODN in 100 µL of PBS, respectively. Mice were immunized intramuscularly (IM) thrice on days 1, 21 and 42. (Mavi et al., 2019)
• Immune Response: Humoral: higher IgG levels in pVitro-SAG1-GRA7 and pVitro-SAG1-GRA7 with CpG-ODN groups, higher IgG levels in pVitro-SAG1 group than in pVitro-GRA7 group. IgG2a levels significantly increased in all experimental groups.
  Cellular: higher lymphocyte proliferation and IFN-γ levels in pVitro-SAG1-GRA7 and pVitro-SAG1-GRA7 with CpG-ODN groups. Difference of SI was statistically significant in mice immunized with pVitro-SAG1-GRA7 with CpG-ODN, compared to that in mice received pVitro-SAG1-GRA7 alone (P<0.001).
  (Mavi et al., 2019)
• Challenge Protocol: Four weeks after the last immunization, nine immunized BALB/c mice from each group were randomly selected and involved in infection experiments. Each mouse was inoculated intraperitoneally (IP) with a single dose of 1×10^3 tachyzoites of the virulent T. gondii, RH strain. Mice were monitored twice daily and the time of death was recorded until all mice were dead. (Mavi et al., 2019)
• Efficacy: All mice in control groups died within 5–8 days after confronting lethal challenge. The survival time in experimental groups was significantly (P<0.05) longer than that in control groups. Mice immunized with pVitro-SAG1–GRA7 vaccine alone and pVitro-SAG1-GRA7 with CpG-ODN vaccine, respectively, survived 9–15 days (13.25±1.85) and 11–18 days (15.0±2.29) after lethal challenges which were significantly longer than that mice immunized with pVitro-SAG1 or pVitro-GRA7 groups did, including 8–14 (10.87±2.02) and 8–12 (10.0±1.41) days after lethal challenges, respectively. Furthermore, in pVitro-SAG1-GRA7 with CpG-ODN group, a longer survival time was observed, compared to that in pVitro-SAG1-GRA7 group. (Mavi et al., 2019)