• Vaccine Name: ISP3 VLP
• Target Pathogen: Toxoplasma gondii
• Target Disease: Toxoplasmosis
• Type: Other
• Status: Research
• Host Species for Licensed Use: Human
• Antigen: ISP3: IMC sub-compartment protein 3 (Lee et al., 2016)
• ISP3 gene engineering:
  • Type: Recombinant protein preparation
  • Description: Total RNA of T. gondii tachyzoites was extracted. Complementary DNA (cDNA) was synthesized and Toxoplasma gondii IMC gene was amplified by PCR from cDNA with primers containing EcoRI and XhoI sites. The gene was cloned into pFastBac vector and was transfected and formed recombinant baculovirus (rBV). Sf9 insect cells was co-infected by rBVs expressing T. gondii IMC or influenza M1, and VLPs containing both T. gondii IMC and influenza M1 were released. (Lee et al., 2016)
  • Detailed Gene Information: Click Here.
• Immunization Route: Nasal spray
• Description: Virus-like particle (VLP) vaccine consisting of the influenza M1 protein as a core protein together with IMC ISP3 of T. gondii. (Lee et al., 2016)

Mouse Response

• Vaccination Protocol: Mice (6 per group) were intranasally immunized twice with 100 μg total VLP protein at 4-week intervals. (Lee et al., 2016)
• Immune Response: Higher levels of IgA and IgG, higher IgG2a than IgG1; higher levels of IFN-γ, IL-6 and IL-11 (Lee et al., 2016)
• Challenge Protocol: Naïve or immunized mice were infected with T. gondii ME49 intraperitoneally with 20 cysts in 100 μl PBS at 1 month after boosting. Body weight changes and survival were observed daily, and cysts in the brain were counted. (Lee et al., 2016)
• Efficacy: Significantly decreased cyst counts and cyst sizes in brain were detected in mice upon challenge infections compared to non-immunized mouse controls (Reduction rate of cyst count: 75%, **P < 0.01; Reduction rate of cyst size: 50%, *P < 0.05) Immunized mice gained body weight whereas control mice lost body weight or died upon challenge. All mice immunized survived whereas control mice showed 60% survival. (Lee et al., 2016)