• Vaccine Name: T. gondii irradiated sterilised tachyzoites
• Target Pathogen: Toxoplasma gondii
• Target Disease: Toxoplasmosis
• Type: Live, attenuated vaccine
• Status: Research
• Host Species for Licensed Use: Human
• Immunization Route: Intraperitoneal injection (i.p.) or oral gavage (v.o.)
• Description: Viable irradiated tachyzoites of T. gondii, maintains morphology and physiology but abolishes reproduction (Zorgi et al., 2016)

Mouse Response

• Host Strain: BALB/c (Zorgi et al., 2016)
• Host gender: male (Zorgi et al., 2016)
• Vaccination Protocol: Groups of five BALB/c mice received three doses of 10^7 irradiated T. gondii tachyzoites (ME-49 or VEG strain) biweekly; the parasites were administered either by i.p. injection or via oral gavage (v.o.) of 10^7 irradiated tachyzoites suspended 1:1 (v/v) in 6 % aluminum hydroxide. The unimmunized mice served as negative controls, and mice chronically infected by ME-49 or VEG strain served as positive control. (Zorgi et al., 2016)
• Immune Response: Humoral: Significant increase in the total IgG and IgM levels in i.p. immunized groups. Higher IgA levels in oral immunized groups. (Zorgi et al., 2016)
  Cellular: Higher levels of IL-10, TNF-α, IFN-ɤ, IL-4, IL-2, and IL-6 in i.p. immunized groups (Zorgi et al., 2016)
• Challenge Protocol: The immunized or control mice were challenged with ten cysts of the respective strain (ME49 or VEG) administered by oral gavage 90 days after the last immunizing dose; the mice were observed for daily survival determination. After 30 days, the surviving animals were killed and the brains were macerated in sterile saline solution. The solution containing the brain was subjected to DNA extraction to analyze the absolute number of parasites. (Zorgi et al., 2016)
• Efficacy: The challenge with both the ME-49 strain and the VEG strain in the intraperitoneally and orally immunized animals showed a significant decrease in the number of parasites in the brain tissue compared with the infected mice without immunization. (Zorgi et al., 2016)