• Vaccine Name: T. cruzi Vaccine TcVac4
• Target Pathogen: Trypanosoma cruzi
• Target Disease: Chagas disease
• Type: Prime-boost vaccine with DNA vaccine priming
• Status: Research
• Host Species for Licensed Use: Human
• Host Species as Laboratory Animal Model: dog
• Antigen: TcG1, TcG2, and TcG4 (Aparicio-Burgos et al., 2015) - T. cruzi encoding plasmids which have elicited a strong Th1 - type antibody response dominated by immunoglobin G2b (IgG2b)/IgG1 isotypes. (Bhatia and Garg, 2008)
• G2 gene engineering:
  • Type: DNA vaccine construction
  • Description:
  • Detailed Gene Information: Click Here.
• protein G4 gene engineering:
  • Type: DNA vaccine construction
  • Description:
  • Detailed Gene Information: Click Here.
• TcG4 gene engineering:
  • Type: DNA vaccine construction
  • Description:
  • Detailed Gene Information: Click Here.
• Adjuvant:
  • Adjuvant name:
  • VO adjuvant ID: VO_0001147
• Adjuvant:
  • Adjuvant name:
  • VO adjuvant ID: VO_0001294
• Immunization Route: Intramuscular injection (i.m.)
• Description: A DNA - prime/T. rangeli - boost (TcVac4) vaccine encoding TcG1, TcG2, and TcG4 antigens plus IL-12 and GM-CSF-encoding plasmids(Aparicio-Burgos et al., 2015)

Dog Response

• Host Strain: Mongrel
• Host age: 3-4 months old
• Host gender: 10 Males and 11 Females
• Vaccination Protocol: Randomly assigned dogs to the following groups: a) pcDNA3.1/ no Tc(empty plasmid DNA and no challenge infection, n = 6); b) pcDNA3.1/Tc (empty plasmid followed by Tc challenge infection, n = 6); c) TcVac4/Tc (two doses of DNA vaccine followed by two doses of TrIE and challenge infection, n = 6); and d) TrIE/Tc (two doses of TrIE followed by challenge infection, n = 3). Each dose of DNA vaccine was delivered at two sites; intramuscular (180 μg each DNA in 0.9 ml PBS) and intradermal (20 μg each DNA in 0.1 ml PBS). TrIE vaccine was also delivered at two sites; subcutaneous (0.9x109 TrIE in 0.9 ml PBS-saponin) and intradermal (1x108 TrIE in 0.1 ml PBS- saponin).(Aparicio-Burgos et al., 2015)
• Immune Response: Immunization with TcVac4, delivered as two doses of subunit DNA vaccine and two doses of TrIE, elicited a strong parasite-specific IgG response with predominance of IgG2 subtype (IgG2/IgG1 = 2.7). Upon challenge infection, IgG1 response was expanded and IgG2 response barely changed, resulting in a balanced IgG2/IgG1 ratio (0.95) in TcVac4/Tc dogs. (Aparicio-Burgos et al., 2015)
• Challenge Protocol: Challenge infection with T. cruzi (3.5 x 10^3 culture-derived trypomastigotes/kg body weight, intraperitoneally) was performed six weeks after the last vaccine dose. The selected dose of the parasites was sufficient to produce acute parasitemia within 1–2 weeks of inoculation, and electrocardiographic changes within 6–8 weeks post-infection. All dogs were observed daily for general physical condition, at weekly intervals for clinical condition, and at 2-week intervals for cardiac function.(Aparicio-Burgos et al., 2015)