• Vaccine Ontology ID: VO_0003005
• Type: Live, attenuated vaccine
• Status: Research
• Host Species as Laboratory Animal Model: Mouse, hamster
• cen1 gene engineering:
  • Type: Gene mutation
  • Description: This cen1 mutant is from Leishmania donovani (Selvapandiyan et al., 2009).
  • Detailed Gene Information: Click Here.
• Immunization Route: Intravenous injection (i.v.)

• Vaccine Ontology ID: VO_0004272
• Type: DNA vaccine
• Status: Research
• Antigen: P1 gene of Leishmania donovani (Arora et al., 2011).
• P1 gene engineering:
  • Type: DNA vaccine construction
  • Description: The purified full-length ORF cloned non-directionally in pGEMT-Easy vector was digested out and then directionally sub-cloned in pVAX1 vector (Invitrogen, USA). The purified plasmid DNA containing full-length ORF was confirmed by DNA sequencing also. The plasmid DNA was made endotoxin-free by using Endofree Plasmid DNA Mega Purification Kit (Qiagen, Hilden, Germany) according to the manufacturer’s instructions. The endotoxin free plasmid DNA (termed pVAX-P1) was used for the immunization of animals as DNA vaccine (Arora et al., 2011).
  • Detailed Gene Information: Click Here.
• Vector: pVAX1 (Arora et al., 2011)
• Immunization Route: Intramuscular injection (i.m.)
• Description: pVAX-P1 DNA vaccine, given in prime-boost mode is protective against L. donovani (Arora et al., 2011).

Mouse Response

• Persistence: A cen1 mutant is attenuated in mice (Selvapandiyan et al., 2009).
• Efficacy: A cen1 mutant induces significant protection in mice from challenge with wild type L. donovani (Selvapandiyan et al., 2009).
• Host Ifng (Interferon gamma) response
  • Description: The results thus indicate an increased IFN-γ secretion coinciding with reduced IL-10 production among the immunized mice. In the restimulated CD4+ T cells from the spleen, the IFN-γ/IL-10 ratio was significantly higher in the immunized mice both at the time of challenge (5 weeks after immunization) and after challenge (5 weeks after immunization plus 10 weeks after challenge) compared with either naive or naive-challenged controls. We also observed an absolute requirement for IFN-γ in LdCen1−/−-induced immunity. IFN-γ knockout mice immunized with LdCen1−/− for 5 wk followed by challenge were not protected (Selvapandiyan et al., 2009).
  • Detailed Gene Information: Click Here.
• Host Ighv1-9 response
  • Description: Sera from BALB/c mice taken 10 wk post challenge after 5, 12, or 16 immunization weeks were measured for Leishmania-specific IgG2a responses. Results indicated a significantly higher level of IgG2a populations in the immune-challenged groups compared with the naive challenged groups (Selvapandiyan et al., 2009).
  • Detailed Gene Information: Click Here.
• Host Il2 response
  • Description: The number of T cells producing IL-2 increased significantly as compared to naive mice 5 weeks after immunization in CD4+ and CD8+ cells as well as 5 weeks after immunization plus 10 weeks after challenge in both CD4+ and CD8+ cells (Selvapandiyan et al., 2009).
  • Detailed Gene Information: Click Here.
• Host TNF-alpha response
  • Description: The number of T cells producing TNF-alpha increased significantly as compared to naive mice 5 weeks after immunization in CD8+ cells as well as 5 weeks after immunization plus 10 weeks after challenge in both CD4+ and CD8+ cells (Selvapandiyan et al., 2009).
  • Detailed Gene Information: Click Here.

Hamster Response

• Persistence: A cen1 mutant is attenuated in hamsters (Selvapandiyan et al., 2009).
• Efficacy: A cen1 mutant induces significant protection in hamsters from challenge with wild type L. donovani (Selvapandiyan et al., 2009).

Hamster Response

• Host Strain: Syrian golden
• Vaccination Protocol: Six weeks old Syrian golden hamsters (Mesocricetus auratus) were immunized in the following groups, with 6 hamsters per group. Group I: Naïve animals (Unimmunized – uninfected) were given PBS only and not challenged, group II: Animals were immunized with recombinant protein vaccine, rLdP1 (50 μg) along with Complete Freund’s adjuvant and two booster doses of same amount of antigen given with Incomplete Freund’s adjuvant, group III: Hamsters immunized with plasmid DNA vaccine alone, pVAX1-P1 single dose, group IV: Hamsters immunized with pVAX-P1 and given a prime-boost dose after 15 days, group V: Hamsters immunized with pVAX1-vector only and group VI: Unimmunized – were given PBS only (Arora et al., 2011).
• Challenge Protocol: All the animals except group I, were challenged with 1 × 10^7 promastigotes (from late log-phase axenic cultures) intracardially (i.c.) on day 28. The hamsters were observed for 6–8 weeks post challenge (p.c.). At the end of 10 weeks post infection, the surviving animals were euthanized and parasitological and immunological parameters were studied (Arora et al., 2011).
• Efficacy: Prime-boost immunization with pVAX-21 DNA vaccine resisted the increase in spleen parasite burden by 75.68% (Arora et al., 2011).