Visceral leishmaniasis (VL) is one of the most important
parasitic diseases with approximately 350 million people at risk. Due to the non availability of an ideal drug, development of a safe, effective, and affordable
vaccine could be a
solution for control and prevention of this disease. In this study, a potential Th1 stimulatory
protein-
Triose phosphate isomerase (TPI), a glycolytic
enzyme, identified through proteomics from a fraction of Leishmania donovani soluble
antigen ranging from 89.9-97.1 kDa, was assessed for its potential as a suitable
vaccine candidate. The
protein- L. donovani TPI (LdTPI) was cloned, expressed and purified which exhibited the homology of 99% with L. infantum TPI. The rLdTPI was further evaluated for its immunogenicity by lymphoproliferative response (LTT),
nitric oxide (NO) production and estimation of
cytokines in cured Leishmania patients/hamster. It elicited strong LTT response in cured patients as well as NO production in cured hamsters and stimulated remarkable Th1-type cellular responses including IFN-ã and
IL-12 with extremely lower level of
IL-10 in Leishmania-infected cured/exposed patients PBMCs in vitro. Vaccination with LdTPI-
DNA construct protected naive golden hamsters from virulent L. donovani challenge unambiguously (∼90%). The vaccinated hamsters demonstrated a surge in IFN-ã, TNF-á and
IL-12 levels but extreme down-regulation of
IL-10 and
IL-4 along with profound delayed type
hypersensitivity and increased levels of Leishmania-specific
IgG2 antibody. Thus, the results are suggestive of the
protein having the potential of a strong candidate
vaccine.