Leishmaniasis, a spectrum of diseases caused by various forms of Leishmania has become a major health problem all over the world. Vaccination against
leishmaniasis has passed through many developmental stages beginning with the ancient practice of 'leishmanization'. Due to various problems and difficulties associated with traditional
vaccines, the interest has been shifted to novel approaches of vaccination like
DNA vaccination, vaccination with live vectors encoding leishmanial
antigens and finally to designer
vaccines. In an effort towards developing an anti-leishmanial
vaccine, our laboratory has been working on various genes present in an amplified locus of Leishmania known as the 'LD1 locus'. Two genes, ORFF and BT1 (previously ORFG), are part of the multigenic LD1 locus on chromosome 35. BT1 encodes a
biopterin transporter, while the function of ORFF gene product is unknown. Immunization of mice with recombinant ORFF (rORFF) and BT1
proteins, individually, or in combination, conferred partial protection against challenge with Leishmania donovani. We also tested the protective efficacy of ORFF
DNA vaccine in BALB/c mice model and found that the level of protection was significantly higher than that of ORFF
protein. Protection conferred by ORFF
DNA vaccine correlated with significant levels of in vitro splenocyte proliferation and low levels of
antigen-specific
antibodies. There was a preferential production of IFN-gamma compared to
IL-4, which indicated the induction of a protective Th1 response, by the
DNA vaccine. Thus,
DNA immunization may offer an attractive alternative strategy against
leishmaniasis. We present here the current status of
vaccine development against
leishmaniasis.