Abstract

Leishmaniasis is a vector-borne disease caused by different species of protozoan parasites of the genus Leishmania. It is a major health problem yet neglected tropical diseases, with approximately 350 million people worldwide at risk and more than 1.5 million infections occurring each year. Leishmaniasis has different clinical manifestations, including visceral (VL or kala-azar), cutaneous (CL), mucocutaneous (MCL), diffuse cutaneous (DCL) and post kala-azar dermal leishmaniasis (PKDL). Currently, the only mean to treat and control leishmaniasis is by rational medications and vector control. However, the number of available drugs is limited and even these are either exorbitantly priced, have toxic side effects or prove ineffective due to the emergence of resistant strains. On the other hand, the vector control methods are not so efficient. Therefore, there is an urgent need for developing a safe, effective, and affordable vaccine for the prevention of leishmaniasis. Although in recent years a large body of researchers has concentrated their efforts on this issue, yet only three vaccine candidates have gone for clinical trial, until date. These are: (i) killed vaccine in Brazil for human immunotherapy; (ii) live attenuated vaccine for humans in Uzbekistan; and (iii) second-generation vaccine for dog prophylaxis in Brazil. Nevertheless, there are at least half a dozen vaccine candidates in the pipeline. One can expect that, in the near future, the understanding of the whole genome of Leishmania spp. will expand the vaccine discovery and strategies that may provide novel vaccines. The present review focuses on the development and the status of various vaccines and potential vaccine candidates against leishmaniasis.

Highlights

  • Leishmaniasis is a vector-borne disease caused by protozoan parasites belonging to the genus Leishmania

  • Leishmaniasis is a group of different manifestations and is the foremost cause of morbidity and mortality, throughout the world

  • Leishmania vaccine development has proven to be a difficult and challenging task, which is mostly hampered by inadequate knowledge of parasite pathogenesis and the complexity of immune responses needed for protection

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Summary

Background

Leishmaniasis is a vector-borne disease caused by protozoan parasites belonging to the genus Leishmania. Vaccinated hamsters showed reversal of T cell anergy with functional IL-2 generation along with vigorous specific anti-KMP-11 CTL-like response This was the first report of a vaccine conferring protection to both antimony-responsive and resistant Leishmania strains, reflecting several aspects of clinical visceral leishmaniasis [94]. Vaccination with plasmid DNA encoding protective Leishmania antigens gives a promising approach to vaccination against leishmaniasis in that it has intrinsic adjuvant properties, induces both humoral and cell-mediated immune responses and results in long lasting immunity. Our result of cellular immune response suggested that, our novel chimeric DNA vaccine could be as a potential immunoprotective candidate and have important implications in future vaccine design This may offer an attractive alternative strategy against leishmaniasis and tuberculosis co-infection [134]. Public-private partnerships have been suggested and the idea seems to have been taken on board by Big Pharma companies

Failure in conferring the immunity
Suitability of adjuvant
Differences in virulence dynamics of the Leishmania species
Findings
Conclusion
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