Preclinical validation of a live attenuated dermotropic Leishmania vaccine against vector transmitted fatal visceral leishmaniasis

Commun Biol. 2021 Jul 30;4(1):929. doi: 10.1038/s42003-021-02446-x.

Abstract

Visceral Leishmaniasis (VL), a potentially fatal disease is caused by Leishmania donovani parasites with no vaccine available. Here we produced a dermotropic live attenuated centrin gene deleted Leishmania major (LmCen-/-) vaccine under Good Laboratory Practices and demonstrated that a single intradermal injection confers robust and durable protection against lethal VL transmitted naturally via bites of L. donovani-infected sand flies and prevents mortality. Surprisingly, immunogenicity characteristics of LmCen-/- parasites revealed activation of common immune pathways like L. major wild type parasites. Spleen cells from LmCen-/- immunized and L. donovani challenged hamsters produced significantly higher Th1-associated cytokines including IFN-γ, TNF-α, and reduced expression of the anti-inflammatory cytokines like IL-10, IL-21, compared to non-immunized challenged animals. PBMCs, isolated from healthy people from non-endemic region, upon LmCen-/- infection also induced more IFN-γ compared to IL-10, consistent with our immunogenicity data in LmCen-/- immunized hamsters. This study demonstrates that the LmCen-/- parasites are safe and efficacious against VL and is a strong candidate vaccine to be tested in a human clinical trial.

Publication types

  • Research Support, N.I.H., Intramural
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Gene Deletion*
  • Genes, Protozoan*
  • Leishmania donovani / genetics
  • Leishmania donovani / immunology*
  • Leishmaniasis Vaccines / immunology*
  • Leishmaniasis, Visceral / immunology
  • Leishmaniasis, Visceral / prevention & control*
  • Protozoan Proteins
  • Vaccines, Attenuated / immunology

Substances

  • Leishmaniasis Vaccines
  • Protozoan Proteins
  • Vaccines, Attenuated

Grants and funding