Vaccine candidates, immuno-dominant antigens, and potent vaccine
adjuvants for preventing cutaneous leishmaniasis: a sys
Abstract
Background: Cutaneous leishmaniasis (CL) is the most common
clinical form of leishmaniasis that causes skin disease. Currently,
there is no licensed prophylactic vaccine for CL, as the mechanisms of
healing and memory T-cell responses that develop after infection with CL
are far from fully understood. A review of the published articles
identifying CL vaccine candidates, immuno-dominant antigens, and potent
vaccine adjuvants is needed to provide comprehensive information.
Therefore, we aimed to review vaccine candidates, immuno-dominant
antigens, and potent vaccine adjuvants for preventing cutaneous
leishmaniasis. Methods: A systematic search of published
studies before December 2023 was identified using electronic databases;
PubMed/MEDLINE, Hinari Research4Life, Google Scholar, and direct Google
search. The Preferred Reporting Items for Systematic Reviews and
Meta-Analyses (PRISMA) guidelines were followed. Data were extracted
using a Microsoft Excel 2010 spreadsheet and data obtained were then
reported using tables and figures and synthesized qualitatively. The
quality of the included studies was assessed using the Joanna Briggs
Institute’s (JBI) quality appraisal tool for experimental studies.
Results: The electronic databases search yielded 661 articles
of which 32 articles met the inclusion criteria. The included articles
were conducted in various animal and human models and included vaccine
candidates, immuno-dominant antigens, and potent vaccine adjuvants. Some
of the first-generation vaccine candidates showed complete protection of
the specified animal model. They induced strong T-cell mediated and
antibody-mediated humoral immune responses (e.g. Curdlan dectin-1, total
Leishmania antigen (TLA), and L. infantum heat shock
proteins ( LiΔHSP70-II)). Almost all second and third-generation
vaccine candidates, and the immuno-dominant antigens of the parasite and
the host enhance T cell-mediated and antibody-mediated immune responses.
We also reviewed potent vaccine adjuvants such as myrrh silver
nanoparticles (MSNPs), and Imiquimod, which play an important role in
enhancing immune responses against Leishmania antigens.
Conclusion and recommendations: The T-cell mediated immune
response was significantly induced in various experimental models (e.g.
IFN-γ and TNF-α response) and also the humoral arm in some instances
(e.g. IgG2). This review thus provides comprehensive information on the
efficacy and induction of protective immunity of vaccine candidates,
antigenic molecules, and vaccine adjuvants against CL. However, there is
still a need for a comprehensive understanding of the
immuno-pathogenesis of the disease upon vaccination.