Phlebotomus papatasi Yellow-Related and Apyrase Salivary Proteins Are Candidates for Vaccination against Human Cutaneous Leishmaniasis

Abstract

Nowadays, there is no available vaccine for human leishmaniasis. Animal experiments demonstrate that pre-exposure to sand fly saliva confers protection against leishmaniasis. Our preceding work in humans indicates that Phlebotomus papatasi saliva induces the production of IL-10 by CD8+ T lymphocytes. The neutralization of IL-10 enhanced the activation of a T-cell CD4+ population-producing IFN-γ. Herein, we used a biochemical and functional genomics approach to identify the sand fly salivary components that are responsible for the activation of the T helper type 1 immune response in humans, therefore constituting potential vaccine candidates against leishmaniasis. Fractionated P. papatasi salivary extracts were first tested on T lymphocytes of immune donors. We confirmed that the CD4+ lymphocytes proliferate and produce IFN-γ in response to stimulation with the proteins of molecular weight >30 kDa. Peripheral blood mononuclear cells from immune donors were transfected with plasmids coding for the most abundant proteins from the P. papatasi salivary gland cDNA library. Our result showed that the "yellow related proteins," PPTSP42 and PPTSP44, and "apyrase," PPTSP36, are the proteins responsible for the aforementioned cellular immune response and IFN-γ production. Strikingly, PPTSP44 triggered the highest level of lymphocyte proliferation and IFN-γ production. Multiplex cytokine analysis confirmed the T helper type 1-polarized response induced by these proteins. Importantly, recombinant PPTSP44 validated the results observed with the DNA plasmid, further supporting that PPTSP44 constitutes a promising vaccine candidate against human leishmaniasis.

RNA-sequencing of the Nyssomyia neivai sialome: a sand fly-vector from a Brazilian endemic area for tegumentary leishmaniasis and pemphigus foliaceus

“…In contrast, mice immunized with P. papatasi yellow-related proteins PpSP42 or PpSP44 (AAL11052 and AAL11051, respectively) elicited Th2 cytokines and exacerbated L. (L.) major infection 78 . Other yellow-related proteins from P. papatasi , specifically PPTSP44 (AGE83095.1), induced a strong Th1 response constituting a potential vaccine candidates against leishmaniasis 79 . It remains to be elucidated whether the protection induced by yellow-related proteins is related to particular protein immunogenicity, to sand fly species, or to the vector- Leishmania host combination, as all of these factors can contribute to vaccine efficacy.…”

Phlebotomus perniciosus Recombinant Salivary Proteins Polarize Murine Macrophages Toward the Anti-Inflammatory Phenotype

“…This enzyme hydrolyzes ADP and ATP, thus destroying the important stimulus of platelet aggregation and inflammation at the bite site, which helps the female fly to complete the bloodmeal (Francischetti, 2011 ). So far, the sand fly apyrases have been tested only in the context of adaptive immunity, employing transfection of the host's cells (Oliveira et al, 2006 , 2008 ; Gomes et al, 2008 ; Xu et al, 2011 ; Marzouki et al, 2012 ; Tlili et al, 2018 ; Gholami et al, 2019 ). In previous studies, two recombinant P. perniciosus salivary apyrases, rSP01 and rSP01B, have been prepared, however, they have been primarily tested as the markers of exposure with sera of bitten hosts (Martin-Martin et al, 2013 , 2014 , 2015 ; Drahota et al, 2014 ; Kostalova et al, 2015 ) and never subjected to test their immunomodulatory properties.…”

Phlebotomus papatasisand fly salivary protein diversity and immune response potential in Egypt and Jordan populations

“…Salivary proteins from various phlebotomine sand fly species have been characterized with regards to their function in blood feeding and their effectiveness as markers of exposure [4–6]. Sand fly salivary proteins can exacerbate or attenuate Leishmania infections [7–9], and have been suggested as potential as vaccine candidates [10,11].…”