Effect of the saliva from different triatomine species on the biology and immunity of TLR-4 ligand and Trypanosoma cruzi-stimulated dendritic cells

Abstract

BackgroundTriatomines are blood-sucking vectors of Trypanosoma cruzi, the causative agent of Chagas disease. During feeding, triatomines surpass the skin host response through biomolecules present in their saliva. Dendritic cells (DCs) play a crucial role in the induction of the protection to aggressive agents, including blood-sucking arthropods. Here, we evaluated if salivary components of triatomines from different genera evade the host immunity by modulating the biology and the function of LPS- or T. cruzi-stimulated DCs.MethodsSaliva of Panstrongylus lignarius, Meccus pallidipennis, Triatoma lecticularia and Rhodnius prolixus were obtained by dissection of salivary glands and the DCs were obtained from the differentiation of mouse bone marrow precursors.ResultsThe differentiation of DCs was inhibited by saliva of all species tested. Saliva differentially inhibited the expression of MHC-II, CD40, CD80 and CD86 in LPS-matured DCs. Except for the saliva of R. prolixus, which induced IL-6 cytokine production, TNF-α, IL-12 and IL-6 were inhibited by the saliva of the other three tested species and IL-10 was increased in all of them. Saliva per se, also induced the production of IL-12, IL-6 and IL-10. Only the saliva of R. prolixus induced DCs apoptosis. The presence of PGE2 was not detected in the saliva of the four triatomines studied. Finally, T. cruzi invasion on DCs is enhanced by the presence of the triatomine saliva.ConclusionsThese results demonstrate that saliva from different triatomine species exhibit immunomodulatory effects on LPS and T. cruzi-stimulated DCs. These effects could be related to hematophagy and transmission of T. cruzi during feeding.Electronic supplementary materialThe online version of this article (doi:10.1186/s13071-016-1890-x) contains supplementary material, which is available to authorized users.

An insight into the salivary gland and fat body transcriptome of Panstrongylus lignarius (Hemiptera: Heteroptera), the main vector of Chagas disease in Peru

“…In a previous review, it was stated that this combination of transcripts suggested a role of triatomine salivary glands in the manufacture of eicosanoids [ 9 ]. However, a search for prostaglandins in the saliva of triatomines was negative [ 16 ]. Since these enzymes are associated with prostaglandin catabolism, it is here speculated that prostaglandins may function as salivary secretagogues and that the enzyme is associated with agonist detoxification.…”

“…lignarius , when compared to saliva of triatomines of the genus Triatoma , Meccus and Rhodnius have a remarkable ability to modulate dendritic cells and facilitate their invasion by T . cruzi [ 16 ].…”

Salivary Gland Extract of Kissing Bug, Triatoma lecticularia, Reduces the Severity of Intestinal Inflammation through the Modulation of the Local IL-6/IL-10 Axis

“…Though we have not explored the effects of T. lecticularia saliva on the apoptosis of mucosal T cells nor its effects on the differentiation of T cells, like Th17 lymphocytes, we cannot underestimate its importance in this context. Our group has shown the ability of T. lecticularia SGE to reduce the differentiation and production of IL-6 in dendritic cells [ 14 ]. Because of the role of these cells in antigen presentation and cell activation or differentiation, the contribution of such modulation to disease amelioration cannot be ruled out.…”

“…After millions of years of coevolution with vertebrate hosts, triatomines, like other blood-feeding arthropods, developed in their saliva complex mechanisms to suppress vertebrate immune and hemostatic responses [ 12 – 14 ]. For this reason, studies have been focusing on the pharmacological potential of molecules in the saliva from different hematophagous arthropods to treat inflammatory/autoimmune conditions.…”

“…Our group has previously demonstrated the in vitro effect of T. lecticularia salivary gland extract (SGE) on DCs stimulated with LPS [ 14 ]. The presence of T. lecticularia SGE in DC cultures reduced the production of TNF- α , IL-6, and IL-12 besides inducing the production of IL-10 in a concentration-dependent manner with no negative impact on cell viability [ 14 ]. However, to the best of our knowledge, the therapeutic role of salivary molecules of triatomines in inflammatory diseases has never been addressed.…”