Dog skin parasite load, TLR-2, IL-10 and TNF-α expression and infectiousness.

Visceral leishmaniosis is a zoonotic disease that is transmitted by Lutzomyia longipalpis sandflies. Dogs are the main peri-urban reservoir of the disease, and progression of canine leishmaniosis is dependent on the type of immune response elaborated against the parasite. Type 1 immunity is characterized by effective cellular response, with production of pro-inflammatory cytokines such as tumour necrosis factor alpha (TNF-α). In contrast, Type 2 immunity is predominantly humoral, associated with progression of the disease and mediated by anti-inflammatory cytokines such as interleukin 10 (IL-10). Although seemly important in the dynamics of leishmaniosis, other gene products such as toll-like receptor 2 (TRL-2) and inducible nitric oxide synthase (iNOS) exert unclear roles in the determination of the type of immune response. Given that the dog skin serves as a micro-environment for the multiplication of Leishmania spp., we investigated the parasite load and the expression of TLR-2, iNOS, IL-10 and TNF-α in the skin of 29 infected and 8 control dogs. We found that increased parasite load leads to upregulation of TLR-2, IL-10 and TNF-α, indicating that abundance of these transcripts is associated with infection. We also performed a xenodiagnosis to demonstrate that increased parasitism is a risk factor for infectiousness to sandflies. © 2017 John Wiley & Sons Ltd.

Citation

D C M Pereira-Fonseca, F M Oliveira-Rovai, L A C Rodas, C A C Beloti, R B P Torrecilha, P K R K Ito, S V Avanço, R S Cipriano, Y T Utsunomiya, R M Hiramoto, L Calvo-Bado, O Courtenay, G F Machado, V M F Lima, C M Nunes. Dog skin parasite load, TLR-2, IL-10 and TNF-α expression and infectiousness. Parasite immunology. 2017 Nov;39(11)

PMID: 28929498

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