Tsetse fly saliva accelerates the onset of Trypanosoma brucei infection in a mouse model associated with a reduced host inflammatory response.
Tsetse flies (Glossina sp.) are the vectors that transmit African trypanosomes, protozoan parasites that cause human sleeping sickness and veterinary infections in the African continent. These blood-feeding dipteran insects deposit saliva at the feeding site that enables the blood-feeding process. Here we demonstrate that tsetse fly saliva also accelerates the onset of a Trypanosoma brucei infection. This effect was associated with a reduced inflammatory reaction at the site of infection initiation (reflected by a decrease of interleukin-6 [IL-6] and IL-12 mRNA) as well as lower serum concentrations of the trypanocidal cytokine tumor necrosis factor. Variant-specific surface glycoprotein-specific antibody isotypes immunoglobulin M (IgM) and IgG2a, implicated in trypanosome clearance, were not suppressed. We propose that tsetse fly saliva accelerates the onset of trypanosome infection by inhibiting local and systemic inflammatory responses involved in parasite control.
Caljon
Guy
G
Unit of Cellular and Molecular Immunology, Flanders Interuniversity Institute for Biotechnology (VIB), Vrije Universiteit Brussel (VUB), Pleinlaan 2, B-1050 Brussels, Belgium. gucaljon@vub.ac.be
Van Den Abbeele
Jan
J
Stijlemans
Benoît
B
Coosemans
Marc
M
De Baetselier
Patrick
P
Magez
Stefan
S
D000818:Animals; D004195:Disease Models, Animal; D015536:Down-Regulation / Q000276:immunology; D005260:Female; D007249:Inflammation / Q000235:genetics / Q000276:immunology / Q000469:parasitology; D007303:Insect Vectors / Q000276:immunology*; D051379:Mice; D018345:Mice, Knockout; D008826:Microbial Sensitivity Tests; D012463:Saliva / Q000276:immunology* / Q000469:parasitology; D014346:Trypanosoma brucei brucei / Q000276:immunology*; D014353:Trypanosomiasis, African / Q000276:immunology* / Q000469:parasitology / Q000473:pathology* / Q000635:transmission; D014370:Tsetse Flies / Q000276:immunology* / Q000469:parasitology