Neutrophils enhance early Trypanosoma brucei infection onset

Guy Caljon, Dorien Mabille, Benoit Stijlemans, Carl De Trez, Massimiliano Mazzone, Fabienne Tacchini-Cottier, Marie Malissen, Jo A. Van Ginderachter, Stefan Magez, Patrick De Baetselier, Jan Van den Abbeele

    Research output: Contribution to journalA1: Web of Science-article

    Abstract

    In this study, Trypanosoma brucei was naturally transmitted to mice through the bites of infected Glossina morsitans tsetse flies. Neutrophils were recruited rapidly to the bite site, whereas monocytes were attracted more gradually. Expression of inflammatory cytokines (il1b, il6), il10 and neutrophil chemokines (cxcl1, cxcl5) was transiently up-regulated at the site of parasite inoculation. Then, a second influx of neutrophils occurred that coincided with the previously described parasite retention and expansion in the ear dermis. Congenital and experimental neutropenia models, combined with bioluminescent imaging, indicate that neutrophils do not significantly contribute to dermal parasite control and elicit higher systemic parasitemia levels during the infection onset. Engulfment of parasites by neutrophils in the skin was rarely observed and was restricted to parasites with reduced motility/viability, whereas live parasites escaped phagocytosis. To our knowledge, this study represents the first description of a trypanosome infection promoting role of early innate immunological reactions following an infective tsetse fly bite. Our data indicate that the trypanosome is not hindered in its early development and benefits from the host innate responses with the neutrophils being important regulators of the early infection, as already demonstrated for the sand fly transmitted Leishmania parasite.

    Original languageEnglish
    Article number11203
    JournalScientific Reports
    Volume8
    Number of pages11
    ISSN2045-2322
    DOIs
    Publication statusPublished - 2018

    Keywords

    • LOCAL SKIN REACTIONS
    • TSETSE-FLY
    • GLOSSINA-MORSITANS
    • AFRICAN TRYPANOSOMES
    • DENDRITIC CELLS
    • SAND FLIES
    • CONGOLENSE
    • HOST
    • CATTLE
    • LEISHMANIASIS

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