The apicomplexan parasite Eimeria arloingi induces caprine neutrophil extracellular traps
- 578 Downloads
As a novel effector mechanism polymorphonuclear neutrophils (PMN) release neutrophil extracellular traps (NETs), which represent protein-labeled DNA matrices capable of extracellular trapping and killing of invasive pathogens. Here, we demonstrate for the first time NET formation performed by caprine PMN exposed to different stages (sporozoites and oocysts) of the goat apicomplexan protozoan parasite Eimeria arloingi. Scanning electron microscopy as well as fluorescence microscopy of sporozoites- and oocysts-PMN co-cultures revealed a fine network of DNA fibrils partially covering the parasites. Immunofluorescence analyses confirmed the co-localization of histones (H3), neutrophil elastase (NE), and myeloperoxidase (MPO) in extracellular traps released from caprine PMN. In addition, the enzymatic activity of NE was found significantly enhanced in sporozoite-exposed caprine PMN. The treatment of caprine NET structures with deoxyribonuclease (DNase) and the NADPH oxidase inhibitor diphenylene iodondium (DPI) significantly reduced NETosis confirming the classical characteristics of NETs. Caprine NETs efficiently trapped vital sporozoites of E. arloingi since 72 % of these stages were immobilized—but not killed—in NET structures. As a consequence, early infection rates were significantly reduced when PMN-pre-exposed sporozoites were allowed to infect adequate host cells. These findings suggest that NETs may play an important role in the early innate host response to E. arloingi infection in goats.
KeywordsEimeria arloingi Apicomplexa NETs Goats Neutrophils
We would like to thank Gerd Magdowski (Institute of Anatomy and Cell Biology, JLU Giessen, Germany) for his excellent assistance and kind help on SEM analyses. We further acknowledge Brigitte Hofmann, Christin Ritter, and Klaus Becker for their excellent technical assistance and blood collection. TMC is a Ph.D. student of the International Giessen Graduate Centre for the Life Sciences (GGL) at the JLU Giessen, Germany and LMRS is a Ph.D. student (grant BD/72032/2010) of the Foundation for Science and Technology (FCT). This work was partially funded by FEDER Funds through the Operational Program for Competitiveness Factors—COMPETE and National Funds through FCT under the Strategic Project PEst-C/AGR/UI0115/2011.
- Brazil JC et al (2013) alpha3/4 Fucosyltransferase 3-dependent synthesis of Sialyl Lewis A on CD44 variant containing exon 6 mediates polymorphonuclear leukocyte detachment from intestinal epithelium during transepithelial migration. J Immunol 191(9):4804–4817. doi: 10.4049/jimmunol.1301307 PubMedCrossRefGoogle Scholar
- Conejeros I, Velasquez ZD, Carretta MD, Alarcon P, Hidalgo MA, Burgos RA (2012) 2-Aminoethoxydiphenyl borate (2-APB) reduces alkaline phosphatase release, CD63 expression, F-actin polymerization and chemotaxis without affecting the phagocytosis activity in bovine neutrophils. Vet Immunol Immunopathol 145(1–2):540–545. doi: 10.1016/j.vetimm.2011.12.006 PubMedCrossRefGoogle Scholar
- Grinberg N, Elazar S, Rosenshine I, Shpigel NY (2008) Beta-hydroxybutyrate abrogates formation of bovine neutrophil extracellular traps and bactericidal activity against mammary pathogenic Escherichia coli. Infect Immun 76(6):2802–2807. doi: 10.1128/IAI.00051-08 PubMedCentralPubMedCrossRefGoogle Scholar
- Hermosilla C, Barbisch B, Heise A, Kowalik S, Zahner H (2002) Development of Eimeria bovis in vitro: suitability of several bovine, human and porcine endothelial cell lines, bovine fetal gastrointestinal, Madin-Darby bovine kidney (MDBK) and African green monkey kidney (VERO) cells. Parasitol Res 88(4):301–307PubMedCrossRefGoogle Scholar
- Hermosilla C, Caro TM, Silva LM, Ruiz A, Taubert A (2014) The intriguing host innate immune response: novel anti-parasitic defence by neutrophil extracellular traps. Parasitology 1–10 doi: 10.1017/S0031182014000316
- Mehlhorn H, Armstrong PM (2001) Encyclopedic reference of parasitology: biology, structure, function. SpringerGoogle Scholar