title: Immune-relevant thrombocytes of common carp undergo parasite-induced nitric oxide-mediated apoptosis.
abstract: Common carp thrombocytes account for 30-40% of peripheral blood leukocytes and are abundant in the healthy animals' spleen, the thrombopoietic organ. We show that, ex vivo, thrombocytes from healthy carp express a large number of immune-relevant genes, among which several cytokines and Toll-like receptors, clearly pointing at immune functions of carp thrombocytes. Few studies have described the role of fish thrombocytes during infection. Carp are natural host to two different but related protozoan parasites, Trypanoplasma borreli and Trypanosoma carassii, which reside in the blood and tissue fluids. We used the two parasites to undertake controlled studies on the role of fish thrombocytes during these infections. In vivo, but only during infection with T. borreli, thrombocytes were massively depleted from the blood and spleen leading to severe thrombocytopenia. Ex vivo, addition of nitric oxide induced a clear and rapid apoptosis of thrombocytes from healthy carp, supporting a role for nitric oxide-mediated control of immune-relevant thrombocytes during infection with T. borreli. The potential advantage for parasites to selectively deplete the host of thrombocytes via nitric oxide-induced apoptosis is discussed.
authors: Cell Biology and Immunology Group, Wageningen Institute of Animal Sciences, Wageningen University, PO Box 338, 6700 AH Wageningen, The Netherlands.
authors: Inge R
authors: IR
authors: Fink
authors: Cell Biology and Immunology Group, Wageningen Institute of Animal Sciences, Wageningen University, PO Box 338, 6700 AH Wageningen, The Netherlands.
authors: Carla M S
authors: CM
authors: Ribeiro
authors: Cell Biology and Immunology Group, Wageningen Institute of Animal Sciences, Wageningen University, PO Box 338, 6700 AH Wageningen, The Netherlands.
authors: Maria
authors: M
authors: Forlenza
authors: Cell Biology and Immunology Group, Wageningen Institute of Animal Sciences, Wageningen University, PO Box 338, 6700 AH Wageningen, The Netherlands.
authors: Anja
authors: A
authors: Taverne-Thiele
authors: Cell Biology and Immunology Group, Wageningen Institute of Animal Sciences, Wageningen University, PO Box 338, 6700 AH Wageningen, The Netherlands.
authors: Jan H W M
authors: JH
authors: Rombout
authors: Cell Biology and Immunology Group, Wageningen Institute of Animal Sciences, Wageningen University, PO Box 338, 6700 AH Wageningen, The Netherlands.
authors: Huub F J
authors: HF
authors: Savelkoul
authors: Cell Biology and Immunology Group, Wageningen Institute of Animal Sciences, Wageningen University, PO Box 338, 6700 AH Wageningen, The Netherlands. Electronic address: geert.wiegertjes@wur.nl.
authors: Geert F
authors: GF
authors: Wiegertjes
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000276:immunology*; D001792:Blood Platelets / Q000276:immunology* / Q000469:parasitology; D002347:Carps / Q000276:immunology* / Q000469:parasitology; D016207:Cytokines / Q000096:biosynthesis / Q000235:genetics / Q000276:immunology; D005393:Fish Diseases / Q000276:immunology / Q000469:parasitology; D005434:Flow Cytometry; D009569:Nitric Oxide / Q000378:metabolism*; D013921:Thrombocytopenia / Q000276:immunology / Q000469:parasitology; D051193:Toll-Like Receptors / Q000096:biosynthesis / Q000235:genetics / Q000276:immunology; D014345:Trypanosoma / Q000276:immunology*
chemical_list: D016207:Cytokines; D051193:Toll-Like Receptors; D009569:Nitric Oxide
keywords: Cell death; Host–pathogen interaction; Nitric oxide; Teleost; Thrombocyte; Trypanoplasma borreli