title: Expression analysis of the Atlantic bluefin tuna (Thunnus thynnus) pro-inflammatory cytokines, IL-1β, TNFα1 and TNFα2 in response to parasites Pseudocycnus appendiculatus (Copepoda) and Didymosulcus katsuwonicola (Digenea).
abstract: Pro-inflammatory cytokines play an important role in teleost defence against numerous types of pathogens, therefore are often used as biomarkers during various infections. In order to evaluate Atlantic bluefin tuna IL-1β, TNFα1 and TNFα2 induction by PAMPs, we quantified their expression during in vitro stimulation of peripheral blood leukocytes by LPS and Poly I:C. Furthermore, their role in acute and chronic parasitic infection was examined during natural infection of Pseudocycnus appendiculatus (Copepoda) and Didymosulcus katsuwonicola (Digenea), as well as during leukocyte exposure to total protein extracts isolated from two parasite species. Induction of ABT IL-1β and TNFα2 by PAMPs and protein extracts from D. katsuwonicola and P. appendiculatus, as well as during natural infection with two parasites, suggests these cytokines play an important role in inflammation, being engaged in controlling parasite infections, in contrast to ABT TNFα1. Cellular innate response to the digenean D. katsuwonicola showed rather chronic character, resulting with parasite encapsulation in connective tissue. Mast cells, eosinophils, goblet cells, and occasional rodlet cells found at the site of infection, along with the induction of TNFα2, suggest the presence of a moderate inflammatory reaction that fails to seriously endanger digenean existence. In contrast, copepod P. appendiculatus, attached to the gill epithelium by clamping, caused direct tissue disruption with undergoing necrotic or apoptotic processes, and extensive proliferation of rodlet and goblet cells. Differential expression patterns of target cytokines in tissue surrounding two parasites and in vitro PBL model suggest that quality and quantity of tuna immune response is conditioned by parasite adaptive mechanisms and pathogenicity.
authors.affiliation: Laboratory for Aquaculture, Institute of Oceanography and Fisheries, Setaliste Ivana Mestrovica 63, 21000 Split, Croatia. Electronic address: lepen@izor.hr.
authors.forename: Ivana Lepen
authors.initials: IL
authors.lastname: Pleić
authors.affiliation: Laboratory for Aquaculture, Institute of Oceanography and Fisheries, Setaliste Ivana Mestrovica 63, 21000 Split, Croatia.
authors.forename: Ivana
authors.initials: I
authors.lastname: Bušelić
authors.affiliation: Center of Marine Studies, University of Split, Livanjska 5/III, 21000 Split, Croatia.
authors.forename: Željka
authors.initials: Ž
authors.lastname: Trumbić
authors.affiliation: Department of Biology, Faculty of Natural Sciences, University of Split, Teslina 12, 21000 Split, Croatia.
authors.forename: Ivana
authors.initials: I
authors.lastname: Bočina
authors.affiliation: Department of Chemistry, Faculty of Natural Sciences, University of Split, Teslina 12, 21000 Split, Croatia.
authors.forename: Matilda
authors.initials: M
authors.lastname: Šprung
authors.affiliation: Laboratory for Aquaculture, Institute of Oceanography and Fisheries, Setaliste Ivana Mestrovica 63, 21000 Split, Croatia.
authors.forename: Ivona
authors.initials: I
authors.lastname: Mladineo
mesh_terms: D000818:Animals; D033342:Copepoda / Q000502:physiology*; D005393:Fish Diseases / Q000235:genetics* / Q000276:immunology* / Q000469:parasitology; D029941:Fish Proteins / Q000235:genetics* / Q000378:metabolism; D053583:Interleukin-1beta / Q000235:genetics* / Q000378:metabolism; D014200:Trematoda / Q000502:physiology*; D014201:Trematode Infections / Q000235:genetics / Q000276:immunology / Q000469:parasitology / Q000662:veterinary*; D014409:Tumor Necrosis Factor-alpha / Q000235:genetics* / Q000378:metabolism; D014413:Tuna
chemical_list: D029941:Fish Proteins; D053583:Interleukin-1beta; D014409:Tumor Necrosis Factor-alpha
keywords: Atlantic bluefin tuna; Copepoda; Digenea; Innate immunity; Interleukin-1β; Parasite protein extracts; Tumour necrosis factor α