title: Streptococcous parauberis infection in starry flounder, Platichthys stellatus: characterization of innate immune responses following experimental infection.
abstract: Streptococcus parauberis causing systemic infections has been recognized as a major bacterial disease in olive flounder Paralichthys olivaceus in South Korea. Although an emerging outbreak of S. parauberis has affected heavily farmed fish species starry flounder Platichthys stellatus, no study of the innate immune responses and pathogenic mechanisms in starry flounder is available. In the present study, starry flounder were intraperitoneally challenged with four S. parauberis strains to investigate changes in innate immune responses. Significant increases in serum lysozyme activities, superoxide production of kidney leucocytes, and serum superoxide dismutase activities were observed following experimental injection of S. parauberis. All these data suggested that the innate immune parameters were highly modulated during the S. parauberis infection process to render protection to the starry flounder. However, S. parauberis also exhibited the mechanisms to complete disease establishment by avoiding host immune responses. S. parauberis could survive and proliferate in the mucus, serum and kidney leucocytes of starry flounder. In particular, the strain isolated from the starry flounder showed the higher survival ability than other originated strains in the tested host fish.
authors.affiliation: Institute of Fisheries Sciences, Pukyong National University, 474 Ilgwang-Ro, Ilgwang-myeon, Gijang-gun, Busan 619-911, South Korea. ily337@daum.net
authors.forename: Sung Ho
authors.initials: SH
authors.lastname: Woo
authors.forename: Soo Il
authors.initials: SI
authors.lastname: Park
mesh_terms: D000818:Animals; D005393:Fish Diseases / Q000276:immunology* / Q000382:microbiology; D005432:Flounder; D007113:Immunity, Innate; D007274:Injections, Intraperitoneal / Q000662:veterinary; D007668:Kidney / Q000276:immunology / Q000382:microbiology; D007962:Leukocytes / Q000276:immunology / Q000382:microbiology; D009113:Muramidase / Q000097:blood; D009580:Nitroblue Tetrazolium / Q000378:metabolism; D009928:Organ Specificity; D013290:Streptococcal Infections / Q000276:immunology / Q000382:microbiology / Q000662:veterinary*; D013291:Streptococcus / Q000502:physiology*; D013482:Superoxide Dismutase / Q000097:blood
chemical_list: D009580:Nitroblue Tetrazolium; D013482:Superoxide Dismutase; D009113:Muramidase
keywords: Bacterial pathogenicity; Innate immune responses; Starry flounder Platichthys stellatus; Streptococcus parauberis