title: Immobilization antigen vaccine adjuvanted by parasitic heat shock protein 70C confers high protection in fish against cryptocaryonosis.
abstract: The immobilization antigen (iAg) has been demonstrated as a protective immunogen against Cryptocaryon irritans infection. In this study, C-terminal domain of heat shock protein 70 cloned from C. irritans (Hsp70C) was tested for its immuno-stimulatory effects. The iAg and Hsp70C cDNAs were constructed independently in secretory forms and were encapsulated in chitosan nanoparticles. In the first immunization trial, grouper fingerlings orally intubated with iAg and iAg:Hsp70C presented 96% and 100% relative percent survival (RPS), respectively, after a lethal challenge. In the second trial, both iAg and iAg:Hsp70C groups showed 100% RPS and the skin trophont burden was significantly lowered. The iAg:Hsp70C still provides a significantly high protection of 51% RPS at 49 days post immunization, when an even more serious lethal infection occurs. RT-qPCR results showed that Hsp70C could up-regulate the expression of i) T cell markers: Cluster of Differentiation 8 alpha (CD8α) and CD4, ii) cytokine genes: Interferon gamma (IFNγ), Tumor Necrosis Factor alpha (TNFα) and Interleukin 12 p40 (IL-12/P40), iii) antibody genes: Immunoglobulin M heavy chain (IgMH) and IgTH, and iv) major histocompatibility complex (MHC-I & MHC-II), in the spleen of iAg:Hsp70C group. Furthermore, significantly high levels of iAg-specific IgM was detected in skin mucus which efficiently immobilized live theronts in iAg- and iAg:Hsp70C-immunized fish at 5 weeks post immunization. Hsp70C significantly increased the number of nonspecific CD8(+) skin leucocytes which exerted cytotoxicity against theronts, although cytotoxic activity showed no difference among the various groups. Because of this complementary cooperation of cellular and humoral immune responses, Hsp70C enhances the efficacy of iAg vaccine and constrains C. irritans infection. In view of the severe loss caused by cryptocaryonosis, application of this parasitic vaccine in farmed and ornamental fish, is worthy to be considered.
authors.affiliation: Department of Life Science, National Taiwan University, Taipei 106, Taiwan.
authors.forename: T A
authors.initials: TA
authors.lastname: Josepriya
authors.affiliation: Department of Life Science, National Taiwan University, Taipei 106, Taiwan.
authors.forename: Kuo-Hsuan
authors.initials: KH
authors.lastname: Chien
authors.affiliation: Department of Life Science, National Taiwan University, Taipei 106, Taiwan.
authors.forename: Hsin-Yun
authors.initials: HY
authors.lastname: Lin
authors.affiliation: Department of Food Science, National Taiwan Ocean University, Keelung, Taiwan; Center for Marine Bioscience and Biotechnology, National Taiwan Ocean University, Keelung, Taiwan.
authors.forename: Han-Ning
authors.initials: HN
authors.lastname: Huang
authors.affiliation: Department of Food Science, National Taiwan Ocean University, Keelung, Taiwan.
authors.forename: Chang-Jer
authors.initials: CJ
authors.lastname: Wu
authors.affiliation: Department of Life Science, National Taiwan University, Taipei 106, Taiwan. Electronic address: song@ntu.edu.tw.
authors.forename: Yen-Ling
authors.initials: YL
authors.lastname: Song
mesh_terms: D000818:Animals; D000953:Antigens, Protozoan / Q000008:administration & dosage / Q000276:immunology*; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology; D016798:Ciliophora / Q000276:immunology; D016770:Ciliophora Infections / Q000276:immunology / Q000517:prevention & control*; D060467:Disease Resistance; D005393:Fish Diseases / Q000276:immunology / Q000517:prevention & control*; D018840:HSP70 Heat-Shock Proteins / Q000008:administration & dosage / Q000235:genetics / Q000276:immunology*; D007075:Immunoglobulin M / Q000276:immunology; D053758:Nanoparticles / Q000008:administration & dosage; D010473:Perciformes; D015800:Protozoan Proteins / Q000008:administration & dosage / Q000276:immunology*; D016052:Protozoan Vaccines / Q000008:administration & dosage*; D012867:Skin / Q000276:immunology; D016808:Tetrahymena thermophila / Q000235:genetics
chemical_list: D000953:Antigens, Protozoan; D018840:HSP70 Heat-Shock Proteins; D007075:Immunoglobulin M; D015800:Protozoan Proteins; D016052:Protozoan Vaccines; C043323:immobilization antigens
keywords: Cryptocaryon irritans; DNA vaccine; Epinephelus coioides; Mucosal IgM; Parasitic Hsp70C; Parasitic iAg; Skin CD8(+) cells