title: Immunological responses and protection in Chinese giant salamander Andrias davidianus immunized with inactivated iridovirus.
abstract: Chinese giant salamander hemorrhage is a newly emerged infectious disease in China and has caused huge economic losses. The causative pathogen has been identified as the giant salamander iridovirus (GSIV). In this study, the immunological responses and protection in Chinese giant salamander immunized with β-propiolactone inactivated GSIV are reported. Red and white blood cell counting and classification, phagocytic activity, neutralizing antibody titration, immune-related gene expression and determination of the relative percent survival were evaluated after vaccination. The red and white blood cell counts showed that the numbers of erythrocytes and leukocytes in the peripheral blood of immunized Chinese giant salamanders increased significantly on days 4 and 7 post-injection (P<0.01). Additionally, the differential leukocyte count of monocytes and neutrophils were significantly different compared to the control group (P<0.01); the percentage of lymphocytes was 70.45±7.52% at day 21. The phagocytic percentage and phagocytic index was 38.78±4.33% and 3.75±0.52, respectively, at day 4 post-immunization which were both significantly different compared to the control group (P<0.01). The serum neutralizing antibody titer increased at day 14 post-immunization and reached the highest titer (341±9.52) at day 21. The quantitative PCR analysis revealed that the immunization significantly up-regulated the expression of immune related genes TLR-9 and MyD88 the first two weeks after immunization. The challenge test conducted at day 30 post-injection demonstrated that the immunized group produced a relative survival of 72%. These results indicate that the inactivated GSIV could elicit significant non-specific and specific immunological responses in Chinese giant salamander that resulted in significant protection against GSIV induced disease.
authors.affiliation: Yangtze River Fisheries Research Institute, Chinese Academy of Fishery Sciences, Wuhan 430223, China; College of Fisheries and Life Sciences, Shanghai Ocean University, Shanghai 201306, China.
authors.forename: Wenzhi
authors.initials: W
authors.lastname: Liu
authors.affiliation: Yangtze River Fisheries Research Institute, Chinese Academy of Fishery Sciences, Wuhan 430223, China.
authors.forename: Jin
authors.initials: J
authors.lastname: Xu
authors.affiliation: Yangtze River Fisheries Research Institute, Chinese Academy of Fishery Sciences, Wuhan 430223, China.
authors.forename: Jie
authors.initials: J
authors.lastname: Ma
authors.affiliation: Research Division, Clear Springs Foods, Inc., P.O. Box 712, Buhl, ID 83316, USA.
authors.forename: Scott E
authors.initials: SE
authors.lastname: LaPatra
authors.affiliation: Yangtze River Fisheries Research Institute, Chinese Academy of Fishery Sciences, Wuhan 430223, China.
authors.forename: Yan
authors.initials: Y
authors.lastname: Meng
authors.affiliation: Yangtze River Fisheries Research Institute, Chinese Academy of Fishery Sciences, Wuhan 430223, China.
authors.forename: Yuding
authors.initials: Y
authors.lastname: Fan
authors.affiliation: Yangtze River Fisheries Research Institute, Chinese Academy of Fishery Sciences, Wuhan 430223, China.
authors.forename: Yong
authors.initials: Y
authors.lastname: Zhou
authors.affiliation: College of Fisheries, Nanjing Agricultural University, Wuxi 214081, China.
authors.forename: Xin
authors.initials: X
authors.lastname: Yang
authors.affiliation: Yangtze River Fisheries Research Institute, Chinese Academy of Fishery Sciences, Wuhan 430223, China; College of Fisheries and Life Sciences, Shanghai Ocean University, Shanghai 201306, China. Electronic address: zlb@yfi.ac.cn.
authors.forename: Lingbing
authors.initials: L
authors.lastname: Zeng
mesh_terms: D000818:Animals; D002681:China; D007114:Immunization / Q000662:veterinary*; D017994:Iridovirus / Q000276:immunology*; D014562:Caudata / Q000276:immunology* / Q000821:virology; D015164:Vaccines, Inactivated; D014765:Viral Vaccines / Q000276:immunology*
chemical_list: D015164:Vaccines, Inactivated; D014765:Viral Vaccines
keywords: Chinese giant salamander; Efficacy of protection; Immunological responses; Inactivated vaccine; Iridovirus