Immunogenicity and protective role of antigenic regions from five outer membrane proteins of Flavobacterium columnare in grass carp Ctenopharyngodon idella

Abstract

Flavobacterium columnare causes columnaris disease in freshwater fi sh. In the present study, the antigenic regions of fi ve outer membrane proteins (OMPs), including zinc metalloprotease, prolyl oligopeptidase, thermolysin, collagenase and chondroitin AC lyase, were bioinformatically analyzed, fused together, and then expressed as a recombinant fusion protein in Escherichia coli . The expressed protein of 95.6 kDa, as estimated by 10% sodium dodecyl sulfate-polyacrylamide gel electrophoresis, was consistent with the molecular weight deduced from the amino acid sequence. The purifi ed recombinant protein was used to vaccinate the grass carp, Ctenopharyngodon idella . Following vaccination of the fi sh their IgM antibody levels were examined, as was the expression of IgM , IgD and IgZ immunoglobulin genes and other genes such as MHC Iα and MHC I I β , which are also involved in adaptive immunity. Interleukin genes ( IL ), including IL -1β , IL -8 and IL -10 , and type I and type II interferon ( IFN ) genes were also examined. At 3 and 4 weeks post-vaccination (wpv), signifi cant increases in IgM antibody levels were observed in the fi sh vaccinated with the recombinant fusion protein, and an increase in the expression levels of IgM , IgD and IgZ genes was also detected following the vaccinations, thus indicating that an adaptive immune response was induced by the vaccinations. Early increases in the expression levels of IL and IFN genes were also observed in the vaccinated fi sh. At four wpv, the fi sh were challenged with F . column a re , and the vaccinated fi sh showed a good level of protection against this pathogen, with 39% relative percent survival (RPS) compared with the control group. It can be concluded, therefore, that the fi ve OMPs, in the form of a recombinant fusion protein vaccine, induced an immune response in fi sh and protection against F . columnare .

Application of Comparative Genome in Aquaculture Diseases Diagnosis

“…Ví dụ, sự biểu hiện của esa1 từ Edwardsiella tarda, một kháng nguyên bề mặt giống D15, trong mô hình cá bơn Nhật Bản kích thích sự biểu hiện của một loạt gen liên quan đến cả khả năng miễn dịch tự nhiên và đặc hiệu, cũng như tăng cao khả năng sống của cá và tạo ra các kháng thể đặc hiệu trong huyết thanh [20], [21]. Tiêm vaccine có thành phần SEPs có tác dụng bảo vệ chống lại nhiễm A. hydrophila [22], [23], Flavobacterium columnare [24], [25], Pseudomonas putida [26], và Edwardsiellosis [27] - [29]. Nghiên cứu gần đây của Zeng et al [30] đã triển khai kết hợp so sánh hệ gen để sàng lọc các gen SEPs từ 17 chủng Leptospira đại diện cho các kiểu huyết thanh dịch tễ từ khắp nơi trên thế giới.…”