Rapid Diagnosis of Necrosis Nervous Virus Infection using Recombinant Single-chain Variable Fragment (scFv)

Abstract

Many fishes have been infected with many kinds of marine pathogens and died, but marine viruses are most threatening pathogens. Marine viruses show a high lethality of ~70% but there is no therapeutic method for virus-infected fishes. Therefore, detection of marine viruses is very important issue for fish pathology. Marine virus Nervous Necrosis Virus (NNV), which is one of the most important marine viruses in Korea, infects high demanded fishes such as Paralichthys olivaceus and Scomber japonicas. NNV belongs to the family Nodaviridae, which has ssRNA (+) genome. This virus can be transmitted not only by tissues from infected fish but also by passive diffusion. Single Chain Variable Fragments (scFv) was chosen to detection and therapeutic methods in this study. Detection methods using scFvs has shown simplicity, speed, relatively high specificity and sensitivity than ordinary antibodies-using methods. To screen specific scFvs, viral coat protein as antigen is expressed by yeast surface display, which has advantages of post-translational process and efficient to use flow cytometry. scFvs expressed by phage display was used for ‘bio-panning’ process to get specific scFvs bound to antigen. After screening specific scFvs to antigen, they will be used to develop the marine virus detection kit.