Indo-Norwegian project for the development of candidate vaccines for fish

This project is a continuation of the preceding Norwegian-Indian project InNoVacc. The project contributes to the development of antigens that may have the potential to be included in fish vaccines. The active researchers in this project will mainly be exchange PhD students and researchers who are in shorter stays in Norway. The project includes three work packages. In work-package, 1 lipid-modified virus antigens were developed for expression in bacteria. Bacterial lipoproteins have high antigenicity because of the adjuvant properties of the added lipids. By modification of proteins with lipids the possibility that a protein antigen may induce an adaptive immune response will increase, and thereby increase antibody production. The project aimed to lipid-modifying proteins from Piscine orthoreovirus, (PRV) Salmonid alphavirus (SAV) and Nodavirus from tropical seabass. The lipid-modified PRV and SAV proteins were tested in a multiplex immunoassay where the humoral response of salmon that has been infected with either PRV or SAV was tested. The PRV antigens were recognized, while the SAV were not. In work package 3 the immunological and morphological responses as well as gene expression in gills and intestines in fish after virus infection have been characterized. A PhD student with fellowship from ICAR will work at NMBU in all of the PhD period. He focuses on a PRV variant from rainbow trout. Our findings indicate that, despite various species preferences for PRV-1 and -3, many genetic, antigenic and structural properties are conserved. The results also show that PRV-3 infection in rainbow trout has much in common with PRV-1 infection in Atlantic salmon regarding immunological response and development of heart pathology, but not in the ability to establish a persistent infection. The work has been carried out in close co-operation with a fellow PhD student from the Technical University of Denmark, Copenhagen.

Fiskehelse er av stor betydning for de involverte institusjonene, og vil være det også etter utfasingen av InNoVacc II. De sentrale forskerne har faste stillinger ved sien respektive vertsinstitusjoner og vil fortsette sine forskningsaktiviteter. Noen av doktorgradsstudentene og postdoc vil fortsette å utføre forskning i akademia, men det også er gode muligheter for kandidatene i privat sektor. Det har vært et nært samarbeid mellom partnere involvert i InNoVacc II, og dette forventes å holdes vedlike i fremtidige felles prosjekter og - søknader. Samarbeid vil også fortsette på mer uformelle måter.

We will focus on continuation of some of the promising activity of the former InNoVacc project related to development of fish vaccine antigens and characterization of immune- and morphological responses. It is applied for support for exchange visits of 3-6 months duration each. The project contains three work-packages: WP1: Develop lipid-modified antigens for viral vaccine Many bacteria have adapted posttranslational modification of some of its proteins into lipoproteins for carrying out a variety of activities at the membrane-aqueous interface. Naturally produced bacterial lipoproteins and lipopeptides derived from them are known for their antigenicity owing the adjuvant property of the lipid. Lipid-modified antigens increase the ability of an antigen to induce an adaptive response and boost the antibody production. The aim is to optimize adjuvant-antigens for the fish immune response and fish vaccine development. WP2: Development of Nodavirus vaccine candidates for protection of viral nervous necrosis in Asian sea bass. In addition to lipid modified Nodavirus capsid protein the capsid protein will be expressed in the replicon expression system based on the replication machinery of Salmonid alphavirus. Testing of efficiency will be done using inactivated, purified antigen from cell-culture derived Nodavirus of Asian sea bass will function as a control. WP3: Characterization of immune and morphological responses in fish after virus infection. In previous works, we have identified mucosal epithelial cells capable of antigen uptake We will aim at further characterising transcriptional and morphological responses in gills and gut of salmon. We will also study immune gene expression in sea bass following vaccination against nodavirus. Students from India will carry out this work in Norway using material from challenge experiments carried out in India.