en fish disease fish disease پژوهشي Orginal research papers Infectious pancreatic necrosis virus (IPNV) is one of the major worldwide leading causes of losses among different fish species, especially in salmonidae. In order to develop a vaccine (First stage), the VP2 gene from an Iranian IPNV isolate was amplified using polymerase chain reaction (PCR), inserted between <em>Spe</em>I and <em>Sca</em>I restriction sites of pNZ8150 expression vector under the control of NICE promoter, and transformed into electrocompetent <em>Lactococcus</em><em> lactis</em> cells using electroporation method regarding production of a recombinant live vector vaccine in fish. The transformed <em>L. lactis</em> cells containing the highest copy of the recombinant plasmid, pNZVP2, were selected using high antibiotic concentration (100 &mu;g/mL of chloramphenicol). These cells are expected to express high level of VP2 protein and consequently will be the best candidates for vaccine formulation. Restriction enzyme digestion using <em>Spe</em>I, colony PCR using gene specific primers and boiling method, and DNA sequencing confirmed construction of the recombinant expression vector, pNZVP2. The present research will pave the way for expression and oral delivery of not only IPNV antigens, but also, any other infectious agents via pNZ8150/<em>L. lactis</em> expression system, potentially as a novel platform for the development of oral delivery vaccines in fish.&nbsp; Fish, Recombinant vaccine, Cloning, IPNV, VP2 gene, Lactococcus lactis 1626 1648 http://jifro.ir/browse.php?a_code=A-10-2627-3&slc_lang=en&sid=1 A. Mohammadi asma.mohammadi.66@gmail.com 100319475328460042726 100319475328460042726 No Department of Health, Aquatic Animal Health and Disease, Faculty of Specialized Veterinary Science, Science and Research Branch, Islamic Azad University, Tehran, Iran M. Afsharnasab mafsharnasab@yahoo.com 100319475328460042727 100319475328460042727 Yes Department of Health, Aquatic Animal Health and Disease, Faculty of Specialized Veterinary Science, Science and Research Branch, Islamic Azad University, Tehran, Iran H. Kohram kohram@can.ut.ac.ir 100319475328460042728 100319475328460042728 No Department of Animal Science, College of Agriculture and Natural Resources, University of Tehran, Karaj, Iran Kh. Aghayipour Khosrow@rvsri.ac.ir 100319475328460042729 100319475328460042729 No Department of Genomics and Genetic Engineering, Razi Vaccine and Serum Research Institute (RVSRI), Agricultural Research, Education and Extension Organization (AREEO), Karaj, Iran A.A. Motalebi Moghanchoghi motalebi@ifro.ir 100319475328460042730 100319475328460042730 No Department of Health, Aquatic Animal Health and Disease, Faculty of Specialized Veterinary Science, Science and Research Branch, Islamic Azad University, Tehran, Iran