A review of vaccine development and research for industry animals in Korea

Lee, Nak-Hyung; Lee, Jung-Ah; Park, Seung-Yong; Song, Chang-Seon; Choi, In-Soo; Lee, Joong-Bok

For examples, the open reading frame 2 (ORF2) protein of porcine circovirus type 2 (PCV2), a major agent responsible for developing post-weaning multi-systemic wasting syndrome in pigs, was recently produced in baculovirus expression system [15] , and the subunit vaccine containing ORF2 protein has been commercialized. This vaccine has been purchased and distributed to pig farms by government since there have been significant economic losses from PCV2. From three years ago, about USD 30 million was annually required for purchase of vaccine. An international pharmaceutical company has governed significant market share, followed by Korean vaccine companies. Meanwhile, a subunit vaccine capable of preventing Newcastle disease virus (NDV) in poultry was successfully registered. Hemagglutinin-neuraminidase (HN) protein, a protective antigen, of NDV was produced in plant cells and demonstrated to protect a vacci-nated chicken once challenged with wild type virus. Also, the fusion (F) and HN proteins derived from the NDV isolate and La Sota strain of NDV were expressed, purified and used as a subunit vaccine. The subunit vaccine reduced significantly the amount of viral shedding after a single application [16] . For foot-and-mouth disease virus (FMDV), VP1 is a structural protein involved in neutralization of virus, whereas 3D is a RNA-dependent RNA polymerase that is highly conserved among other serotypes and strongly immunogenic. Recombinant proteins of both VP1 and 3D induce antigen-specific immune responses, indicating that they can be subunit vaccine candidates against FMDV [17] . The pre-membrane (prM) and envelop (E) proteins of Japanese encephalitis (JEV) were expressed in insect Sf9 cells. The immunogenicity of the recombinant prM and E proteins was demonstrated by complete protection mice from a virulent virus challenge, providing valuable information for developing efficacious subunit vaccines against JEV [18] .