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

Conventional vaccines are developed to primarily control disease in animals upon infection with pathogenic microorganisms. Vaccines are increasingly assessed for their ability to reduce virus transmission and thus for the establishment of herd immunity [21] . However, to control and eradicate animal viral disease, vaccine should not only prevent diseases but also reduce transmission of the virus from one animal to another. If the transmission of virus was sufficiently reduced by vaccination, the given virus will eventually be eradicated from a defined population [21] . Marker vaccines have been constructed and allow infected animals to be distinguished from vaccinated animals when a companion diagnostic technique is applied [22] . A new concept vaccine, DIVA vaccine was established [21] , describing as a vaccine that carries at least one antigenic protein less than the corresponding wild type virus. The DIVA vaccines are unable to produce antibodies against the protein of the deleted genes, but wild type virus invokes antibody against that protein so that the antibodies can be differentiated using proper diagnostic techniques. With this type of vaccine, the infected animals carrying wild type virus can be identified but not the vaccinated animals. The diagnostic tools can be used for monitoring transmission of wild type virus in populations vaccinated with a DIVA vaccine. This type of vaccine is actively under development since genetic manipulation of pathogens can be easily achieved by great advanced techniques. Additionally, DIVA vaccines are at the cutting edge of vaccine development since they include the deletion of genes responsible for virulence and have no way to revert to the virulent wild type in vaccinated animals.