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

As a delivery vehicle, nonpathogenic live virus carrying foreign DNA can be administered into a host, creating proper immunity to the inserted proteins. Once a live delivery virus is injected, the gene of interest introduced within the vector vehicle is expressed in the vaccinated host so that the host elicits immune responses against the expressed protein [19] . The immune response against the expressed protein carried by vehicle virus would follow a very natural immune stimulatory pathway. Interestingly, host-restricted vector virus itself will not be replicated within the tissues of the vaccinated animals but is able to temporarily express the foreign protein [19] . These vaccines are free of adverse effects and are stable, nonadjuvanted, and allow for differentiating infected from vaccinated animals (DIVA). Approved vehicle viruses are currently in use for several veterinary diseases, including adenovirus, fowl pox, yellow fever and vaccinia virus. Among them, poxviruses have been widely used for the delivery of vaccine antigen due to their ability to accommodate a large amount of exogenous genes and infect various types of mammalian cells, as well as express a high level of protein. They can replicate in mammalian cells even though 10% of its genome was deleted. In particular, both fowl pox and canary pox virus have a host-restrictive advantage compared with other vaccine viruses. consequently, animal vaccines have been developed using this system.