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

Developing procedures for most animal vaccines still relies on a classical strategy with live pathogens that possess a strong immunogenicity either with high virulence or without virulence. However, over the decade there has been great acceleration in the advancement of modern molecular techniques and the compilation of genomic data of many pathogens. Such advances provide a great opportunity to create desirable vaccine strains which are less dangerous but more effectively immunogenic than those of vaccines achieved by classical methods. It is well established that the immune system has several effector mechanisms to cope with various pathogens, which would be dependent on their lifecycle and the microenvironment of the infected host. Since killed vaccines are still mainly used for livestock, it is absolutely necessary to develop novel adjuvants in order to enhance satisfactory immunity for such vaccines. Potent adjuvants should be able to effectively elicit cellular immunity in animals that are vaccinated with less immunogenic vaccines including killed or subunit vaccines. The other way to resolve this issue would be to develop a new delivery system, such as plasmid DNA, liposome, microparticles, and live viral or bacterial vectors, which can introduce vaccine antigens into intracellular compartments. Another notable advancement in immunology is the increased recognition on the major roles of innate immunity in vaccine adjuvant functions, which is often ignored despite their significant influence on vaccine developments. Recently discovered innate immunity receptors are screened as new adjuvant materials having activities, and they are used for inducing or enhancing vaccine reactions. Currently many types of adjuvants are in use for animal vaccines.