Application of radiation technology in vaccines development

One of the earliest methods used in the manufacture of stable and safe vaccines is the use of chemical and physical treatments to produce inactivated forms of pathogens. Although these types of vaccines have been successful in eliciting specific humoral immune responses to pathogen-associated immunogens, there is a large demand for the development of fast, safe, and effective vaccine manufacturing strategies. Radiation sterilization has been used to develop a variety of vaccine types, because it can eradicate chemical contaminants and penetrate pathogens to destroy nucleic acids without damaging the pathogen surface antigens. Nevertheless, irradiated vaccines have not widely been used at an industrial level because of difficulties obtaining the necessary equipment. Recent successful clinical trials of irradiated vaccines against pathogens and tumors have led to a reevaluation of radiation technology as an alternative method to produce vaccines. In the present article, we review the challenges associated with creating irradiated vaccines and discuss potential strategies for developing vaccines using radiation technology.

Efficacy and clinical trials of Salenvac-T, bivalent killed vaccine containing Salmonella Enteritidis and Salmonella Typhimurium / 대한수의학회지

Commercial bivalent killed Salmonella vaccine Salenvac-T has been used in several countries in order to prevent salmonellosis with Salmonella enterica serovars Enteritidis (SE) and Typhimurium (ST) in poultry. However, this vaccine has not been used in poultry farms in South Korea. In this study, we evaluated the efficacy of Salenvac-T vaccine to protect against the challenge of virulent SE and ST, and the effect of the vaccine on egg production and mortality in layer hens. The colonization of liver, spleen and cecum with challenged SE and ST was reduced in vaccinated chickens compared with that of unvaccinated control group. The twice vaccination with Salenvac-T induced elevated antibody responses against both SE and ST detected by enzyme-linked immunosorbent assay (ELISA). The higher average hen-day production was observed in the vaccinated layer hens than in the unvaccinated layer hens without significance. The average mortality was lower in the vaccinated layer hens during the experiment period. The antibody responses to both SE and ST were persistently detected in the vaccinated layers. In summary, vaccination with Salenvac-T reduces colonization of internal organs and induces good antibody responses, thereby results in higher performance and lower egg contamination with SE and ST in layer hens.

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

Vaccination has proven to be the most cost-effective strategy for controlling a wide variety of infectious diseases in humans and animals. For the last decade, veterinary vaccines have been substantially developed and demonstrated their effectiveness against many diseases. Nevertheless, new vaccines are greatly demanded to effectively control newly- and re-emerging pathogens in livestock. However, development of veterinary vaccines is a challenging task, in part, due to a variety of pathogens, hosts, and the uniqueness of host-susceptibility to each pathogen. Therefore, novel concepts of vaccines should be explored to overcome the limitation of conventional vaccines. There have been greatly advanced in the completion of genomic sequencing of pathogens, the application of comparative genomic and transcriptome analysis. This would facilitate to open opportunities up to investigate a new generation of vaccines; recombinant subunit vaccine, virus-like particle, DNA vaccine, and vector-vehicle vaccine. Currently, such types of vaccines are being actively explored against various livestock diseases, affording numerous advantages over conventional vaccines, including ease of production, immunogenicity, safety, and multivalency in a single shot. In this articles, the authors present the current status of the development of veterinary vaccines at large as well as research activities conducted in Korea.

Protective effects and immunogenicity of Salmonella Enteritidis killed vaccine strains selected from virulent Salmonella Enteritidis isolates / 대한수의학회지

Salmonella Enteritidis (SE) has been a major causative agent of food-borne human disease due to consumption of contaminated eggs and poultry meat. To prevent SE infection in poultry, and therefore minimize human infections, vaccination with either killed or live SE vaccine is suggested. We evaluated a newly developed killed bacterin using a representative SE isolate in Korea. Among pool of SE isolates, two highly virulent isolates (the one isolate from chicken, the other from human) were selected by measuring mortality in mouse and chickens administered. The chickens were injected intramuscularly with killed vaccine and were challenged with highly virulent SE strain 3 week after vaccination. The recovered colony count (cfu/g) of spleen and cecal content in the vaccinated groups was reduced compared with those of the unvaccinated control group. The antibody level in the vaccinated groups was higher at 3 week post vaccination. These results indicate that vaccination with killed vaccine was effective in preventing the infection of virulent SE. Further study for a large number of layers should be needed for the effect of egg production, SE shedding in feces, persistence of antibody level.