Production of viral vaccines for veterinary use.

This review provides inside information on the production of vaccines for veterinary use. The vaccines against rinderpest as well as foot and mouth disease are considered milestones in the history of veterinary vaccine production. Modern vaccines are based on the scientific progress in virology, cell biology and immunology. While naturally occurring attenuated viruses or viruses obtained after passage in different animal species or cell culture were used as vaccine strains in the early vaccines, nowadays targeted mutagenesis can be applied to generate vaccine virus strains. In principle, the antigen production process is the same for live and inactivated vaccines. The vaccine virus is usually grown in cell culture, either in roller bottles or bioreactors. Most live vaccines are freeze-dried in order to enable storage in the refridgerator for a longer period. To this end, a so-called stabilizer is added to the culture medium. The inactivation of the vaccine virus for the production of killed vaccines is done by physical or chemical treatments that lead to denaturation of the proteins or damage of the nucleic acids. The inactivated antigen may be further purified and mixed with an adjuvant. The quality standards for vaccines are layed down in international regulations and laws. Numerous tests are performed during the different production steps and on the final product in order to warrant the quality of each batch.