The development of veterinary vaccines: a review of traditional methods and modern biotechnology approaches

The immunization of animals has been carried out for centuries and is generally accepted as the most cost-effective and sustainable method of controlling infectious veterinary diseases. Up to twenty years ago, most veterinary vaccines were either inactivated organisms that were formulated with an oil-based adjuvant or live attenuated vaccines. In many cases, these formulations were not very effective. The discovery of antigen/gene delivery systems has facilitated the development of novel prophylactic and therapeutic veterinary vaccines. To identify vaccine candidates in genomic sequences, a revolutionary approach was established that stems from the assumption that antibodies are more readily able to access surface and secreted than cytoplasm proteins; as such, they represent ideal vaccine candidates. The approach, which is known as reverse vaccinology, uses several bioinformatics algorithms to predict antigen localization and it has been successfully applied to immunize against many veterinary diseases. This review examines some of the main topics that have emerged in the veterinary vaccine field with the use of modern biotechnology techniques.