In the last 20 years there have been tremendous advancements in immunology and biotechnology which are now being utilized to develop novel cattle respiratory vaccines. Richard Harland, DVM, MVetSc, Novartis Animal Health Canada Inc., says the ideal vaccine focuses the appropriate immune response against only the essential antigens, is not distracted by non-essential antigens, is not reactive, acts quickly, and has an immune response that is distinguishable from a post infection immune response.
The first and obvious critical part of vaccine development is to identify the conserved and protective antigens. One approach to identify antigens is to focus on suspected or known necessary virulence or metabolic functions of the pathogen.
The field of adjuvant technology has advanced. Early adjuvants were based on trying to achieve a balance of antigen depot, inflammation and safety to improve the vaccine response. “With our better knowledge of immunology, we can now target specific innate immune responses to stimulate the appropriate response for the vaccine,” Harlan says. “A number of strategies have been devised to deliver the required antigens in a manner that is safe and generates the appropriate immune response.”
Novel technologies should give us greater flexibility in the timing of the administration of vaccines allowing animals to be properly immunized prior to exposure,” he adds. “The use of more purified antigens, new adjuvants, deletion mutants, vectors and