Traditional approaches to vaccination, which have relied on the delivery of inactivated or attenuated organisms, have had a major impact on the control of livestock diseases. However, there remain many important diseases for which vaccines are either not available or for which the current vaccines are only partially effective. Traditional vaccination approaches utilising inactivated organisms or attenuated strains, selected by passage in vitro or in an unnatural host, have a number of shortcomings. Thus, inactivated organisms may induce inappropriate immune responses or immunity may be of short duration; incomplete attenuation or inactivation of organisms can result in disease; and it is not always possible to produce stable attenuated organisms or "marker vaccines" by in vitro or in vivo passage.
Developments in DNA technology have created new opportunities for vaccine production, both through genetic manipulation of pathogens and by enabling the identification of defined antigens that induce protective immune responses. These opportunities, together with a detailed understanding of the components of the immune response that mediate protection, and knowledge of how these responses can be induced and regulated at an appropriate location in vivo, provide a conceptual framework for the rational development of new vaccines.
The Vaccinology Group, which has expertise in bovine and porcine immunology, molecular virology and cell biology, is a cross-site group. Scientists at Compton Laboratory work on endemic viruses, such as respiratory syncytial virus (RSV), whilst scientists at Pirbright study exotic viruses such as African swine fever virus (ASFV), foot-and-mouth disease virus (FMDV) and bluetongue virus. The main focus of the Group is to:
- Analyse the molecular determinants of virulence of BRSV in order to identify suitable attenuated virus vaccine candidates
- determine the mechanisms of immunity to these viruses
- identify the antigens recognised by protective immune responses
- determine the role of viral proteins in evasion of the protective immune response
- determine the type of antigen delivery system required for effective vaccination
BRSV is the most important primary viral cause of respiratory disease in young calves in the UK.
The other viruses that we study are exotic to the UK, although they are a potential threat. Indeed, bluetongue virus caused outbreaks in England in 2007. ASFV, although normally found in Africa, is encroaching into Europe, as has happened most recently in 2007. There is no vaccine against ASFV. We are also investigating novel approaches to the control of FMDV.