Dissecting the neutralising antibody response to the porcine reproductive and respiratory syndrome virus to identify novel vaccine targets

Porcine reproductive and respiratory syndrome (PRRS) is the most important infectious disease affecting the global pig industry. PRRS viruses (PRRSV) are a major threat to both animal welfare and food security, as demonstrated by the pig high fever disease outbreak that rapidly spread across Southeast Asia with devastating consequences. PRRSV exists as two genetically and antigenically distinct species, PRRSV-1 and -2, which are both rapidly evolving.

The emergence of highly pathogenic strains from both species and the failure of current live attenuated vaccines to provide broad protection against an ever-expanding diversity of viral strains pose significant challenges to effective disease control world-wide. There is therefore an urgent requirement to explore alternative approaches to vaccine development to combat PRRSV. Neutralizing antibodies confer protection against PRRSV and recent studies have shown antibody responses can neutralize a wide diversity of PRRSV strains. An improved understanding of conserved antigenic targets would enable the design of novel vaccines.

Aims of the project:
1. To identify and characterise naturally occurring porcine monoclonal antibodies capable of neutralising PRRSV from single B cell sequencing.
2. To map the binding sites of neutralising antibodies to the minor (GP2a, GP3 and GP4) and major (GP5 and M) envelope proteins of the virus at a structural level.

Experimental plan:
Fluorescent Activated Cell Sorting (FACS) will be used to isolate porcine B cells that bind to PRRSV antigens through surface expressed IgG receptors. Variable regions cDNAs will be recovered by PCR, sequenced and produced as recombinant porcine IgGs and Fab fragments by transient expression. Reactivity to PRRSV envelope proteins will be characterised by surface plasmon resonance and antibodies tested in viral neutralisation assays. Structural Industrial CASE Studentship Advertisement – 2019-20 analysis of antibody-antigen binding will be carried out by a combination of X-ray crystallography and cryo-EM analysis of antibody-antigen complexes.

The project is a collaboration between The Pirbright Institute and University of Oxford and the student will be working at both locations during the course of the project. Work on the porcine immune response and sequence analyses will be undertaken in Simon Graham and John Hammond’s groups at the Pirbright Institute. Protein production and structural studies will be carried out in Ray Owens’s laboratory at the Research Complex at Harwell and Jon Grimes group in the Structural Biology Division of the Nuffield Department of Medicine in Oxford and using the facilities at the Diamond Light Source. Time will also be spent in the vaccine development laboratory of Zoetis to gain experience of the potential commercial application of the research. This multi-disciplinary project will provide training in a range of molecular biology, biochemical and structural methods leading to a mechanistic insight into the antibody response in pigs to the one of the most important veterinary viral pathogens.

Attributes of suitable applicants: First degree (at least 2.1) in biochemistry or related subject.

How to apply:
If you are interested in applying for a BBSRC iCASE studentship please contact the named supervisor, Ray Owens ([Email Address Removed]) for further information and to determine whether they would encourage you to apply. Applicants who wish to apply for a BBSRC iCASE studentship should make an enquiry to the Interdisciplinary Bioscience DTP via [Email Address Removed] for advice on making a full and formal application to the University.