A major cause of immunosuppression in poultry is infection with B-cell tropic viruses such as infectious bursal disease virus (IBDV) and the oncogenic retroviruses avian leukosis virus (ALV) and reticuloendotheliosis virus (REV). In vivo studies, while informative, can cause significant morbidity to infected birds. Recently, it has become possible to culture chicken primary B cells ex vivo. We have shown these cells can support IBDV replication and our data suggest they may be of relevance in vivo. Our aim is to establish a chicken primary B cell culture model to study the pathogenesis and improve the control of immunosuppressive B cell-tropic viruses of importance to the poultry industry that will replace the use of live birds in infection studies and reduce the total number of birds used experimentally in this field.
We will achieve this aim by addressing the following objectives:
1.) Validate the chicken primary B cell model for studying IBDV-host interactions,
2.) Expand the model to include ALV and REV,
3.) Evaluate the use of chicken primary B cells to test the immunogenicity of vaccine candidates prior to challenge and produce stocks of challenge viruses. Primary B cells will be harvested from chickens, cultured ex vivo, and infected in the laboratory with IBDV. The host-cell transcriptional response to infection will be characterised by RNA-Seq and the relevance of the model will be evaluated by comparing the results to the gene expression profile of infected tissue from in vivo studies. The model will then be expanded to include ALV and REV. The feasibility of using the cells to produce stocks of IBDV will be evaluated by determining the peak virus titre, the pathogenicity, and sequence changes compared to stocks produced in embryonated eggs. Finally, the cells will be used in neutralisation assays to quantify neutralising antibody titres in serum from vaccinated birds against very virulent IBDV strains.
Principal investigatorDr Andrew Broadbent
InstitutionThe Pirbright Institute
Co-InvestigatorProfessor Venugopal Nair
Dr Michael Skinner