EASTBIO: Development of an E. coli O157 subunit vaccine for cattle based on knowledge of CD8 and CD4 T cell responses to target antigens

Over the last 15 years our grouping has made significant progress in understanding how the zoonotic pathogen Escherichia coli O157 colonises the terminal rectum in cattle and we have taken that knowledge forward with development of an experimental sub-unit vaccine aimed at reducing transmission of this organism between animals and therefore protect human health. The current formulation primarily stimulates an antibody response to the antigens present in the vaccine, but we know from our on-going work that a cell-mediated response also occurs and we have evidence of bacterial protein processing and presentation from in vitro studies of peptide presentation on MHCI of epithelial cells infected with E. coli O157. This project would be an exciting opportunity to develop the research from this advanced starting point with the tremendous advantage of developed reagents, an established research team and an industrial partner that has invested in commercializing the vaccine.
Specifically, the PhD would be in the following research areas with the techniques you would acquire also defined: (1) Culture of fibroblasts from cattle previously infected with E. coli O157 and co-culture with expanded CD8+ T-cells from the blood of the same animals. Peptides from our defined antigens would then be added and T-cell activation monitored by IFN release. This system matches MHC type on antigen presenting cells and T-cell receptors from exposed animals and should verify the recognition of specific antigen epitopes. (2) Continue development of an MHCI-deleted bovine epithelial cell line using CRISPR-Cas9. Previous work has already integrated Cas9 into the genome of the EBL cells and this has been shown to be active. Delivery of specific guide RNAs will allow deletion of all MHCI alleles and allow us to generate cell lines expressing only the MHCI alleles provided by transfection (or knock-ins). These will be valuable reagents for vaccine studies and you would use them to match T-cells from infected cattle with these epithelial cells to examine responses to E. coli O157 +/- specific antigens. (3) We already have patented technology based on flagellin-delivery of antigens which focuses on TLR5 stimulation and generation of a mucosal IgA and IgG responses. New vaccine constructs would be made and tested with the aim of establishing immune memory that would promote a cell-mediated response. These would include viral vectored, nucleic acid and nano-particle delivery. (4) Another concept that will be tested is to determine if natural exposure of E. coli O157 on the feedlot/farm can act as the primary inoculation with vaccination then targeting boosting of naturally-established memory prior to movement of animals for slaughter. We have serum samples stored from a feedlot vaccine trial that will allow the immunology underpinning natural and vaccine responses to be investigated in detail. Overall, the PhD will provide excellent training in immunology, pathogen molecular biology and vaccine development with a commercial partner.

Funding information and application procedures:
This 4 year PhD project is part of a competition funded by EASTBIO BBSRC Doctoral Training Partnership (DTP) http://www.eastscotbiodtp.ac.uk/how-apply-0 .

EASTBIO Application and Reference Forms can be downloaded via http://www.eastscotbiodtp.ac.uk/how-apply-0

Please send your completed EASTBIO Application Form along with a copy of your academic transcripts to [Email Address Removed]

You should also ensure that two references have been send to [Email Address Removed] by the deadline using the EASTBIO Reference Form.