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Frederik Larsen

Immune correlates of protection in peripheral blood of infectious bronchitis virus vaccinated MHC-B chicken lines

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Vaccination programs are employed in the poultry industry to limit outbreaks and spread of pathogens such as infectious bronchitis virus (IBV), which cause substantial economic loses each year. Correlates of IBV- vaccine-induced protection are used to assess vaccine efficacy, and hence predict risk of outbreaks in vaccinated commercial flocks. Easy measureable correlates of IBV-vaccine-induced protection in chicken, however, have proved difficult to identify, as serum antibody titres do not correlate well with vaccine- induced protection. In order to find correlates of protection, therefore, we employed a whole-blood no-lyse no-wash flow cytometric assay to quantify peripheral leucocyte subsets and expression of cell surface markers pre-and post IBV challenge of non-vaccinated and vaccinated MHC-B haplotypes B2, B12, B14, B15, B19, and B21. Peripheral blood was sampled 1 week and 3 weeks post primary vaccination, 2 weeks post boost-vaccination, and 1 week post IBV challenge. Non-vaccinated and vaccinated chickens presented differential tracheal IBV viral load post IBV challenge. Highest variation in tracheal IBV viral load between vaccinated MHC-B haplotypes was found 3 days post infection (d.p.i.). At 3 d.p.i., vaccinated MHC-B haplotypes B2 and B21 chickens showed a lower tracheal IBV viral load compared to MHC-B haplotypes B12, B15, and B19. Positive correlations were found between tracheal IBV viral load at 3 d.p.i. and counts of MHC-B haplotype leucocyte subsets TCRγδ-CD4+CD25+T cells, TCRγδ+CD8-T cells, TCRγδ-CD8+T cells, and heterophils as well as cell surface marker expression of CD8αβ on CD8β+T cells and MHCII on monocytes at all sampling time points. In conclusion, the results suggests that correlates of IBV-vaccine- induced protection can be identified by the whole-blood no-lyse no-wash flow cytometric high-throughput method, useful for screening large flocks.
Original languageEnglish
Publication year5 Sep 2018
Publication statusPublished - 5 Sep 2018
EventXVth Avian Immunology Research Group (AIRG) Meeting 2018 - St. Cathrines College, Oxford, United Kingdom
Duration: 5 Sep 201814 Sep 2018
Conference number: 15


ConferenceXVth Avian Immunology Research Group (AIRG) Meeting 2018
LocationSt. Cathrines College
CountryUnited Kingdom
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