PMID- 34452057 OWN - NLM STAT- PubMed-not-MEDLINE LR - 20231115 IS - 2076-393X (Print) IS - 2076-393X (Electronic) IS - 2076-393X (Linking) VI - 9 IP - 8 DP - 2021 Aug 22 TI - In Vitro Priming of Human T Cells by Dendritic Cells Provides a Screening Tool for Candidate Vaccines for Burkholderia pseudomallei. LID - 10.3390/vaccines9080929 [doi] LID - 929 AB - Murine dendritic cells, when pulsed with heat-killed Burkholderia pseudomallei and used to immunise naive mice, have previously been shown to induce protective immunity in vivo. We have now demonstrated the in vitro priming of naive human T cells against heat-killed B. pseudomallei, by co-culture with syngeneic B. pseudomallei-pulsed dendritic cells. Additionally, we have enriched the DC fraction such that a study of the differential response induced by pulsed DCs of either myeloid or plasmacytoid lineage in syngeneic human T cells was achievable. Whilst both mDCs and pDCs were activated by pulsing, the mDCs contributed the major response to B. pseudomallei with the expression of the migration marker CCR7 and a significantly greater secretion of the proinflammatory TNFalpha and IL1beta. When these DC factions were combined and used to prime syngeneic T cells, a significant proliferation was observed in the CD4(+) fraction. Here, we have achieved human T cell priming in vitro with unadjuvanted B. pseudomallei, the causative organism of melioidosis, for which there is currently no approved vaccine. We propose that the approach we have taken could be used to screen for the human cellular response to candidate vaccines and formulations, in order to enhance the cell-mediated immunity required to protect against this intracellular pathogen and potentially more broadly against other, difficult-to-treat intracellular pathogens. To date, the polysaccharide capsule of B. pseudomallei, fused to a standard carrier protein, e.g., Crm, looks a likely vaccine candidate. Dendritic cells (DCs), providing, as they do, the first line of defence to infection, process and present microbial products to the immune system to direct downstream immune responses. Here, we have sought to use DCs ex vivo to identify immunogenic products from heat-killed B. pseudomallei. Using practical volumes of fresh human donor blood, we show that heat-killed B. pseudomallei activated and stimulated the expression of pro-inflammatory cytokines TNF-alpha, IL-1beta and IL-6 from both myeloid and plasmacytoid DCs. Furthermore, B. pseudomallei-pulsed DCs cultured with naive syngeneic T cells ex vivo, induced the activation and proliferation of the CD4(+) T-cell population, which was identified by cell surface marker staining using flow cytometry. Thus, both DC subsets are important for driving primary T helper cell responses to B. pseudomallei in healthy individuals and have the potential to be used to identify immunogenic components of B. pseudomallei for future therapies and vaccines. FAU - Reddi, Durga AU - Reddi D AD - Antigen Presentation Research Group, Imperial Centre for Translational and Experimental Medicine, 72 Du Cane Road, London W12 0NN, UK. FAU - Durant, Lydia AU - Durant L AUID- ORCID: 0000-0002-5068-1479 AD - Antigen Presentation Research Group, Imperial Centre for Translational and Experimental Medicine, 72 Du Cane Road, London W12 0NN, UK. FAU - Bernardo, David AU - Bernardo D AD - Antigen Presentation Research Group, Imperial Centre for Translational and Experimental Medicine, 72 Du Cane Road, London W12 0NN, UK. FAU - Noble, Alistair AU - Noble A AD - Antigen Presentation Research Group, Imperial Centre for Translational and Experimental Medicine, 72 Du Cane Road, London W12 0NN, UK. AD - Gut Microbes & Health Program, Quadram Institute Bioscience, Norwich NR4 7UQ, UK. FAU - English, Nicholas R AU - English NR AD - Antigen Presentation Research Group, Imperial Centre for Translational and Experimental Medicine, 72 Du Cane Road, London W12 0NN, UK. FAU - Hendy, Philip AU - Hendy P AD - Antigen Presentation Research Group, Imperial Centre for Translational and Experimental Medicine, 72 Du Cane Road, London W12 0NN, UK. AD - St Mark's Hospital, London North West University Healthcare NHS Trust, Harrow UT 84124, UK. FAU - Clark, Graeme C AU - Clark GC AD - Defence Science and Technology Laboratory, Porton Down SP4 0JQ, UK. FAU - Prior, Joann L AU - Prior JL AD - Defence Science and Technology Laboratory, Porton Down SP4 0JQ, UK. FAU - Williamson, Ethel Diane AU - Williamson ED AD - Defence Science and Technology Laboratory, Porton Down SP4 0JQ, UK. FAU - Knight, Stella C AU - Knight SC AD - Antigen Presentation Research Group, Imperial Centre for Translational and Experimental Medicine, 72 Du Cane Road, London W12 0NN, UK. LA - eng GR - BBS/E/F/000PR10353/BB_/Biotechnology and Biological Sciences Research Council/United Kingdom GR - BBS/E/F/000PR10355/BB_/Biotechnology and Biological Sciences Research Council/United Kingdom GR - BBS/E/F/000PR10356/BB_/Biotechnology and Biological Sciences Research Council/United Kingdom PT - Journal Article DEP - 20210822 PL - Switzerland TA - Vaccines (Basel) JT - Vaccines JID - 101629355 PMC - PMC8402564 OTO - NOTNLM OT - Burkholderia pseudomallei OT - T cell priming OT - dendritic cells COIS- The authors declare no conflict of interest. EDAT- 2021/08/29 06:00 MHDA- 2021/08/29 06:01 PMCR- 2021/08/22 CRDT- 2021/08/28 01:05 PHST- 2021/06/24 00:00 [received] PHST- 2021/08/10 00:00 [revised] PHST- 2021/08/18 00:00 [accepted] PHST- 2021/08/28 01:05 [entrez] PHST- 2021/08/29 06:00 [pubmed] PHST- 2021/08/29 06:01 [medline] PHST- 2021/08/22 00:00 [pmc-release] AID - vaccines9080929 [pii] AID - vaccines-09-00929 [pii] AID - 10.3390/vaccines9080929 [doi] PST - epublish SO - Vaccines (Basel). 2021 Aug 22;9(8):929. doi: 10.3390/vaccines9080929.