{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,5,16]],"date-time":"2026-05-16T00:43:35Z","timestamp":1778892215926,"version":"3.51.4"},"reference-count":27,"publisher":"MDPI AG","issue":"6","license":[{"start":{"date-parts":[[2024,6,9]],"date-time":"2024-06-09T00:00:00Z","timestamp":1717891200000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Vaccines"],"abstract":"<jats:p>There are varying data concerning the effect of prior anti-vector immunity on the T-cell response induced by immunisation with an identical vectored vaccine containing a heterologous antigen insert. To determine whether prior exposure to ChAdOx1-SARS-CoV2 immunisation (Vaxzevria\u00ae) impacts magnitudes of antigen-specific T-cell responses elicited by subsequent administration of the same viral vector (encoding HBV antigens, ChAdOx1-HBV), healthy volunteers that had received Vaxzevria\u00ae (n = 15) or the Pfizer or Moderna mRNA COVID-19 vaccine (n = 11) between 10 and 18 weeks prior were recruited to receive a single intramuscular injection of ChAdOx1-HBV. Anti-ChAdOx1-neutralising antibody titers were determined, and vector or insert-specific T-cell responses were measured by a gamma-interferon ELISpot and intracellular cytokine staining (ICS) assay using multiparameter flow cytometry. Participants were followed for three months after the ChAdOx1-HBV injection, which was well-tolerated, and no dropouts occurred. The baseline ChAdOx1 neutralisation titers were higher in the Vaxzevria\u00ae cohort (median of 848) than in the mRNA cohort (median of 25). T-cell responses to HBV antigens, measured by ELISpot, were higher on day 28 in the mRNA group (p = 0.013) but were similar between groups on day 84 (p = 0.441). By ICS, these differences persisted at the last time point. There was no clear correlation between the baseline responses to the adenoviral hexon and the subsequent ELISpot responses. As vaccination within 3 months using the same viral vector backbone affected the insert-specific T-cell responses, a greater interval after prior adenoviral immunisation using heterologous antigens may be warranted in settings in which these cells play critical roles.<\/jats:p>","DOI":"10.3390\/vaccines12060644","type":"journal-article","created":{"date-parts":[[2024,6,10]],"date-time":"2024-06-10T10:08:43Z","timestamp":1718014123000},"page":"644","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":2,"title":["Effect of Prior ChAdOx1 COVID-19 Immunisation on T-Cell Responses to ChAdOx1-HBV"],"prefix":"10.3390","volume":"12","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-2701-2226","authenticated-orcid":false,"given":"Charlotte","family":"Davis","sequence":"first","affiliation":[{"name":"Barinthus Biotherapeutics, Harwell, Didcot OX11 0DF, UK"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Dave","family":"Singh","sequence":"additional","affiliation":[{"name":"Medicines Evaluation Unit Ltd., Manchester M23 9QZ, UK"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-7910-8003","authenticated-orcid":false,"given":"Katie","family":"Anderson","sequence":"additional","affiliation":[{"name":"Barinthus Biotherapeutics, Harwell, Didcot OX11 0DF, UK"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Antonella","family":"Vardeu","sequence":"additional","affiliation":[{"name":"Barinthus Biotherapeutics, Harwell, Didcot OX11 0DF, UK"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Jakub","family":"Kopycinski","sequence":"additional","affiliation":[{"name":"Barinthus Biotherapeutics, Harwell, Didcot OX11 0DF, UK"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Alice","family":"Bridges-Webb","sequence":"additional","affiliation":[{"name":"Barinthus Biotherapeutics, Harwell, Didcot OX11 0DF, UK"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Alice","family":"Trickett","sequence":"additional","affiliation":[{"name":"Barinthus Biotherapeutics, Harwell, Didcot OX11 0DF, UK"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Susanne","family":"O\u2019Brien","sequence":"additional","affiliation":[{"name":"Barinthus Biotherapeutics, Harwell, Didcot OX11 0DF, UK"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-3623-8059","authenticated-orcid":false,"given":"Matthew","family":"Downs","sequence":"additional","affiliation":[{"name":"Barinthus Biotherapeutics, Harwell, Didcot OX11 0DF, UK"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Randip","family":"Kaur","sequence":"additional","affiliation":[{"name":"Barinthus Biotherapeutics, Harwell, Didcot OX11 0DF, UK"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Radka","family":"Kolenovska","sequence":"additional","affiliation":[{"name":"Barinthus Biotherapeutics, Harwell, Didcot OX11 0DF, UK"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Louise","family":"Bussey","sequence":"additional","affiliation":[{"name":"Barinthus Biotherapeutics, Harwell, Didcot OX11 0DF, UK"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Kathryn","family":"Rutkowski","sequence":"additional","affiliation":[{"name":"Barinthus Biotherapeutics, Harwell, Didcot OX11 0DF, UK"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Sarah","family":"Sebastian","sequence":"additional","affiliation":[{"name":"Barinthus Biotherapeutics, Harwell, Didcot OX11 0DF, UK"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-2863-0835","authenticated-orcid":false,"given":"Tamsin","family":"Cargill","sequence":"additional","affiliation":[{"name":"Nuffield Department of Medicine, University of Oxford, Oxford OX1 2JD, UK"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Eleanor","family":"Barnes","sequence":"additional","affiliation":[{"name":"Nuffield Department of Medicine, University of Oxford, Oxford OX1 2JD, UK"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Thomas G.","family":"Evans","sequence":"additional","affiliation":[{"name":"Barinthus Biotherapeutics, Harwell, Didcot OX11 0DF, UK"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Paola","family":"Cicconi","sequence":"additional","affiliation":[{"name":"Centre for Clinical Vaccinology and Tropical Medicine (CCVTM), University of Oxford, Oxford OX1 2JD, UK"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2024,6,9]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"616","DOI":"10.1016\/j.ymthe.2004.07.013","article-title":"Adenoviruses as vaccine vectors","volume":"10","author":"Tatsis","year":"2004","journal-title":"Mol. 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