Replication-incompetent viral vaccine vectors ChAdOx1 and MVA as tools for evaluating T-cell responses to naturally
Salik Nazki1, Jesús Reiné2, Reshma Kailath3
1Chinese Academy of Medical Science (CAMS) Oxford Institute (COI), University of Oxford, Oxford OX3 7FZ, United Kingdom; Pandemic Sciences Institute, Nuffield Department of Medicine, University of Oxford, Institute of Developmental & Regenerative Medicine, Old Road Campus, Roosevelt Drive, Oxford, OX3 7TY, United Kingdom.
Abstract:
Assessing T-cell responses is critical for vaccine development. In vitro methods using SARS-CoV-2 or recombinant vaccinia virus with B cells effectively activate T-cells but require stringent biosafety conditions. As an alternative, we explored attenuated, replication-incompetent viral vectors, such as modified vaccinia Ankara (MVA) and chimpanzee adenoviral vectors (ChAdOx1 and ChAdOx2). These vectors successfully transduced B cells, as confirmed by GFP expression. B cells transduced with ChAdOx1 nCoV-19 (encoding SARS-CoV-2 Spike) activated autologous CD8⁺ and CD4⁺ T-cells. Similarly, B cells transduced with MVA encoding Spike activated autologous CD4⁺ T-cells. Our findings provide proof-of-concept support for the use of these safer viral vectors in vitro studies of vaccine-induced cellular immunity.
