Antigen presenting cell targeted T cell DNA vaccine inducing strong and specific cellular responses across multiple T cell epitopes of SARS-COV-2

Abstract

Abstract The severe respiratory syndrome coronavirus 2 (SARS-CoV-2) causing COVID-19 has continuously evolved with successive new virus variants of concern (VOC). A key challenge is to develop vaccines that can prevent infection and/or protect against severe disease caused VOCs that evade vaccine induced Spike neutralizing antibodies. T cell responses likely contribute to the efficacy of approved vaccines against VOCs and provide the rationale for the development of T-cell based vaccines. VB10.2210 is a T-cell based vaccine that was developed using Nykode’s easily adaptable DNA plasmid (pDNA) vaccine platform. VB10.2210 pDNA encodes homodimers consisting of i) a targeting unit that binds chemokine receptors on antigen-presenting cells, ii) a dimerization unit, and iii) an antigenic unit consisting of a selection of validated immunogenic SARS-CoV-2-specific T cell epitopes. The T cell epitopes were identified by Adaptive using T cell receptor sequencing of more than 6500 samples from COVID-19 individuals representing diverse geographies. The vaccine candidate was designed with broad HLA coverage and contains a diversity of both MHCI and MHCII T-cell epitopes across multiple viral proteins and known VOCs. In vitro characterization of the VB10.2210 pDNA showed that intact protein was expressed and secreted in human cell culture. The immunogenicity of the vaccine candidate was evaluated in transgenic HLA-A2.1, C57BL/6 and BALB/c mice. Preclinical data in these three mouse models demonstrate that VB10.2210 consistently induced strong, broad, dose-dependent, and persistent T cell responses across multiple T cell epitopes. VB10.2210 is currently being evaluated for safety and immunogenicity in a Phase I clinical trial (NCT05069623).