Conserved SARS-CoV-2 T-cell epitopes from non-Spike viral proteins (Non-Spike T-cell epitopes)

Conserved SARS-CoV-2 T-cell epitopes from non-Spike viral proteins are specific peptide sequences derived from internal viral components such as the Nucleocapsid (N), Membrane (M), and non-structural proteins (nsps) like ORF1ab (Grifoni et al., 2020, Cell). Unlike the Spike protein, which is prone to frequent mutations that allow the virus to evade neutralizing antibodies, these non-Spike proteins are highly conserved across different SARS-CoV-2 variants and even other betacoronaviruses (Tarke et al., 2021, Cell Reports Medicine). These epitopes are processed and presented by Major Histocompatibility Complex (MHC) molecules on the surface of infected cells or antigen-presenting cells to activate CD4+ helper and CD8+ cytotoxic T cells. The primary therapeutic goal of targeting these epitopes is to induce a broad, durable cellular immune response that can recognize and eliminate virus-infected cells regardless of mutations in the Spike protein. This approach is currently being utilized in next-generation vaccine candidates, such as UB-612 and GRT-R910, to provide variant-proof protection and enhance long-term immunity (Wang et al., 2022, The Lancet Infectious Diseases). By focusing on the cellular arm of the immune system, these targets complement antibody-focused strategies and are particularly relevant for preventing severe disease and hospitalization. Research indicates that T-cell responses to these conserved regions remain largely intact against variants of concern, including Omicron (Tarke et al., 2022, Cell). Consequently, these epitopes are considered high-priority targets for the development of universal coronavirus vaccines.

Other names

Non-spike SARS-CoV-2 antigensConserved T-cell epitopesSARS-CoV-2 internal protein epitopesNucleocapsid, Membrane, and ORF1ab epitopesSARS-CoV-2 non-Spike T-cell antigens

Induction of cellular immunity through the presentation of conserved viral peptides on Major Histocompatibility Complex (MHC) Class I and II molecules to activate CD8+ cytotoxic and CD4+ helper T cells (Grifoni et al., 2020, Cell).