Major histocompatibility complex class I and class II molecules presenting conserved SARS-CoV-2 S2, nucleocapsid, and membrane peptide epitopes (MHC-SARS-CoV-2 pMHC)

The Major Histocompatibility Complex (MHC) class I and II molecules are essential glycoproteins that present peptide fragments to the adaptive immune system. In the context of SARS-CoV-2, these molecules present epitopes derived from the S2 subunit of the Spike protein, the Nucleocapsid (N) protein, and the Membrane (M) protein, which are significantly more conserved across viral variants than the S1 subunit (Grifoni et al., 2020, Cell Host & Microbe). MHC Class I molecules present these conserved peptides to CD8+ cytotoxic T cells to trigger the destruction of infected cells, while MHC Class II molecules present them to CD4+ helper T cells to coordinate the broader immune response and B-cell activation (He et al., 2021, Immunity). This target complex is the focus of next-generation 'T-cell vaccines' like CoVac-1, which aim to provide broad-spectrum protection that is less susceptible to escape by variants of concern (Heitmann et al., 2022, Nature). The interaction between the peptide-MHC (pMHC) complex and the T-cell receptor (TCR) is the fundamental unit of cellular immunity, making it a critical target for both prophylactic vaccines and therapeutic interventions in COVID-19.

Other names

HLA-SARS-CoV-2 peptide complexpMHC complexSARS-CoV-2 T-cell epitope-MHC complexAntigen-presenting MHC-peptide complex

Presentation of viral peptide fragments on the cell surface to T-cell receptors (TCRs), leading to the activation and proliferation of virus-specific CD4+ and CD8+ T cells.