Conserved and Novel Mouse CD8 T Cell Epitopes within SARS-CoV-2 Spike Receptor Binding Domain Protein Identified following Subunit Vaccination

The prior existence of human ACE2 protein-expressing mice used to study SARS-CoV and the rapid development of mouse-adapted virus strains have allowed the study of SARS-CoV-2 in mice, even as we are still learning about its natural pathology in humans. With myriad genetically altered strains on the C57BL/6 background and the abundance of immunological reagents available to interrogate its immune responses, the C57BL/6 mice may provide useful insight into the immunology of SARS-CoV-2 infection and vaccination. To conduct more detailed studies on their T cell responses to vaccines and infection, the epitopes eliciting those responses must be characterized in further detail. In this study, we mapped CD8 T cell epitopes within the receptor binding domain of the SARS-CoV-2 spike protein in C57BL/6 mice. Our study identified five major CD8 T cell epitopes in immunized C57BL/6 mice, including one, VVLSFELL, presented by H-2K(b) and common between SARS-CoV and SARS-CoV-2.

Automated summary

The use of human ACE2 protein-expressing mice to study SARS-CoV and SARS-CoV-2 has provided insights into the pathology of SARS-CoV-2 in mice, particularly in the C57BL/6 strain. By mapping CD8 T cell epitopes in immunized C57BL/6 mice, five major CD8 T cell epitopes were identified, including one common epitope between SARS-CoV and SARS-CoV-2. Further characterization of epitopes is necessary for detailed studies on T cell responses to vaccines and infection.