Identification of a Spike-Specific CD8⁺ T-Cell Epitope Following Vaccination Against the Middle East Respiratory Syndrome Coronavirus in Humans

Licensed vaccines against the Middle East respiratory syndrome coronavirus (MERS-CoV), an emerging pathogen of concern, are lacking. The modified vaccinia virus Ankara vector-based vaccine MVA-MERS-S, expressing the MERS-CoV-spike glycoprotein (MERS-S), is one of 3 candidate vaccines in clinical development and elicits robust humoral and cellular immunity. Here, we identified for the first time a MERS-S-specific CD8(+) T-cell epitope in an HLA-A*03:01/HLA-B*35:01-positive vaccinee using a screening assay, intracellular cytokine staining, and in silico epitope prediction. As evidence from MERS-CoV infection suggests a protective role of long-lasting CD8(+) T-cell responses, the identification of epitopes will facilitate longitudinal analyses of vaccine-induced T-cell immunity.