Public T cell receptors (TCRs) recurrently emerge across individuals in response to common pathogens, yet the structural and biophysical basis distinguishing public from private clonotypes remains incompletely defined. Here, we combine epitope mapping, single-cell TCR sequencing, and single-particle cryo-electron microscopy to dissect CD8+ T cell responses to the immunodominant SARS-CoV-2 ORF3a(207-215) epitope presented by HLA-A*01:01. Among responding clonotypes, we identify a shared public TC