Identification of TCR repertoires in functionally competent cytotoxic T cells cross-reactive to SARS-CoV-2
Kanako Shimizu, Tomonori Iyoda, An Sanpei, Hiroshi Nakazato, Masahiro Okada, Shogo Ueda, M. Kato-Murayama, Kazutaka Murayama, Mikako Shirouzu, Naoko Harada, Michihiro Hidaka, Shin‐ichiro Fujii
Abstract
Abstract SARS-CoV-2-specific CD8 + T cells are scarce but detectable in unexposed healthy donors (UHDs). It remains unclear whether pre-existing human coronavirus (HCoV)-specific CD8 + T cells are converted to functionally competent T cells cross-reactive to SARS-CoV-2. Here, we identified the HLA-A24-high binding, immunodominant epitopes in SARS-CoV-2 spike region that can be recognized by seasonal coronavirus-specific CD8 + T cells from HLA-A24 + UHDs. Cross-reactive CD8 + T cells were clearly reduced in patients with hematological malignancy, who are usually immunosuppressed, compared to those in UHDs. Furthermore, we showed that CD8 + T cells in response to a selected dominant epitope display multifunctionality and cross-functionality across HCoVs in HLA-A24 + donors. Cross-reactivity of T-cell receptors isolated from them exhibited selective diversity at the single-cell level. Taken together, when stimulated well by immunodominant epitopes, selective pre-existing CD8 + T cells with high functional avidity may be cross-reactive against SARS-CoV-2.