{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,11,6]],"date-time":"2025-11-06T11:55:31Z","timestamp":1762430131857,"version":"build-2065373602"},"reference-count":65,"publisher":"Frontiers Media SA","license":[{"start":{"date-parts":[[2025,11,6]],"date-time":"2025-11-06T00:00:00Z","timestamp":1762387200000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":["frontiersin.org"],"crossmark-restriction":true},"short-container-title":["Front. Immunol."],"abstract":"<jats:p>\n                    In the post-pandemic era, SARS-CoV-2 variants continue to circulate and evolve. T cell-mediated immunity is essential for antiviral defense, but its evasion by emerging variants remains poorly defined. In this study, we screened spike-derived CD8\n                    <jats:sup>+<\/jats:sup>\n                    T cell epitopes using bioinformatic algorithms and validated them experimentally in COVID-19 vaccine recipients. LYNSASFSTF (LYN), located in the receptor-binding domain (S\n                    <jats:sub>368\u2013377<\/jats:sub>\n                    ), was identified as an HLA-A*24:02-restricted epitope harboring mutations observed in Omicron BA.1 (S371L, S373P, and S375F) and BA.2 (S371F, S373P, S375F, and T376A). BA.2 mutations more profoundly attenuated LYN-specific cellular immunity than those from BA.1 with T376A as a major contributor to immune evasion, as supported by structural analysis of altered peptide\u2013HLA interactions. This effect was mitigated by BA.1\/BA.2 breakthrough infection and appears unlikely to persist in the currently dominant NB.1.8.1 lineage, where the LYN sequence remains conserved. Our findings suggest that LYN may function both as an immune-evasive hotspot and as a cross-reactive epitope, underscoring the importance of continued epitope-level surveillance as future variants emerge.\n                  <\/jats:p>","DOI":"10.3389\/fimmu.2025.1684193","type":"journal-article","created":{"date-parts":[[2025,11,6]],"date-time":"2025-11-06T11:46:56Z","timestamp":1762429616000},"update-policy":"https:\/\/doi.org\/10.3389\/crossmark-policy","source":"Crossref","is-referenced-by-count":0,"title":["Impaired and restored CD8+ T cell responses to a sequentially mutated spike epitope in Omicron variants"],"prefix":"10.3389","volume":"16","author":[{"given":"Eun 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