Heliyon (Oct 2023)

SARS-CoV-2 mutations affect antigen processing by the proteasome to alter CD8+ T cell responses

  • Dannielle Wellington,
  • Zixi Yin,
  • Zhanru Yu,
  • Raphael Heilig,
  • Simon Davis,
  • Roman Fischer,
  • Suet Ling Felce,
  • Elie Antoun,
  • Philip Hublitz,
  • Ryan Beveridge,
  • Danning Dong,
  • Guihai Liu,
  • Xuan Yao,
  • Yanchun Peng,
  • Benedikt M. Kessler,
  • Tao Dong

Journal volume & issue
Vol. 9, no. 10
p. e20076

Abstract

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Mutations within viral epitopes can result in escape from T cells, but the contribution of mutations in flanking regions of epitopes in SARS-CoV-2 has not been investigated. Focusing on two SARS-CoV-2 nucleoprotein CD8+ epitopes, we investigated the contribution of these flanking mutations to proteasomal processing and T cell activation. We found decreased NP9-17-B*27:05 CD8+ T cell responses to the NP-Q7K mutation, likely due to a lack of efficient epitope production by the proteasome, suggesting immune escape caused by this mutation. In contrast, NP-P6L and NP-D103 N/Y mutations flanking the NP9-17-B*27:05 and NP105-113-B*07:02 epitopes, respectively, increased CD8+ T cell responses associated with enhanced epitope production by the proteasome. Our results provide evidence that SARS-CoV-2 mutations outside the epitope could have a significant impact on proteasomal processing, either contributing to T cell escape or enhancement that may be exploited for future vaccine design.