Poster Presentation 9th Australasian Vaccines & Immunotherapeutics Development Meeting 2022

Ablation of CD8+ T-cell recognition of an immunodominant epitope in SARS-CoV-2 Omicron    (#111)

Srividhya Swaminathan 1 2 , Katie Lineburg 1 , Archana Panikkar 1 , Jyothy Raju 1 , Lawton D Murdolo 3 , Christopher Szeto 3 4 , Pauline Crooks 1 , Laetitia Le Texier 1 , Sweera Rehan 1 , George Robin Ambalathingal Thomas 1 , Michelle Neller 1 , Kirsty R Short 5 , Stephanie Gras 3 4 , Rajiv Khanna 1 2 , Corey Smith 1 2
  1. QIMR Berghofer Centre for Immunotherapy and Vaccine Development and Translational and Human Immunology Laboratory, Department of Immunology, QIMR, Herston, QLD, Australia
  2. University of Queensland, HERSTON, QLD, Australia
  3. Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, VIC, Australia
  4. Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, Clayton, Victoria 3800, Australia
  5. School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, QLD 4072, Australia

The emergence of the SARS-CoV-2 Omicron variant has raised concerns of escape from vaccine-induced immunity. A number of studies have demonstrated a reduction in antibody-mediated neutralization of the Omicron variant in vaccinated individuals. Preliminary observations have suggested that T cells are less likely to be affected by changes in Omicron. However, the complexity of human leukocyte antigen genetics and its impact upon immunodominant T-cell epitope selection suggests that the maintenance of T-cell immunity won’t be universal. In this study, we describe the impact that changes in Omicron have on recognition by spike-specific T cells. These T cells constitute the immunodominant CD8+ T-cell response in HLA-A*29:02+ COVID-19 convalescent and vaccinated individuals; however, they fail to recognize the Omicron-encoded sequence. We also failed to detect other immunodominant responses in vaccinated HLA-A*29:02+ individuals, suggesting that the Omicron variant may have an increased capacity to escape immune recognition in this population.