Negligible impact of SARS-CoV-2 variants on CD4+ and CD8+ T cell reactivity in COVID-19 exposed donors and vaccinees

Tarke et al (BioRxiv). DOI: 10.1101/2021.02.27.433180

 

Keywords

  • SARS-CoV-2 variants

  • SARS-CoV-2 specific T cells

  • SARS-CoV-2 T cell epitopes

Main Findings

Accumulating evidences highlight the impact of the mutations in SARS-CoV variants of concern (VOC) on antibody responses but the impact on T cell reactivity is still unknow. The study performed a combined experimental and bioinformatics approach to address how SARS-CoV-2 variants of concern impact T cell responses on Individuals who recovered from mild COVID-19 infection or mRNA vaccinees. Overall, memory CD4 or CD8 T cells from individuals that have been infected with the ancestral SARS-CoV-2 strain recognize the ancestral reference strain and the variant genome-wide sequences with similar efficiency. Similarly, T cell responses to the ancestral and variant strains are comparable in mRNA vaccinees. Furthermore, analysis of sets of defined SARS-CoV-2 CD4 and CD8 T cell epitopes suggest that the majority of CD8 T cell epitopes are unaffected by mutations found in all the different variants. The corresponding mutations are considered to have minor effects on the total T cell response, thus providing insights for the marginal impact on T cell reactivity by COVID-19 convalescent subjects and recipients of COVID-19 mRNA vaccines.

Limitations

​As discussed by authors, the study used overlapping peptide pools, which might not address if the mutations might involve alterations in terms of antigen processing 

Significance/Novelty

The study for the first time provides an insight to protective immunity or un-effected T cell responses to the mutations found in the SARS-CoV-2 variants of concern (VOC) in COVID-19 exposed individuals and vaccinees. 

Credit 

Reviewed by Aljawharah Alrubayyi​ as part of the cross-institutional journal club of the Immunology Institute of the Icahn School of Medicine, Mount Sinai and the Kennedy Institute of Rheumatology, University of Oxford.