1. Omicron BA.1 Mutations in SARS-CoV-2 Spike Lead to Reduced T-Cell Response in Vaccinated and Convalescent Individuals.
- Author
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Emmelot, Maarten E., Vos, Martijn, Boer, Mardi C., Rots, Nynke Y., de Wit, Jelle, van Els, Cécile A. C. M., and Kaaijk, Patricia
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SARS-CoV-2 Omicron variant ,SARS-CoV-2 ,VACCINATION ,T cells ,IMMUNOLOGIC memory ,CELLULAR immunity - Abstract
Omicron BA.1 variant can readily infect people with vaccine-induced or naturally acquired SARS-CoV-2 immunity facilitated by escape from neutralizing antibodies. In contrast, T-cell reactivity against the Omicron BA.1 variant seems relatively well preserved. Here, we studied the preexisting T cells elicited by either vaccination with the mRNA-based BNT162b2 vaccine or by natural infection with ancestral SARS-CoV-2 for their cross-reactive potential to 20 selected CD4
+ T-cell epitopes of spike-protein-harboring Omicron BA.1 mutations. Although the overall memory CD4+ T-cell responses primed by the ancestral spike protein was still preserved generally, we show here that there is also a clear loss of memory CD4+ T-cell cross-reactivity to immunodominant epitopes across the spike protein due to Omicron BA.1 mutations. Complete or partial loss of preexisting T-cell responsiveness was observed against 60% of 20 nonconserved CD4+ T-cell epitopes predicted to be presented by a broad set of common HLA class II alleles. Monitoring such mutations in circulating strains helps predict which virus variants may escape previously induced cellular immunity and could be of concern. [ABSTRACT FROM AUTHOR]- Published
- 2022
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