Computational assessment of the spike protein antigenicity reveals diversity in B cell epitopes but stability in T cell epitopes across SARS-CoV-2 variants

Ge, Anni; Rioux, Melissa; Kelvin, Alyson A.

Since its emergence into the human population at the end of 2019, SARS-CoV-2 has caused significant morbidity and mortality worldwide. Efforts to develop a protective vaccine against COVID-19 have yielded several vaccine platforms currently in distribution targeting the original SARS-CoV-2 spike protein sequence from the first cases of infection. In recent months, variants of SARS-CoV-2 have raised concerns that viral mutation may undermine vaccination efforts through viral escape of host immune memory acquired from infection or vaccination. We therefore used a computational approach to predict changes in spike protein antigenicity with respect to host B cell and CD8+ T cell immunity across six SARS-CoV-2 variants (D614G, B.1.1.7, B.1.351, P.1, B.1.429, and mink-related). Our epitope analysis using DiscoTope suggests possible changes in B cell epitopes in the S1 region of the spike protein across variants, in particular the B.1.1.7 and B.1.351 lineages, which may influence immunodominance. Additionally, we show that high-affinity MHC-I-binding peptides and glycosylation sites on the spike protein appear consistent between variants with the exception of an extra glycosylation site in the P.1 variant. Together, these analyses suggests T cell vaccine strategies have the most longevity before reformulation.