T-cell Stimulation with SARS-CoV-2 and VOC Peptides
Whole blood was incubated with 1 μg/mL SARS CoV-2 Spike glycoprotein (S), or variant B.1.1.7 Spike (B.1.1.7). For patients with previous infection, additional peptides were tested. These included virus membrane protein (VME), nucleoprotein (NCAP), protein 3A (AP3A), and non-structural protein 7A (NS7A) (JPT Peptide Technologies GmbH, Berlin, Germany). For all conditions, Brefeldin A and anti-CD28/CD49d (BD Biosciences, San Jose, CA) were added and incubated for 9 hours at 37OC. Negative and positive controls included cells not incubated with peptides and those stimulated with phytohemagglutinin (PHA).