2.3 Peptide pools
15- to 18-mer peptides with 10 amino acids of overlap were synthesized
and covered the full length of S, M, and N proteins. Meanwhile, the
peptide pools spanned WT and BA.1 RBD were also designed. PBMCs were
cultured for 9 days with S1, S2, M, and N peptide pools stimulation,
respectively (Supplementary Methods).3