Fig. 4: ELISpot responses to prototype, B.1.1.7, B.1.351 and P.1.

T cell responses were measured using IFN-γ ELISpot assays in 24 healthy volunteers, 7–17 days after receiving the 2nd dose of BNT162b2. a T cell responses to 15–18-mer peptides in B strain overlapping by 10 amino-acids and spanning the entire spike region. b Summed T cell responses to peptides from B strain that mapped to sites with mutations in B.1.1.7 (n = 17 peptides), B.1.351 (n = 21 peptides) and P.1 (n = 22 peptides). c Percentage contribution T cells (using B peptides) that target mutational regions within B.1.1.7, B.1.351 and P.1, relative to the total T cell spike response in each of the 24 volunteers. d T cell responses to 22 individual peptides in B strain that have corresponding mutations in B.1.1.7, B.1.351 and P.1 variants. Standardised ELISpot assays were run in triplicate for background and spike peptides and duplicates for all others to allow cell preservation. DMSO control with matching percent DMSO was also used in all assays to account for DMSO content in peptide pools. Each bar represents one volunteer with a positive response (defined as a response to the peptide minus the background that was greater than twice the background). SFC/10⁶ PBMC = spot forming cells per million peripheral blood mononuclear cells, with background subtracted.