FIG 2.

Summary of peak T cell responses during convalescence and in healthy donors (HD). (A) Overall peak ELISpot assay responses against SARS-CoV-2 structural proteins (N/E/M/S1/S2) in convalescent patients with mild, moderate, and severe disease as well as in nonsymptomatic healthy donors. Spot numbers were combined for each structural protein, and the peak total response within each patient’s time points was selected for IFN-γ, IL-2, and GzmB. Healthy donors indicated with an asterisk were assayed with spike peptide pool containing only the RBD and TM regions. HD1 to -11 were asymptomatic, seronegative, postpandemic donors with no recent respiratory illness; HD12 to -17 were healthy prepandemic donors. (B) Comparison of PBMC and CD4-depleted peptide matrix IFN-γ ELISpot assay responses. IFN-γ ELISpot assay responses of PBMC from a subject with severe disease (OM8086) and CD4-depleted PBMC against SARS-CoV-2 structural proteins (N/E/M/S-RBD+TM) via matrix and total peptide pools, and with complete DMSO as a negative control and CMV and SEB as positive controls. IFN-γ ELISpot assay responses were reduced significantly (>90%; 2,617 total spots in PBMC versus 190 in CD4-depleted PBMC) in the majority of the wells after CD4 depletion. The bottom shows the plate layout used for the peptide matrix IFN-γ ELISpot assay.