Figure 3.

Younger donors' CD8⁺ T cell response to influenza A epitopes. A) Frequency of peptide specific cells from control donors after three weeks of aAPC stimulation as determined by ICS for IFNg secretion and analyzed by flow cytometry. A positive result is defined as a clear population of cells secreting IFNg 5 fold above background. Background levels were determined by stimulating CD8⁺ T cells with unpulsed T2 cells, as described in Figure 2. Figure 2 is a representative example of background levels for all donors. All data points displayed are 5 fold above background. B) Comparison of the immunodominant response in control donors. The percent of positive donors with peptide specific cells is compared to the percent of positive donors for IFNg secretion by ELISpot at wk 0 from control donors. C) Comparison of aAPC based stimulation to ELISpot assays for the subdominant influenza-specific responses.