FIG. 2.

Screening of candidate individual epitopes in the NP, NA, NS1, M1, and HA proteins using EliSpot assays. Panels A–E show the peptides in the C57BL/10 (red) and SJL (blue) mouse strains screened as individual peptides in the NP, NA, NS1, M1, and HA proteins, as indicated in each panel. Peptides were used at a final concentration of 10 μM, and the number of reactive CD4 T cells was quantified by the number of IL-2 EliSpots per 10⁶ CD4 T cells, as described in the Materials and Methods section. All peptides were tested in at least two individual experiments, with the data presented as the average number of spots per 10⁶ CD4-enriched T cells, and error bars representing the standard error over all experiments. Note that the standard error for peptide NP 46 in SJL mice in panel A is not fully depicted on the graph shown, as indicated by an asterisk, but is equal to 130 spots per 10⁶ CD4 T cells. Peptides were determined to be negative using either peptide-pooling matrices or by screening individual peptides.