We therefore assessed the functional avidities of epitope-specific CD8+ T cell populations from both the lungs and spleens of adult and neonatal mice at day 7 post-infection by measuring IFN-γ production following stimulation with peptide concentrations ranging between 1×10−6 and 1×10−12 M. The percentages of cells producing IFN-γ upon stimulation with each dose of peptide were normalized to the percentages of cells producing cytokine at a saturating peptide concentration (10−6M) for each epitope, and log transformation and nonlinear fits were performed using Graphpad PRISM. The gene discussed is IFNG; the disease is infection.