Fig. 3.

Correlation between age and influenza virus-specific T cell responses. The percentage of virus-specific CD8⁺ IFN-γ⁺ T cells (A and B) and CD4⁺ IFN-γ⁺ T cells (C and D) was determined and plotted as a function of the age of the individual subjects. Each dot represents the result for an individual subject, and the correlation between all subjects of one group was calculated and is indicated by the black line. Data for both unvaccinated control children (A and C) and vaccinated children with CF (B and D) are shown. The correlation between age and the percentage of CD8⁺ IFN-γ⁺ T cells was significantly different (P < 0.05) between the two study groups.