Figure 4.

CD8⁺ T-cells mediated perforin and GrB responses to 4 commercial vaccines. PBMCs from pre- (light circles) and post-immunized (dark circles) elderly individuals were stimulated with live A/H3N2 influenza virus. Phenotype of the stimulated T-cells was measured by flow cytometry and percentages of CD8⁺ T-cells expressing perforin (panel A) or both perforin and GrB (panel B) were then measured by ICC. Individual values are expressed as percentages of CD8⁺ cells expressing perforin alone or with GrB, while the group geometric mean percentage is denoted with a bold star (*). Horizontal bars represents 95% confidence of intervals. Paired t-tests were used to compare means of pre and post vaccinated individuals in each group (*statistical significance p < 0.005). Panel A shows significant increases after 3 vaccines and Panel B after all 4 vaccines. TIV1 = subunit vaccine; ADV = subunit vaccine with MF59 adjuvant; TIV2 = split-virus vaccine; IDV = split-virus vaccine given intradermally.