Figure 3.
Patient pp65 ELISpot responses following DI-TMZ and sequential pp65-DC vaccination. A, pp65 antigen-specific T-cell responses as measured by IFN-γ ELISpot ex vivo. Before-and-after pp65 ELISpot following three vaccinations of pp65-DCs from Vaccine-1 to Pheresis-2 (mean ± sem spot-forming cells (SFC) per 106 PBMC) in all patients (n = 11) are shown after stimulation with 138 15-mer peptides overlapping by 11 amino acids spanning the entire pp65 gene (P = 0.019 Wilcoxon signed rank). B, Kinetics of pp65 ELISpot throughout continuous pp65-DC vaccination and intervening DI-TMZ cycles. Timing of DI-TMZ cycles are shown as detached lines. C, Fold changes in functional pp65 ELISpot from baseline pp65 reactivity prior to Vaccine-1. Fold increases stratified by patient OS > 40 months (n = 6) and OS < 40 months (n = 5). Post Vaccine-1: mean 1.51 vs. 3.75 (P = 0.031), Post Vaccine-2: mean 2.20 vs. 5.14 (P = 0.031), Post Vaccine-3: mean 3.45 vs. 9.79 (P = 0.031 Wilcoxon signed rank). ELISpot 0 values normalized to [0 + 1] for calculation of fold change from baseline.