Enhancement of Cytomegalovirus-Specific Cytokine Production after Modulation of the Costimulation in Kidney Transplant Patients

Figure 2

Increase of CMV-specific cytokine secretion by PD-1 and combined PD-L1 and PD-1 antibodies. The figure shows both the IL-21 production without and with the addition of PD-1 antibodies (a) and the IFN-γ (b) and IL-21 (c) production without and with the combined addition of PD-L1 and PD-1 antibodies. Lymphocytes of 28 kidney transplant patients were either stimulated with CMV IE-1, pp65, CMV lysate (lysate), or HEL-299 lysate or remained unstimulated (neg). Unstimulated cells (neg) served as a negative control for stimulation with IE-1 and pp65, and the HEL-299 lysate as a negative control for the CMV lysate. For the PD-1 blockade, the antibody was added to the cell cultures at concentrations of 0.5, 1, and 5 μg/ml. For the combined blockade, the PD-L1 antibody was used at a concentration of 10 μg/ml, and the PD-1 antibody at a concentration of 5 μg/ml. IL-21 secretion after addition of PD-1 antibodies was determined in 15 patients, IFN-γ and IL-21 production after addition of both antibodies in seven patients each. Mean and standard of the mean (SEM) of spot numbers are depicted. The effect of PD-1 antibodies was analyzed by one-way ANOVA with a posthoc test. Values above the bold horizontal lines indicate significant values obtained by the Friedman test, a significant result of Dunn’s posthoc test (to compare the various concentrations) is given above the thin horizontal line (). The effect of both antibodies in combination was determined by the Wilcoxon matched pairs test.

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