CD154 transgene expression by Ad-CD154–infected CLL B cells and in vivo modulation of costimulatory molecules on bystander leukemia cells following Ad-CD154-CLL infusion.

(A) Following Ad-CD154 infection, blood mononuclear cells were stained with fluorochrome-labeled mAbs specific for CD19 and CD154 or an irrelevant specificity (isotype control). Cells were analyzed by multiparameter flow cytometry. The histograms depict the logarithmic fluorescence intensity of the gated CD19⁺ B-cell population stained with mAb against CD154 or an isotype control mAb. (B) Blood mononuclear cells were isolated from patients immediately before the infusion of autologous Ad-CD154–transduced CLL cells and on days 1, 2, 4, 7, and 14 thereafter. The cells were stained with fluorochrome-labeled mAbs specific for CD19 and another surface antigen, or an isotype control, as indicated. The histograms depict the staining of the gated CD19⁺ B-cell population with the respective mAbs or an isotype control mAb.