Fig. 3.

CD8⁺ T cell responses to Ad vectors. The graphs show the frequencies of transgene product-specific CD8⁺ T cells induced by adenoviral vectors of the human serotype 5 (bottom) and chimpanzee serotype 68 (top). Mice were injected intramuscularly with 10¹⁰ vp of vector. Ten days later, splenocytes were cultured for 5 h with the peptide carrying the immunodominant epitope of the transgene product (right) or an unrelated peptide (left) in presence of brefeldin. Cells were then stained with a FITC-labeled antibody to CD8 and, upon permeabilization of the membrane, with a PE-labeled antibody to interferon (IFN-γ). Cells were analyzed by two-color flow cytometry; data were analyzed by WimnDi software. Events were gated onto live cells. The percentages of double-positive cells (CD8 cell producing IFN-γ) over FITC-positive cells (CD8⁺ cells) were determined and are displayed in the upper right quadrants.