CD40L expressed by recombinant ALVAC virus enhances specific antiviral CTL activity. CD4 + T cell-containing or -depleted PBMCs from four HIV-1-infected individuals and three HIV-1-uninfected individuals were cocultured with autologous MDDCs that were either pulsed or not with HLA-restricted epitopes of HIV-1 proteins (for HIV-1 infected individuals) or EBV proteins (for HIV-1-uninfected individuals). MDDCs were previously infected or not (medium) with parental ALVAC II or ALVAC recombinant vA3131-2 expressing human CD40L at an MOI of 10 for 48 h. On day 10, specific CTL activity was assessed by intracellular flow cytometric analysis of IFN-γproducing CD8 + T cells and 51 Cr release assay. (A) Representative intracellular IFN-γ flow cytometric data obtained from HIV-1-positive participant #1. (B) Summary data from intracellular IFN-γ flow cytometry of HIV-1-positive participant #2–#4 are graphically depicted. Open bars represent CD4 + T cell-containing condition and dark bar represent CD4 + T cell -depleted conditions. (C) A representative 51 Cr release assay result from HIV-1-positive participant #1 is shown. Similar results were obtained with HIV-1-positive participant #2 (data not shown). (D) Summary data from intracellular IFN-γ flow cytometric analysis of EBV-positive participant #5–#7 are graphically depicted. Open bars represent CD4 + T cell -containing condition and dark bars represent CD4 + T cell -depleted conditions. (E) A representative 51 Cr release assay result from EBV-positive participant #6 is shown. Similar results were obtained with EBV-positive participant #5 (data not shown). DC, MDDCs not pulsed with peptide; DCp, MDDCs pulsed with peptide; vA3131-2/DCp, vA3131-2-infected MDDCs pulsed with peptide; ALVAC/DCp, parental ALVAC II-infected MDDCs pulsed with peptide.