Figure 4

CD4⁺T-cell activation and proliferation is enhanced by antigen recognition but not by the presence of HIV-1. A. Gating strategy for the analysis of CD4⁺ T-cell activation and proliferation after co-culture with mDC. CD69, CD25, and proliferation parameters were analyzed in cells within the CD2-positive, CD11c-negative singlet gate. As positive controls, CD4⁺ T cells alone or with mDC were cultured in the presence of SEA or α-CD3. B. CD69 expression in CD4⁺ T cells after co-culture for 16 hours or 5 days with autologous mDC (red bars) or allogeneic mDC (blue bars) in the presence or absence of HIV-1. Expression of CD69 surface marker was higher in CD4⁺ T cells co-cultured with allogeneic mDC. No differences were observed in the presence of HIV-1 compared with control co-cultures without virus. C. CD25 expression in CD4⁺ T cells after co-culture for 16 hours or 5 days with autologous mDC (red bars) or allogeneic mDC (blue bars) in the presence or absence of HIV-1. Stimulation with allogeneic mDC induced higher levels of CD25 expression in CD4⁺ T lymphocytes (p < 0.05). The presence of HIV-1 did not exert a detectable effect on CD25 expression. D. and E. Percentage of CD4⁺ T cells divided (D) and proliferation index of CD4⁺ T cells (number of cell divisions/number of divided cells) (E) after co-culture for 5 days with autologous mDC (red bars) or allogeneic mDC (blue bars) in the presence or absence of HIV-1. Allogeneic co-cultures exhibited more CD4⁺ T-cell proliferation than autologous co-cultures, although no significant differences were observed with regard to the presence or absence of HIV-1. Positive controls consisting of co-cultures with SEA or α-CD3 are shown. Data are expressed as mean and SEM from three independent experiments including cells from at least six different donors. Asterisks denote significant differences (p < 0.05).