HIV-1-infected DCs cannot significantly increase resting CD4⁺ T cell proliferation in DC-T cell co-cultures.

<p>(A) Schematic representation of the experiment procedures. Primary MDDCs and autologous resting CD4⁺ T cells were used. (B) DCs infected with replication-competent WT or Nef-mutated HIV-1 were co-cultured with uninfected resting CD4⁺ T cells and HIV-1 p24 production in the supernatants was measured at the indicated times of co-cultures. Immature DCs were generated from purified monocytes by treatment with GM-CSF and IL-4 for 5 days. Resting CD4⁺ T cells were isolated from PBMCs using immunomagnetic particles and were cultured in the presence of IL-2 for 8 days. (C) Co-culture with HIV-1-infected DCs increases the surface expression of the transient T-cell activation marker CD69 on resting CD4⁺ T cells. CD69 expression was assessed at 3 days of co-cultures by flow cytometry. Mock-infected cells were used as background controls. These data are donor matched to <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0034521#pone-0034521-g006" target="_blank">Figure 6B</a>. (D) CD4⁺ T cell proliferation in the co-cultures of HIV-1 infected DCs. DCs were mock infected or infected with WT or Nef-mutated HIV-1 for 3 days prior to co-culture with CFSE-labeled, uninfected resting CD4⁺ T cells. T cell proliferation was measured by flow cytometry at the indicated times of co-cultures. Data represent five independent experiments using cells from five different donors. Each symbol in the plots represents a single experiment result and the horizontal bars in the plots indicate the mean values of five independent experiments.