IL-21 Expands HIV-1-Specific CD8⁺ T Memory Stem Cells to Suppress HIV-1 Replication In Vitro

Figure 1

Identification of human immunodeficiency virus type 1- (HIV-1-) specific CD8⁺ T memory stem cells among the peripheral blood mononuclear cells of HIV-1-infected individuals. (a) Flow cytometric analysis of peripheral blood mononuclear cells (PBMCs) from HIV-1-infected individuals. Dot plots show the gating strategy to identify HIV-1-antigen-specific CD95⁺CD122⁺CD8⁺ T memory stem cells (T_SCMs). The numbers in the graphs show the percentages of subsets. The data are representative of five independent experiments (). (b) The percentages of circulating HIV-1-specific CD8⁺ T_SCM subsets in 20 HIV-1-infected individuals are shown as the error of the mean (SEM). A Kruskal–Wallis test with Dunn’s multiple comparisons was performed to assess statistical significance. (c) Intracellular interferon gamma (IFN-γ) staining in PBMCs from a representative HIV-1-infected individual after stimulation with the corresponding peptide. PBMCs from HIV-1-infected individuals were incubated with the ovalbumin (OVA)_257−264 peptide (negative peptide, abbreviated as NP), SL9, IL9, or TL9 (2 μM) and purified anti-CD28 antibody (1 μg/ml) and recombinant IL-2 (20 ng/ml) for 6 hours at 37°C, in the presence of brefeldin A (2 μg/ml) for the final 2 hours of incubation. The numbers represent the percentages of CD95⁺CD122⁺ T_SCMs producing IFN-γ. The data are representative of six independent experiments (). (d) The percentages of CD8⁺ T_SCM subsets producing IFN-γ; data from 20 HIV-1-infected individuals are shown as the . The Kruskal–Wallis test with Dunn’s multiple comparisons was performed to assess statistical significance. . (e) The mean fluorescence intensities of CD8⁺ T_SCM subsets producing IFN-γ are shown as the . The Kruskal–Wallis test with Dunn’s multiple comparisons was performed to assess statistical significance. The data are representative of four independent experiments (). .

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