Higher when naive T-cells from CI on ART subjects were cultured
Higher when naive T-cells from CI on ART subjects were cultured under Th1 (IL-2 only) versus Th17 conditions (12.9 versus 1.3 ; median; n = 10; Wilcoxon p-value = 0.001; data not shown), consistent with the well-established inhibition of Th1 polarization under Th17 conditions [33-35,56]. Together, these results provide evidence that phenotypically naive CD4+ T-cells from HIV+ subjects are impaired in their differentiation and survival potential in response to Th17- but not Th1-polarizing signals. This deficit is observed in CI subjects despite an efficient control of viral replication under ART.Phenotypically naive CD25highCD127-FoxP3+ and CD25+CD127+ FoxP3- T-cells preferentially acquire Th17 features in vitroa regulatory phenotype (nTregs: CD25highCD127-FoxP3+) but not from conventional naive cells (nT: DM-3189 web CD45RA + CD25-CD127+FoxP3-) [35,50]. In addition to nTregs and nT, the differential expression of CD25, CD127, and FoxP3 identifies two other phenotypically naive CD4+ T-cell subsets with yet undocumented ability to undergo Th17 polarization: double positive (DP: CD25+CD127+FoxP3-) and double negative (DN: CD25-CD127-FoxP3-) subsets (Figure 2A). Here, we investigated the relative contribution of these four naive-like T-cell subsets to the PubMed ID:https://www.ncbi.nlm.nih.gov/pubmed/28494239 pool of Th17 cells in HIV-uninfected subjects. Flow cytometrysorted subsets (Additional file 2: Figure S2) were cultured under Th17 polarizing conditions, as in Figure 1A. Consistent with previous studies [35,50], Th17-polarized nTregs generated the highest frequency of IL-17Aexpressing cells in vitro (Figure 2C-D). A significant fraction of cells producing IL-17A in the presence (IL17A+IFN-+; Th1Th17 profile) or the absence of IFN- (IL-17A+IFN–; Th17 profile) also originated from DP cells (Figure 2C-D). Consistent with PubMed ID:https://www.ncbi.nlm.nih.gov/pubmed/26740125 other studies [33,34,54], a subset of Th17-polarized nTregs but also DP cells acquired Th1 features (IL-17A-IFN-+) when cultured under Th17 polarizing conditions (Figure 2C-D). Finally, IL-17A+ cells also differentiated from Th17polarized nT and DN cells, although their frequency was significantly lower compared to nTregs (Figure 2C-D). Together, these results emphasize the phenotypic heterogeneity of phenotypically naive CD4+ T-cells in terms of Th17 polarization potential and identify nTregs and DP cells as being relatively enriched in Th17 lineagecommitted cells.The frequency of nTregs and DP cells is reduced in HIV-infected subjects receiving ARTPrevious studies demonstrated that Th17 cells differentiate from naive CD4+ T-cells (defined as CD45RA+ cells) withWe further investigated whether the Th17 polarization deficit in HIV-infected subjects was associated with the paucity of nTregs and DP cells. To this aim, we quantified the frequency/counts of total naive CD4+ T-cells and subsets expressing a nTreg and DP phenotype in the peripheral blood of CI on ART (n = 18), RI subjectsDaFonseca et al. Retrovirology (2015) 12:Page 7 ofFigure 2 Phenotypically naive CD25highCD127-FoxP3+ and CD25+CD127+FoxP3- T-cells preferentially differentiate into Th17 cells. PBMCs from HIV- controls were stained with a cocktail of CD3, CD4, CD45RA, CCR7, CD25 and CD127 Abs on the surface and intracellularly with FoxP3 Abs. (A) The differential expression of CD25 and CD127 distinguished four CD45RA+CCR7+ CD4+ T-cells subsets: CD25highCD127- (nTregs), CD25-CD127+ (nT, conventional), CD25+CD127+ (DP, double positive) and CD25-CD127- (DN, double negative). (B) Shown is the expression of FoxP3 on these four.
