[PubMed] [Google Scholar] 30

[PubMed] [Google Scholar] 30. with the expansion of memory (both central and effector memory) subsets of V9V2 T cells. Overall, our results provide a further piece of information on the complex relationship between these two populations of cells with innate immunity features during inflammatory responses. stimulation with interleukin (IL)-3 and TLR9 agonist-like CpG ODNs they acquire a typical DC morphology and many functional properties and participate to activation of other cell types like monocytes, B, NK and T lymphocytes. Moreover, recent studies have shown that pDCs upregulate MHC class II molecules upon inflammation and induce both T cell mediated immunity and tolerance [4], thus highlighting their role in adaptive immunity. V9V2 cells represent a major peripheral blood T cell subset in humans (up to 1/20 of the peripheral blood lymphoid pool), which display broad reactivity against microbial agents and tumors. They recognize phosphoantigens (PAgs) of microbial (intermediates of the non-mevalonate (MVA) pathway of isoprenoid biosynthesis) and endogenous (metabolites of the MVA pathway) origin, whose production is upregulated upon cell stress Rabbit polyclonal to TUBB3 [5]. Pharmacological agents can block either upstream (statins) or downstream (aminobisphosphonates (ABPs), alkylamines) MVA pathway leading, respectively, to decreased or increased intracellular isopentenyl pyrophosphate (IPP) levels. Alternatively, IPP could be presented by surface receptors unrelated to the MVA pathway. In fact, IPP metabolites can be converted into triphosphoric acid 1-adenosin-5-yl ester 3-(3-methylbut3-enyl) ester (ApppI), an ATP analogue, which could then be processed and presented at the cell surface. Butyrophilin (BTN) 3A1 molecule controls activation of human V9V2 T cells by direct or indirect presentation of self and non self PAgs. Similar to CD4 and CD8 T cells, V9V2 T lymphocytes are heterogeneous and comprise distinct populations that can be distinguished on the basis of surface marker expression and effector functions, such as cytokine secretion and cytotoxicity. Naive (Tnaive) CD45RA+CD27+ and central memory (TCM) CD45RA?CD27+ cells express lymph node homing receptors, abound in lymph nodes, and lack immediate effector functions. Conversely, effector memory (TEM) CD45RA?CD27? and terminally differentiated (TEMRA) CD45RA+CD27? cells express receptors for migration to inflamed tissues, are poorly represented in the lymph nodes while abounding at sites of inflammation, where they display immediate effector functions (cytokine production and cytotoxicity, respectively) [6]. Since T cells and pDCs represent distinct components of the innate compartment, we investigated on their interactions and the underlying mechanism. RESULTS TLR-9 engagement on human pDCs induces V9V2 T cell proliferation Previous studies MF63 have shown that V9V2 T cell clones secrete IFN- upon 24-hrs stimulation by TLR8/9-activated pDCs [7]. To ascertain the influence of pDCs on resting V9V2 T cells, immature pDCs or pDCs that had been activated by IL-3 and the TLR9 ligand CpG-A ODN2216, were cultured with CFSE-labelled V9V2 T cells freshly sorted from PBMC of healthy donors. Proliferation was assessed after 6 days of culture according to loss of CFSE labelling. Cumulative data from 12 individual experiments, expressed as the mean SD, are shown in Figure ?Figure1a,1a, and representative data are shown in Figure ?Figure1b1b. Open in a separate window Figure 1 Human activated pDCs induce V9V2 T cells proliferationImmature or activated pDCs were co-cultured with purified, CFSE-labeled V9V2 T cells for 6 days. a. shows cumulative data of V9V2 T cells division, as assessed by CSFE. Error bars indicate the mean with SD (* 0.05) from 12 individual experiments, each carried out in triplicate. b. shows flow cytometry histogram of a representative experiment. Viable lymphocytes were gated by ahead and part scatter, and analysis was performed on 100,000 acquired events for each sample by using FlowJo and MF63 the following gating strategy to detect lymphocytes: FSC/SSC, live cells, solitary cells, double positive CD3 and V9V2 T cells. Immature pDCs induced significant V9V2 T cells proliferation (18.1% 2), but IL-3 and CpG-A activated pDCs induced substantial proliferation (48.3% 12.5) which was comparable to that achieved by V9V2 upon activation with the homeostatic cytokines IL-7 and IL-15 (60.3% 17) used as positive settings. Tradition with IL-3 and CpG-A only failed to induce detectable proliferation of V9V2 T cells (1.8% 1.1), MF63 as a result excluding any direct effect of.