Whereas CD56brightCD11c+cells were CD80/86high, NKG2Dhigh, and HLA-DRhigh, CD56intCD11c+cells were CD80/86low, NKG2Dlow, and HLA-DRlow, as previously reported[25]

Whereas CD56brightCD11c+cells were CD80/86high, NKG2Dhigh, and HLA-DRhigh, CD56intCD11c+cells were CD80/86low, NKG2Dlow, and HLA-DRlow, as previously reported[25]. underlying the regulation of CD56brightCD11c+cells. CD14+monocytes pre-incubated with IL-2/IL-18 formed intensive interactions with CD56intCD11c+cells to promote their differentiation to CD56brightCD11c+cells with helper function. The development of CD56brightCD11c+cells was suppressed in an IFN- dependent manner. These results indicate that CD14+monocytes pretreated with IL-2/IL-18, but neither DCs nor monocytes, play a determining role on the development and proliferation of CD56brightCD11c+cells, which in turn modulate the expansion of T cells. CD56brightCD11c+NK-like cells may be a novel target for immunotherapy utilizing T cells, by overcoming the limitation of T cells proliferation. == Introduction == Human T cells recognize pathogens and autologous stress antigens and are involved in stress surveillance responses and maintenance of homeostasis in hosts[1],[2]. They belong to the innate immune system and regulate acquired immunity through cytokine production and antigen presentation[3][6]. Because T cells distinguish infected cells and cancer cells from normal cells by detecting stress-induced molecules using T cell receptors (TCRs) and natural killer (NK) cell receptors, stimulation of T cells has gained attention as a potential therapeutic intervention for infections and malignancies[7][12]. However, cancer immunotherapy targeting T cells has met with limited success because of the difficulty of inducing the expansion of T cells in some cancer patients. T cells are effectively activated by small foreign and self metabolites such as (E)-4-hydroxy-3-methylbut-2-enyl diphosphate and isopentenyl diphosphate in a classical MHC and MHC-related WAY-100635 molecule-independent manner[13],[14]. It is important to note, however, that CD14+antigen-presenting cells are required for the recognition of metabolite antigens by T cells, yet the precise mechanism for the recognition at the molecular level remains unclear[15]. In addition, the involvement of other immune cells such as NK cells and dendritic cells (DCs) in this WAY-100635 recognition process has not been thoroughly explored[16][21]. It was previously demonstrated that human peripheral NK cells activated byMycobacterium tuberculosisaugmented the proliferation of T cells[22]. Rabbit Polyclonal to PDCD4 (phospho-Ser67) Peripheral blood DCs expressing CD56, an NK cell marker, promoted Th1-type responses of T cells stimulated by bisphosphonate and IL-2[23]. We previously observed that CD56brightCD11c+cells were involved in the IL-18-mediated expansion of T cells stimulated by IL-2 and zoledronic acid (ZOL)[24],[25]. In addition, it was demonstrated that IL-18-induced NK cells exhibited helper functions in the development of cytotoxic T lymphocytes (CTLs), although whether these NK cells also acted on WAY-100635 T cells is yet to be determined[26],[27]. IL-18 was originally identified as an IFN–inducing factor that activates NK cells[28]. Recent studies showed that IL-18 is produced by a wide variety of cells including non-immune as well as immune cells and the physiological roles of IL-18 extend far beyond serving merely as a cytokine inducer. For example, IL-18 is involved in angiogenesis[29]and metabolic syndromes[30],[31]. Therefore, it is necessary to determine the various functions of IL-18 to clarify its central, biological and pathophysiological roles. IL-18 is produced as an inactive precursor and converted to WAY-100635 an active form by the catalytic action of the inflammasome, which is composed of NLRP3, ASC, and caspase-1. Because it is activated by various stresses such as oxidation[32], IL-18 is considered to be one of the stress-sensing molecules. As IL-18 activates intracellular signals related to cell viability in NK cells[33]and memory-type CD8+T cells[34]it is likely that IL-18 promotes proliferation and differentiation of certain cells expressing IL-18 receptors through activation of survival signals. It was previously reported that IFN- promoted the differentiation of monocytes to IFN–DCs that promote the generation of CD8+CTLs, in addition to its anti-viral properties[35][37]. Several studies also indicated that IFN- might activate T cells during infection[38][40]. In the present study, we examined how the development and proliferation of novel NK-like CD56brightCD11c+cells were differentially regulated by CD14+monocytes under the influence of IL-2/IL-18 or other cytokines including IFN-, which will hopefully contribute to our understanding of the mechanisms behind the efficient expansion of human T cells. == Materials and Methods == == Reagents == Recombinant human IL-18 and ZOL were kindly provided by GlaxoSmithKline plc (Research Triangle Park, NC) and Novartis AG (Basel, Switzerland), respectively. We synthesized 2-Methyl-3-butenyl-1-diphosphate (2M3B1PP) as described previously (25). GM-CSF, IL-2, IL-4, TNF-, IFN-, anti-IL-18R monoclonal antibody (mAb, clone: 70625.1111) were purchased from R&D Systems Inc. (Minneapolis, MN). Human AB serum was purchased from GemCell (Gemini, Bio-Products, West Sacramento, CA). All of the.