Regulatory T cells (Treg) and tumor-exosomes are thought to play a role in preventing the rejection of malignant cells in patients bearing nasopharyngeal carcinoma (NPC). Treg recruitment by exosomes derived from NPC cell lines (C15/C17-Exo), exosomes isolated from NPC patients' plasma (Patient-Exo), and CCL20 were tested in vitro using Boyden chamber assays and in vivo using a xenograft SCID mouse model (n = 5), both in the presence and absence of anti-CCL20 monoclonal antibodies (mAb). Impact of these NPC exosomes (NPC-Exo) on Treg phenotype and function was determined using adapted assays (FACS, Q-PCR, ELISA, and MLR). Experiments were performed in comparison with exosomes derived from plasma of healthy donors (HD-Exo). The Student's t test was used for group comparisons. All statistical tests were two-sided. CCL20 allowed the intratumoral recruitment of human Treg. NPC-Exo also facilitated Treg recruitment (3.30±0.34 fold increase, P < .001), which was statistically significantly inhibited (P < .001) by an anti-CCL20 blocking mAb. NPC-Exo also recruited conventional CD4+CD25- T cells and mediated their conversion into inhibitory CD4+CD25high cells. Moreover, NPC-Exo enhanced (P = .0048) the expansion of human Treg, inducing the generation of Tim3Low Treg with increased expression of CD25 and FOXP3. Finally, NPC-Exo induced an overexpression of cell markers associated with Treg phenotype, properties and recruitment capacity. For example, GZMB mean fold change was 21.45±1.75 (P < .001). These results were consistent with a stronger suppression of responder cells' proliferation and the secretion of immunosuppressive cytokines (IL10, TGFB1). Interactions between NPC-Exo and Treg represent a newly defined mechanism that may be involved in regulating peripheral tolerance by tumors and in supporting immune evasion in human NPC.
The purpose of this study was to assess the direct effect of CCL18’ a chemokine elevated in allergic diseases and induced by Th2 cytokines’ on the polarization of human CD4+ T cells. Purified human T cells from healthy subjects were pretreated or not with CCL18’ and evaluated for cytokine production. CCL18-pretreated memory but not naive CD4+ T cells exhibited an increased production of IL-10 (12.3±2.6 vs. 5.6±0.9 ng/ml for medium) and TGF-β 1 but not IL-4’ IFN-Y’ and IL-17 compared with control cells. Pretreatment of highly purified CD4+CD25” memory T cells with CCL18 led to their conversion to CD4+CD25+Foxp3+ regulatory T cells able to inhibit the proliferation of CD4+CD25– effector T cells by both cytokine and cell contact-dependent mechanisms. However’ this regulatory effect of CCL18 was lost when T cells originated from allergic subjects in relation with a decreased binding of CCL18 to these cells [0.7±0.3 mean fluorescence intensity (MFI)] as compared to those from healthy subjects (6.0±1.7 MFI). This study is the first to define a chemokine that generates adaptive regulatory T cells from CD4+CD25– memory T cells. This mechanism appears defective in allergic patients and may underlie the decreased tolerance observed in allergic diseases.—Chang’ Y.’ de Nadai’ P.’ Azza-oui’ I.’ Morales’ O.’ Delhem’ N.’ Vorng’ H.’ Tomavo’ S.’ Ait Yahia’ S.’ Zhang’ G.’ Wallaert’ B.’ Chenivesse’ C.’ Tsicopou-los’ A. The chemokine CCL18 generates adaptive regulatory T cells from memory CD4+ T cells of healthy but not allergic subjects. FASEBJ. 24’ 5063–5072 (2010). www.fasebj.org
Background Inflammatory bowel diseases (IBD) are chronic inflammatory diseases of the gastrointestinal tract, which clinically present as one of two disorders, Crohn’s disease (CD) and ulcerative colitis (UC). The CD23 is a multifunctional molecule expressed on various cells. It is know as the low-affinity receptor for the Fc portion of IgE. It expression at the cell surface of phagocytic cells has been associated with the development of many inflammatory processes. The aim of this work was to study the involvement of Th2 (IL-4) and TNF-a in bowel disease pathogenesis through the CD23/NO Pathway in Algerian patients with IBD.
CCL18 is both a constitutively expressed and an inducible chemokine, whose role in the inflammatory reaction is poorly known. The aim of this study was to evaluate whether CCL18 has the capacity to attract human T cells with a regulatory function (regulatory T cells [Treg]). Results from chemotaxis assays performed on different types of Treg showed that CD4(+)CD25(+)CD127(low) cells, but neither T regulatory type 1 clones nor Treg differentiated in vitro with anti-CD3/CD46 mAbs, were recruited by CCL18 in a dose-dependent manner. CCL18-recruited memory CD4(+) T cells were enriched in CD25(high), CD25(+)CD127(low), latency-associated peptide/TGF-β1, and CCR4-expressing T cells, whereas there was no enrichment in Foxp3(+) cells as compared with controls. Stimulated CCL18-recruited memory T cells produced significantly increased amounts of the regulatory cytokines IL-10 and TGF-β1, as well as IL-4, but not IFN-γ and IL-17. Cell surface CCL18 binding was found predominantly on IL-10(+) (26.3 ± 5.8%) and on a few latency-associated peptide/TGF-β1(+) (18.1 ± 1.9%) and IL-4(+) (14.5 ± 2.9%) memory T cells. In an in vivo model of SCID mice grafted with human skin and reconstituted with autologous PBMCs, the intradermal injection of CCL18 led to the cutaneous recruitment of CD4(+), CD25(+), and IL-10(+) cells, but not Foxp3(+) cells. Furthermore, CCL18-recruited memory T cells inhibited the proliferation of CD4(+)CD25(-) effector T cells through an IL-10-dependent mechanism. These data suggest that CCL18 may contribute to maintaining tolerance and/or suppressing deleterious inflammation by attracting memory Tregs into tissues, particularly in the lung, where it is highly and constitutively expressed.
Inflammatory bowel diseases (IBDs) are chronic inflammatory diseases of the gastrointestinal tract, which are clinically present as 1 of the 2 disorders, Crohn's disease (CD) or ulcerative colitis (UC) (Rogler 2004). The immune dysregulation in the intestine plays a critical role in the pathogenesis of IBD, involving a wide range of molecules, including cytokines. The aim of this work was to study the involvement of T-helper 17 (Th17) subset in the bowel disease pathogenesis by the nitric oxide (NO) pathway in Algerian patients with IBD. We investigated the correlation between the proinflammatory cytokines [(interleukin (IL)-17, IL-23, and IL-6] and NO production in 2 groups of patients. We analyzed the expression of messenger RNAs (mRNAs) encoding Th17 cytokines, cytokine receptors, and NO synthase 2 (NOS2) in plasma of the patients. In the same way, the expression of p-signal transducer and activator of transcription 3 (STAT3) and NOS2 was measured by immunofluorescence and immunohistochemistry. We also studied NO modulation by proinflammatory cytokines (IL-17A, IL-6, tumor necrosis factor α, or IL-1β) in the presence or absence of all-trans retinoic acid (At RA) in peripheral blood mononuclear cells (PBMCs), monocytes, and in colonic mucosa cultures. Analysis of cytokines, cytokine receptors, and NOS2 transcripts revealed that the levels of mRNA transcripts of the indicated genes are elevated in all IBD groups. Our study shows a significant positive correlation between the NO and IL-17A, IL-23, and IL-6 levels in plasma of the patients with IBD. Interestingly, the correlation is significantly higher in patients with active CD. Our study shows that both p-STAT3 and inducible NOS expression was upregulated in PBMCs and colonic mucosa, especially in patients with active CD. At RA downregulates NO production in the presence of proinflammatory cytokines for the 2 groups of patients. Collectively, our study indicates that the IL-23/IL-17A axis plays a pivotal role in IBD pathogenesis through the NO pathway.
Background: We analyzed telomere maintenance mechanisms (TMMs) in lymph node samples from HL patients treated with standard therapy. The TMMs correlated with clinical outcomes of patients. Materials and Methods: Lymph node biopsies obtained from 38 HL patients and 24 patients with lymphadenitis were included in this study. Seven HL cell lines were used as in vitro models. Telomerase activity (TA) was assessed by TRAP assay and verified through hTERT immunofluorescence expression; alternative telomere lengthening (ALT) was also assessed, along with EBV status. Results: Both TA and ALT mechanisms were present in HL lymph nodes. Our findings were reproduced in HL cell lines. The highest levels of TA were expressed in CD30-/CD15- cells. Small cells were identified with ALT and TA. Hodgkin and Reed Sternberg cells contained high levels of PML bodies, but had very low hTERT expression. There was a significant correlation between overall survival (p < 10-3), event-free survival (p < 10-4), and freedom from progression (p < 10-3) and the presence of an ALT profile in lymph nodes of EBV+ patients. Conclusion: The presence of both types of TMMs in HL lymph nodes and in HL cell lines has not previously been reported. TMMs correlate with the treatment outcome of EBV+ HL patients.
