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Cell Subsets (cell + subset)
Kinds of Cell Subsets Selected AbstractsRequirement of toll-like receptor 7 for pristane-induced production of autoantibodies and development of murine lupus nephritis,ARTHRITIS & RHEUMATISM, Issue 4 2008Emina Savarese Objective The detection of high titers of antibodies against small nuclear ribonucleoproteins (snRNP) is a diagnostic finding in patients in whom systemic lupus erythematosus (SLE) is suspected. Endogenous RNA molecules within snRNP trigger Toll-like receptor 7 (TLR-7) activation in B cells and dendritic cells, leading to anti-snRNP antibody production, which is associated with the development of immune complex nephritis in SLE. The purpose of this study was to investigate the role of TLR-7 in anti-snRNP antibody production and renal disease in SLE induced by an exogenous factor in the absence of genetic predisposition, using the pristane-induced murine lupus model. Methods Serum autoantibodies, IgG isotypes, and cytokine levels in pristane-treated wild-type and TLR-7,deficient mice were analyzed by enzyme-linked immunosorbent assay. Histopathologic changes in mouse kidneys were determined by light immunofluorescence microscopy. Cell subsets in splenocytes and peritoneal lavage cells from the mice were examined by flow cytometry. Results We found that anti-snRNP antibody production induced by pristane treatment was entirely dependent on the expression of TLR-7, whereas anti,double-stranded DNA antibody production was not affected by a lack of TLR-7. Impaired anti-snRNP antibody production in TLR-7,deficient mice was paralleled by lower levels of glomerular IgG and complement deposits, as well as less severe glomerulonephritis. Conclusion TLR-7 is specifically required for the production of RNA-reactive autoantibodies and the development of glomerulonephritis in pristane-induced murine lupus, a model of environmentally triggered SLE in the absence of genetic susceptibility to autoimmunity. Specific interference with TLR-7 activation by endogenous TLR-7 ligands may therefore be a promising novel strategy for the treatment of SLE. [source] Proliferation and interleukin,5 production by CD8hiCD57+ T cellsEUROPEAN JOURNAL OF IMMUNOLOGY, Issue 4 2008Abstract CD8hiCD57+ T cells have previously been described as effector memory T cells with minimal expansion capacity and high susceptibility to activation-induced cell death. In contrast, we demonstrate here that CD8hiCD57+ T cells are capable of rapid expansion using multiple techniques including [3H]thymidine uptake, flow cytometric bead-based enumeration and standard haemocytometer counting. Previous reports can be explained by marked inhibition of activation-induced expansion and increased 7-amino-actinomycin,D uptake by CD8hiCD57+ T cells following treatment with CFSE, a dye previously used to measure their proliferation, combined with specific media requirements for the growth of this cell subset. The ability of CD8hiCD57+ T cells to further differentiate is highlighted by a distinct cytokine profile late after activation that includes the unexpected release of high levels of interleukin,5. These data indicate that CD8hiCD57+ T cells should not be considered as "end-stage" effector T cells incapable of proliferation, but represent a highly differentiated subset capable of rapid division and exhibiting novel functions separate from their previously described cytotoxic and IFN-, responses. [source] Both CD133+ and CD133, medulloblastoma cell lines express ligands for triggering NK receptors and are susceptible to NK-mediated cytotoxicityEUROPEAN JOURNAL OF IMMUNOLOGY, Issue 11 2007Roberta Castriconi Abstract Adoptive cellular immunotherapy has been proposed as an additional treatment of medulloblastoma, an intracranial tumor characterized by a particularly poor prognosis. However, little is known on the ability of the immune system to effectively attack this tumor. In this study, we show that activated human NK cells efficiently kill medulloblastoma cell lines in vitro. NK-mediated killing involved different activating receptors (including NKp46, NKp30, DNAM-1 and NKG2D) and correlated with the presence of their specific ligands on tumor cells. In contrast, the absence of major adhesion interactions, such as LFA-1/ICAM did not impair the NK-mediated cytotoxicity. Medulloblastoma expressed a number of tumor-associated molecules including CD146 and CD133, considered a marker for cancer stem cells. Remarkably, both CD133-positive and CD133-negative cell lines were susceptible to lysis. Tumor cells also expressed molecules that are currently used as diagnostic tools for neuroblastoma cell identification. In particular, B7 homolog 3 (B7-H3) was expressed by all the medulloblastoma cell lines analyzed, while the presence of GD2 and NB84 was restricted to given cell lines and/or marked a defined tumor cell subset. [source] MR1-restricted V,19i T cells , a second population recognizing lipid antigens?EUROPEAN JOURNAL OF IMMUNOLOGY, Issue 7 2007Jens Schümann Abstract There is increasing evidence that T cells recognizing lipid antigens contribute to the immunological regulation of different disease conditions including autoimmunity. The best-known subset is CD1d-restricted lipid-reactive T cells characterized by the expression of an invariant TCR, chain. Much less is known about the biology of another invariant T cell subset, which is restricted to the MHC class I-like molecule MR1. A beneficial role of MR1-restricted T cells has been suggested in a mouse EAE model. However, the nature of antigens that can be presented by MR1 to this invariant T cell subset remained largely unclear. An article in this issue of the European Journal of Immunology presents strong indications that derivatives of ,-mannosyl ceramide (,-ManCer), i.e. glycolipids, can serve as ligands for MR1-restricted invariant T cells. In addition to that, the structure of the ,-ManCer sphingosine chain influences the Th1-Th2 polarization of the cytokine response. These important new findings will foster further research on the identity of physiological ligands for MR1-restricted T cells and on their relation with immunoregulation. See accompanying article: http://dx.doi.org/10.1002/eji.200636689 [source] Comparative analysis of NK cell subset distribution in normal and lymphoproliferative disease of granular lymphocyte conditionsEUROPEAN JOURNAL OF IMMUNOLOGY, Issue 10 2004Véronique Pascal Abstract We have characterized the heterogeneity of human blood NK cell subsets defined by expression of KIR, lectin like receptors and NK cell differentiation markers within a cohort of 51 healthy Caucasian individuals. High inter-individual variability in cell surface expression of most NK cell markers is observed. Range values defining NK cell subsets in healthy donors were further used as references to characterize 14 patients with NK-type lymphoproliferative disease of granular lymphocytes (NK-LDGL). Alterations of the KIR repertoire were noted in all NK-LDGL patients. NK cell expansions were classified as oligoclonal KIR+ or as non-detectable KIR (ndKIR) using anti-KIR2DL1/2DS1, anti-KIR2DL2/2DL3/2DS2, anti-KIR3DL1 and anti-KIR2DS4 monoclonal antibodies. A major reduction in the size of the CD56bright NK cell subset was a constant feature of NK-LDGL. Altered distribution of CD94+, CD161+, and CD162R+ NK cell subsets was also observed in NK-LDGL patients. Considering the potential role of NK cells in eliminating tumors or virus-infected cells, the reference values defined in this study should be valuable to characterize both quantitative and qualitative alterations of the NK cell repertoire in pathological conditions and to monitor NK cell reconstitution following hematopoietic transplantation. [source] Cell culture,produced hepatitis C virus does not infect peripheral blood mononuclear cells,HEPATOLOGY, Issue 6 2008Svetlana Marukian Hepatitis C virus (HCV) replicates primarily in the liver, but HCV RNA has been observed in association with other tissues and cells including B and T lymphocytes, monocytes, and dendritic cells. We have taken advantage of a recently described, robust system that fully recapitulates HCV entry, replication and virus production in vitro to re-examine the issue of HCV infection of blood cell subsets. The HCV replicase inhibitor 2,C-methyl adenosine was used to distinguish HCV RNA replication from RNA persistence. Whereas cell culture,grown HCV replicated in Huh-7.5 hepatoma cells, no HCV replication was detected in B or T lymphocytes, monocytes, macrophages, or dendritic cells from healthy donors. No blood cell subset tested expressed significant levels of Claudin-1, a tight junction protein needed for HCV infection of Huh-7.5 cells. A B cell line expressing high levels of Claudin-1, CD81, and scavenger receptor BI remained resistant to HCV pseudoparticle infection. We bypassed the block in HCV entry by transfecting HCV RNA into blood cell subsets. Transfected RNA was not detectably translated and induced high levels of interferon-,. Supernatants from HCV RNA,transfected macrophages inhibited HCV replication in Huh-7.5 cells. Conclusion: We conclude that multiple blocks prevent blood cells from supporting HCV infection. (HEPATOLOGY 2008;48:1843-1850.) [source] CD56bright natural killer (NK) cells: an important NK cell subsetIMMUNOLOGY, Issue 4 2009Aurélie Poli Summary Human natural killer (NK) cells can be subdivided into different populations based on the relative expression of the surface markers CD16 and CD56. The two major subsets are CD56bright CD16dim/, and CD56dim CD16+, respectively. In this review, we will focus on the CD56bright NK cell subset. These cells are numerically in the minority in peripheral blood but constitute the majority of NK cells in secondary lymphoid tissues. They are abundant cytokine producers but are only weakly cytotoxic before activation. Recent data suggest that under certain conditions, they have immunoregulatory properties, and that they are probably immediate precursors of CD56dim NK cells. CD56bright NK cell percentages are expanded or reduced in a certain number of diseases, but the significance of these variations is not yet clear. [source] Functional characterization of human natural killer cells responding to Mycobacterium bovis bacille Calmette-GuérinIMMUNOLOGY, Issue 1 2004Semih Esin Summary The kinetics of activation and induction of several effector functions of human natural killer (NK) cells in response to Mycobacterium bovis bacille Calmette-Guérin (BCG) were investigated. Owing to the central role of monocytes/macrophages (MM) in the initiation and maintenance of the immune response to pathogens, two different experimental culture conditions were analysed. In the first, monocyte-depleted nylon wool non-adherent (NW) cells from healthy donors were stimulated with autologous MM preinfected with BCG (intracellular BCG). In the second, the NW cells were directly incubated with BCG, which was therefore extracellular. In the presence of MM, CD4+ T lymphocytes were the cell subset mainly expressing the activation marker, CD25, and proliferating with a peak after 7 days of culture. In contrast, in response to extracellular BCG, the peak of the proliferative response was observed after 6 days of stimulation, and CD56+ CD3, cells (NK cells) were the cell subset preferentially involved. Such proliferation of NK cells did not require a prior sensitization to mycobacterial antigens, and appeared to be dependent upon contact between cell populations and bacteria. Following stimulation with extracellular BCG, the majority of interferon-, (IFN-,)-producing cells were NK cells, with a peak IFN-, production at 24,30 hr. Interleukin (IL)-2 and IL-4 were not detectable in NK cells or in CD3+ T lymphocytes at any time tested. IL-12 was not detectable in the culture supernatant of NW cells stimulated with extracellular BCG. Compared to the non-stimulated NW cells, the NW cells incubated for 16,20 hr with BCG induced the highest levels of expression of apoptotic/death marker on the NK-sensitive K562 cell line. BCG also induced expression of the activation marker, CD25, and proliferation, IFN-, production and cytotoxic activity, on negatively selected CD56+ CD3, cells. Altogether, the results of this study demonstrate that extracellular mycobacteria activate several NK-cell functions and suggest a possible alternative mechanism of NK-cell activation as the first line of defence against mycobacterial infections. [source] Pregnenolone Sulfate, a Naturally Occurring Excitotoxin Involved in Delayed Retinal Cell DeathJOURNAL OF NEUROCHEMISTRY, Issue 6 2000C. Cascio Abstract: The present study was designed to investigate the neurosteroid pregnenolone sulfate (PS), known for its ability to modulate NMDA receptors and interfere with acute excitotoxicity, in delayed retinal cell death. Three hours after exposure of the isolated and intact retina to a 30-min PS pulse, DNA fragmentation as assessed by genomic DNA gel electrophoresis and a modified in situ terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end-labeling (TUNEL) method appeared concurrently with an increase in superoxide dismutase (SOD) activity and thiobarbituric acid-reactive substances (TBARS) levels. At 7 h, the increased amount of DNA laddering was accompanied by a higher number of TUNEL-positive cells in the inner nuclear and ganglion cell layers. Necrotic signs were characterized by DNA smear migration, lactate dehydrogenase (LDH) release, and damage mainly in the inner nuclear layer. PS-induced delayed cell death was markedly reduced by the NMDA receptor antagonists 4-(3-phosphonopropyl)-2-piperazinecarboxylic acid and 3,-hydroxy-5,-pregnan-20-one sulfate but completely blocked after concomitant addition of the non-NMDA receptor antagonist 6-cyano-7-nitroquinoxaline-2,3-dione. Steroids with antioxidant properties (progesterone, dehydroepiandrosterone and its sulfate ester, and 17,-estradiol) differently prevented PS-induced delayed cell death. Cycloheximide treatment protected against DNA fragmentation and LDH release but failed to prevent the rise in SOD activity and TBARS level. We conclude that a brief PS pulse causes delayed cell death in a slowly evolving apoptotic fashion characterized by a cycloheximide-sensitive death program downstream of reactive oxygen species generation and lipid peroxidation, turning into secondary necrosis in a retinal cell subset. [source] Prevention of red cell alloimmunization by CD25 regulatory T cells in mouse modelsAMERICAN JOURNAL OF HEMATOLOGY, Issue 8 2007Jin Yu Transfusion therapy is currently an effective therapeutic intervention in a number of diseases, including sickle cell disease. However, its use is complicated by a high incidence of red blood cell (RBC) alloimmunization in the transfusion recipients. The identification of T regulatory cells (Tregs) among the CD4+ CD25+ T cell subset as key regulators of peripheral tolerance in mice as well as humans has opened an exciting era in the prevention and treatment of autoimmune disease and for improving organ transplantation. However, their potential in inducing transfusion tolerance remains to be explored. We used red cells from mice transgenic for human glycophorin A blood group antigen as donor cells and transfused wild-type mice to induce alloantibodies, as an experimental system to study RBC alloimmunization. We found that depletion with anti-CD25 enhanced the alloantibody production, indicating that CD25 Tregs play an important role in regulation of alloantibody responses. More importantly, adoptive transfer of purified population of CD4+CD25+ but not CD4+CD25, cells from naïve mice prevented the induction of IgG and IgM alloantibody production in transfusion recipients, with a concomitant reduction in activated splenic B cells and macrophages. Similarly, adoptive transfer of purified populations of CD4+CD25+ cells from naïve mice into naïve syngeneic recipients inhibited the anti-Ig response to rat RBCs in the recipients but transfer of control CD4+CD25, cells did not. Altogether, our results demonstrate that Tregs participate in the control of transfusion-associated RBC alloantibody responses, opening up the possibility that Treg immunotherapy may be exploited for suppressing transfusion immunization events. Am. J. Hematol., 2007. © 2007 Wiley-Liss, Inc. [source] ORIGINAL ARTICLE: Mifepristone as an Anti-Implantation Contraceptive Drug: Roles in Regulation of Uterine Natural Killer Cells during Implantation PhaseAMERICAN JOURNAL OF REPRODUCTIVE IMMUNOLOGY, Issue 1 2009Hong-Xia Zhu Problem, To investigate the immunological mechanism of low-dose mifepristone acting as a contraceptive at the level of the endometrium. Method of study, Endometrial explants were cultured in vitro with or without mifepristone treatment for 24 hr. Some tissues were fixed and immunostained for CD56, while other tissues were dissociated and cells analysed by three colour flow cytometry for CD3, CD56 and CD16. Results and conclusion, Results showed a significant increase in the number of CD56+ natural killer (NK) cells and the percentages of CD3, CD56+ CD16, NK cell subset in the tissue treated with mifepristone, while the percentage of CD3, CD56+ CD16+ NK cell subset remained unaffected. It shows that low-dose mifepristone increases the number of CD56+ NK cells and the percentage of CD3, CD56+ CD16, NK subset in receptive endometrium and provides new insights into the immunological mechanism of low-dose mifepristone as an anti-implantation contraceptive drug. [source] Age-related changes in leukocytes and T cell subsets in peripheral blood of Japanese Black cattleANIMAL SCIENCE JOURNAL, Issue 3 2008Sachi TANAKA ABSTRACT It is well known that the immune system changes with age during development and maturation in Holstein cattle. But age-related changes in leukocytes and T cell subsets in peripheral blood of Japanese Black cattle still remain unclear. The aim of the present study was to investigate comparative changes of leukocytes (granulocytes, monocytes, B cells and T cells) and T cell subsets (CD4+, CD8+, ,,, CD8+,, and WC1+,, T cells) in Japanese Black cattle aged 0.5, 1, 2, 6, 18 and 36,41 (adult) months on flow cytometry using specific monoclonal antibodies for the cell surface markers. T cell proportion was approximately 40% in 2-month-old cattle and decreased to 20.6% in adults. In contrast, B cell proportion significantly increased from 7.4% to 28.2% with age. In T cell subsets the percentage of CD4+ T cells significantly increased from 40.5% to 60%, but that of WC1+,, T cell subset significantly decreased with age. The percentages of CD8+ and CD8+,, T cells did not change. The present study details the proportional changes in leukocyte and T cell subsets with age in the peripheral blood of Japanese Black cattle and these findings are similar to those described for Holstein cattle. [source] CD4+CD25+ regulatory T cells: I. Phenotype and physiologyAPMIS, Issue 10 2004Review article The immune system protects us against foreign pathogens. However, if fine discrimination between self and non-self is not carried out properly, immunological attacks against self may be launched leading to autoimmune diseases, estimated to afflict up to 5% of the population. During the last decade it has become increasingly clear that regulatory CD4+CD25+ T cells (Treg cells) play an important role in the maintenance of immunological self-tolerance, and that this cell subset exerts its function by suppressing the proliferation or function of autoreactive T cells. Based on human and murine observations, this review presents a characterization of the phenotype and functions of the Treg cells in vitro and in vivo. An overview of the surface molecules associated with and the cytokines produced by the Treg cells is given and the origin, activation requirements and mode of action of the Treg cells are discussed. Finally, we address the possibility that Treg cells may play a central role in immune homeostasis, regulating not only autoimmune responses, but also immune responses toward foreign antigens. [source] Prolactin alters the mechanisms of B cell tolerance inductionARTHRITIS & RHEUMATISM, Issue 6 2009Subhrajit Saha Objective Autoimmune diseases predominantly affect women, suggesting that female sex hormones may play a role in the pathogenesis of such diseases. We have previously shown that persistent mild-to-moderate elevations in serum prolactin levels induce a break in self tolerance in mice with a BALB/c genetic background. The aim of this study was to evaluate the effects of hyperprolactinemia on the mechanisms of B cell tolerance induction. Methods Effects of prolactin on splenic B cell subsets were studied in female BALB/c mice. B cell receptor (BCR),mediated apoptosis and proliferation of transitional B cells were analyzed by flow cytometry. Expression of apoptotic genes was examined by microarrays and real-time polymerase chain reaction analysis. B cells coexpressing ,/, light chains were assessed by flow cytometry and immunohistochemistry. Activation status of transitional type 3 (T3) B cells was evaluated by BCR-induced calcium influx studies. Results BCR-mediated apoptosis of the T1 B cell subset, a major checkpoint for negative selection of autoreactive specificities, was decreased in prolactin-treated mice. Microarray studies indicated that this event may be mediated by the prolactin-induced up-regulation of the antiapoptotic gene interferon-, receptor type II and down-regulation of the proapoptotic gene Trp63. Prolactin treatment also altered the amount of receptor editing, as indicated by the increased number of transitional B cells coexpressing ,/, light chains. Additionally, hyperprolactinemia modified the level of B cell anergy by increasing the degree of BCR-induced calcium influx in the T3 B cells. Conclusion Persistently elevated serum prolactin levels interfere with B cell tolerance induction by impairing BCR-mediated clonal deletion, deregulating receptor editing, and decreasing the threshold for activation of anergic B cells, thereby promoting autoreactivity. [source] Effector CD8+ T cells in systemic sclerosis patients produce abnormally high levels of interleukin-13 associated with increased skin fibrosisARTHRITIS & RHEUMATISM, Issue 4 2009Patrizia Fuschiotti Objective T lymphocytes play an important role in systemic sclerosis (SSc), a connective tissue disease characterized by inflammation, fibrosis, and vascular damage. While their precise role and antigen specificity are unclear, T cell,derived cytokines likely contribute to the induction of fibrosis. The aim of this study was to establish the role of cytokine dysregulation by T cells in the pathogenesis of SSc. Methods To identify relationships between a specific cytokine, T cell subset, and the disease course, we studied a large cohort of patients with diffuse cutaneous SSc (dcSSc) or limited cutaneous SSc (lcSSc). Using Luminex analysis and intracellular cytokine staining, we analyzed the intrinsic ability of CD4+ and CD8+ T cell subsets to produce cytokines following in vitro activation. Results High levels of the profibrotic type 2 cytokine interleukin-13 (IL-13) were produced following activation of peripheral blood effector CD8+ T cells from SSc patients as compared with normal controls or with patients with rheumatoid arthritis. In contrast, CD4+ T cells showed a lower and more variable level of IL-13 production. This abnormality correlated with the extent of fibrosis and was more pronounced in dcSSc patients than in lcSSc patients. Conclusion Dysregulated IL-13 production by effector CD8+ T cells is important in the pathogenesis of SSc and is critical in the predisposition to more severe forms of cutaneous disease. Our study is the first to identify a specific T cell phenotype that correlates with disease severity in SSc and can be used as a marker of immune dysfunction in SSc and as a novel therapeutic target. [source] Dysfunctional CD4+,CD25+ regulatory T cells in untreated active systemic lupus erythematosus secondary to interferon-,,producing antigen-presenting cellsARTHRITIS & RHEUMATISM, Issue 3 2008Bing Yan Objective To explore whether there are extrinsic factors that impair the suppressive function of CD4+,CD25+ regulatory T cells in patients with untreated active systemic lupus erythematosus (SLE). Methods We studied 15 patients with untreated active SLE, 10 patients with SLE in remission, and 15 healthy control subjects. Percentages of CD4+,CD25+,FoxP3+ Treg cells and levels of forkhead box P3 (FoxP3) protein were analyzed by flow cytometry. Expression of messenger RNA (mRNA) for FoxP3 in purified Treg cell populations was assessed by real-time polymerase chain reaction analysis. Experiments examining Treg cell function in SLE were designed to distinguish primary from secondary T cell dysfunction. Levels of interferon-, (IFN,) in supernatants from the function assays were determined with an IFN-stimulated response element,luciferase reporter assay. Results The percentage of CD4+,CD25+, FoxP3+ cells in peripheral blood was significantly increased in SLE patients as compared with controls (mean ± SEM 9.11 ± 0.73% versus 4.78 ± 0.43%; P < 0.0001). We found no difference in FoxP3 expression at either the mRNA or protein level in any CD4+,CD25+ T cell subset from SLE patients as compared with controls. Antigen-presenting cells (APCs) from SLE patients were responsible for decreased Treg cell activity and could also render dysfunctional Treg cells from healthy control subjects. CD4+,CD25+ Treg cells from SLE patients exhibited normal suppressive activity when cultured with APCs from healthy controls. A partial Treg cell blockade effect was induced by the high levels of IFN, derived from SLE patient APCs. Conclusion We suggest that blockade of Treg cell,mediated suppression by IFN,-producing APCs in SLE patients may contribute to a pathogenic loss of peripheral tolerance in this disease. [source] Characterization of human peritoneal dendritic cell precursors and their involvement in peritonitisCLINICAL & EXPERIMENTAL IMMUNOLOGY, Issue 3 2005M. L. McCully Summary Scattered evidence suggests that the human peritoneal cavity contains cells of the dendritic cell (DC) lineage but their characterization is missing. Here, we report that the peritoneal cavity of normal subjects and of stable patients on peritoneal dialysis (PD) contains a population of CD14+ cells that can differentiate into DCs or macrophages. Within this pool, we characterized a CD14+CD4+ cell subset (2·2% of the peritoneal cells) fulfilling the definition of myeloid DC precursors or pre-DC1 cells. These cells expressed high levels of HLA-DR, CD13, CD33, and CD86, and low levels of CD40, CD80, CD83, CD123, CD209, TLR-2 and TLR-4. These cells retained CD14 expression until late stages of differentiation, despite concomitant up-regulation of DC-SIGN (CD209), CD1a, CD80 and CD40. Peritoneal pre-DC1 cells had endocytic capacity that was down-regulated upon LPS/IFN-, stimulation, were more potent allo-stimulators than peritoneal CD14+CD4,/lo cells and monocyte-derived macrophages, and induced Th1 cytokine responses. More importantly, the number of peritoneal pre-DC1 cells increased during PD-associated peritonitis, with a different profile for Gram positive and Gram negative peritonitis, suggesting that these cells participate in the induction of peritoneal adaptive immune responses, and may be responsible for the bias towards Th1 responses during peritonitis. [source] Circulating ,/, T lymphocytes from systemic sclerosis (SSc) patients display a T helper (Th) 1 polarizationCLINICAL & EXPERIMENTAL IMMUNOLOGY, Issue 2 2001R. Giacomelli Systemic sclerosis (SSc) is a connective tissue disease in which immune system activation is evidenced by high levels of different cytokines in the sera and/or in the supernatants of cultured peripheral blood mononuclear cells (PBMC) and by the presence of specific autoantibodies. ,/, T cells accumulate in the lung and the skin of SSc patients suggesting their potential role in the development and maintenance of the disease. The aim of this study was to assess cytokine production and cytotoxic activity of circulating ,/, T lymphocytes obtained from SSc patients and to evaluate their potential role during this disorder. Our results showed that both the proportion and the absolute number of IFN- ,,/, -producing cells (i.e. displaying a Th1 polarization) in SSc was significantly higher than either the proportion and the absolute number of IL-4 ,/, -producing cells in SSc or the proportion and the absolute number of IFN- ,,/, -producing cells in healthy controls (P < 0·05 for both groups). Furthermore, the cytotoxic activity of enriched ,/, T cells was significantly increased in SSc patients compared with controls. The results concerning the V,1+ T cell subset paralleled those of total ,/, T lymphocytes. In contrast, ,/, T cells from SSc and control subjects displayed Th2 cytokine production. All these findings were independent of both disease subset and clinical status. Our data demonstrate that, although SSc is generally considered a Th2 autoimmune disease, Th1 polarization of ,/, T cells and an increase in their cytotoxic activity is observed in SSc, suggesting that ,/, T cells could have a relatively autonomous role in the pathogenesis in this disease. [source] Myeloid-derived suppressor cells in inflammation: Uncovering cell subsets with enhanced immunosuppressive functionsEUROPEAN JOURNAL OF IMMUNOLOGY, Issue 10 2009Vincenzo Bronte Abstract Although originally described in tumor-bearing hosts, myeloid-derived suppressor cells (MDSC) have been detected under numerous pathological situations that cause enhanced demand of myeloid cells. Thus, MDSC might be part of a conserved response to different endogenous and exogenous stress signals, including inflammation. Two processes are fundamental for MDSC biology: differentiation from myeloid progenitors and full activation of their immune regulatory program by factors released from activated T cells or present in the microenvironment conditioned by either tumor growth or inflammation. How these two processes are controlled and linked is still an open question. In this issue of the European Journal of Immunology, a paper demonstrates that a combination of the known inflammatory molecules, IFN-, and LPS, sustains MDSC expansion and activation while suppressing differentiation of DC from bone marrow precursors. Moreover, this paper contributes to defining the cell subsets that possess immunoregulatory properties within the broad population of CD11b+Gr-1+ cells, often altogether referred to as MDSC. [source] Type,I interferon-dependent and -independent expression of tripartite motif proteins in immune cellsEUROPEAN JOURNAL OF IMMUNOLOGY, Issue 3 2008Ricardo Rajsbaum Abstract The tripartite motif (TRIM) proteins are important in a variety of cellular functions additional to anti-viral activity. We systematically analysed mRNA expression of representative TRIM molecules in mouse macrophages, myeloid and plasmacytoid dendritic cells, and a selection of CD4+ T cell subsets. We defined four clusters of TRIM genes based on their selective expression in these cells. The first group of TRIM genes was preferentially expressed in CD4+ T cells and contained the COS-FN3 motif previously shown to be involved in protein interactions. Additional TRIM genes were identified that showed up-regulation in macrophages and dendritic cells upon influenza virus infection in a type,I IFN-dependent manner, suggesting that they have anti-viral activity. In support of this notion, a subset of these TRIM molecules mapped to mouse chromosome,7, syntenic to human chromosome,11, where TRIM family members such as TRIM5, shown to have anti-viral activity, are localized. A distinct group of TRIM was constitutively expressed in plasmacytoid dendritic cells independently of viral infection or signalling through the type,I IFN receptor. Our findings on expression and regulation of TRIM genes in cells of the immune system that have different effector functions in innate and adaptive immune responses, may provide leads for determining functions of this diverse family of molecules. [source] Expression of the NKG2D ligand UL16 binding protein-1 (ULBP-1) on dendritic cellsEUROPEAN JOURNAL OF IMMUNOLOGY, Issue 1 2006David Schrama Abstract Innate and adaptive immunity have not evolved separately. In this regard, the NKG2D molecule first identified on NK cells and classified as an activating NK cell receptor is also an important receptor for CD8+ T,cells. Functional analyses of human NKG2D and its ligands, i.e. UL16 binding proteins (ULBP) and MHC class I chain-related (MIC), have so far focused on immune cell-target cell situations because of the expression of NKG2D ligands on infected, stressed or transformed cells. Here, however, we address a possible function of NKG2D/ULBP-1 during the initiation of T cell responses. ULBP-1 can be detected on mature dendritic cells both in situ in the T cell areas of lymph nodes as well as in vitro after artificial maturation. FCM analysis further demonstrated that although NKG2D is expressed to some degree on all analyzed T cell subsets from peripheral blood, in vitro stimulation of T cells results in up-regulation of NKG2D on proliferating T cells. Using the sentinel lymph nodes of primary melanoma as a model for induction of defined T cell responses in vivo, we were able to demonstrate the expression of NKG2D on melanoma-associated antigen-specific T cells. Thus, our results suggest a role for NGK2D-ULBP-1 in the induction or reactivation of T cell responses. [source] Recruitment and selection of marginal zone B,cells is independent of exogenous antigensEUROPEAN JOURNAL OF IMMUNOLOGY, Issue 7 2005Peter Abstract Marginal zone B (MZ-B) cells of the spleen contribute significantly to the immunity against invasive infections with polysaccharide-encapsulated bacteria. Recent evidence indicates that recruitment and selection of MZ-B,cells occurs on the basis of positive selection constraints that likely operate via B,cell receptor (BCR) signaling. Previous studies have shown that MZ-B,cells carry relatively shorter immunoglobulin (Ig) heavy (H) chain complementarity-determining region,3 (H-CDR3) sequences and express BCR which are thought to be polyreactive. In this scenario, MZ-B,cell selection proceeds via engagement of the BCR with exogenous (i.e. microbial gut flora-derived) and/or endogenous (self) antigens. Here, we studied the influence of exogenous antigens on the selection process of MZ-B,cells using non-genetically manipulated adult germ-free and conventionally reared infant rats. This study was carried out by H-CDR3 spectratype analysis of VH(PC7183)-encoded Ig VHDJH -, transcripts expressed by purified splenic MZ-B,cells and other B,cell subsets. We show that MZ-B,cells in both adult germ-free and conventionally reared infant (14-day-old) rats are H-CDR3-selected cells, providing strong evidence that recruitment and selection of MZ-B,cells is driven by self antigens. [source] Expression and function of the adaptor protein Gads in murine B,cellsEUROPEAN JOURNAL OF IMMUNOLOGY, Issue 4 2005Thomas Abstract Nearly all hematopoietic receptors are dependent on adaptor proteins for the activation of downstream signaling pathways. The Gads adaptor protein is expressed in many hematopoietic tissues, including bone marrow, lymph node, and spleen. Using intracellular staining, we detected Gads protein in a number cells, including B,cells, T,cells, NK cells, monocytes, and plasmacytoid DC, but not in macrophages, neutrophils, or monocyte-derived DC. In the B,cell compartment, Gads was first expressed after immature B,cells leave the bone marrow and was down-regulated after B,cell antigen receptor (BCR) ligation. Female Gads,/, mice had increased numbers of splenic B,cells, as compared to female Gads+/+ mice, suggesting a role for Gads in B,cell homeostasis. Although B,cell production and turnover of splenic B,cell subsets appeared normal in Gads,/, mice, homeostatic proliferation was significantly impaired in Gads,/, B,cells. Whereas BCR ligation can induce apoptosis in wild-type transitional stage 1 (T1) B,cells, Gads,/, T1 B,cells were resistant to BCR-induced apoptosis. Gads,/, B,cells also showed increased BCR-mediated calcium mobilization. We conclude that Gads may have a negative regulatory role in signaling through survival pathways, and is necessary for normal homeostatic proliferation in B,cells. [source] Salmonella typhimurium infection halts development of type 1 diabetes in NOD miceEUROPEAN JOURNAL OF IMMUNOLOGY, Issue 11 2004Paola Zaccone Abstract Infectious disease has been proposed as an environmental modifier of autoimmunity in both human populations and the NOD mouse. We found that infection of NOD mice with attenuated, but not killed, Salmonella typhimurium can reduce the incidence of type 1 diabetes (T1D), even if infection occurs after the development of a peri-islet pancreatic infiltrate. Functional diabetogenic effector T,cells are still present, as demonstrated by the initiation of diabetes in NOD- scid recipients of transferred splenocytes. High levels of IFN-, are secreted by splenocytes of infected mice, but there is no evidence of involvement of IL-10 in the protective effect of the infection. Finally, prolonged changes in cell subsets are observed in infected mice involving invariant V,14J,281 NKT and dendritic cells. These data reinforce the idea that prevention of T1D in the NOD mouse cannot be reduced to the simple Th1/Th2 paradigm and that different infections may involve different protective mechanisms. [source] Comparative analysis of NK cell subset distribution in normal and lymphoproliferative disease of granular lymphocyte conditionsEUROPEAN JOURNAL OF IMMUNOLOGY, Issue 10 2004Véronique Pascal Abstract We have characterized the heterogeneity of human blood NK cell subsets defined by expression of KIR, lectin like receptors and NK cell differentiation markers within a cohort of 51 healthy Caucasian individuals. High inter-individual variability in cell surface expression of most NK cell markers is observed. Range values defining NK cell subsets in healthy donors were further used as references to characterize 14 patients with NK-type lymphoproliferative disease of granular lymphocytes (NK-LDGL). Alterations of the KIR repertoire were noted in all NK-LDGL patients. NK cell expansions were classified as oligoclonal KIR+ or as non-detectable KIR (ndKIR) using anti-KIR2DL1/2DS1, anti-KIR2DL2/2DL3/2DS2, anti-KIR3DL1 and anti-KIR2DS4 monoclonal antibodies. A major reduction in the size of the CD56bright NK cell subset was a constant feature of NK-LDGL. Altered distribution of CD94+, CD161+, and CD162R+ NK cell subsets was also observed in NK-LDGL patients. Considering the potential role of NK cells in eliminating tumors or virus-infected cells, the reference values defined in this study should be valuable to characterize both quantitative and qualitative alterations of the NK cell repertoire in pathological conditions and to monitor NK cell reconstitution following hematopoietic transplantation. [source] Differential effects of US2, US6 and US11 human cytomegalovirus proteins on HLA class,Ia and HLA-E expression: impact on target susceptibility to NK cell subsetsEUROPEAN JOURNAL OF IMMUNOLOGY, Issue 10 2003Manuel Llano Abstract We compared in an inducible expression system the individual effect of US2, US6 and US11 human cytomegalovirus (HCMV) proteins on HLA-E and HLA class,Ia surface expression, assessing in parallel their influence on target susceptibility to NK cell clones. To this end, the RPMI,8866 B,lymphoma cell line (HLA-A2, HLA-A3, HLA-B7, HLA-Cw7, HLA-ER, HLA-EG) was stably cotransfected with the ecdysone receptor, together with the US sequences under the control of an ecdysone-inducible promoter. Biosynthesis of viral proteins was turned on by incubating transfectants with Ponasterone,A. US6 down-regulated expression of all class,I molecules, hampering target resistance to NK cell clones controlled by the CD94/NKG2A, KIR2DL2 and/or CD85j (ILT2 or LIR-1) inhibitory receptors. By contrast, US11 reduced the surface levels of class,Ia molecules but preserved HLA-E; this rendered US11+ cells sensitive to NK clones under the control of KIR2DL2 and/or CD85j, while their resistance to CD94/NKG2A+KIR2DL2, effector cells was maintained. US2 preserved as well HLA-E expression but selectively targeted class,Ia molecules; in fact, HLA-A and HLA-C allotypes were down-modulated whereas HLA-B7 remained unaltered. US2+ targets became sensitive to KIR2DL2+ cells but remained resistant to CD94/NKG2A+CD85j+ NK clones. The differential effects of US proteins on HLA class,Ia and HLA-E likely reflect the evolutionary adaptation of HCMV to counteract NK-mediated surveillance. [source] Rational design of new CpG oligonucleotides that combine B cell activation with high IFN-, induction in plasmacytoid dendritic cellsEUROPEAN JOURNAL OF IMMUNOLOGY, Issue 6 2003Gunther Hartmann Abstract Two different types of CpG motif-containing oligonucleotides (CpG ODN) have been described: CpG-A with high induction of IFN-, in plasmacytoid dendritic cells; and CpG-B with little induction of IFN-,, but potent activation of B cells. In this study, we demonstrate that CpG-A fail to activate B cells unless plasmacytoid dendritic cells are present. We identified a new set of CpG ODN sequences which induces high levels of IFN-, in plasmacytoid dendritic cells but remains capable of directly activating B cells. These new CpG ODN (termed CpG-C) are more potent stimulants of B cells than CpG-B due to their ability of directly and indirectly (via plasmacytoid dendritic cells) activating B cells. The sequence of CpG-C combines structural elements of both CpG-A and CpG-B. The most potent sequence, M362, contains a 5,-end ,TCGTCG-motif' and a ,GTCGTT-motif', both of which are present in CpG-B (ODN,2006); a palindromic sequence characteristic for CpG-A (ODN,2216); but no poly,G motif required for CpG-A. In conclusion, we defined the first CpG-containing sequences that potently activate both TLR9-expressing immune cell subsets in humans, the plasmacytoid dendritic cell and the B cell. CpG-C may allow for improved therapeutic immuno-modulation in vivo. [source] Murine thymic plasmacytoid dendritic cellsEUROPEAN JOURNAL OF IMMUNOLOGY, Issue 4 2003Tomoyuki Okada Abstract We report herein heterogeneous murine thymic cell subsets expressing CD11c and B220 (CD45R). The CD11c+B220+ subset expresses Ly6Chigh and MHC class IIlow in contrast with previously described thymic DC (CD11c+B220, cells). Freshly isolated thymic CD11c+B220+ cells show typical plasmacytoid morphology which differentiates to mature DC, in vitro with CpG oligodeoxynucleotides (ODN) 2216; we term this subset thymic plasmacytoid DC (pDC). These thymic pDC are highly sensitive to spontaneous apoptosis in vitro and induce low T cell allo-proliferation activity. Thymic pDC express low TLR2, TLR3 and TLR4 mRNA, normally found on human immature DC, and high TLR7 and TLR9 mRNA, normally found on human pDC. Thymic pDC also produce high amounts of IFN-, following culture with CpG ODN 2216 (TLR9 ligands) as compared with the previously defined thymic DC lineage which expresses low TLR9 mRNA and produce high IL-12 (p40) with CpG ODN 2216. These results indicate that thymic pDC are similar to IFN-producing cells as well as human pDC. The TLR and cytokine production profiles are consistent with a nomenclature of pDC. The repertoire of this cell lineage to TLR9 ligands demonstrate that such responses are determined not only by the quantity of expression, but also cell lineage. [source] Osteopontin and the skin: multiple emerging roles in cutaneous biology and pathologyEXPERIMENTAL DERMATOLOGY, Issue 9 2009Franziska Buback Abstract:, Osteopontin (OPN) is a glycoprotein expressed by various tissues and cells. The existence of variant forms of OPN as a secreted (sOPN) and intracellular (iOPN) protein and its modification through post-translational modification and proteolytic cleavage explain its broad range of functions. There is increasing knowledge which receptors OPN isoforms can bind to and which signaling pathways are activated to mediate different OPN functions. sOPN interacts with integrins and CD44, mediates cell adhesion, migration and tumor invasion, and has T helper 1 (Th1) cytokine functions and anti-apoptotic effects. iOPN has been described to regulate macrophage migration and interferon-, secretion in plasmacytoid dendritic cells. Both sOPN and iOPN, through complex functions for different dendritic cell subsets, participate in the regulation of Th cell lineages, among them Th17 cells. For skin disease, OPN from immune cells and tumor cells is of pathophysiological relevance. OPN is secreted in autoimmune diseases such as lupus erythematosus, and influences inflammation of immediate and delayed type allergies and granuloma formation. We describe that OPN is overexpressed in psoriasis and propose a model to study OPN function in psoriatic inflammation. Through cytokine functions, OPN supports immune responses against Mycobacteria and viruses such as herpes simplex virus. OPN is also implicated in skin tumor progression. Overexpression of OPN influences invasion and metastasis of melanoma and squamous cell carcinoma cells, and OPN expression in melanoma is a possible prognostic marker. As OPN protein preparations and anti-OPN antibodies may be available in the near future, in-depth knowledge of OPN functions may open new therapeutic approaches for skin diseases. [source] Treatment of neutral glycosphingolipid lysosomal storage diseases via inhibition of the ABC drug transporter, MDR1FEBS JOURNAL, Issue 9 2006Cyclosporin A can lower serum, liver globotriaosyl ceramide levels in the Fabry mouse model We have shown that the ABC transporter, multiple drug resistance protein 1 (MDR1, P-glycoprotein) translocates glucosyl ceramide from the cytosolic to the luminal Golgi surface for neutral, but not acidic, glycosphingolipid (GSL) synthesis. Here we show that the MDR1 inhibitor, cyclosporin A (CsA) can deplete Gaucher lymphoid cell lines of accumulated glucosyl ceramide and Fabry cell lines of globotriaosyl ceramide (Gb3), by preventing de novo synthesis. In the Fabry mouse model, Gb3 is increased in the heart, liver, spleen, brain and kidney. The lack of renal glomerular Gb3 is retained, but the number of verotoxin 1 (VT1)-staining renal tubules, and VT1 tubular targeting in vivo, is markedly increased in Fabry mice. Adult Fabry mice were treated with ,-galactosidase (enzyme-replacement therapy, ERT) to eliminate serum Gb3 and lower Gb3 levels in some tissues. Serum Gb3 was monitored using a VT1 ELISA during a post-ERT recovery phase ± biweekly intra peritoneal CsA. After 9 weeks, tissue Gb3 content and localization were determined using VT1/TLC overlay and histochemistry. Serum Gb3 recovered to lower levels after CsA treatment. Gb3 was undetected in wild-type liver, and the levels of Gb3 (but not gangliosides) in Fabry mouse liver were significantly depleted by CsA treatment. VT1 liver histochemistry showed Gb3 accumulated in Kupffer cells, endothelial cell subsets within the central and portal vein and within the portal triad. Hepatic venule endothelial and Kupffer cell VT1 staining was considerably reduced by in vivo CsA treatment. We conclude that MDR1 inhibition warrants consideration as a novel adjunct treatment for neutral GSL storage diseases. 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