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Cell Sorting Analysis (cell + sorting_analysis)
Selected AbstractsDepletion of functionally active CD20+ T cells by rituximab treatmentARTHRITIS & RHEUMATISM, Issue 12 2009Esther Wilk Objective Rituximab is a therapeutic anti-CD20 antibody used for in vivo depletion of B cells in proliferative and autoimmune diseases. However, the mechanisms of action are not fully understood, since not all of the therapy-mediated effects can be explained by the depletion of antibody-secreting cells. In addition to B cells, there is also a small population of T cells coexpressing CD20 in all individuals. This study was conducted to examine the phenotype and function of CD3+CD20+ T cells in patients with rheumatoid arthritis (RA) and healthy controls. Methods The phenotype and apoptosis of peripheral blood mononuclear cells from healthy donors and RA patients were examined by 4-color fluorescence-activated cell sorting analyses. Cytokine production was determined by intracellular staining and measurement of cytokines in the supernatants. Proliferation of sorted T cell populations was analyzed using 3H-thymidine uptake assays. Results In healthy individuals, 0.1,6.8% of peripheral blood T cells (mean 1.6%; n = 142) coexpressed CD20, which was not significantly different from that in the peripheral blood of RA patients, in whom 0.4,2.6% of T cells (mean 1.2%; n = 27) were CD20+. During rituximab therapy, the CD20+ T cells along with the B cells were eliminated from the RA peripheral blood. Among the CD20+ T cells, 45% coexpressed CD8 and 55% coexpressed CD4. Polyclonal CD3+CD20+ cells were functionally characterized by constitutive cytokine production (i.e., interleukin-1, and tumor necrosis factor ,), a low proliferative capacity, a high activation state, and enhanced susceptibility to apoptosis. Conclusion These findings suggest that CD20+ T cells represent a terminally differentiated cell type with immune-regulatory and proinflammatory capacities. Depletion of CD20+ T cells may be an additional mechanism by which anti-CD20 therapy functions in patients with RA. [source] Glucocorticoids increase ,5 integrin expression and adhesion of synovial fibroblasts but inhibit ERK signaling, migration, and cartilage invasionARTHRITIS & RHEUMATISM, Issue 12 2009Torsten Lowin Objective In rheumatoid arthritis (RA), integrins mediate cell adhesion, migration, and invasion, and their expression is regulated by cytokines and growth factors. The aim of this study was to investigate whether hormones such as cortisol or other steroids can influence integrin expression and function in the synovial cells of patients with RA. Methods We performed immunofluorescence and fluorescence-activated cell sorting analyses to quantify surface integrin levels. Adhesion and migration assays were performed to study the function of synovial fibroblasts (SFs). ERK activation was measured by cellular activation of a signaling enzyme-linked immunosorbent assay. Invasion of SFs into cartilage was determined in the SCID mouse coimplantation model of RA in vivo. Results In RA, expression of integrin subunits ,5, ,v, and ,1 was higher at the site of invasion compared with the sublining zone. Testosterone and 17,-estradiol had no influence on integrin levels, but cortisol up-regulated expression of the ,5 subunit in a time-dependent and dose-dependent manner. In addition, cortisol increased the adhesion of SFs to fibronectin and inhibited ERK signaling upon integrin activation or upon stimulation with tumor necrosis factor. Small interfering RNA or a neutralizing antibody to ,5 integrin increased SF migration, indicating that up-regulated ,5 integrin is responsible for an immobile phenotype. In addition, in the SCID mouse model, SF invasion into cartilage was attenuated by glucocorticoid treatment in vivo. Conclusion Glucocorticoids increase integrin expression and the adhesion of cells to fibronectin, inhibit ERK signaling, and down-regulate the invasiveness of SFs in vivo. This study demonstrates that an important antiinflammatory aspect of glucocorticoids is regulating the expression and function of ,5 integrin. [source] Viability of Preadipocytes In Vitro: The Influence of Local Anesthetics and pHDERMATOLOGIC SURGERY, Issue 8 2009MAIKE KECK MD BACKGROUND Autogenous fat transfer with lipoinjection for soft tissue augmentation is a commonly used surgical technique. Abundant donor tissue availability and relative ease of harvesting have made autologous fat an attractive soft tissue filler. The overall reliability of this technique is often disputed, and different authors describe different results after autologous fat transplantation despite using similar techniques. In this study, we examined the influence of different local anesthetics commonly used in fat harvest and the pH of the anesthetic solution on the viability of harvested preadipocytes. METHODS AND MATERIALS Preadipocytes were incubated with 1% lidocaine, 1% articaine plus epinephrine 1:200,000, 0.75% ropivacaine, and 1% prilocaine or our standardized tumescent solution (1 L of 0.9% sodium chloride solution plus 25 mL of 1% articaine plus epinephrine 1:200,000 plus 25 mL of bicarbonate) for 30 minutes. Additionally, we incubated cells with the local anesthetics as described above but diluted 1:2 with phosphate buffered saline (pH 7.4). Viability was measured using trypan blue dying as well as propidium iodine staining and fluorescence-activated cell sorting analysis. RESULTS There are significant differences in the viability of preadipocytes under the influence of various local anesthetics. DISCUSSION Our data could partially explain the varying results after autogenous fat transfer. [source] Cytotoxic T lymphocytes recognize and lyse chondrocytes under inflammatory, but not non-inflammatory conditionsIMMUNOLOGY, Issue 1 2003E. Suzanne Cohen Summary The human major histocompatibility complex (MHC) class I allele HLA-B27 is strongly associated with seronegative spondyloarthropathies including ankylosing spondylitis and reactive arthritis. Although of unknown aetiology, one hypothesis suggests that a cytotoxic T cell (CTL) response against a self-antigen at sites of inflammation, such as entheses or joints may be involved. The chondrocyte is one of the major specialized cell types found both in articular cartilage and cartilaginous entheses and therefore is a possible source of such an antigen. CTL recognition of these cells is a potential mechanism for inflammation and cartilage damage, both through direct lysis of chondrocytes and the secretion of pro-inflammatory cytokines such as tumour necrosis factor and interferon-, (IFN-,). We test the feasibility of this hypothesis by examining the ability of chondrocytes to present antigen to CTL in vitro. Chondrocytes isolated from the ribcages of mice did not constitutively express detectable levels of MHC class I by fluorescence-activated cell sorting analysis. In addition, they were resistant to lysis by alloreactive and influenza A virus nucleoprotein (NP)-specific CTL. However, treatment of chondrocytes with IFN-, up-regulated MHC class I expression and rendered the cells susceptible to lysis by CTL. Similarly, IFN-,-treated chondrocytes infected with influenza A virus were recognized by NP-specific CTL, though with variable efficiency. Thus, we suggest that under certain circumstances CTL-mediated lysis of chondrocytes is potentially a potent mechanism for cartilage damage in vivo, but that low levels of MHC class I on healthy chondrocytes protects from immune recognition in health. [source] Isolation and potential existence of side population cells in adult human kidneyINTERNATIONAL JOURNAL OF UROLOGY, Issue 3 2008Toshihiko Inowa Abstract: The existence of adult stem-like cells such as side population (SP) cells is reported in various kinds of animal tissues, and we recently reported that mice kidney SP cells differentiate into multilineage. However, there has thus far been no report about human kidney SP cells. In the present study, we examined the existence of SP cells in human kidney tissue by using Hoechst 33342 staining and fluorescence-activated cell sorting analysis. We used porcine kidney tissue to optimize the analysis conditions for human tissue, and found that the SP population in human kidney was 1.3%. The existence of SP cells in human kidney suggests that the cells could be good targets for clinical renal regenerative medicine. [source] Nickel-responding T cells are CD4+ CLA+ CD45RO+ and express chemokine receptors CXCR3, CCR4 and CCR10BRITISH JOURNAL OF DERMATOLOGY, Issue 1 2004H. Moed Summary Background Whereas T lymphocytes are widely accepted as effector cells determining the pathogenesis of allergic contact dermatitis, contradictory results have been found regarding the roles of different T-cell subsets. The use of various experimental models, involving long-term cultured T-cell lines or clones, may explain these contradictory results. Objective To investigate the involvement of distinct T-cell subsets in patients with nickel contact allergy. Methods Different T-cell subsets were directly isolated from peripheral blood mononuclear cells (PBMCs) of nickel-allergic patients, and their proliferative capacity, type-1 or type-2 cytokine secretion [measured by interferon (IFN)-, or interleukin (IL)-5 release] and phenotypical marker expression were analysed after stimulation with nickel. Results Only CD4+ CLA+ CD45RO+ and not CD8+ T cells proliferate and produce both type-1 (IFN-,) and type-2 (IL-5) cytokines in response to nickel. Moreover, cells expressing the marker CLA in combination with CD4, CD45RO or CD69 are increased after nickel-specific stimulation. Interestingly, in addition, CD45RA+ CLA+ cells showed an increased frequency after allergen-specific stimulation. Analysis of nickel-reactive T cells for expression of distinct chemokine receptors showed that both proliferative capacity and cytokine production are restricted to subsets expressing CXCR3, CCR4 but not CCR6. Fluorescence-activated cell sorting analysis of chemokine receptors expressed on nickel-stimulated T cells confirmed these results; a subset of T cells expressing CLA and CXCR3, CCR4 and, most importantly, CCR10 increased in response to allergen, while these CLA+ nickel-reactive T cells were all negative for CCR6. Conclusions These findings demonstrate that freshly isolated nickel-reactive T cells can be characterized as CD4+ CLA+ memory T cells which express the chemokine receptors CXCR3, CCR4 and CCR10, but not CCR6. [source] |