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PubMed2006

Distinctive pattern of cytokine production and adhesion molecule expression in peripheral blood memory CD4+ T cells from patients with active Crohn's disease.

An expansion of both circulating and intestinal lamina propria CD4+ CD45RO+ T cells has been described in patients with Crohn's disease. We studied both the cytokine profile and the expression of adhesion molecules on this T-cell subset. Peripheral blood CD4+ CD45RO+ T cells from patients with Crohn's disease (n=45) were assessed by flow cytometry and RT-PCR methods. The cytokine profile was also measured in intestinal lamina propria from seven patients. They were classified according to the CDAI and the results were compared with those of patients with ulcerative colitis (n=21) and noninflammatory intestinal conditions (n=15), and healthy controls (n=39). The mean percentage of circulating CD4+ CD45RO+ T cells producing intracellular TNF was higher in active than in inactive Crohn's disease patients (p < 0.001), active (p = 0.49) and inactive ulcerative colitis (p = 0.019), and healthy controls (p =0. 017). TNF expression correlated with CDAI (p < 0.001). An increased expression of intracellular IL-2, IL-6, and IL-10 in active Crohn's disease patients was also found. CD62L was downregulated in active Crohn's disease patients while no differences were observed in CD49d and CD11a expression. Lamina propria CD4+ CD45RO+ T cells from active Crohn's disease lesions showed an increased intracellular staining of TNF, IFN-gamma, and IL-10. Both peripheral and intestinal mucosa CD4+ CD45RO+ T cells from active Crohn's disease patients show an increased production of TNF. In addition, the circulating CD4+ CD45RO+ T-cell subset expresses a pattern of adhesion molecules that promotes homing to extranodal lymphoid tissues. This T-cell subset may play a relevant role in the immunopathogenesis of Crohn's disease.

Adolescent↗
PubMed2006

Progressive multifocal leukoencephalopathy and multiple sclerosis: lessons from natalizumab.

Three patients have developed progressive multifocal leukoencephalopathy while being treated with natalizumab for their autoimmune diseases. One patient had relapsing-remitting multiple sclerosis (RRMS), one had Crohn's disease, and one (who had been enrolled in an RRMS phase III trial) had no evidence of multiple sclerosis on autopsy. The patient with RRMS now has severe, permanent neurologic damage and the other two patients died. In this article, we recommend revised entry and diagnostic criteria to prevent enrollment of RRMS patients with a favorable prognosis or questionable diagnosis into trials of drugs with unknown safety profiles. In light of the risk of progressive multifocal leukoencephalopathy, we strongly recommend that RRMS patients who are at low risk of disability not be treated with natalizumab. Finally, we discuss what additional natalizumab efficacy data need to be presented before any decisions should be made about treating RRMS patients with a high risk of developing long-term disability.

Antibodies, Monoclonal↗
PubMed1995

Distinct roles of L-selectin and integrins alpha 4 beta 7 and LFA-1 in lymphocyte homing to Peyer's patch-HEV in situ: the multistep model confirmed and refined.

Circulating lymphocytes home to the mucosal lymphoid organs, Peyer's patches (PP), through high endothelial venules (HEV). In situ analyses revealed that transfused lymph node cells (LNCs) interact with PP-HEV in a series of overlapping adhesion events: L-selectin (CD62L) > alpha 4 beta 7 initiates interaction, L-selectin and alpha 4 beta 7 both participate in rolling, and G alpha i-linked activation triggers arrest that requires both alpha 4 beta 7 and LFA-1. alpha 4 beta 7 dramatically reduces rolling velocity, and appears to be required for engagement of LFA-1. In contrast with resting LNC, preactivated LNC or alpha 4 beta 7hi lymphoma cells require only alpha 4 beta 7 for arrest in PP-HEV. The predominant PP-HEV ligand for alpha 4 beta 7 but also apparently for L-selectin is the mucosal addressin MAd-CAM-1. These results validate the concept of multimolecular adhesion/decision cascades in physiologic lymphocyte-endothelial recognition, define a novel role for alpha 4 integrins as a "bridge" between selectin and beta 2 integrin-dependent events, and reemphasize the potential for direct adhesion through preactivated alpha 4 integrins alone.

Animals↗
PubMed2005

Anti-adhesion therapies.

Cell adhesion molecules are key mediators of inflammatory processes and are attractive targets for discovery of novel therapeutics. There have been significant positive advances in both basic research and clinical development in this area. Basic research has yielded detailed insight into the structural basis of cell adhesion molecule function, especially the interaction of integrins with their ligands. Co-crystals of several integrin-ligand complexes have been published, including alpha v beta3 with ligand fragments, alpha IIb beta3 with multiple therapeutic ligands and alpha L beta2 (leukocyte function-associated antigen-1 [LFA-1]) with its cell-based ligand intercellular adhesion molecule-1. This has stimulated development of models of integrin function and also the mode of action of small-molecule inhibitors. The most exciting recent advances in the field of clinical development have come with the successful approval of two new anti-adhesion therapeutics: efalizumab (Raptiva) targeting LFA-1 for the treatment of chronic plaque psoriasis, and natalizumab (Tysabri/Antegren) targeting very late antigen-4 for the treatment of relapsing-remitting multiple sclerosis. However, the latter therapeutic ran into a surprising safety issue earlier this year and was withdrawn from the market, casting a shadow over what had seemed a promising new drug.

Antibodies, Monoclonal↗
PubMed2004

Analyzing T-cell responses to cytomegalovirus by cytokine flow cytometry.

T-cell responses to human cytomegalovirus (CMV) are readily detected in chronically infected adults, and are thought to be important for protection from CMV-related pathology. Antigen-specific cytokine flow cytometry (CFC) has been used to establish the range of CMV-specific CD4 and CD8 T-cell frequencies in healthy CMV-seropositive (and seronegative) adults, as well as the dynamics of these cells over time. There are also emerging data regarding the primary CD4 and CD8 T-cell response to CMV in children and adults. Finally, CFC has been used to analyze CMV responses in chronic human immunodeficiency virus infection, as well as during immune reconstitution after bone marrow or stem cell transplantation. These data will be reviewed in terms of what they suggest about the threshold of protective T-cell immunity to CMV, and other factors in addition to T-cell frequencies that could be important in protecting from CMV-associated disease.

Aging↗
PubMed2004

Properties of CD4(+) T cells in human cytomegalovirus infection.

The correlates of protective immunity to disease-inducing viruses in man remain to be elucidated. We determined the kinetics and properties of cytomegalovirus (CMV)-specific CD4(+) T cells in healthy individuals and renal transplant recipients during different stages of CMV infection. Our data reveal that circulating CMV-specific CD4(+) T cells displayed an effector-memory phenotype, and produced the T helper 1 cytokines interferon-gamma and tumor necrosis factor-alpha. In addition, they lacked molecules for secondary lymphoid organ homing and expressed the cytotoxic molecule granzyme B, inferring a direct role of these cells at target sites of infection. In asymptomatic individuals the CMV-specific CD4(+) T-cell response preceded CMV-specific CD8(+) T-cell responses, whereas in symptomatic individuals the CMV-specific effector memory CD4(+) T-cell response was delayed and only detectable after antiviral therapy. The appearance of disease symptoms in these patients suggests that functional CD8(+) T cell and antibody responses are insufficient to control viral replication and that formation of effector memory CD4(+) T cells is necessary for recovery of infection.

ADP-ribosyl Cyclase↗
PubMed2005

RUNX3 regulates the activity of the CD11a and CD49d integrin gene promoters.

The leukocyte integrins CD11a/CD18 (LFA-1, alphaLbeta2) and CD49d (VLA-4, alpha4beta1, alpha4beta7) mediate leukocyte transendothelial migration during immune and inflammatory responses and provides co-stimulatory signals for the activation of T lymphocytes. Our previous studies demonstrate that the CD11a gene promoter directs CD11a/CD18 integrin expression, and it depends on two overlapping sequences within the MS7 element, RUNX-110 and CEBP-100, which are recognized by RUNX and C/EBP transcription factor families, respectively. Recognition of MS7 differs in lymphoid (RUNX) and myeloid (C/EBP and RUNX) cells and its in vivo occupancy is regulated in a competitive and differentiation-dependent manner. The functional relevance of these elements are illustrated by the fact that RUNX3 overexpression leads to enhanced CD11a/CD18 levels, whereas RUNX1-ETO-expressing cells exhibit a weak/absent CD11a/CD18 integrin cell surface expression. We now provide evidence that RUNX3 also transactivates the CD49d gene promoter, and that the increased expression of CD49d mRNA and CD49d integrins on mature monocyte-derived dendritic cells correlates with an up-regulation of RUNX3 mRNA. The regulation of CD49d and CD11a integrins by RUNX3 could potentially contribute to the enhancement of transendothelial migration, antigen presentation and T cell stimulatory capabilities of mature dendritic cells.

Base Sequence↗
PubMed2005

Rules of recruitment for Th1 and Th2 lymphocytes in inflamed liver: a role for alpha-4 integrin and vascular adhesion protein-1.

The mechanisms that mediate the recruitment of Th1 and Th2 lymphocytes in vivo are poorly understood. We demonstrate that the mechanisms by which exogenously produced CD4(+) Th1 and Th2 cells roll and adhere in Con A-inflamed liver microcirculation differ dramatically: Th1 cells use alpha(4)beta(1)-integrin and Th2 cells use the vascular adhesion protein (VAP)-1. P-selectin plays no detectable role in Th1 or Th2 cell trafficking in liver microcirculation. Cellular recruitment in the liver sinusoids has previously been shown to be independent of many known adhesion molecules, leading to the suggestion that recruitment in these structures is mediated by physical trapping. While this may still be true for neutrophils, Th1 and Th2 cells use alpha(4)-integrin and VAP-1, respectively, to adhere within the liver sinusoids.

Amine Oxidase (Copper-Containing)↗
PubMed2006

Differential effects of single dose FTY720 on CD62L+ B-cells in stable renal allograft recipients.

FTY720, a sphingosine-1-phosphate receptor agonist, is the archeotype of a new class of immune modulators, which redirects lymphocytes from the peripheral blood into secondary lymphatic tissue. Previously, it was shown that FTY720 differentially decreases peripheral T-cells, expressing specific chemokine and adhesion receptors. Here, we investigated the effect of single doses FTY720 on peripheral B-cells expressing CD62L, CD11a, CD49d and CXCR4 in stable human renal allograft recipients. Peripheral blood lymphocytes were isolated by Ficoll density centrifugation and stained with monoclonal antibodies against CD3 or CD19 and CD62L, CD11a, CD49d, CXCR4 to determine the percentage of these T- and B-cell subpopulations. Total lymphocyte counts were measured by routine laboratory diagnostics to calculate absolute lymphocyte subset counts. In FTY720 treated patients, total lymphocyte counts decreased by 31.8% (0.25-2 mg) and 60.4% (3.5 mg), and total T-cell counts by 38.8% (0.25-2 mg) and 70.9% (3.5 mg). In comparison, total B-cell counts decreased by 32.2% (0.25-2 mg) and 61.1% (3.5 mg). The reduction of CD62L+ B-cells was less pronounced as compared to CD62L+ T-cells (0.25-2 mg: 15.7% vs. 57.3%; 3.5 mg: 57.2% vs. 86.9%). CD11a+ B-cells decreased by 15.4% (0.25-2 mg) and 57.1% (3.5 mg), and CD49d+ B-cells by 15.0% (0.25-2 mg) and 56.7% (3.5 mg). CXCR4+ B-cells decreased by 19.9% (0.25-2 mg) and 57.2% (3.5 mg). In vitro experiments showed that FTY720 did not change the mean expression of CD62L, CD11a, CD49d and CXCR4 on CD19+ B-cells. In conclusion FTY720 treatment reduces B-cells expressing CD62L to a significant lesser degree than T-cells expressing CD62L.

B-Lymphocytes↗
PubMed2005

In vitro anti-allergic activities of a newly concocted traditional Chinese medicine--the wheeze-relief formula.

Asthma is one of the most common chronic diseases worldwide. Western medications such as glucocorticoids are effective therapeutic agents but may be associated with side effects. Traditional Chinese medicine (TCM) has been used for treating allergic diseases with observable clinical benefits. The present study investigated whether a novel TCM concoction, the wheeze-relief formula (WRF), possesses in vitro anti-allergic activities. We measured the effects of WRF on the release of eosinophil cationic protein (ECP) by human eosinophils using fluorescence enzyme immunoassay, expression of chemokine receptor CCR3 and adhesion molecule CD49d on eosinophils using immunophenotyping, cytokine induction from peripheral blood mononuclear cells (PBMC) using cytometric bead array (CBA), and the gene expression of cytokines and cytokine receptors using cDNA expression array. Results demonstrated that WRF dose-dependently and significantly: (1) suppressed ECP release from eosinophils activated with granulocyte macrophage-colony stimulating factor (GM-CSF) and platelet activating factor (PAF); (2) inhibited the expression of CCR3 and CD49d on PAF-activated eosinophils; and (3) attenuated the production of tumor necrosis factor alpha and gene expression of IL-2 receptor chain alpha (CD25) on house dust mite (Der p 1) activated PBMC. The above results suggest a possible anti-allergic role of WRF and provide a biochemical basis for further clinical trial on human subjects.

Anti-Allergic Agents↗
PubMed2004

Antisense oligonucleotide blockade of alpha 4 integrin prevents and reverses clinical symptoms in murine experimental autoimmune encephalomyelitis.

We investigated the use of an antisense oligonucleotide (ASO) specific for mRNA of the alpha chain (CD49d) of mouse VLA-4 to down-regulate VLA-4 expression and alter central nervous system (CNS) inflammation. ISIS 17044 potently and specifically reduced CD49d mRNA and protein in cell lines and in ex-vivo-treated primary mouse T cells. When administered prophylactically or therapeutically, ISIS 17044 reduced the incidence and severity of paralytic symptoms in a model of experimental autoimmune encephalomyelitis (EAE). This was accompanied by a significant decrease in the number of VLA-4+ cells, CD4(+) T cells, and macrophages present in spinal cord white matter of EAE mice. ISIS 17044 was found to accumulate in lymphoid tissue of mice, and oligonucleotide was also detected in endothelial cells and macrophage-like cells in the CNS, apparently due to disruption of the blood-brain barrier during EAE. These results demonstrate the potential utility of systemically administered antisense oligonucleotides for the treatment of central nervous system inflammation.

Animals↗
PubMed2004

Platelet factor 4 enhances the adhesion of normal and leukemic hematopoietic stem/progenitor cells to endothelial cells.

Platelet factor 4 (PF4) is a growth regulator of hematopoietic stem/progenitor cells (HSPCs), but its role in modulating the adhesive property of normal and leukemic cells remains unclear. We used CD34(+) cord blood cells, KG1a cell line, human umbilical vein endothelial cells (HUVECs) and a transformed HUVECs ECV-304 cells to study the effect of PF4 on cell adhesion. When CD34(+) cord blood cells were cultured either in fibronectin-coated (FN) culture plate or over the layer of HUVECs for 2h, a concentration-dependent increase of the number of adhered cells was observed in the culture containing PF4. FACS analysis revealed that the treatment of PF4 resulted in an increased expression of CD49d and CXCR-4 on CD34(+) cells. Moreover, when CD34(+) cells were expanded in the presence of PF4, the adhesive ability to culture plate of CD34(+) cells was significantly increased. To elucidate the mechanism of action of PF4, KG1a cells were incubated with or without PF4 for 2h on pre-established layer of ECV-304 cells. The percentage of CD49d(+) KG1a cells increased about 1.56 +/- 0.4 fold, and that of CD54(+) ECV-304 increased about 1.7 +/- 0.6 fold. Furthermore, the mRNA expression of CD49d and CD54 was upregulated when KG1a or ECV-304 cells were incubated with PF4. The adhesion capacity of KG1a cells was reduced after incubation with the blocking monoclonal antibodies against CD49d and CD54, respectively. Our data demonstrate that PF4 is able to enhance the adhesive ability of normal and leukemia HSPCs.

Antigens, CD34↗
PubMed2004

Senescence-associated decline of lymphocyte migration in gut-associated lymphoid tissues of rat small intestine.

Scenescence-induced changes in gut-associated lymphoid tissues may contribute largely to the impaired immune responses during aging. Age-related changes in lymphocyte recirculations were investigated in Peyer's patches of rat small intestine. Cell dynamics of labeled T lymphocytes were observed under an intravital fluorescence microscope and compared between young and aged rats. Lymphocyte transport through intestinal lymph was decreased in aged rats. The lymphocyte rolling and adherence in postcapillary venules (PCV) of Peyer's patches was also significantly impaired in aged rats, with decreased expression of L-selectin on lymphocyte surfaces. Immunohistochemical analysis revealed a significant decrease in the CD8-positive cell population in Peyer's patches of the aged group, although mucosal addressin cell adhesion molecule-1 (MAdCAM-1) expression in postcapillary venules was unaltered. Lymphocyte adoptive-transfer studies indicated that although both the donor and recipient factors influence the adherence of T cells, the former may play a predominant role in the age-related change. This study clearly demonstrated in situ that T cell migration into Peyer's patches is significantly decreased in the aged intestine, which may reflect the impaired immune responses in the aging process.

Adoptive Transfer↗
PubMed2004

Heme oxygenase modulates hepatic leukocyte sequestration via changes in sinusoidal tone in systemic inflammation in mice.

Heme oxygenase (HO) modulates the accumulation of leukocytes within the liver during the early stages of a systemic inflammatory response syndrome (SIRS), but the anti-inflammatory mechanism(s) remain to be tested. The influence of HO on the adhesion molecule expression within the liver and on circulating leukocytes was assessed. In addition, the effect of HO and nitric oxide synthase (NOS) on the liver microcirculation was tested. Mice were subjected to 1 h bilateral hindlimb ischemia followed by 3 h of reperfusion, at which time blood samples and the liver were harvested and adhesion molecule expression determined (ICAM-1, CD49d and CD11b). Direct measures of sinusoidal diameter and estimates of volumetric blood flow were obtained using intravital microscopy. HO was specifically induced and inhibited by hemin and chromium mesoporphyrin (CrMP), respectively, whereas NOS was inhibited by N-nitro-L-arginine methyl ester (L-NAME). ICAM-1 expression was increased following hindlimb ischemia-reperfusion. Hemin caused only a modest, but significant decrease in ICAM-1 expression, whereas inhibition of HO had no effect. However, HO inhibition significantly reduced sinusoidal diameters and volumetric flow and such vessels were correlated with significantly increased numbers of stationary leukocytes. Inhibition of NOS had no effect on sinusoidal diameter or volumetric flow. In conclusion, the anti-inflammatory benefits afforded by HO activity within the liver appear to involve the control of sinusoidal diameter and volumetric blood flow rather than altered adhesion molecule expression during the early stages of SIRS.

Animals↗
PubMed2006

Intracellular cytokine staining for the characterization and quantitation of antigen-specific T lymphocyte responses.

Standard proliferation assays used for analysis of T cell function have significant shortcomings, including limited sensitivity, lack of quantitative readouts, and considerable variability. Recently, flow cytometric methods have been developed to allow multiparametric detection of cell surface antigens and intracellular cytokine expression in response to polyclonal stimuli and antigen. We have optimized an intracellular cytokine staining assay in the non-human primate model of AIDS, which allows us to identify antigen-specific T lymphocytes at the single cell level with high sensitivity, while reducing background staining to a minimum. Central to our optimized protocol is the addition of cross-linked costimulatory anti-CD28 and anti-CD49d Mabs, a modification that results in up to 3-fold enhancement of the frequency of cytokine-secreting CD4(+) T cells following superantigen or antigen-specific stimulation. Optimization of the antigen concentration and duration of antigenic stimulation resulted in a convenient and highly reproducible assay, which permits delineation of antigen-specific cells at the single cell level, thereby providing new insights into pathogen-specific immune responses and allowing detailed phenotypic analysis of extremely low frequency events.

Antibodies, Monoclonal↗
PubMed2000

Activation of peripheral leukocytes in rat pregnancy and experimental preeclampsia.

OBJECTIVE: The aim of this study was to search for activation markers of peripheral leukocytes in experimental preeclampsia in the rat. STUDY DESIGN: Experimental preeclampsia was induced in 14-day-pregnant rats by infusion of endotoxin (1.0 microg/kg body weight). For comparison, rats with normal pregnancies that were infused with sodium chloride solution and cyclic rats that were infused with either endotoxin or sodium chloride solution were used. At various points before and after the infusion, blood samples were withdrawn and analyzed by means of whole-blood flow cytometry to evaluate expression of inflammation-associated adhesion molecules (CD11b, CD11a, CD49d, and CD62L) and CD14 on the leukocytes. RESULTS: Normal pregnancy was associated with increased CD11b (granulocytes and monocytes), CD11a (monocytes and lymphocytes), and CD49d (granulocytes, monocytes, and lymphocytes) expression. In addition to these changes found in normal pregnancy, reduced CD62L and increased CD11a and CD49d expression was found on granulocytes after endotoxin treatment of pregnant rats. No effect of endotoxin was observed in cyclic rats. CONCLUSION: Leukocytes of rats with experimental preeclampsia and, to a lesser extent, those of rats with normal pregnancies had an activated phenotype. These results are consistent with our previous findings in human subjects and suggest that (experimental) preeclampsia results from a generalized inflammatory response.

Animals↗
PubMed1999

A soluble gradient of the neuropeptide secretoneurin promotes the transendothelial migration of monocytes in vitro.

Secretoneurin, derived from the chromogranin secretogranin II, triggers the selective migration of human monocytes, eosinophils, fibroblasts, endothelial and smooth muscle cells. More recently, we located specific binding sites on the human monocytic cell line MonoMac-6. Differentiated U937 transendothelial diapedesis was evaluated using an in vitro model of the vascular wall and specific monoclonal antibodies against CD11/CD18 and the alpha-chains of the very late activation antigen (VLA)-4 were used to evaluate involved adhesion molecules. Results showed a significant migratory response to secretoneurin between 10(-8) to 10(-10) M. Migration was comparable to a maximal effect induced by the monocyte chemotactic agent N-formyl-Met-Leu-Phe (fMLP, 10(-8) M). Rabbit anti-secretoneurin antibodies were able to block the neuropeptide effect but not of fMLP and a trypsinized secretoneurin preparation as well as the secretogranin II-fragment EL-17 were ineffective in eliciting migration. Transmigration of U937 across endothelial-layers toward secretoneurin is inhibited by antibodies to CD11/CD18 adhesion molecules. The novel neuropeptide secretoneurin may play a role in regulating migration of monocytes into the subendothelial space, supposing a role in inflammatory responses.

Animals↗