Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0155339 (Brown)
 12,436 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

CD2 is a T lymphocyte cell-adhesion molecule (CAM) belonging to the immunoglobulin superfamily (IgSF) which mediates transient adhesion of T cells to antigen-presenting cells and target cells. Reported ligands for human CD2 include the structurally-related IgSF CAMs CD58 (LFA-3) and CD48 as well as, more controversially, the unrelated cell-surface glycoprotein CD59. Using surface plasmon resonance technology, which avoids several pitfalls of conventional binding assays, we recently reported that rat CD2 binds rat CD48 with a very low affinity (Kd 60-90 microM) and dissociates rapidly (koff > or = 6 s-1) [van der Merwe, P. A., Brown, M. H., Davis, S. J., & Barclay, A. N. (1993) EMBO J. 12, 4945-4954]. In contrast, a study using conventional equilibrium binding methods reported a much higher affinity (Kd 0.4 microM) for human CD2 binding CD58 which suggested that the weak binding of rat CD2 to CD48 may not represent a typical CAM interaction. In the present study we have used surface plasmon resonance to obtain definitive affinity and kinetic data on the interactions of a soluble, recombinant form of human CD2 with soluble forms of CD58, CD48, and CD59. Binding of CD2 to CD58 was readily detected but we were unable to detect any direct interaction between CD2 and either CD59 or CD48 under conditions in which very low affinity interactions (Kd approximately 0.5 mM) would have been detected. In contrast to previous reports we found that human CD2 bound CD58 with a very low affinity (Kd 9-22 microM) and dissociated with an extremely fast dissociation rate constant (koff > or = 4 s-1). The association rate constant (kon) could not be measured directly but was calculated to be > or = 400,000 M-1s-1. Taken together, these results provide conclusive evidence that CAM interactions can have very low affinities and extremely fast dissociation rate constants.
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PMID:Human cell-adhesion molecule CD2 binds CD58 (LFA-3) with a very low affinity and an extremely fast dissociation rate but does not bind CD48 or CD59. 752 Feb 78

Arterial wall is the main site involved in the chronic rejection process. The rat aortic allograft model was used here to characterize and describe the sequential evolution of the different targets and effectors of arterial wall immunological injury and response during arterial allograft rejection. Rat abdominal aortae were isografted or allografted from Brown-Norway to Lewis rats. Endothelial and smooth muscle cell injury and humoral and cellular immunological effectors were characterized from 0 to 60 days after transplantation using a battery of specific antibodies. The intimal proliferative response was also characterized over this time. Isografted Brown-Norway aorta adventitia had very few cellular components, which suggests that donor adventitia would be poorly antigenic in allografts. In contrast, allograft adventitia was the site of a major inflammatory cell invasion in which the expression of an adhesion molecule by colonizing capillary endothelial cells could play a main role. This adventitial infiltration continued as long as medial smooth muscle persisted. The luminal endothelial cells disappeared early, probably associated with macrophage margination. In contrast, medial smooth muscle cell disappearance occurred later and was specifically targeted by immunoglobulins. Intimal proliferation was the most delayed phenomenon, involving both inflammatory cell infiltration at an early stage and later myofibroblastic proliferation, and could be related to the specific expression of growth factors in this layer. The rat aortic allograft model appeared useful for characterizing specific targets and effectors of chronic arterial graft rejection, demonstrating an early stage of endothelial injury and the presence of immunoglobulins involved in chronic medial smooth muscle cell injury.
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PMID:Sequential immunological targeting of chronic experimental arterial allograft. 767 87

Endothelial monolayers were prepared from neonatal heart or liver tissue of Lewis (Le) rats. Cells in their first passage of culture were used to investigate the short-term (1 hr at 37 degrees) binding of 51Cr-labelled Le rat lymphocytes prepared from the mesenteric lymph node (MLN), peripheral lymph node (PLN) or Peyer's patches (PP) to those endothelia, or the activation by concanavalin A (Con A) or irradiated (Lewis x Brown Norway)F1 (LBNF1), of Le cells on the monolayers after 84 hr in culture. MLN and PP showed preferential binding to, and activation on, liver endothelium compared with heart endothelium (approximately twofold difference), while the converse was seen with PLN. No inhibition of binding was seen with antibodies to intracellular adhesion molecule-1 (ICAM-1) or lymphocyte function-associated antigen-1 (LFA-1). Preincubation of endothelial cells with plasma isolated from the portal or hepatic vein of normal adult mice (5% plasma, 37 degrees for 14 hr) caused a 1.5-2-fold stimulation of binding of MLN/PP to heart endothelium, which was inhibited (> or = 75%) by anti-ICAM-1 or anti-LFA-1, and a fourfold stimulation of binding to liver endothelium, which was not inhibited by these monoclonal antibodies (< or = 25% inhibition). In contrast, antibodies to tumour necrosis factor-alpha (TNF-alpha) or interleukin-6 (IL-6) caused inhibition of activation of liver endothelium (> or = 75%), while producing little affect on activation of heart endothelium. Similar results were seen when lymphocyte activation on endothelial cells rather than adhesion cells was investigated. Our data suggest a heterogeneity in lymphocyte-endothelial interactions, which is further regulated, under physiological conditions, by the liver.
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PMID:Hepatic regulation of lymphocyte adhesion to, and activation on, syngeneic endothelial monolayers. 782 67

We investigated the potential role of intercellular-adhesion molecule-1 (ICAM-1) in allergen-induced bronchial hyperresponsiveness (BHR) and inflammation in sensitised Brown-Norway rats. Rats were sensitised with ovalbumin (OA) intraperitoneally and 21 days later they were either exposed to 0.9% NaCl or 1% OA aerosol for 15 min. Rats exposed to OA aerosol were pretreated either with ICAM-1 antibody (3 mg/kg i.p. and i.v., 45 min prior to OA exposure) or with the diluent for the antibody. Eighteen to twenty-four hours after OA or 0.9% NaCl exposure, rats were anaesthetised, tracheostomised and mechanically ventilated, and airway responsiveness to acetylcholine (ACh) aerosol was measured as the provocative concentration of ACh needed to increase pulmorary resistance by 100% (PC100). Mean -log PC100 was increased in rats exposed to OA but pretreated with diluent (2.75 +/- 0.06) compared to rats treated with ICAM-1 antibody (2.51 +/- 0.08; < 0.05). However, only the former group showed significantly higher mean -log PC100 compared to the sensitised group exposed to 0.9% NaCl alone (2.22 +/- 0.12; p < 0.01). There was a significant increase in eosinophil and lymphocyte counts in bronchoalveolar lavage fluid at 24 h in rats pretreated with diluent compared to saline exposed rats. However, in ICAM-1 antibody-pretreated rats, eosinophil and lymphocyte counts were significantly different from diluent-treated ones. We conclude that ICAM-1 antibody inhibits BHR without reducing the influx of inflammatory cells.
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PMID:Contribution of intercellular-adhesion molecule-1 in allergen-induced airway hyperresponsiveness and inflammation in sensitised brown-Norway rats. 791 57

Many groups have reported that preoperative injection of donor-derived whole spleen cells or major histocompatibility complex antigens prolongs organ allograft survival in experimental models, but the immunosuppressive mechanism(s) responsible remains unclear. A central, confounding issue is how to reconcile documentation of comparable levels of mRNA for IL-2 in suppressed versus control groups with obvious host hyporesponsiveness. We used a model of tolerance induction involving perioperative injection of donor spleen cells and injection of CsA at day 2 after transplant to analyze the serial expression of several proinflammatory cytokines relevant to development of alloresponsiveness within cardiac allografts and recipients' spleens. Four experimental groups of Lewis rats receiving vascularized heterotopic cardiac allografts from Brown Norway (BN) donors were evaluated: (1) untreated controls; (2) animals receiving intraoperative injection of donor BN spleen cells; (3) those receiving a single injection of CsA on day 2 post-Tx; and (4) animals given the combination of intraoperative BN spleen cells and CsA on day 2 post-Tx. Graft survival was significantly prolonged in Lewis rats receiving the combined spleen cell/CsA therapy (mean 64 days, with 40% of grafts surviving > 100 days, n = 15) compared with acute rejection at about 8 days (range 6-13, n = 20) in each of the 3 control groups (P < 0.0001). By comparison with acutely rejecting allografts in the control untreated group at day 7 post-Tx, allografts in rats receiving the combined perioperative spleen cell/CsA treatment showed (1) significantly reduced graft cellularity and interstitial edema; (2) significantly decreased features of immune activation, including infiltration by mononuclear cells expressing IL-2R or proliferating cell nuclear antigen; (3) decreased intragraft expression of the cytokines IL-2 and IFN-gamma; and (4) suppression of endothelial activation as evidenced by both failure of up-regulation of intracellular adhesion molecule-1 and maintenance of thrombomodulin expression by graft endothelium. Analysis of sections of recipients' spleens showed that spleen cell/CsA therapy led to significant reductions versus untreated controls, in expression of IL-2, IFN-gamma, and IL-2R. Similarly, mixed lymphocyte response cultures showed that responder cells from rats receiving combined therapy proliferated by 93-95% less than untreated animals. Our results suggest that the efficacy of this clinically relevant protocol is associated with suppression of IL-2 or IFN-gamma protein production, and that in the absence of such molecules, it appears that T cell-receptor occupancy by alloantigens readily induces a state of anergy in vivo.
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PMID:Mechanism of a clinically relevant protocol to induce tolerance of cardiac allografts. Perioperative donor spleen cells plus cyclosporine suppress IL-2 and interferon-gamma production. 827 94

We used flow cytometry and treatment in vivo with a monoclonal antibody (mAb), TA-2, to the alpha 4 integrin to investigate the role of alpha 4 beta 1, CD49d/CD29 (VLA-4) in antigen-induced lung inflammation in Brown Norway (BN) rats. Ovalbumin (OVA) inhalation induced an accumulation of eosinophils and lymphocytes in the lungs and bronchoalveolar lavage (BAL) fluid of sensitized BN rats at 24 h after challenge. Phenotypic analyses demonstrated that the percentages of T cells expressing detectable alpha 4 and CD25 in the bronchial lumen after antigen challenge were dramatically increased compared with blood and lymph node T cells. The mean channel fluorescence values of alpha 4 expression were also increased on BAL T cells compared with blood or lymph node T cells. Treatment of OVA-sensitized rats in vivo with total cumulative doses of 0.75 to 6 mg/kg TA-2 mAb intraperitoneally produced dose-related increases in circulating TA-2 and a peripheral blood lymphocytosis, basophilia, and eosinophilia. Flow cytometric analysis of the peripheral blood T cells after in vivo TA-2 mAb administration showed decreases in detectable alpha 4 when these cells were examined ex vivo. Treatment with TA-2, but not an isotype-matched control mouse immunoglobulin G1 mAb, markedly inhibited the OVA-induced recruitment of lymphocytes and eosinophils into the airway lumen. Very few CD3+CD49d+ cells migrated into BAL fluid following anti-alpha 4 mAb treatment in vivo. Treatment with TA-2 also significantly attenuated OVA-induced inflammatory histopathology. We conclude that VLA-4 is a critically important adhesion molecule involved in antigen-specific lung inflammation in sensitized BN rats.
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PMID:Role of very late activation antigen-4 in the antigen-induced accumulation of eosinophils and lymphocytes in the lungs and airway lumen of sensitized brown Norway rats. 870 73

Clinical and experimental studies indicate that nonimmunologic factors may modulate the alloreactivity of a renal transplant. Nitric oxide (NO) is an essential modulator of endothelial function. It was postulated that, in renal allografts, inhibition of constitutive NO synthase may lead to an aggravation of immunologic damage to endothelia and therefore may enhance dysfunction of the graft. Male Lewis (RT1l) rats received syngeneic or allogeneic Brown Norway (RT1n) renal grafts and were treated with cyclosporin A (CyA) or with CyA and an NO synthase blocker (NOS-B): N omega-nitro-L-arginine (L-NNA) or NG-monomethyl-L-arginine (L-NMMA). CyA was given at a dose of 3.5 mg/kg body weight for 14 days and the NOS-B at a dose of 66 mg/L drinking water for up to 28 days postoperatively. Animals (N = 6/group) were studied at 4 to 7, 14, and 28 days posttransplantation. Four to 5 days posttransplantation, renal blood flow and glomerular filtration rate of allogeneic grafts did not differ between animals treated only with CyA and those treated with CyA and NOS-B. Mean arterial pressure was significantly elevated by NOS-B (CyA+L-NNA: 115 +/- 13 versus CyA: 78 +/- 16 mm Hg). Combined NOS-B and CyA administration led to a pronounced increase in vascular and tubulointerstitial damage. The number of mononuclear cells in vessels, glomeruli, and tubulointerstitium increased significantly in allografts upon treatment with NOS-B. During NOS-B administration, adhesion molecules (intracellular adhesion molecule-1; leukocyte-function-associated molecules-1 alpha and-beta) were strongly expressed in endothelial and leukocytic cells of the allograft. A pronounced positivity for mRNA and protein of cytokines tumor necrosis factor-alpha and transforming growth factor-beta could be demonstrated in the inflammatory infiltrate. With L-NNA treatment, the total vascular injury index was 10-fold higher (14 days posttransplantation, CyA+L-NNA: 59.8 +/- 11.7 versus CyA: 6.0 +/- 1.8; p < 0.05). The tubulointerstitial damage score rose more than 2.5-fold after CyA and L-NNA therapy (28 days posttransplantation: CyA+L-NNA: 83 +/- 1 versus CyA:29 +/- 1). L-NNA was more potent than L-NMMA at the dosages used. Thus, pronounced vascular leukostasis, vasculitis, and T-cell and monocyte infiltration of the tubulointerstitium led to a severe damage of the allograft under therapy with CyA and NOS-B. Inhibition of NO synthesis may aggravate alloreactive immunemediated injury in kidney transplants acting primarily by a disturbance of endothelial function.
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PMID:Enhanced renal allograft rejection by inhibitors of nitric oxide synthase: a nonimmunologic influence on alloreactivity. 878 Jan 67

Tumor necrosis factor-alpha (TNF) is a multifunctional cytokine evoked in response to alloantigen stimulation and may be involved in lymphocyte activation, adhesion molecule expression, and regulation of MHC class II antigens. Anti-TNF treatment prolongs cardiac allograft survival. We investigated the role of anti-TNF in the regulation of MHC class II antigens and cytokine mRNA expression of TNF, interferon-gamma (IFN), IL-2, IL-4, and IL-10 in cardiac allografts to elucidate its immunological mechanism. These in vivo studies were conducted using a rat MHC mismatch Brown-Norway to Lewis (BN to LEW) heterotopic cardiac transplant model. In control untreated rats, allografts were rejected at 6.8 +/- 0.6 days. Allograft survival was significantly prolonged to 12.7 +/- 1.4 days with anti-TNF treatment. MHC class II expression, analyzed by indirect immunofluorescence cytometry, demonstrated that MHC class II-positive cells increased by 25% in spleens of untreated allografted rats compared to naive rats, while anti-TNF-treated allografted rats had a similar percentage of MHC II cells as naives. Further, naive, untransplanted rats and both anti-TNF and untreated, transplanted rats had heart and spleens harvested on Day 5 post-transplant. Cytokine mRNA expression was determined by semiquantitative RT-PCR. In heart and spleen cells from naives, TNF mRNA expression was undetectable or very weak. However, in rejecting allografts and spleen cells from untreated recipients, TNF expression was remarkably increased, while anti-TNF attenuated this TNF expression in both heart graft and spleen cells. Furthermore, IL-2, IL-10, and IFN expression were absent in naive hearts. However, in untreated allografts IL-2, IL-10, and IFN were strongly expressed, which was markedly decreased after anti-TNF treatment. Finally, IL-4 expression was found equally in naive hearts, untreated allografts, and anti-TNF-treated allografts. These results suggest that anti-TNF antibody treatment may not only neutralize TNF activity but also play a role in altering cytokine mRNA expression and MHC class II expression.
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PMID:Anti-TNF antibody modulates cytokine and MHC expression in cardiac allografts. 992 30

Mercuric-chloride (HgCl2) induces a lymphoproliferative disorder and autoimmune glomerulonephritis in Brown Norway rats. The effects of a new immunosuppressant FK 506 on this model of glomerulonephritis were studied. Brown Norway rats were treated with HgCl2 according to a standard protocol (HgCl2 1 mg/kg s.c. 3 times/ week). Rats developed proteinuria at day 7, which reached a plateau level at day 14. On day 14, renal histology showed prominent mesangial cellular proliferation and the expansion of mesangial matrix. Electron microscopic study showed the effacement of visceral epithelial foot processes and the microvillous transformation of the visceral epithelium. Immunofluorescence study showed a strong linear staining for IgG and the adhesion molecule ICAM-1 in all glomeruli. Coadministration of FK 506 (1 mg/kg s.c. daily) prevented the appearance of proteinuria at day 14 (621.4 +/- 30.5 vs. 2.2 +/- 2.7 mg/day) and the morphological lesions. These findings suggest that FK 506 could be useful for the therapy of certain types of human glomerulonephritis.
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PMID:Effect of a novel immunosuppressant, FK 506, on autoimmune glomerulonephritis in Brown Norway rats. 993 58

Mercuric chloride (HgCl2) induces a lymphoproliferative disorder and autoimmune glomerulonephritis in Brown Norway (BN) rats. The effects of a new immunosuppressant, FK 506, on this model of glomerulonephritis were studied. BN rats were treated with HgCl2 according to a standard protocol (HgCl2 1 mg/kg s.c. 3 times/week). FK 506 was inoculated subcutaneously daily from day 15 to day 28. Animals were divided into 4 groups: group 1, rats were treated with normal saline alone and sacrificed on day 28; group 2, rats were treated with HgCl2 alone and sacrificed on day 14; group 3, rats were treated with HgCl2 alone and sacrificed on day 28, and group 4, rats were treated with HgCl2 and FK 506 (from day 15 to day 28) and sacrificed on day 28. Rats developed proteinuria by day 7, which reached a plateau level by day 14. On day 14, renal histology showed prominent mesangial cellular proliferation and the expansion of mesangial matrix. Electron microscopic study showed the effacement of visceral epithelial foot processes and the microvillous transformation of the visceral epithelium. Immunofluorescence study showed strong linear staining for IgG and the adhesion molecule ICAM-1 in all glomeruli. Treatment with FK 506 (1 mg/kg s.c. daily) resulted in a remarkable reduction in proteinuria on day 28 (493.5 +/- 48.3 vs. 24.4 +/- 13.5 mg/day) and an improvement in the morphological lesions. These findings suggest that FK 506 could be useful in the treatment of some human glomerulonephritides.
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PMID:Effect of FK 506 in the treatment of autoimmune glomerulonephritis in Brown Norway rats. 1009 78


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