A dimeric crystal structure for the N-terminal two domains of intercellular adhesion molecule-1

The 3.0-A structure of a 190-residue fragment of intercellular adhesion molecule-1 (ICAM-1, CD54) reveals two tandem Ig-superfamily (IgSF) domains. Each of two independent molecules dimerizes identically with a symmetry-related molecule over a hydrophobic interface on the BED sheet of domain 1, in agreement with dimerization of ICAM-1 on the cell surface. The residues that bind to the integrin LFA-1 are well oriented for bivalent binding in the dimer, with the critical Glu-34 residues pointing away from each other on the periphery. Residues that bind to rhinovirus are in the flexible BC and FG loops at the tip of domain 1, and these and the upper half of domain 1 are well exposed in the dimer for docking to virus. By contrast, a residue important for binding to Plasmodium falciparum-infected erythrocytes is in the dimer interface. The presence of A' strands in both domains 1 and 2, conserved hydrogen bonds at domain junctions, and elaborate hydrogen bond networks around the key integrin binding residues in domain 1 make these domains suited to resist tensile forces during adhesive interactions. A subdivision of the intermediate (I) set of IgSF domains is proposed in which domain 1 of ICAM-1 and previously described I set domains belong to the I1 set and domain 2 of ICAM-1, ICAM-2, and vascular cell adhesion molecule-1 belong to the I2 set.     

Immunosuppression by inhibition of cellular adhesion mediated by leukocyte function-associated antigen-1/intercellular adhesion molecule-1 in murine cardiac transplantation

BACKGROUND: Donor alloantigen-specific tolerance to vascularized allografts can be induced by several treatments, but the immunological mechanism(s) of these effects remain unclear. One hypothesis is that allograft unresponsiveness is correlated with a shift in the pattern of expression of the T helper 1 versus T helper 2 T-cell cytokines. We report here an extensive analysis of murine cardiac allografts, during normal first set rejection and in mice treated with anti-adhesion molecule monoclonal antibodies (mAbs), a regimen that results in prolonged unresponsiveness. METHODS: A combination of immunohistochemical staining with a panel of mAbs, and in situ hybridization with a panel of digoxigenin-labeled riboprobes, was performed on frozen-tissue sections of cardiac allografts. RESULTS: In several strain combinations, injection of anti-leukocyte function-associated antigen-1 and anti-intercellular adhesion molecule-1, from day 0 to day 6 after transplantation, results in significant long-term survival. Examination of tolerated cardiac allografts by in situ hybridization and immunohistochemical staining shows an altered cytokine expression pattern, although the frequency of CD3 and CD4 cells is not dramatically reduced. These allografts show a decreased frequency of interferon-gamma and interleukin (IL)-2-expressing cells and a slightly increased frequency of cells expressing IL-4 and IL-10, compared with unmodified acute rejection. A direct role of these changes in T-cell cytokine expression is demonstrated by reversal of tolerance induction and rejection of the allograft by in vivo injection of either anti-IL-10 or anti-IL-4 mAb. CONCLUSIONS: Although there are significant differences in the frequency of different cellular subsets and patterns of cytokine gene expression, these differences are quantitatively subtle, suggesting a delicately balanced immune response that can develop a pattern of specific unresponsiveness, with relatively minor alterations in the specific T-cell response.     

淋巴细胞功能相关抗原-1/细胞间黏附分子-1介导的细胞因子诱导的杀伤细胞体外抑瘤机制

目的 探讨淋巴细胞功能相关抗原-1(LFA-1)/细胞间黏附分子-1(ICAM-1)介导的细胞因子诱导杀伤细胞(CIK)的体外抑瘤机制.方法 从白血病患儿外周血分离淋巴细胞,经过干扰素-γ(IFN-γ)、抗CD3单克隆抗体(CD3McAb)、白细胞介素-2(IL-2)诱导并与树突状细胞(DC)共培养,获得大量的DC-CIK.在经10、20μg/ml等不同质量浓度小鼠抗人LFA-1单克隆抗体处理后,采用MTT法研究DC-CIK细胞对多种白血病细胞株的杀伤活性,RT-PCR与Western blotting方法检测GATA-3和T-bet基因表达水平的变化.ELISA方法测定DC-CIK细胞释放细胞因子IL-12、IFN-γ、肿瘤坏死因子-α(TNF-α)的表达水平.结果 诱导后的DC-CIK细胞形态规则,经不同浓度的LFA-1单克隆抗体处理后,MTT结果:20μg/ml LFA-1单克隆抗体封闭组DC-CIK细胞对B95细胞杀伤作用下降最为明显(t=10.138,P＜0.05);RT-PCR与Western blotting结果:20μg/ml LFA-1单克隆抗体封闭的B95细胞组,GATA-3基因mRNA水平和蛋白水平表达增加最为明显(t=16.386,P＜0.05;t=22.652,P＜0.05);同时T-bet基因mRNA水平和蛋白水平表达降低最为明显(t=17.728,P＜0.05;t=17.452,P＜0.05);ELISA结果:20μg/ml LFA-1单克隆抗体封闭的B95细胞组中细胞因子IL-12、IFN-γ、TNF-α分泌水平下降最为明显(t=21.621,P＜0.05;t=13.739,P＜0.05;t=15.278,P＜0.05).结论 GATA-3和T-bet基因参与了LFA-1/ICAM-1介导的DC-CIK抑瘤途径,并且通过分泌Th1型细胞因子IL-12、IFN-γ、TNF-α等发挥抑瘤作用.     

Expression of intercellular adhesion molecule-1 in mice with Pseudomonas-induced pyelonephritis

PURPOSE: To investigate the role of intercellular adhesion molecule-1 (ICAM-1) in the renal inflammatory process, we studied the time-course fluctuation of ICAM-1 expression on inflammatory lesions in mice with experimentally induced bacterial pyelonephritis and the effect of in vivo administration of an anti-ICAM-1 monoclonal antibody (mAb) on leukocytic migration. MATERIALS AND METHODS: Ascending pyelonephritis was induced by transurethral instillation of Pseudomonas aeruginosa, and the expression of ICAM-1 in the pyelonephritic lesions was studied by immunohistochemical methods. RESULTS: The expression of ICAM-1 on the pyelonephritic lesions closely paralleled the degree of infiltration of neutrophils and macrophages until 3 days after infection. At 7 days after infection, though the degree of infiltration of these cells was quite high, expression of ICAM-1 was reduced. Treatment with the anti-ICAM-1 mAb in mice with bacterial pyelonephritis resulted in suppression of influx of neutrophils and macrophages in the infected sites until 3 days after infection. However, at 7 days after infection inhibition of the influx of these cells was not seen. CONCLUSIONS: These results suggest that ICAM-1 expression is transient and plays a key role in the influx of neutrophils and macrophages associated with the early-phase response, and that in the late phase ICAM-1 independent adhesion molecules may be more predominant.     

Rickettsia conorii infection enhances vascular cell adhesion molecule-1- and intercellular adhesion molecule-1-dependent mononuclear cell adherence to endothelial cells

Leukocyte adherence to the endothelium is an essential component of the inflammatory response during rickettsial infection. In vitro, Rickettsia conorii infection of endothelial cells enhances the expression of adhesive molecules E-selectin, intercellular adhesion molecule-1 (ICAM-1), and vascular cell adhesion molecule-1 (VCAM-1) in a time- and dose-dependent manner. Rickettsial lipopolysaccharide does not seem to be involved, because polymyxin B does not reduce their expression. The intracellular presence of the organism and de novo host protein synthesis are required for expression of cell adhesive molecules, since rickettsial inactivation by formol and pretreatment of cells with cycloheximide inhibits an increase in expression. The contribution of interleukin-1alpha (IL-1alpha) to this endothelial adhesive phenotype was shown by inhibitory experiments 8 and 24 h after infection with IL-1 receptor antagonist and IL-1alpha blocking antibodies. Enhanced adherence of mononuclear cells to infected endothelial cells involved VCAM-1- and ICAM-1-dependent mechanisms at the late phase of the inflammatory response. This endothelial adhesive phenotype may constitute a key pathophysiologic mechanism in R. conorii-induced vascular injury.     

Expression of membrane and soluble intercellular adhesion molecule-1 in Graves'' disease

Understanding the epidemiology of equine colic is directly relevant to the management of individual horses with colic. In this article, the epidemiology of colic is reviewed with emphasis on epidemiologic studies that have identified specific factors associated with increased risk of colic and epidemiologic studies that are designed to predict the need for surgery and prognosis in horses with colic. Despite the magnitude of the problem of equine colic, much remains to be learned about the epidemiology of this disease.     

Reduced susceptibility to collagen-induced arthritis in mice deficient in intercellular adhesion molecule-1

Intercellular adhesion molecule-1 (ICAM-1) plays an important role in the firm adhesion of leukocytes to venular endothelium and facilitates leukocyte extravasation from the vasculature into inflamed tissue. In addition, ICAM-1 is an important costimulatory molecule during Ag presentation to lymphocytes. Using mice deficient in ICAM-1, we have investigated the role of this molecule in the development of collagen-induced arthritis. After immunization with type II collagen, 71% of wild-type mice developed arthritis compared with 50% of ICAM-1 heterozygote mutants and 18% of ICAM-1 homozygous mutants. In those ICAM-1 mutants that developed arthritis, the mean day of onset, the mean number of involved paws, and the severity of paw inflammation were not significantly different from those in wild-type mice. The reduced incidence of arthritis in the ICAM-1 homozygous mutant mice was not due to lack of immunity to type II collagen, since these mice developed similar levels of anti-type II collagen IgG compared with wild-type mice and had a positive delayed-type hypersensitivity reaction to type II collagen. The reduction of arthritis in heterozygous as well as homozygous deficient mice indicates that expression of ICAM-1 can be a pivotal variable in the pathogenesis of collagen-induced arthritis in mice. The results suggest that naturally occurring genetic variation in the expression of ICAM-1 or related inflammatory cell adhesion molecules might influence susceptibility to the complex disease of rheumatoid arthritis in humans and support the concept that pharmacologic approaches to chronic reduction in the expression or the function of ICAM-1 may be of therapeutic value.     

新生儿败血症血清降钙素原和可溶性细胞间黏附分子-1的变化

目的 观察新生儿败血症患儿血清降钙素原(PCT)和可溶性细胞间黏附分子-1(sICAM-1)的变化.方法 新生儿败血症患儿56例,其中30例患儿血培养阳性(病原确诊组),26例血培养阴性(临床诊断组),取同期出生的新生儿25名作为对照组,分别应用化学发光法和酶联免疫吸附法测定患儿血清PCT和sICAM-1水平,同时进行新生儿危重评分.结果 败血症组血清sICAM-1和PCT明显高于对照组,且病原确诊组的血清PCT和sICAM-1水平又明显高于临床诊断组,差异均有统计学意义(P＜0.01).血清sICAM-1和PCT水平与新生儿危重评分呈负相关(γ=-0.778,P＜0.01;γ=-0.851,P＜0.01).结论 PCT和sICAM-1可作为新生儿败血症早期诊断的敏感指标.     

Circulating soluble adhesion molecules E-cadherin, E-selectin, intercellular adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1) in patients with gastric cancer

The concentrations of the soluble adhesion molecules E-cadherin, E-selectin, intercellular adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1) were investigated in 45 patients with gastric cancer before treatment and their correlation with clinical, histological and routine laboratory parameters was examined. Data were collected on tumour stage at presentation, presence and sites of metastatic disease, tumour pathology, survival and results of routine laboratory tests. Serum concentrations of ICAM-1 and VCAM-1 were significantly elevated in the patients with gastric cancer in comparison with the group of healthy subjects (P < 0.00001 and P < 0.0001 respectively). Increased serum concentrations of VCAM-1 were associated with locally advanced and metastatic disease whereas ICAM-1 was significantly elevated both in local and in advanced/metastatic disease. Soluble E-cadherin and E-selectin concentrations did not show any significant elevation in gastric cancer patients. Concentrations of soluble adhesion molecules showed significant correlation with each other (except E-selectin and VCAM-1) and with alkaline phosphatase. Soluble ICAM-1 and VCAM-1 were significantly associated with an elevated total white cell count. Patients with elevated VCAM-1 had significantly poorer survival in comparison with patients with normal serum levels (P = 0.0361).     

In vitro intercellular adhesion molecule-1 expression on brain endothelial cells in multiple sclerosis

To investigate the origin of intercellular adhesion molecule-1 (ICAM-1) and its expression on brain endothelial cells, we studied the expression in vitro of ICAM-1 on human brain endothelial cells after incubation of T cells from patients with multiple sclerosis (MS) using a histochemical technique and flow cytometry. We determined soluble forms of ICAM-1 (ICAM-1) in the supernatants after mixtures of brain endothelial cells and T cells from patients with MS using an enzyme-liked immunosorbent assay. Flow cytometric analysis showed that a number of ICAM-1-positive cells were significantly increased after incubation of brain endothelial cells with T cells from patients with acute relapsing MS during an exacerbation as compared with those of controls (P < 0.01). Patients with acute relapsing MS during an exacerbation and chronic progressive MS exhibited higher levels of ICAM-1 in the supernatants of mixtures with brain endothelial cells and lymphocytes than those of controls (P < 0.001 and P < 0.01, respectively). These results suggest that lymphocytes from patients with acute relapsing MS during an exacerbation lead to an increased expression of ICAM-1 on the brain endothelial cells and add to evidence involving this adhesion molecule in the pathogenesis of MS.     

Soluble intercellular adhesion molecule-1 in patients with lung cancer and benign lung diseases

Intercellular adhesion molecule-1 (ICAM-1) expression correlates with tumour progression in patients with malignant melanoma or renal cell carcinoma. To assess the value of soluble ICAM-1 (sICAM-1) for lung cancer patients, sICAM-1 was determined by means of an enzyme-linked immunosorbent assay. Sera from 147 patients with lung cancer, from 75 patients with benign lung diseases and from 108 healthy adults were investigated for sICAM-1 expression. Significant differences in sICAM-1 levels were detected in lung cancer patients (387 +/- 176 ng/ml) and patients with benign lung diseases (365 +/- 110 ng/ml) compared to the group of healthy adults (310 +/- 90 ng/ml). There was no difference in sICAM-1 level among the subtypes of lung cancer. Advanced tumour stages and patients with progressive disease tended to be associated with higher sICAM-1 levels, the site of metastasis being relevant for the level attained. Patients with liver metastasis had the highest sICAM-1 levels (547 +/- 295 ng/ml) compared to patients with cerebral metastasis (317.8 +/- 92.2 ng/ml). An increase of sICAM-1 expression during the progression of the disease coincided with a poorer survival prognosis for the patients compared to patients with stable or falling sICAM-1 levels.     

Soluble forms of intercellular adhesion molecule-1 inhibit insulitis and onset of autoimmune diabetes

Increased concentration of circulating adhesion molecules in human serum have been described in different immune-mediated diseases. Recently, we proposed an immunomodulatory function of soluble forms of the intercellular adhesion molecule-1 (ICAM-1) during the pathogenesis of human Type I (insulin-dependent) diabetes mellitus. To test this hypothesis in nonobese diabetic (NOD) mice, a spontaneous animal model for human Type I diabetes, two recombinant forms of soluble murine ICAM-1 were generated, one monomeric soluble ICAM-1 containing all five extracellular Ig-like domains of ICAM-1 (rICAM-1) and one dimeric protein with the N-terminal extracellular domains fused to the constant regions of murine IgG2a (rICAM-1-Ig). Beginning at age 35 days prediabetic NOD mice received i. p. injections of 5 microg recombinant ICAM-1-proteins three times a week for 4.5 months. At day 170 diabetes development was reduced (p < 0.001) in NOD mice receiving rICAM-1 (8%) or rICAM-1-Ig (8%) treatment in comparison with sham treated animals (45%). After termination of therapy animals treated with multimeric rICAM-1-Ig were protected longer than animals treated with rICAM-1. Prevention of diabetes was associated with decreased infiltration of pancreatic islets by mononuclear cells. A selective downregulation of Th1-type cytokine expression was observed in a second set of experiments in which diabetes development was synchronised by cyclophosphamide. These data support the hypothesis that circulating forms of adhesion molecules have an immunomodulatory function and can intervene in islet inflammation.     

Soluble intercellular adhesion molecule-1 level in sera is elevated in perennial allergic rhinitis

Soluble intercellular adhesion molecule-1 (sICAM-1) in sera was measured in some allergic disorders, but serum sICAM-1 levels in perennial allergic rhinitis remain to be determined. Our study was aimed at elucidating whether the serum sICAM-1 levels in patients with perennial allergic rhinitis are different from those in nonatopic healthy volunteers and whether immunotherapy can modulate sICAM-1 levels. Serum sICAM-1 was determined in 20 nonallergic volunteers and 137 patients with perennial allergic rhinitis by a sandwich enzyme-linked immunosorbent assay. Our study demonstrated that the level of sICAM-1 in untreated patients is significantly elevated, as compared with nonatopic subjects. Immunotherapy could decrease sICAM-1 in perennial allergic rhinitis, but this suppressive effect became apparent only after many years of immunotherapy. In patients on immunotherapy, a close correlation was observed between sICAM-1 and nasal symptom scores. To take these lines of evidence together, a decrease in sICAM-1 might be related to the working mechanism of immunotherapy, and serum sICAM-1 could be used to monitor the effect of immunotherapy.