UMLS:C0001511 - FACTA Search

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Query: UMLS:C0001511 (Adhesion)
5,955 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

In order to analyze the onset mechanism of experimental autoimmune uveoretinitis (EAU), two experimental models were used; one was EAU induced by one injection of purified bovine interphotoreceptor retinoid-binding protein (IRBP) with complete Freund's adjuvant in Lewis rat, and the other was an IRBP-induced autoimmune uveoretinitis that occurred spontaneously in nude (nu/nu) mice at 4 weeks of age reconstituted by the grafting of rat embryonic thymus (TG nude mouse). EAU develops when the IRBP-reactive lymphocytes in the regional lymph-nodes are activated. Activation begins when the T lymphocyte recognizes the peptide for the epitope bound to a major histocompatibility complex (MHC) molecule in the antigen-presenting cell by way of the T-cell receptor (TCR). In EAU, ten peptide residues p1182-1191 of the IRBP amino acid sequence, were revealed to be sufficiently capable of lymphocyte activation for EAU, and it was also shown that amino acid positions 1182W (tryptophane), 1185G (glycine), 1186V (valine) and 1188P (proline) of IRBP play important roles as the epitopes or agretopes in developing EAU. On the other hand, two amino acids of IRBP, amino acid positions 1182W (tryptophane) and 1194P (proline) were shown to be the agretopes inducing autoimmune uveoretinitis in the TG nude mouse. A study of the variable region of the TCR with a residual p1182-1194 specific T-cell line from the TG nude mouse revealed that as many as 96% utilized the T-cell receptor V beta 6 gene and that the peptide-MHC molecule complex was recognized by restricted receptors. Adhesion molecules such as ICAM-1 and LFA-1 were also found to play an important role as cofactors in activation of lymphocytes in the antigen-recognition process of EAU. Uveoretinitis seemed to result from an immune reaction in the eye occurring when the T lymphocyte arrives there, activating the immunological process. ICAM-1 and LFA-1 were also found to be involved in the infiltration process of inflammatory cells: our immunohistological examination revealed that ICAM-1 was present in the retinal pigment epithelium and epithelium of the ciliary body composing the blood-ocular barrier. In contrast, LFA-1 was expressed in the infiltrating cells. Finally, the tolerance of IRBP was discussed and it was experimentally demonstrated that the absence of IRBP-induced uveoretinitis in human beings and certain experimental animals resulted from endogenous IRBP serving as a tolerogen; we assumed that the breakdown of this self-tolerance would induce EAU due to thymic dysfunction or IRBP antigen injection.
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PMID:[The onset mechanism of experimental autoimmune uveoretinitis induced by interphotoreceptor retinoid-binding protein]. 128 51

We have studied the role of major histocompatibility complex (MHC) molecules in the regulation of intercellular adhesion of human B cells. We found that molecules able to bind to MHC class II molecules, such as monoclonal antibodies or staphylococcal enterotoxins, induced rapid and sustained homotypic adhesion of Epstein-Barr virus (EBV)-transformed B cell lines as well as peripheral blood B lymphocytes. Moreover, anti-MHC class I monoclonal antibodies also stimulated intercellular adherence. Adhesion induced upon MHC engagement was faster and stronger than that triggered by phorbol esters. It needed active metabolism, but divalent cations were not required. Monoclonal antibodies directed against LFA-1 (CD11a/CD18) or its ligand ICAM-1 (CD54) did not inhibit MHC class II-induced homotypic adhesion of various EBV-transformed B cell lines, nor of a variant of the B cell line Raji expressing very low LFA-1 surface levels. Moreover, EBV-transformed B cells from a severe lymphocyte adhesion deficiency patient, lacking surface CD11/CD18, also aggregated in response to anti-MHC class I or class II monoclonal antibodies. Together these data indicate that engagement of MHC molecules may transduce signals to B cells resulting in up-regulation of intercellular adhesion, via an LFA-1-independent mechanism. This may play a role in the stabilization of T cell/antigen-presenting cell conjugates at the moment of antigen recognition.
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PMID:Engagement of major histocompatibility complex class I and class II molecules up-regulates intercellular adhesion of human B cells via a CD11/CD18-independent mechanism. 134 12

Intercellular adhesion molecule-1 (ICAM-1) is a cell surface adhesion glycoprotein that mediates leukocyte adhesion through interaction with the leukocyte CD11/CD18 adhesion complex. The aim of this study was to determine whether ICAM-1 is expressed by normal or neoplastic colonic epithelial cells. Immunohistochemical studies on human colonic tissue demonstrated focal ICAM-1 expression by colonic carcinomas but not by normal colonic epithelium. ICAM-1 expression by colonic carcinomas showed a positive correlation with the presence of a peritumoral inflammatory infiltrate. Surface expression of ICAM-1 was also observed in HT-29 cultured human colon cancer cells by both immunohistochemistry and enzyme immunoassay. Interferon-gamma and interleukin-1 beta significantly increased ICAM-1 surface expression by HT-29 cells in a dose-dependent manner. Upregulation of ICAM-1 surface expression became evident some hours after cytokine stimulation and was inhibited by both actinomycin D and cycloheximide, indicating a requirement for de novo RNA and protein synthesis. HT-29 monolayers supported adhesion of human lymphocytes as determined by a quantitative 111In-labeled leukocyte adhesion assay. Adhesion was mediated in part via interaction of ICAM-1 on HT-29 cells with lymphocyte function-associated antigen-1 (CD11a/CD18) on lymphocytes, as defined by using blocking monoclonal antibodies. Expression of ICAM-1 and/or other leukocyte adhesion receptors by neoplastic epithelial cells may play a role in directing leukocyte trafficking and leukocyte-epithelial cell interactions in colonic carcinoma.
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PMID:Human colon cancer cells express ICAM-1 in vivo and support LFA-1-dependent lymphocyte adhesion in vitro. 136 41

Certain stages of the immune response require interaction of leukocytes with each other and with non-hematopoietic cells. One of the systems implicated in these interactions involves an integrin, LFA-1 (Lymphocyte Function Antigen-1), expressed by all leukocytes at their cell surface, and a molecule belonging to the immunoglobulin superfamily, ICAM-1 (Intercellular Adhesion Molecule-1). The avidity of LFA-1 for ICAM-1 is transient. It is modulated both by regulation of ICAM-1 expression and by activation of LFA-1 molecules constitutively expressed on leukocyte membranes. This activation, which induces a conformational change in the molecule, depends on the presence of divalent cations, notably Mg++. This has been demonstrated by using a specific monoclonal antibody, MAb 24. In addition to being a ligand for LFA-1, ICAM-1 is sometimes used as a cell receptor by pathogens such as Plasmodium falciparum, the causative organism of malaria. Very careful study of the binding site of this pathogen using specific antibodies, mutagenesis studies and the construction of a three-dimensional model of the molecule suggests some interesting therapeutic possibilities for the treatment of malaria.
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PMID:Leukocyte integrin activation. 136 59

CD54/Intercellular Adhesion Molecule-1 (ICAM-1) is a cell adhesion molecule largely distributed among normal and neoplastic tissues. Through the binding to its ligand(s) CD54 plays a key role in cell to cell interactions leading to the immune response. Recently, CD54 expression has been investigated on hematopoietic cells: the antigen is predominantly expressed in the early stages of normal hematopoiesis and during the activation of blood cells. As regards to hematological malignancies, CD54 is strongly expressed on neoplastic cells from "stem cell derived" neoplasms. In AML, CD54 expression is related with other differentiation-linked molecules such as CD34 and HLA-DR and is significantly correlated with FAB morphological classification. In lymphoproliferative disorders, a high CD54 expression is associated with germinal centre lymphomas. This review summarizes our current understanding of CD54 with emphasis on recent advances and reference to unresolved issues such as its prognostic role in the clinical outcome of oncohematological diseases.
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PMID:Expression and functional role of CD54/Intercellular Adhesion Molecule-1 (ICAM-1) on human blood cells. 136 19

Patients with the leukocyte adhesion deficiency (LAD) syndrome have a genetic defect in the common beta 2-chain (CD18) of the leukocyte integrins. This defect can result in the absence of cell surface expression of all three members of the leukocyte integrins. We investigated the capacity of T cell clones obtained from the blood of an LAD patient and of normal T cell clones to adhere to human umbilical vein endothelial cells (EC). Adhesion of the number of LAD T cells to unstimulated EC was approximately half of that of leukocyte function-associated antigen (LFA)-1+ T cells. Stimulation of EC with human rTNF-alpha resulted in an average 2- and 2.5-fold increase in adhesion of LFA-1+ and LFA-1- cells, respectively. This effect was maximal after 24 h and lasted for 48 to 72 h. The involvement of surface structures known to participate in cell adhesion (integrins, CD44) was tested by blocking studies with mAb directed against these structures. Adhesion of LFA-1+ T cells to unstimulated EC was inhibited (average inhibition of 58%) with mAb to CD11a or CD18. Considerably less inhibition of adhesion occurred with mAb to CD11a or CD18 (average inhibition, 20%) when LFA-1+ T cells were incubated with rTNF-alpha-stimulated EC. The adhesion of LFA-1- T cells to EC stimulated with rTNF-alpha, but not to unstimulated EC, was inhibited (average inhibition, 56%) by incubation with a mAb directed to very late antigen (VLA)-4 (CDw49d). In contrast to LAD T cell clones and the LFA-1+ T cell line Jurkat, mAb to VLA-4 did not inhibit adhesion of normal LFA-1+ T cell clones to EC, whether or not the EC had been stimulated with rTNF-alpha. We conclude that the adhesion molecule pair LFA-1/intercellular adhesion molecule (ICAM)-1 plays a major role in the adhesion of LFA-1+ T cell clones derived from normal individuals to unstimulated EC. Adhesion of LFA-1-T cells to TNF-alpha-stimulated EC is mediated by VLA-4/vascular cell adhesion molecule (VCAM)-1 interactions. Since we were unable to reduce significantly the adhesion of cultured normal LFA-1+ T cells to 24 h with TNF-alpha-stimulated endothelium with antibodies that block LFA-1/ICAM-1 or VLA-4/VCAM-1 interactions, and lectin adhesion molecule-1 and endothelial leukocyte adhesion molecule-1 appeared not to be implicated, other as yet undefined cell surface structures are likely to participate in T cell/EC interactions.
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PMID:Role of LFA-1 and VLA-4 in the adhesion of cloned normal and LFA-1 (CD11/CD18)-deficient T cells to cultured endothelial cells. Indication for a new adhesion pathway. 137 Nov 31

The adhesion of circulating leukocytes to the vascular endothelium is essential for effective host inflammatory and immune responses. Adhesion proteins expressed by both the leukocyte and endothelial cell have been well characterized, and studies of these molecules have shown that both cell types are actively involved in regulating these binding events. Most leukocyte (leukocyte integrins) and endothelial cell (vascular selectins, ICAM-1, and VCAM) adhesion proteins increase in expression and function in response to mediators released by inflamed tissues. In contrast, the expression and function of one type of leukocyte molecule, L-selectin (previously called LECAM-1, LAM-1, gp90MEL-14), is "down-regulated" by inflammatory signals. The purpose of this review is to summarize in vitro and in vivo regulatory and functional studies of some of the molecular mechanisms which regulate leukocyte-endothelial cell adhesion, with particular emphasis on L-selectin, and to present a hypothetical model of how these molecules may be orchestrated in vivo resulting in the control of host inflammatory responses.
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PMID:Leukocyte traffic to sites of inflammation. 137 85

Adhesion molecules CD58 and CD54 are involved in cell-cell interactions that are potentially important in the biology of acute leukemia (AL). Expression of these molecules was studied in 79 cases of adult AL including 50 cases of acute non-lymphoid leukemia (ANLL) and 29 cases of acute lymphoid leukemia (ALL) using an indirect immunofluorescence technique. CD58 was expressed in 45 +/- 26% of ANLL cells and 43 +/- 32% of ALL cells, and its expression did not correlate with any other marker. In ALL, the expression of CD58 was inversely correlated with the presence of a clinical tumoral syndrome (p = 0.0009), leucocytosis (p = 0.005), and the percent of peripheral blast cells (p = 0.001). The major finding in this study was the association between CD58 expression and prognosis. In ANLL, higher expression of CD58 was independently associated with higher CR rate (p = 0.04), longer overall survival (p = 0.02), and longer disease-free survival (p = 0.007). In ALL, higher expression of CD58 was associated with longer survival (p = 0.05). CD54 was expressed only on 17 +/- 16% of ANLL cells and 11 +/- 11% of ALL cells; its expression on ANLL was positively correlated with that of CD11 (p = 0.03), CD15 (p = 0.001) and CD34 (p = 0.01). CD54 expression did not correlate with clinical and hematologic characteristics. We conclude that the expression of adhesion molecule CD58, but not CD54, in AL is related to initial characteristics and evolution of the disease.
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PMID:Expression of surface adhesion molecules CD54 (ICAM-1) and CD58 (LFA-3) in adult acute leukemia: relationship with initial characteristics and prognosis. 137 2

Hematopoietic stem cell interaction with elements of the underlying stroma is essential for sustained normal hematopoiesis. Here we have determined that adhesion receptors in the integrin family play a role in promoting adhesion of human hematopoietic stem cells to cultured human marrow stromal cells. Enriched CD34hi progenitor cells expressed VLA-4, VLA-5, and at least one or more beta 2 integrins. Homogeneous marrow stromal cell monolayers capable of supporting proliferation of cocultivated CD34hi cells expressed VCAM-1 and fibronectin (ligands for VLA-4 and VLA-5) as well as ICAM-1 (ligand for LFA-1 and Mac-1). Adhesion-blocking experiments indicated that VLA-4/VCAM-1, VLA-5/fibronectin, and beta 2-integrin/ICAM-1 pathways all are important for CD34hi cell attachment to stromal cells. Consistent with this suggestion, IL-1 stimulation of stromal cells caused both increased VCAM-1 and ICAM-1 expression and increased attachment by CD34hi bone marrow cells. In addition, CD34hi cells utilized VLA-4 to adhere to purified VCAM-1 and employed VLA-5 (and to a lesser extent VLA-4) to adhere to purified fibronectin. Together these results suggest that CD34hi stem cells may utilize multiple integrin-mediated adhesion pathways to localize within specialized microenvironmental niches created by marrow stromal cells.
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PMID:Role of beta 1 and beta 2 integrins in the adhesion of human CD34hi stem cells to bone marrow stroma. 137 10

When activated under physiologic or pathologic conditions leukocytes adhere to one another or to other cell types. Adhesion receptors mediate these interactions. In the study reported here, the distribution of the adhesion receptors LFA-1 (CD11a/CD18), ICAM-1 (CD54), CD2 and LFA-3 (CD58) in recurrent oral ulcers (ROU) were studied. Nine tissue specimens from five female patients (mean age 33 yr, age range 21-40 yr) with ROU were studied using the avidin-biotin-peroxidase complex (ABC) method. The main mononuclear cell infiltrations were in lamina propria (LP) and the epithelium next to the basement membrane (BM), laterally to the ulcers. In this area, ICAM-1 was strongly expressed in capillaries and in postcapillary venules. LFA-1, LFA-3 and CD2 were expressed in 65 +/- 1.1%, 70 +/- 16% and 80 +/- 1%, respectively, of all mononuclear cells. The findings indicate that LFA-1/ICAM-1 and CD2/LFA-3 interactions may play roles in cell to cell adhesion events in ROU.
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PMID:Distribution of adhesion receptors in recurrent oral ulcers. 138 99

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