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

The modulation of adhesive interaction between lymphocyte progenitors and bone marrow stroma may critically determine the maturation and migration of B cell progenitors. mAb against CD9 and beta 1 integrins are reported to induce the homotypic adhesion of pre-B cells. We present evidence that the anti-CD9 mAb 50H.19 and ALB6 but not the proaggregatory anti-VLA-4 mAb 44H6 also enhance the Fc-independent heterotypic adhesion of the human pre-B cell lines NALM-6 and HOON to bone-marrow stromal fibroblasts (BM-FB) but not to bone marrow stroma. CD9-enhanced binding of NALM-6 cells to BM-FB was inhibited 58% by the anti-VLA-4 mAb HP2/1, 36% by the anti-VLA-5 mAb BIIG2, and 99% by their combination. The mAb effectively inhibited adhesion when prebound to NALM-6 cells but not when prebound to BM-FB. The anti-VCAM-1 mAb E1/6 inhibited CD9-enhanced adhesion by only 14% suggesting the involvement of other ligands. Adhesion was inhibited by mAbs against the COOH-terminus and central cell binding domains of fibronectin, as well as by the corresponding CS1 and RGD peptides. Adhesion was not affected by H-7 and sphingosine, inhibitors of protein kinase C. These results suggest that perturbation of CD9 on pre-B cells promotes recognition of stromal cell fibronectin by VLA-4 and VLA-5 and implicates CD9 as a novel regulator of inside-out signaling relevant to B lymphopoiesis.
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PMID:CD9-regulated adhesion. Anti-CD9 monoclonal antibody induce pre-B cell adhesion to bone marrow fibroblasts through de novo recognition of fibronectin. 751 26

Human peripheral blood eosinophils adhered specifically to microtitre plates coated with plasma fibronectin (Fn) in a dose- and time-dependent fashion. Adhesion was optimal at 60 min at a concentration of 100 micrograms/ml. Adherence to Fn was up-regulated by platelet-activating factor (PAF; optimum concentration of 10(-6) M) and was significantly inhibited by a polyclonal anti-Fn antibody (P < 0.05). The following evidence suggested that eosinophil adhesion to Fn was mediated by alpha 4 beta 1: (1) eosinophil adherence to Fn was not inhibited by an Arg-Gly-Asp-Ser (RGDS) synthetic peptide; (2) there was a dose-dependent adherence of eosinophils to microtitre plates coated with the 40,000 MW proteolytic fragment of Fn that contains the CS-1 alpha 4 beta 1 binding region, whereas adherence to the 120,000 MW chymotryptic fragment of Fn, which contains the RGD-dependent binding site, was weak and only observed at high concentrations (> 250 micrograms/ml); (3) significant inhibition of eosinophil adherence to Fn was achieved by monoclonal antibodies (mAb) against the alpha chain of VLA-4 but not by a mAb against CD45 or a mouse myeloma antibody as negative controls. After adhesion to Fn, eosinophils were investigated for their capacity to release leukotriene C4 in response to stimulation with a suboptimal concentration of calcium ionophore (2 x 10(-6) M). Significant enhancement of release was detected with Fn-coated plates but not with the control bovine serum albumin (BSA) (P < 0.01). Furthermore, this enhancement was significantly inhibited by the alpha 4 beta 1 mAb HP2/1 (P < 0.05) but not by an anti-CD45 mAb. From these studies we conclude that (1) alpha 4 beta 1 (VLA-4) integrin is a major receptor for Fn on human eosinophils and (2) adhesion to Fn may prime eosinophils for mediator release during allergic inflammation.
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PMID:Adhesion to fibronectin primes eosinophils via alpha 4 beta 1 (VLA-4). 792 93

We have previously reported that propolypeptide of von Willebrand factor (pp-vWF) promotes melanoma cell adhesion in a beta1 integrin-dependent manner. In this report, we identified the alpha subunit of the cell adhesion receptor for pp-vWF as alpha4. Human leukemia cell lines that express alpha4beta1 integrin (very late antigen-4, VLA-4), but not cell lines which lack VLA-4, attached well to pp-vWF substrate and these adhesions were completely inhibited by anti-alpha4 integrin monoclonal antibody HP2/1. Adhesion of mouse melanoma expressing alpha4 integrin was also inhibited by anti-mouse alpha4 mAb PS/2. Furthermore, transfection of human alpha4 cDNA into alpha4(-) Chinese hamster ovary cells resulted in an acquisition of adhesive activity to pp-vWF, indicating that pp-vWF is a ligand for VLA-4 integrin. Using a recombinant fragment of pp-vWF, the cell attachment site was shown to be located within amino acid residues 376-455 of pp-vWF. A series of synthetic peptides covering this region were tested for the ability to promote cell attachment and a 15-residue peptide designated T2-15 (DCQDHSFSIVIETVQ, residues numbered 395-409) promoted VLA-4 dependent cell adhesion. The peptide was also capable of inhibiting cell adhesion to pp-vWF, suggesting that this sequence represents the cell attachment site. By affinity chromatography using peptide T2-15-Sepharose, it was found that alpha4beta1 integrin complex from extracts of surface iodinated B16 cells specifically bound to the peptide. These results strongly suggest that pp-vWF is a novel physiological ligand for VLA-4.
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PMID:Propolypeptide of von Willebrand factor is a novel ligand for very late antigen-4 integrin. 907 71

We recently reported that the heparin (Hep) III domain of fibronectin contains the H2 cell adhesion site in repeat III5 which binds activated alpha4 integrins. We have now further characterized the heparin and cell binding activities of this domain. A recombinant fragment containing repeats III4-III5 (FN-III4-5) induced Jurkat cell adhesion upon integrin activation with Mn2+ or TS2/16 monoclonal antibody (anti-beta1). Adhesion of Mn2+-treated cells to FN-III4-5 or FN-III5 fragments was inhibited by chondroitinase ABC and ACII but not by the anti-alpha4 monoclonal antibody HP2/1. In contrast, HP2/1 completely blocked adhesion of TS2/16-treated cells while chondroitinase had a partial (FN-III4-5) or minor (FN-III5) effect. Thus, the role of each receptor depended on the stimulus used to activate alpha4 beta1. The combination of HP2/1 and chondroitinase at dilutions which did not inhibit when used individually abolished adhesion of Mn2+ or TS2/16-treated cells to both fragments, indicating a cooperative effect between alpha4beta1 and chondroitin sulfate proteoglycans (CSPG). Furthermore, we have identified a 20-amino acid sequence in III5 (HBP/III5) which binds heparin and induces cell adhesion via CSPG exclusively. Although soluble HBP/III5 was a poor inhibitor, when combined with H2, it abolished adhesion to FN-III4-5 and FN-III5 fragments. These results establish that adhesion to the Hep III domain involves the cooperation of activated alpha4 beta1 and CSPG and show that HBP/III5 is a novel heparin and CSPG-binding site contributing to cell adhesion to this domain.
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PMID:Cooperative role for activated alpha4 beta1 integrin and chondroitin sulfate proteoglycans in cell adhesion to the heparin III domain of fibronectin. Identification of a novel heparin and cell binding sequence in repeat III5. 986 21

Migration of blood-borne lymphocytes into lymphoid tissues is initiated by the L-selectin and alpha4beta7 integrin adhesion molecules. Previous studies have shown that L-selectin adhesion is dynamically regulated by febrile temperatures. It is now reported that fever-range hyperthermia also acts directly on lymphocytes to enhance selected adhesive functions of alpha4beta7 integrin. Fever-range hyperthermia treatment in vitro (40 degrees C, 12 h) of murine TK1 lymphoma cells and human peripheral blood lymphocytes (PBL) stimulates alpha4beta7 integrin-dependent adhesion to high endothelial venules (HEV) in Peyer's patch and mesenteric lymph node frozen sections. TK1 cells are alpha4beta7hi L-selectin(lo), allowing for the analysis of alpha4beta7 integrin without contributions from L-selectin. Adhesion was further shown to involve alpha4beta7 integrin and its endothelial counter-receptor, mucosal addressin cell adhesion molecule-1 (MAdCAM-1) using function-blocking antibodies (i.e. DATK32, HP2/1, MECA-367). Fever-range hyperthermia also promotes alpha4beta7 integrin-mediated aggregation of TK1 cells. In sharp contrast, hyperthermia fails to increase alpha4beta7 integrin adhesion to fibronectin by TK1 cells. Expression of the alpha4beta7 heterodimer on TK1 cells or human PBL is not altered by hyperthermia, suggesting that hyperthermia stimulates adhesion by enhancing alpha4beta7 integrin avidity rather than its cell surface density. These results provide a mechanism whereby febrile temperatures during infection or clinical hyperthermia potentially amplify the immune response by stimulating L-selectin and alpha4beta7 integrin-dependent homing of immune effector cells to lymphoid tissues.
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PMID:Fever-range hyperthermia stimulates alpha4beta7 integrin-dependent lymphocyte-endothelial adhesion. 1066 16

Recent research demonstrates that the beta1 integrins may be involved in neutrophil migration. Here, we investigate the role of nitric oxide in the expression and function of the very late antigen-4 (VLA-4) and Mac-1 integrins on human neutrophils. Human blood neutrophils were treated with N(omega)-nitro-L-arginine methyl ester (L-NAME) and their adhesion to fibronectin (FN) and serum observed. Adhesion of neutrophils to FN and serum increased significantly following incubation with 0.1mM L-NAME by 65.5 and 44.6%, respectively. Increased adhesions to FN and serum were abolished by a VLA-4-specific monoclonal antibody, HP2/1, and a Mac-1-specific monoclonal antibody, ICRF 44, respectively. The microfilament- and microtubule-depolymerizing agents, dihydrochalasin B and nocodazole, were also able to reverse L-NAME-induced adhesion to both FN and serum. L-NAME induced a discrete increase in the expression of CD49d (VLA-4, 25.3+/-4.8%), but not CD11b, on the neutrophil cell surface, as detected by flow cytometry. Results indicate that NO has a role in regulating VLA-4 and Mac-1 function on the human neutrophil cell surface and that this modulation in integrin function is accompanied by cytoskeletal rearrangements and changes in the ability of the neutrophil to adhere to the extracellular matrix.
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PMID:Nitric oxide has a role in regulating VLA-4-integrin expression on the human neutrophil cell surface. 1281 64