Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0001511 (Adhesion)
 5,955 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The mechanisms responsible for the accumulation of eosinophils at sites of allergic and other inflammatory reactions are unknown, but recent studies have implicated both eosinophil and endothelial adhesion molecules in this process. However, less well studied have been the adhesive interactions between eosinophils and the subendothelial basement membrane and interstitial connective tissues. To test the hypothesis that eosinophils might interact with extracellular matrix proteins, we analyzed purified human eosinophils for the expression and function of various beta 1 integrins. Using indirect immunofluorescence and flow cytometry, purified eosinophils from mildly allergic donors were found to consistently express the integrin subunits beta 1 (CD29), alpha 4 (CD49d, very late activation antigen [VLA]-4 alpha), and alpha 6 (CD49f, VLA-6 alpha). No significant expression of the alpha 1, alpha 2, alpha 3, alpha 5, or beta 4 subunits was detected. Platelet contamination of the eosinophil preparations was excluded by light microscopy and by the inability to detect expression of platelet glycoproteins alpha v, CD41b, and CD42b. Immunoprecipitation and sodium dodecyl sulfate-polyacrylamide gel electrophoresis analysis of eosinophils confirmed the expression of cell-surface beta 1, alpha 4, and alpha 6. Furthermore, eosinophils purified from allergic donors were shown to adhere to plate-bound laminin, but not to type 1 or type 4 collagen. Adhesion to laminin was concentration-dependent, required divalent cations, and was completely and specifically inhibited by the anti-alpha 6 monoclonal antibody (MoAb) GoH3 and by the anti-beta 1 MoAb 33B6. Interestingly, the anti-beta 1 MoAb 18D3 (which like 33B6 blocks eosinophil binding to VCAM-1) did not inhibit eosinophil adhesion to laminin, suggesting that there are functionally distinct epitopes on the beta 1 subunit. Eosinophils purified from 4 healthy, nonallergic donors also showed alpha 6-dependent adhesion to laminin, although these cells adhered less well. These studies establish the expression of alpha 6 beta 1 on human eosinophils and document its function as a laminin receptor. Interaction of eosinophil alpha 6 beta 1 with laminin, eg, in basement membranes, may contribute to the localization of these cells at inflammatory sites in vivo.
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PMID:Expression of a functional laminin receptor (alpha 6 beta 1, very late activation antigen-6) on human eosinophils. 821 35

Megakaryocytes generate cytoplasmic processes (CP) that penetrate endothelial cells in the bone marrow sinus, and these processes may release platelets into the circulation at their terminal stage. Adhesion between the CP and endothelial cells may be important during the extension of CP. We examined the expression of adhesion molecules of the integrin family (CDw49b, CDw49d, CDw49e, CDw49f, CD18, CD11a CD11c, and CD11b), the immunoglobulin superfamily (CD54, CD56, CD58, and CD31), the selectin family (ELAM-1, LECAM-1, and CD62), and CD44, CD41b, and CD42b on platelets, megakaryocytes, and megakaryocytes with CP. No specific adhesion molecules were observed on the megakaryocytes with CP. Three staining patterns of adhesion molecules-homogeneous, speckled, and accumulated-were observed on the megakaryocytes with CP, but not on those without CP. Platelet integrins (i.e., CD41a, CDw49b, CDw49e and CDw49f) and GPIb (CD42b) were strongly and homogeneously stained on the CP. GMP-140 CD62) was weakly stained, in a speckled pattern. CD31 (PECAM-1) was also weakly stained but accumulated selectively on the tip of the CP. ANTI-CD31 suppressed CP formation of megakaryocytes. We speculate that the homodimerization of CD31 expressed on the tips of CP and endothelial cells is important for the extension of the processes and for the migration of megakaryocytes.
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PMID:Expression of adhesion molecules on cytoplasmic processes of human megakaryocytes. 863 24