title: Mitogen stimulation promotes human T lymphocyte adhesion to fibronectin.
abstract: Purified human peripheral blood T lymphocytes were shown to adhere to growth substrata coated with purified human plasma fibronectin (pFn) and its Mr 120,000-140,000 proteolytic fragments containing the cell-binding site. In contrast, significant binding to laminin- or type I collagen-coated surfaces could not be demonstrated. Binding of T cells to pFn could be inhibited by the synthetic peptide Arg-Gly-Asp-Ser. Activation of T lymphocytes with concanavalin A (Con A) and a phorbol ester, 12-O-tetradecanoyl-phorbol-13-acetate (TPA), led to a higher adherence to pFn than in unstimulated, resting T cells. Activation with only Con A in the presence of accessory cells also promoted binding. Increased adherence of T cells to pFn could be demonstrated as early as 2 h after the onset of stimulation and reached its maximum in 2-3 days. Furthermore, activated but not resting T cells actively spread on pFn-coated surfaces and displayed an altered F-actin organization. In an overlay assay of electrophoretically separated polypeptides of activated T lymphocytes, pFn bound to a high molecular weight polypeptide of Mr 190,000, suggesting that the cells bind to pFn via a receptor-like molecule. Thus, adhesion ot pFn may be a two-stage process. At the first stage cells bind to Fn. Activated T cells proceed to the second stage, where cells begin to spread on pFn. This may be due to an altered relationship between Fn receptors and microfilaments.
mesh_terms: D000938:Antigen-Presenting Cells / Q000276:immunology; D002448:Cell Adhesion / Q000187:drug effects*; D003208:Concanavalin A / Q000494:pharmacology*; D005353:Fibronectins / Q000378:metabolism*; D006801:Humans; D008213:Lymphocyte Activation / Q000187:drug effects; D017469:Receptors, Fibronectin; D011971:Receptors, Immunologic / Q000378:metabolism; D013601:T-Lymphocytes / Q000166:cytology / Q000187:drug effects* / Q000276:immunology; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology*
chemical_list: D005353:Fibronectins; D017469:Receptors, Fibronectin; D011971:Receptors, Immunologic; D003208:Concanavalin A; D013755:Tetradecanoylphorbol Acetate