title: Expression and secretion of type beta transforming growth factor by activated human macrophages.
abstract: Alveolar macrophages activated with concanavalin A and peripheral blood monocytes activated with lipopolysaccharide secrete type beta transforming growth factor (TGF-beta). There is minimal TGF-beta secretion in unactivated monocytes, even though TGF-beta mRNA is expressed in these cells at a level similar to that in activated, lipopolysaccharide-treated cultures. U937 lymphoma cells, which have monocytic characteristics, also express mRNA for TGF-beta. Freshly isolated monocytes, both control and lipopolysaccharide-treated, secrete an acid-labile binding protein that inhibits TGF-beta action. We conclude the following: (i) that expression of TGF-beta mRNA is unrelated to monocyte activation, (ii) that secretion of TGF-beta is induced by monocyte activation, and (iii) that cosecretion of TGF-beta and its monocyte/macrophage-derived binding protein may modulate growth factor action. In contrast, monocytic expression of other growth factor genes, such as the B chain of platelet-derived growth factor, is not constitutive and requires activation.
mesh_terms: D002460:Cell Line; D006801:Humans; D066298:In Vitro Techniques; D008262:Macrophage Activation; D008264:Macrophages / Q000378:metabolism*; D009000:Monocytes / Q000378:metabolism; D010455:Peptides / Q000378:metabolism*; D012333:RNA, Messenger / Q000378:metabolism; D011956:Receptors, Cell Surface / Q000378:metabolism; D018125:Receptors, Transforming Growth Factor beta; D015291:Transforming Growth Factors
chemical_list: D010455:Peptides; D012333:RNA, Messenger; D011956:Receptors, Cell Surface; D018125:Receptors, Transforming Growth Factor beta; D015291:Transforming Growth Factors