title: Biosynthesis of the complement components and the regulatory proteins of the alternative complement pathway by human peripheral blood monocytes.
abstract: Short-term cultures of human peripheral blood monocytes were shown to synthesize the alternative pathway complement components C3, factors B (B) and D (D), and properdin, the regulatory proteins C3b inactivator (C3bINA) and beta 1H, in addition to C2, C4, and C5. B, D, properdin, C3bINA, and C2 were detected by functional assays, whereas beta 1H, C4, C3, and C5 could only be detected using immunochemical procedures. Immunoperoxidase localization studies showed that all the cells in each culture contained each component, so it is possible that all monocytes synthesize each component. It is concluded that cells of the monocyte-macrophage series form a mobile source of complement components and regulatory proteins which can be concentrated at sites of inflammation.
mesh_terms: D002478:Cells, Cultured; D003166:Complement Activating Enzymes / Q000096:biosynthesis*; D003167:Complement Activation; D003175:Complement C2 / Q000096:biosynthesis; D003180:Complement C3b Inactivator Proteins / Q000096:biosynthesis*; D011415:Complement Factor B / Q000096:biosynthesis*; D011416:Complement Factor D / Q000096:biosynthesis*; D017242:Complement Factor H; D003170:Complement Pathway, Alternative; D003165:Complement System Proteins / Q000096:biosynthesis*; D003513:Cycloheximide / Q000494:pharmacology; D003593:Cytoplasm / Q000378:metabolism; D004792:Enzyme Precursors / Q000096:biosynthesis*; D006801:Humans; D007124:Immunoenzyme Techniques; D009000:Monocytes / Q000378:metabolism*; D011414:Properdin / Q000096:biosynthesis*
chemical_list: C493495:CFH protein, human; D003175:Complement C2; D003180:Complement C3b Inactivator Proteins; D004792:Enzyme Precursors; D011414:Properdin; D017242:Complement Factor H; D003165:Complement System Proteins; D003513:Cycloheximide; D003166:Complement Activating Enzymes; C493488:CFD protein, human; D011416:Complement Factor D; D011415:Complement Factor B