title: Expression of the binding molecules for factor B and its fragment, Bb, of human complement on human monocytes after in vitro cultivation.
abstract: We have examined the expression of the binding molecules for Bb of human complement on the surface of resting and cultured human monocytes. Flow cytometry using biotinylated anti-B antibodies and phycoerythrin-avidin showed that although resting monocytes did not bind Bb significantly, monocytes cultivated for 24 h in the presence of fetal calf serum were capable of binding with Bb and its precursor B, but not with Ba fragment. The Bb-binding molecules were pronase-sensitive, suggesting that membrane proteins are associated with the Bb-binding molecules. In addition to human monocytes, liquid paraffin-induced guinea pig inflammatory macrophages were also found to express Bb-binding molecules on their surface. This implies that Bb receptor-like molecules become expressed during activation and differentiation of monocytes, just as observed with the C3d-receptor of monocytes.
authors.affiliation: Department of Hygienic Chemistry, Faculty of Pharmaceutical Sciences, Hokkaido University, Sapporo, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Saeki
authors.forename: S
authors.initials: S
authors.lastname: Nagasawa
mesh_terms: D000818:Animals; D001665:Binding Sites; D051561:Complement C3 Convertase, Alternative Pathway; D003179:Complement C3b / Q000378:metabolism*; D011415:Complement Factor B / Q000378:metabolism*; D004792:Enzyme Precursors / Q000378:metabolism*; D005455:Fluorescent Antibody Technique; D006168:Guinea Pigs; D006801:Humans; D066298:In Vitro Techniques; D008264:Macrophages / Q000276:immunology / Q000378:metabolism; D009000:Monocytes / Q000276:immunology* / Q000378:metabolism; D010446:Peptide Fragments / Q000378:metabolism*; D011951:Receptors, Complement / Q000378:metabolism*
chemical_list: D004792:Enzyme Precursors; D010446:Peptide Fragments; D011951:Receptors, Complement; D003179:Complement C3b; D051561:Complement C3 Convertase, Alternative Pathway; D011415:Complement Factor B