title: CD32 expression and signaling is down-regulated by transforming growth factor-beta 1 on human monocytes.
abstract: CD32 (Fc gamma RII) is the most abundantly distributed class of IgG Fc receptors in the human body. In this study, we analyzed the effect of transforming growth factor (TGF)-beta 1, a cytokine with strong immunosuppressive function, on the expression and function of CD32 on freshly isolated peripheral blood monocytes and three human monocytic cell lines, U937, THP-1 and Mono mac-6. We found that TGF-beta 1 down-regulates CD32 expression on monocytes and all monocytic cell lines in a dose- and time-dependent fashion. A mean down-regulation of CD32 expression on THP-1 cells of 54 +/- 3.2% after 24 h was found at a concentration of 1 ng/ml TGF-beta 1. At the mRNA level, TGF-beta 1 induced a twofold down-regulation of CD32. Cross-linking of CD32 induced an increase in the concentration of intracellular Ca2+, which was reduced by 50% by TGF-beta 1, suggesting a decreased downstream signaling mediated by the receptor.
authors.affiliation: Department of Nephrology, Leiden University Hospital, The Netherlands.
authors.forename: T J
authors.initials: TJ
authors.lastname: Reterink
authors.forename: N
authors.initials: N
authors.lastname: Klar-Mohamad
authors.forename: P H
authors.initials: PH
authors.lastname: Nibbering
authors.forename: L A
authors.initials: LA
authors.lastname: van Es
authors.forename: M R
authors.initials: MR
authors.lastname: Daha
mesh_terms: D000954:Antigens, Surface / Q000096:biosynthesis; D003432:Cross-Linking Reagents; D015536:Down-Regulation / Q000187:drug effects / Q000276:immunology*; D006801:Humans; D009000:Monocytes / Q000187:drug effects* / Q000276:immunology / Q000378:metabolism*; D012333:RNA, Messenger / Q000096:biosynthesis; D017452:Receptors, IgG / Q000096:biosynthesis* / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects / Q000276:immunology*; D016212:Transforming Growth Factor beta / Q000494:pharmacology*
chemical_list: D000954:Antigens, Surface; D003432:Cross-Linking Reagents; D012333:RNA, Messenger; D017452:Receptors, IgG; D016212:Transforming Growth Factor beta