2692 M. Sironi, C. Mufioz, T. Pollicino et al. Eur. J. Immunol. 1993. 23: 2692-2695 zy Short paper Marina Sioni, Cecilia Muiioz, Teresa Pollicino, Andrea Siboni, Francesca Luisa Sciacca, Sergio Bernasconi, Annunciata Vecchi, Francesco Colotta and AIberto Mantovani Centro Daniela e Catullo Borgomainerio, Istituto di Ricerche Farmacologiche “Mario Negri”, Milano 1 Introduction Divergent effects of interleukin-10 on cytokine production zyxw by mononuclear phagocytes and endothelial cells* Interleukin-10 (IL-lo), a product of T helper type 2 (TH2) cells and monocytes, inhibits cytokine production in mononuclear phagocytes. Given the similarities and interrelationship between cells of the monocyte-macrophage lineage and endothelial cells, we examined the effects of IL-10 on vascular endothelium. Murine IL-10 induced low levels of IL-6 production and amplified induction of IL-6 by lipopolysaccharide (LPS) or IL-1 in the murine tEND.l endothelioma line, used for these studies because it retains properties of normal endothelium. The effect was more evident after prolonged (48-72 h) exposure to IL-10. IL-10 had similar activity on other endothelioma lines, whereas it inhibited IL-6 production by peritoneal macrophages. Induction and amplification of cytokine production by IL-10 was associated with higher levels of mRNA, which were maintained longer (up to 48 h) than in controls. In addition to IL-6, murine IL-10 induced or amplified expression of the chemoattractant cytokines monocyte chemotactic protein-1 (MCP-1) and KC. Human IL-10 inhibited IL-6 release by LPS-stimulated human peripheral blood mononuclear cells, whereas it did not interfere with cytokine production by LPS- or IL-1-stimulated human umbilical vein endothelial cells. The selective inhibitory action of IL-10 on mononuclear phagocytes versus endothelial cells may play a role in the pathophysiology of THZdirected responses. Interleukin-10 (IL-10) was first identified as a cytokine synthesis inhibitory factor produced by TH2 clones and acting on TH1 cells via macrophage accessory cells zyxwvu [ 1,2]. Subsequent work revealed that IL-10 is in fact a pleiotropic cytokine, its action encompassing T and B cells, mast cells and monocytes (for review see [3]). IL-10 inhibits various functions of mononuclear phagocytes, including h4HC class I1 antigen expression and production of various cytokines [4-81. Endothelial cells (EC) play an important, active role in inflammatory and immunological reactions (for review see [9, lo]). Their properties are profoundly altered by cyto- kines [lo]. Given the long recognized similarities and interrelationship between mononuclear phagocytes and EC [9, lo], we decided to investigate the effects of IL-10 on EC. [I 116021 * This work was supported by Istituto Superiore di Sanith (National AIDS Project) and by CNR (Project ACRO). The generous contribution of the Italian Association for Cancer Research is gratefully acknowledged. Correspondence: Albert0 Mantovani, Istituto di Ricerche Farma- cologiche “MARIO NEGRI” Via Eritrea 62,l-20157 Milano, Italy (Fax: 39-2-354 62 77) Abbreviations: EC: Endothelial cells MCP-1: Monocyte che- motactic protein-1 Key words: Interleukin-10 zyxwvutsrq I Interleukin-6 I Chemokines I Endo- thelial cells We found that IL-10 has contrasting actions on cytokine production by mononuclear phagocytes and EC. 2 Materials and methods 2.1 Cytokines Recombinant human IL-1 zyxw a (specific activity lo5 U/mg protein) was obtained from Dr. zyx l? Lomedico, Hoffmann-La Roche, Nutley, NJ; recombinant human IL-6 was obtained from Dr. S. Gillis, Immunex, Seattle, WA; recombinant murine IL-10, expressed in baculovirus, was obtained from DNAX, Palo Alto, CA; one unit is defined as the amount that gives 50% maximum response in MU9 cells. Recom- binant human IL-10 was obtained, either as COS superna- tant or as purified material from CHO cells (specificactivity lo7 U/mg), from Dr. J. de Vries, DNAX. IL-6 was mea- sured as hybridoma growth factor (HGF) activity, as de- scribed [ll]. An anti-IL-6 antibody was used to confirm the specificity of the bioassay with supernatants [ 111. Results (mean k SD, four replicates) are representative of at least three experiments performed. 2.2 EC and mononuclear phagocytes Human umbilical vein EC were cultured as described [9-111. The mouse endothelioma cell line tEND.l was originally obtained through the courtesy of Dr. E. EWagner (IMP,Wien, Austria). Endothelioma cells were maintained in D-MEM (Biochrom KG, Berlin, FRG) + 10% FCS (HyClone, Logan, UT). The properties of this cell line, including cytokine production and expression of adhesion 00 14-2980l93l101 0-2692$10.00 + .25/0 zyxwvuts 0 VCH Verlagsgesellschaft mbH, D-69451 Weinheim, 1993