Only the soluble form of the scavenger receptor CD163 acts inhibitory on phorbol ester-activated T-lymphocytes, whereas membrane-bound protein has no effect.
The extracellular moiety of the hemoglobin/haptoglobin scavenger receptor CD163 (RM3/1 antigen) can be shed from monocytes and is a normal plasma component. We found that in a dose-dependent manner soluble CD163 induces a decrease in CD69 expression, a reduced [(3)H]thymidine uptake and a down-regulated matrix metalloproteinase-9 RNA expression in phorbol myristate acetate-stimulated T-cells. Co-culturing T-cells on transgenic fibroblasts, expressing membrane-bound CD163, yielded no differences compared to culture on non-transfected cells. We conclude that CD163 has at least two distinct functions: the clearance of hemoglobin in its cell-bound form and participation in anti-inflammation as a soluble factor, exhibiting cytokine-like functions.
Institute of Experimental Dermatology, Westfälische Wilhelms-Universität, Münster, Germany. werner.frings@covance.com
Werner
W
Frings
Jens
J
Dreier
Clemens
C
Sorg
D015703:Antigens, CD / Q000235:genetics; D015214:Antigens, Differentiation, Myelomonocytic / Q000235:genetics / Q000302:isolation & purification / Q000502:physiology*; D000945:Antigens, Differentiation, T-Lymphocyte / Q000235:genetics; D017209:Apoptosis; D002846:Chromatography, Affinity; D005786:Gene Expression Regulation; D006801:Humans; D037181:Lectins, C-Type; D008213:Lymphocyte Activation / Q000187:drug effects / Q000502:physiology*; D019278:Matrix Metalloproteinase 3 / Q000235:genetics; D020780:Matrix Metalloproteinase 9 / Q000235:genetics; D011956:Receptors, Cell Surface / Q000235:genetics / Q000302:isolation & purification / Q000502:physiology*; D011994:Recombinant Proteins / Q000302:isolation & purification / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013601:T-Lymphocytes / Q000187:drug effects / Q000276:immunology*; D013755:Tetradecanoylphorbol Acetate; D000098902:CD163 Antigen; D000099192:CD69 Antigens
D015703:Antigens, CD; D015214:Antigens, Differentiation, Myelomonocytic; D000945:Antigens, Differentiation, T-Lymphocyte; D037181:Lectins, C-Type; D019278:Matrix Metalloproteinase 3; D020780:Matrix Metalloproteinase 9; D011956:Receptors, Cell Surface; D011994:Recombinant Proteins; D013755:Tetradecanoylphorbol Acetate; D000098902:CD163 Antigen; D000099192:CD69 Antigens