A monoclonal antibody to the DEC-205 endocytosis receptor on human dendritic cells

DEC-205 is a multilectin receptor for adsorptive endocytosis, expressed in mouse dendritic cells (DC) and some epithelia, DEC-205 is homologous to the macrophage mannose receptor (MMR). A cDNA for murine DEC-205 was used to i dentify 3 overlapping human DEC-2Q5 clones from a lymphocyte library. The h uman homologue is a transmembrane protein of 1722 aminoacids with 10 extern ally disposed C-type lectin domains having 77% identity to the mouse counte rpart. The NH2 terminal cysteine-rich and fibronectin type II domains were expressed and used to immunize mice. A hybridoma, MG38, which specifically recognized the immunogen was obtained from a DEC-205 knockout mouse. The an tibody precipitated a 205 kD protein from metabolically labeled, monocyte-d erived DCs. MG38 labeled mature monocyte-derived DCs but showed weak or no labeling of other peripheral blood mononuclear cells. In tissue sections, M G38 identified DEC-205 on thymic cortical epithelium and DCs in the thymic medulla and tonsillar T cell areas. In contrast, an anti-MMR antibody stain ed DEC-205 negative, macrophages in the thymus cortex, the trabeculae of th e thymus and tonsil, as well as efferent lymphatics in the tonsil. Therefor e, the MG38 anti-DEC-205 antibody is useful for identifying DCs and reveals clear differences in sites where MMR and DEC-205 are expressed in lymphoid tissues. Human Immunology 61, 729-738 (2000). (C) American Society for His tocompatibility and Immunogenetics, 2000. Published by Elsevier Science Inc .