DEC-205, A 205-KDA PROTEIN ABUNDANT ON MOUSE DENDRITIC CELLS AND THYMIC EPITHELIUM THAT IS DETECTED BY THE MONOCLONAL-ANTIBODY NLDC-145 - PURIFICATION, CHARACTERIZATION, AND N-TERMINAL AMINO-ACID-SEQUENCE

The monoclonal antibody NLDC-145 detects an antigen expressed at high levels by mouse dendritic cells (DCs) and thymic epithelial cells. Her e we report on the purification and biochemical characterization of th is antigen. The antigen detected by the NLDC-145 mAb is an integral me mbrane glycoprotein, with an apparent molecular mass of 205 kDa by imm unoprecipitation and Western blotting. The isoelectric point is pH 7.5 , and carbohydrates comprise about 7 kDa of the total mass. Lectin blo tting and FACE analysis revealed heterogeneous biantennary N-linked gl ycans. O-linked glycans were not detected. N-terminal sequence analysi s revealed that the antigen is a novel protein, Polyclonal antibodies prepared either to a synthetic N-terminal peptide or to whole purified protein bind the same 205-kDa protein recognized by NLDC-145. We refe r to the protein as DEC-205, in view of its abundant expression by den dritic and thymic epithelial cells, and the revised molecular mass. (C ) 1995 Academic Press, Inc.