hOSCAR is a cell-surface monomeric glycoprotein. (A) SDS-PAGE analysis of hOSCAR immunoprecipitated from ¹²⁵I-labeled hOSCAR-transfected human U937 cells (left panels) and ¹²⁵I-labeled mono-DCs (right panels). The cell lysate was immunoprecipitated as indicated with either isotype-matched control mAb (control IgG) or anti-hOSCAR mAb. Upon gel exposure on phosphorscreen and phosphoImager detection, hOSCAR appears as an approximately 45-kDa band under both nonreducing and reducing conditions. (B) Glycosylation of anti-hOSCAR precipitates from hOSCAR-transfected ¹²⁵I-labeled human U937 cells. Deglycosylation was performed with N-glycosidase F or with neuraminidase and/or O-glycosidase, before SDS-PAGE and detection as above. Upon digestion of the N-linked sugars, hOSCAR appears as a thin band of approximately 30 kDa, corresponding to its totally unglycosylated form. The data are representative of 3 independent experiments.