Determination of LDL receptors on cultured lymphocytes using fluorescein-labeled LDL

A rapid, sensitive procedure for the detection of LDL receptors on cell surface without using radioisotopes is described. Fluorescein-isothiocyanate (FITC) labeled LDL bound with cultured human lymphocytes, and the degree of that binding was compatible with that of 125 I-labeled LDL. The staining of cells with FITC-LDL allows identification and enumeration of LDL-binding cells using fluorescence microscopy or a fluorescence activated cell sorter (FACS). It is suggested that FITC-LDL can be applied for screening of patients with various degrees of activity in LDL receptors on their cell surfaces.