Improved detection of cell surface proteins using an electrochemiluminescent cell-binding assay

Cell surface protein profiling is a generic tool to determine the quality of cultured mammalian cell lines. Flow cytometry is commonly employed as the screening technique of choice, but it consumes a large quantity of cells. We have evaluated an electrochemiluminescent (ECL)-based platform, the Meso Scale Discovery (MSD) Sector 6000 Imager, for cell surface protein detection with fewer than 100 cells per well. The detection of CD13 on human foreskin fibroblast (HFF) cells was evaluated using indirect detection of the reverse-phase immunoassays in 96-well and 384-well plate formats. The study has shown robust cell surface detection of CD13 on HFF cells using the 384-well plate format, with a LOD of 15.3 ± 6.5 cells (n=3). The 96-well plate format exhibited far greater variability between experiments, such that the best LOD obtained was 42.5 cells per well. We have demonstrated, with our model system, the feasibility to perform cell-binding assays with as few as 15 cells per well of a 384-well microplate using the MSD platform.