I have to use an indirect labeling method for my cells, is this compatible with Quantum Simply Cellular beads?
A very common question, and one that we speak at length with various users about.
Whenever possible, we recommend that a direct labeling strategy is used with cell samples and Quantum Simply Cellular (QSC) beads. This is advantageous as indirect labeling methods often have multivalent binding between the secondary antibody conjugate and the primary monoclonal Ab. The fluorescence signal from one antigen binding event on the cells can thus be multiplied by several-fold, the exact rate of which is usually unknown. That said, a fair number of our customers use an indirect labeling strategy out of necessity, i.e. where the primary mAb is not available as a fluorescently-labeled conjugate.
Ultimately, if absolute quantitation is required, then direct staining with primary antibodies will be crucial towards obtaining accurate values. If however relative expression levels are acceptable, or a fluorescent primary mAb isn’t available, then an indirect strategy may be used to obtain semi-quantitative results.