Bead-Based Immunoassays

The immune cells microenvironment is largely shaped by secreted factors such as cytokines, chemokines, growth factors etc. The nature of this environment can profoundly influence cellular processes as proliferation, differentiation, regulatory function and so on.

This flow cytometry application allows users to quantify multiple secreted proteins simultaneously using a single sample (up to 30 proteins) of cell culture supernatant, serum or plasma. The system uses the broad dynamic range of fluorescence detection offered by flow cytometry and antibody-coated beads to efficiently capture analytes. Each bead in the array has unique fluorescence intensity so that beads can be mixed and run simultaneously in a single tube.

The application utilizes polystyrene beads with distinct fluorescence intensities coated with capture antibodies of differing specificities. A combination of different beads is then mixed with the sample followed by the addition of a detection antibody coupled to a fluorescent protein such as phycoerythrin (PE). The flow cytometer classifies the beads according to analyte specificity, and detects the magnitude of the fluorescent dye-derived signal as a measure of analyte abundance.


The application significantly reduces sample volume requirements and time to results in comparison with other available techniques and provides more data.