Bead-Based Immunoassays

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

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 utilizes 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 a unique fluorescence intensity, allowing beads to be mixed and run simultaneously in a single tube.

The application employs polystyrene beads with distinct fluorescence intensities, each 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.

This application significantly reduces sample volume requirements and time to results compared to other available techniques, providing more data.