What are immunoassays and what are they useful for?
Immunoassays are analytical methods that utilize antigen-antibody chemistry and their interactions for the detection and quantitation of analytes, such as cytokines, chemokines, growth factors and other proteins. Radioimmunoassays (RIAs) and enzyme-linked immunosorbent assays (ELISAs) are some of the most commonly used immunoassays. ELISAs have been the gold standard for immunoassay analyses due to their remarkable sensitivity, specificity and precision. Enzyme-linked immunosorbent spot (ELISPOT) is another powerful immunoassay for analyzing specific antibody-secreting cells. More recently, capture bead–based immunoassays have provided a sensitive option for the measurement of a wide variety of analytes and offer the ability to multiplex at a larger scale compared to the other formats.
BD Biosciences offers multiple tools and assay platforms for cytokine and chemokine quantitation
- BD® CBA Solutions for multiplexed detection and analysis
- BD OptEIA™ Kits and Sets for routine ELISA research applications
- BD® ELISPOT Assays for determining the frequency of cytokine production
Tools and Techniques for Cytokine Quantitation
| Tool/Technology | BD® Cytometric Bead Array (CBA) | ELISA | ELISPOT |
|---|---|---|---|
| Molecules detected | Secreted or intracellular | Secreted | Secreted (in situ) |
| Multiparameter | Yes | No | No |
| Single-cell / cell-subset information | No | No | Frequencies, no subset information |
| Antigen-specific | Yes | Yes | Yes |
| Post-assay viability | Yes | Yes | No |
| Protein quantitation | Yes | Yes | No |
| Instrumentation | Flow cytometer | Spectro-photometer | ELISPOT reader |
Bead-based immunoassays
Bead-based assays utilize fluorescently barcoded beads instead of a plate for binding with fluorescent antibodies and are interrogated using flow cytometry methods. Bead-based immunoassays enable multiplex detection of targets several folds higher than what is conceivable using normal ELISA formats, saving time and sample.
Introduction to BD® Cytometric Bead Arrays (CBA)
CBA assays are bead-based immunoassays that use fluorescent antibodies for the detection of a variety of soluble and intracellular proteins, including cytokines, chemokines, growth factors and phosphorylated signaling proteins.
Each capture bead in the array has a unique fluorescence intensity and is coated with a capture antibody specific for a single analyte. A combination of different beads is mixed with a sample or standard and a mixture of detection antibodies that are conjugated to a reporter molecule (PE). Following incubation and subsequent washing, the samples are acquired on a flow cytometer.
BD® CBA Solutions offer the ability to add any protein or antibody of interest to increase flexibility
BD® CBA Functional Beads can be used to conjugate antibodies or proteins of interest for unique requirements. The conjugation procedure uses sulfo-SMCC chemistry and takes less than four hours using common laboratory supplies along with the buffers in the BD® CBA Functional Bead Conjugation Buffer Kit. This is an ideal platform for converting existing ELISAs into bead-based immunoassays that can be mixed with our portfolio of BD® CBA Flex Set Assays. The availability of multiple bead positions enables creation of novel multiplex panels, while the ability to prepare up to 1,000 tests in a single reaction ensures consistency across many tests.
BD® CBA Solutions are available in preconfigured kits or in an open, configurable format for unique needs.
Explore BD® CBA Solutions.
