PHOTO BY MICHAEL MAGGS, WIKIMEDIA COMMONSCytokines are small proteins secreted by diverse cell types in the body that orchestrate myriad immune reactions depending on the other cytokines in the milieu. For example, when interleukin-4 (IL-4) is acting alone, it signals B-cells to proliferate and churn out particular types of antibodies. But the simultaneous presence of a cytokine called interferon-γ (IFN-γ) contradicts that message, reducing the numbers of B-cells and changing the kinds of antibodies they produce.
The bottom line: “It is very likely that it won’t be a single molecule that will mean something about an immune response,” says Amit Bar-Or, director of the Experimental Therapeutics Program at the Montreal Neurological Institute of McGill University.
Enter multiplexing. In the past 10 years, many of the major life-science product companies have come out with kits for measuring as many as several dozen cytokines at the same time, in the same well.
Multiplex kits use a pair of antibodies, one to capture the cytokine and another to detect it. Some kits attach the capture antibodies to a flat surface, as in the traditional ELISA. But in the more popular bead-based kits, researchers add their sample to a well containing a mixture of bead ...
