Multiplex Protein Detection with Quantibody® Arrays

Quantibody array is an array-based multiplex sandwich ELISA system for simultaneous quantitative measurement the concentration of multiple cytokines in serum, plasma, CSF, cell lysate, conditioned media and other body fluid. It combines the advantages of the high detection specificity/ sensitivity of ELISA and the high throughput of the arrays. Like a traditional sandwich-based ELISA, it uses a pair of cytokine-specific antibodies for detection. A capture antibody is first bound to the glass surface. After incubation with the sample, the target cytokine is trapped on the solid surface. A second biotin-labeled detection antibody is then added, which can recognize a different isotope of the target cytokine. The cytokine-antibody-biotin complex can then be visualized through the addition of the streptavidin-labeled Fluorescent dye using a laser scanner. Unlike the traditional ELISA, Quantibody products use array format. By arraying multiple cytokine specific capture antibodies onto a glass support, multiplex detection of cytokines in one experiment is made possible. In detail, one standard glass slide is spotted with 16 wells of identical cytokine antibody arrays. Each antibody, together with the positive and negative control is arrayed in quadruplicate. The slide comes with a holder that includes a 16-well removable gasket that allows for the processing of up to 16 samples on one slide. Four slide holders can be nested into a tray, which matches a standard microplate and allows for automated robotic high-throughput process of 64 arrays simultaneously. For cytokine quantification, the array specific cytokine standards, whose concentration has been predetermined, are provided to generate a five-point standard curve of each cytokine. In a real experiment, standard cytokines and samples will be assayed in each array simultaneously through a sandwich ELISA procedure. By comparing signals from unknown samples to the standard curve, the unknown cytokine concentration in the samples will be determined.