Flow immunochemical bio-recognition detection for the determination of interleukin-10 in cell samples

On- and off-line heterogeneous non-competitive flow immunoassays for the determination of Interleukin-10 are described. The sample containing IL-10 is mixed, either on-line in a reaction coil or off-line in a test tube, with fluorescent labelled anti-IL-10 antibodies to form an antibody-antigen complex. The labelled unbound antibodies are trapped on an immobilized IL-10 column whereas the IL-10-antibody complexes are eluted and detected downstream by a fluorescence detector. The optimization of the systems was performed with respect to choice of affinity support, flow rate, carrier buffer additives, pH and antibody-antigen association. Both bio recognition assays were tested with a spiked cell medium and the IL-10 detection limits in this matrix was found to be 8 fmol using the off-line incubation mode and 40 fmol using the on-line incubation mode. The sample through-put was 26 and 40 samples per hour in the on-line and off-line incubation modes, respectively. IL-10 identification in the sample fractions was achieved using MALDI-TOF MS.