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P2076
New SA-PE Conjugates Reduce Capture-Antibody-Specific Background in Sandwich Immunoassays Performed Using Luminex® xMAP® Technology
Presenter Bruce Amsden, ProZyme, USA
Additional Authors: Archie Chen and Sherry A. Dunbar
Achieving high signal levels with low background is a principle objective of Luminex xMAP assay development. The conjugated reporter dye, streptavidin-phycoerythrin (SA-PE), can greatly influence both the signal strength and the background in an assay. We present as an example a panel of antibody-coupled microspheres which showed significant variation in background binding of SA-PE in the absence of both antigen and detection antibody. Several different types of SA-PE were tested against this panel for background binding. These same SA-PEs were tested in commercial assays for Human IL-4 and IFN-ã to compare relative signal strengths.Three new SA-PEs showed dramatic reduction of high backgrounds observed with some of the antibodies. These conjugates also produced higher signal strength. These improved properties can make a major contribution to assay optimization, and are illustrative of the continuous improvement we are making in this area.