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P2002
FMAT Based Assay to Detect Antibodies Against Cell Surface Receptors
Presenter Hans-Willi Krell, Roche Diagnostics GmbH, Germany
Additional Authors: Roberta Schmieder, Ildiko Wünsche, Anton Belousov, Birgit Bossenmaier, Hans-Willi Krell
Therapeutic antibodies have revolutionized modern cancer treatment.
To identify monoclonal antibodies against a clinically important surface receptor family (RTK X), two different assay formats ELISA and FMAT have been developed and compared. In both assay formats, the relevant receptor was tagged with Streptavidin binding protein (SBP) to allow receptor binding to Streptavidin beads respectively Streptavidin coated microtiter plates.
The assays have been validated in terms of selectivity and matrix effects. Both formats have been applied to a pilot screen using 704 hybridoma supernatants.FMAT ( fluorometric microvolume assay technology ) enables homogeneous bead- or cell-based immunoassays in which no wash steps are required. The assay is simple to process and hands-on-time as well as the total time is significantly shorter compared to ELISA. In our pilot screen we conclude that FMAT  identifies more primary hits than the ELISA due to its higher sensitivity, but most of the hits identified by ELISA could be identified as well. No direct correlation of the ranking of primary hits between both formats were found. A disadvantage of the FMAT is the hook effect which shortens the linear range and causes problems with the hybridoma supernatant screening.