Human serum titrated with anti-PCSK9 mAb J16.

<p>(A) Raw data trace of fluorescence (in Volts) as a function of time recorded by the KinExA instrument for a typical experiment: (I) packing of mAb-coated beads inside the flow cell; (II) baseline signal; (III) auto-fluorescence signal obtained from serum components (presumably porphyrins); (IV) buffer wash; (V) detection of bead-captured PCSK9 with a Dylight-labeled mAb; and (VI) buffer wash, after which the final fluorescence signal for bead-captured PCSK9 is recorded (relative to the baseline signal). (B) Global fit of normalized data obtained from titrating J16 into different dilutions of serum prepared in PBS. (C) Error plots for K_D and PCSK9 concentration for the global analysis in panel B with best fit values (solid line) and 95% confidence interval (dotted lines). (D) Comparison of the fits obtained for single-curve and multi-curve (global) analysis of the data in panel B. The PCSK9 concentration is back-calculated for undiluted serum. Open and closed symbols indicate independent experiments performed with the same dilution factor.