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. 2021 Jul 28;12:4586. doi: 10.1038/s41467-021-24874-3

Fig. 4. RAPPID enables monitoring of clinically relevant antibodies.

Fig. 4

a Schematic overview of RAPPID sensors for the detection of anti-drug antibodies (ADAs). The use of a commercially available therapeutic antibody conjugated to both Gx-LB and Gx-SB enables binding of the ADA and the formation of a luminescent ternary complex. b Ratiometric sensor response curves in buffer (PBS (pH 7.4), 0.1% (w/v) BSA) of RAPPID sensors for anti-cetuximab, anti-adalimumab, and anti-infliximab, respectively. c Schematic overview of RAPPID sensors for detection of therapeutic antibodies adalimumab and infliximab using target antigen TNFα fused to SB, and the type 2 anti-infliximab and type 3 anti-adalimumab conjugated to Gx-LB. d Intensiometric detection of infliximab without calibrator luciferase. Luminescent measurements were performed at various intervals following the addition of the NanoLuc substrate. e Sensor response for adalimumab (left) and infliximab (right) detection in 10% plasma, diluted in the buffer. The same sample was used for detection with a digital camera (top) and the plate reader (bottom). Gray boxes represent the clinically relevant concentration range of each therapeutic antibody from cut-off value to trough concentration (8.5–53 nM and 3.3–47 nM for adalimumab and infliximab, respectively45–48), corrected for dilution. f Sensor response over time after one-step incubation of all assay components for both adalimumab (top row) and infliximab detection (bottom row), with varying ratios between sensor components antibody-LB and TNFα-SB, as indicated. Antibody-LB (1 nM) and TNFα-SB (1, 10, or 100 nM), therapeutic antibody (sample; 0, 0.1, or 1 nM), calibrator luciferase (cal.; 3–6 pM), and NanoLuc substrate (1000 × dilutions) were added simultaneously at t = 0. In (b), (d), (e) individual data points are represented as circles, and dashed lines connect mean values. In (f) data are represented as mean ± sd. All experiments were performed in technical triplicate, with n = 3 independent preparations of the analyte. Source data are provided as a Source Data file.