Fig. 1 | Scientific Reports

Fig. 1

From: Novel fully human IgG1 targeting folate receptor α demonstrates antitumor efficacy driven by avidity rather than monovalent binding affinity

Fig. 1

Affinity measured by SPR analysis of AFRA hIgG1 and ChiMOv19. (a, b) Functional affinity (measured by SCK). 700 RU of recombinant FRα was immobilized on a CM5 sensor chip. Antibodies were injected in SCK (no regeneration between injections). AFRA hIgG1 and ChiMOv19 were tested from 12.5 to 0.8 nM (b). (a) AFRA hIgG1: Ka = 6.6 × 10⁶ (1/Ms), Kd = 0.008 (1/s), KD = 1.2 × 10⁻9 M, RUmax = 488, χ² = 36. (b) ChiMOv19: Ka = 9.5 × 105 (1/Ms), Kd = 2.4 × 10⁻⁴ (1/s), KD = 2.6 × 10⁻¹⁰ M, RUmax = 882, χ² = 48. (c, d) Intrinsic affinity (measured by MCK). Soluble recombinant FRα (200–0.4 nM) was injected over immobilized AFRA hIgG1 (c) or ChiMOv19 (d). (c) AFRA hIgG1: Ka = 1.0 × 10⁶ (1/Ms), Kd = 0.27 (1/s), KD = 2.6 × 10⁻7 M, RUmax = 67, χ² = 0.03. (d) ChiMOv19: Ka = 1.3 × 106 (1/Ms), Kd = 4.5 × 10⁻⁴ (1/s), KD = 3.5 × 10⁻¹⁰ M, RUmax = 42, χ² = 1.6. Binding is expressed as responsive unit (RU; y-axis) over time (x-axis). Kinetics were obtained by global fitting to a 1:1 model using Biacore T200 software.

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