Figure 4. Trade-offs between antibody non-specific interactions in physiological conditions and self-interactions in a standard formulation condition.

Comparison of antibody self-interactions (k_D, diffusion interaction parameter) and nonspecific binding using (A) ELISA #1, (B) ELISA #2, (C) PSP #1 and (D) PSP #2. The dotted line at a k_D value of 20 mL/g indicates a previously reported threshold for strongly repulsive self-interactions corresponding to desirable viscoelastic and opalescent properties for concentrated antibody formulations.¹⁰ The dotted line is the normalized non-specific binding value for trastuzumab, which is used as a threshold for low levels of non-specific binding in each assay. The parental antibodies are indicated in open circles. Notably, antibodies with low non-specific binding generally also display low levels of repulsive self-interactions (small k_D values). Conversely, antibodies that generally display highly repulsive self-interactions (large k_D values) also generally display high levels of non-specific binding.