(255b) Purification of Monoclonal Antibodies by Affinity Precipitation Using Thermally Responsive Elastin-Like Polypeptides(ELPs) Fused to IgG Binding Domains: High Throughput Analysis and Scale up Considerations

Elastin like polypeptides (ELPs) are smart biopolymers which exhibit reversible precipitation above a certain temperature called as inverse transition temperature (T_t). ELPs fused to IgG binding domains can be used as novel tools for antibody purification. Robotic high-throughput screening was employed to investigate the performance of an ELP-Z affinity precipitation system, and the effects of operating conditions on IgG precipitation, elution and product quality were examined. High levels of IgG recovery were obtained using a range of conditions with good results occurring even at low ELP:IgG molar ratios and relatively high elution pH (pH 4.2). Product quality issues such as aggregation were observed to be very sensitive to elution conditions and were evaluated using SEC, DLS and Dye binding studies. Conditions which exhibited both low aggregation and high product recovery were identified using a multidimensional high throughput screen and the robustness of the process was evaluated. Finally, key scale-up properties such as precipitation kinetics, precipitate morphology and particle size distributions were also examined at various stages of the process using DLS, confocal microscopy and turbidity measurements. This work sets the stage for the industrial implementation of this technology.