Single-step purification of bispecific monoclonal antibodies for immunotherapeutic use by hydrophobic interaction chromatography.

A method for large scale production and single-step purification of bispecific antibodies is described. Hybrid-hybridomas were grown in hollow-fibre bioreactors with an average yield of 8 to 12 g of immunoglobulin per month. Bispecific antibodies were purified from the bioreactor supernatant by hydrophobic interaction chromatography which resolves bispecific antibodies, monospecific immunoglobulins, and culture medium supplements in one single chromatographic step. Proteins were analyzed by ELISA, SDS-PAGE, isoelectric focussing, indirect fluorescence staining, CTL-stimulation and T-cell proliferation assays. Finally, antibody preparations were checked for the presence of endotoxin and mouse DNA. Our results suggest that functional bispecific antibodies for use in therapeutic applications can be batch purified from bioreactor harvest by hydrophobic interaction chromatography in a single step. Compared to other methods such as affinity chromatography (protein A/G), ion-exchange or hydroxyapatite chromatography, our protocol offers a substantial reduction in labor time, cost, protein loss, and risk of contamination.