Rapid discovery and optimization of therapeutic antibodies against emerging infectious diseases

Rogers, J.; Schoepp, R.J.; Schröder, O.; Clements, T.L.; Holland, T.F.; Li, J.Q.; Li, J.; Lewis, L.M.; Dirmeier, R.P.; Frey, G.J.; Tan, X.; Wong, K.; Woodnutt, G.; Keller, M.; Reed, D.S.; Kimmel, B.E.; Tozer, E.C.

Using a comprehensive set of discovery and optimization tools, antibodies were produced with the ability to neutralize SARS coronavirus (SARS-CoV) infection in Vero E6 cells and in animal models. These anti-SARS antibodies were discovered using a novel DNA display method, which can identify new antibodies within days. Once neutralizing antibodies were identified, a comprehensive and effective means of converting the mouse sequences to human frameworks was accomplished using HuFR™ (human framework reassembly) technology. The best variant (61G4) from this screen showed a 3.5–4-fold improvement in neutralization of SARS-CoV infection in vitro. Finally, using a complete site-saturation mutagenesis methodology focused on the CDR (complementarity determining regions), a single point mutation (51E7) was identified that improved the 80% plaque reduction neutralization of the virus by greater than 8-fold. These discovery and evolution strategies can be applied to any emerging pathogen or toxin where a causative agent is known.