iBio, Inc. announced that its proprietary iBioLaunch™ technology for the production of biotherapeutic proteins and vaccine antigens in whole green plants has been used to produce a functional monoclonal antibody copy of palivizumab, a humanized monoclonal antibody that binds to respiratory syncytial virus (RSV) glycoprotein fusion protein (F), and inhibits viral entry into cells.
Palivizumab is used to reduce RSV associated hospitalizations, but its high cost limits treatment to high-risk infants who receive monthly intramuscular injections throughout the RSV season. Worldwide annual sales of palivizumab exceed $900 million.
Scientists at iBio’s research and development partner, Fraunhofer USA Center for Molecular Biotechnology, have expressed the antibody heavy and light chains in green tissues of plants using an iBioLaunch vector system developed for multi-chain proteins such as antibodies. The expression of palivizumab in plants resulted in self-assembly of the appropriate antibody quaternary structure, which was then recovered from the plant tissue.
iBioLaunch-produced palivizumab was shown to bind inactivated RSV, indicating that it recognizes F antigen presented on the virus’ surface. Furthermore, plant-produced palivizumab was demonstrated to have a dose-dependent RSV neutralizing activity in a plaque reduction neutralization test. The effective concentration to observe 50% plaque reduction is comparable for plant-produced palivizumab to that reported for palivizumab manufactured in recombinant mammalian cells. The virus neutralizing activity observed is specific to palivizumab, as demonstrated with the use of an unrelated, plant-produced monoclonal antibody as a negative control for any plant-specific activity.
The production of functional palivizumab in plants extends the number of monoclonal antibodies that have been produced using the iBioLaunch™ system. All the monoclonal antibodies manufactured using iBioLaunch technology have been shown to be correctly assembled and fully active in appropriate bioassays.
Source: iBio, Inc. press release