Engineering Cell-Free Biology for Pharmaceuticals and Vaccines
CBEMS 298 Department Seminar
Featuring Professor James R. Swartz
Chemical Engineering and Bioengineering
Location: ICS 147
This talk will describe the potential offered by recent cell-free protein synthesis (CFPS) advances. CFPS has now been converted from an expensive laboratory method into a potentially disruptive technology for the development and large-scale production of biopharmaceuticals and vaccines. Breakthroughs came with the realization that standard microbial metabolism could be activated and controlled. Central catabolism coupled with oxidative phosphorylation now provides a plentiful energy supply from inexpensive energy sources such as pyruvate, glutamate, or glucose. Nucleoside monophosphates can also be used instead of the more expensive triphosphates to further reduce variable costs. Cell extract costs have also been dramatically reduced using new fermentation protocols and streamlined extract preparation procedures. With the activation of respiration in CFPS reactions comes the need to supply oxygen. However, antifoam additions allow the use of standard bioreactors for scaling up the cell-free reactions. Thus, CFPS can now be practiced at any scale using conventional bioprocessing equipment.
In many ways, new CFPS technology has borrowed from existing E.coli production technologies. Yet the unique attributes of CFPS allow unprecedented control over the reaction substrates, catalysts, and environment. Using the T7 promoter and RNA polymerase, all of the biosynthetic resources are channeled to the product. Although the total macromolecular concentrations are only about 5% of those in a living cell, this turns out to be a significant advantage. The ribosomes function more slowly, but all are making the product of interest. The slower elongation rate coupled with the more dilute reaction environment allows proteins to fold more efficiently without forming aggregates. This is especially beneficial for proteins requiring the formation of multiple disulfide bonds. The sulfhydral redox potential can be readily stabilized and adjusted and the optimal level of disulfide isomerase added. In this way, a generic oxidative folding environment is produced within the same compartment that is conducting the transcription and translation reactions; a process not known to occur in nature. We will show several examples of complex multi-disulfide proteins that are successfully folded by these protocols. We will also show how this same approach can be used to efficiently produce virus-like particles that can be modified to produce designer vaccines.
Now that this new platform is cost-effective, scaleable, and able to produce disulfided mammalian proteins and complex assemblies, we can conduct process development at the 15 microliter scale with confidence that the basic principles learned will translate to large scale production. In essence, researchers can hold a large research and development pilot plant in their hands. Tens of production reactions can be conducted and analyzed in a single day with more control and consistency than is normally obtained using conventional fermentation and cell culture technologies.
About the Speaker:
Dr. Swartz obtained his B.S.Ch.E. from South Dakota School of Mines and Technology with highest honors. After working for two years for Union Oil Co. of California as a petroleum engineer, he attended M.I.T. where he earned his M.S. and D.Sc. in chemical engineering and biochemical engineering, respectively. His focus on the development and control of fermentation processes led him to a scientific exchange visit to the U.S.S.R. and to initial employment at Eli Lilly and Co. in
In 1998, he moved to