Genetic engineering techniques have been used to produce proteins with modified functions and to isolate proteins that are difficult to purify from natural sources. The most commonly used technology, based on expression in prokaryotic cells, is not satisfactory in all cases because the proteins are not appropriately modified and are often produced in relatively insoluble forms. The baculovirus expression system has been used as an alternative because insect cells infected with baculovirus vectors produce proteins that are post-translationally modified and that are expressed in high levels in the appropriate cell compartment. In addition, large DNA fragments have been successfully incorporated into baculovirus vectors. The complexity of the culture conditions for insect cells and the requirements for specialized equipment for scale-up have limited the application of this technology. An inexpensive and relatively simple alternative is to produce the recombinant protein in insect larvae. While this method has been used in research laboratories to generate recombinant proteins, the potential for use in large-scale manufacturing has not been demonstrated. Biotechnology Transfer, Inc. proposes to examine the technical, operational, and economic feasibility of using the insect larval system for expression of a lymphokine using a baculovirus expression system. The gene for IL-2 will be cloned into baculovirus and the recombinant virus fed to larvae. The protein will be purified using ion exchange and immunoaffinity chromatography, and characterized biochemically and functionally. Finally, issues of reproducibility and scale-up will be examined.
