Protein production with recombinant baculoviruses in lepidopteran larvae.

With an increasing need for functional analysis of proteins, there is a growing demand for fast and cost-effective production of biologically active eukaryotic proteins. The baculovirus expression vector system is widely used, and in the vast majority of cases cultured insect cells have been the host of choice. A low cost alternative to bioreactor-based protein production exists in the use of live insect larvae as "mini bioreactors." In this chapter, we focus on Trichoplusia ni as the host insect for recombinant protein production, and explore three different methods of virus administration to the larvae. The first method is labor-intensive, as extracellular virus is injected into each larva, whereas the second lends itself to infection of large numbers of larvae via oral inoculation. While these first two methods require cultured insect cells for the generation of recombinant virus, the third relies on transfection of larvae with recombinant viral DNA and does not require cultured insect cells as an intermediate stage. We suggest that small-to mid-scale recombinant protein production (mg-g level) can be achieved in T. ni larvae with relative ease.