Chrysalises as natural production units for recombinant subunit vaccines

The baculovirus vector expression system (BEVS) combines cultured insect cells and genetically modified Autographa californica nuclear polyhedrosis virus (AcMNPV)-derived baculovirus vectors. This expression system has been widely used for the expression of hundred of proteins for more than 30 years, existing commercial products manufactured at large scale by this methodology, mainly subunit vaccines. At an industrial scale, insect cells, as any other cultured cells, require artificial media and a strict control of environmental sterile conditions in the complex and expensive bioreactors. Here we describe an efficient alternative to produce recombinant biologics using the versatile and productive baculovirus vectors. It consists in natural biocapsules (pupae from Trichoplusia ni (Hübner) Lepidoptera), containing millions of insect cells in perfect physiological conditions, ready to be programmed by a genetically modified AcMNPV-derived baculovirus vector to produce large quantities of any recombinant protein. This technology, denominated CrisBio, has been tested to produce dozens of proteins, reaching productivities on the range of milligrams per infected pupa, that can be translated into dozens of vaccine doses, for example. The biologics production by CrisBio was industrialized with the design of both insect rearing and pupae storage single-use plastic devices, compatible with machines specifically designed for the automation of pupae manipulation and inoculation. These devices and machines reduce manual operations, increase batches consistency and facilitate the scaled production of any recombinant protein. As a mode of examples, the productivity in CrisBio technology platform of two virus-like particle (VLP) vaccine antigens is described in this work.