Optimization of Zika virus VLP production in chemically defined medium using Quality by Design principles

Abstract

Responsible for causing a series of congenital diseases in humans, such as microcephaly in newborns and Guillain-Barré syndrome in adults, the Zika virus (ZIKV) began to spread throughout the Americas in 2015, quickly becoming a public health problem in at least 33 countries on the continent. This epidemic generated demand for the formulation of prevention against this infectious agent. In this scenario, developing safe and effective vaccines to mitigate or neutralize the consequences of ZIKV infection has become essential. Unfortunately, there is still no approved vaccine that provides immunization against ZIKV. Given the above, virus-like particles (VLPs), nanostructures composed of viral proteins capable of self-assembly, are revealed as vaccine candidates against ZIKV. This biotechnological product mimics the virus, inducing an immune response, but inside it, there is no viral genetic material, meaning the particle is not infectious. The present project aims to produce and characterize ZIKV VLPs through the recombinant Sf9/baculovirus cell expression system in a chemically defined medium using Quality by Design strategies as a tool for optimizing this bioprocess. For the work to be in line with the biopharmaceutical production model, initially, it will be necessary to evaluate and optimize, in shake flasks (suspension culture), the multiplicity of viral infection (MOI) and the time of infection (TOI), in addition to the time harvesting (HT), of recombinant baculovirus carrying the ZIKV structural protein genes (BV-E-ZIKV) for better expression of VLPs in quantity and size through experimental design. Then, using a bioreactor operating discontinuously, the concentration of dissolved oxygen in the medium and the temperature for VLP expression will be studied and optimized by experimental design. In parallel, nutrients and metabolites will be monitored offline in both experiments.