Improved Production Efficiency of Virus-Like Particles by the Baculovirus Expression Vector System

Abstract

Vaccines based on virus-like particles (VLPs) have proven effective in humans and animals. In this regard, the baculovirus expression vector system (BEVS) is one of the technologies of choice to generate such highly immunogenic vaccines. The extended use of these vaccines for human and animal populations is constrained because of high production costs, therefore a significant improvement in productivity is crucial to ensure their commercial viability. Here we describe the use of the previously described baculovirus expression cassette, called TB, to model the production of two VLP-forming vaccine antigens in insect cells. Capsid proteins from porcine circovirus type 2 (PCV2 Cap) and from the calicivirus that causes rabbit hemorrhagic disease (RHDV VP60) were expressed in insect cells using baculoviruses genetically engineered with the TB expression cassette. Productivity was compared to that obtained using standard counterpart vectors expressing the same proteins under the control of the polyhedrin promoter. Our results demonstrate that the use of the TB expression cassette increased the production yields of these vaccine antigens by around 300% with respect to the standard vectors. The recombinant proteins produced by TB-modified vectors were fully functional, forming VLPs identical in size and shape to those generated by the standard baculoviruses, as determined by electron microscopy analysis. The use of the TB expression cassette implies a simple modification of the baculovirus vectors that significantly improves the cost efficiency of VLP-based vaccine production, thereby facilitating the commercial viability and broad application of these vaccines for human and animal health.

Exploitation of stable nanostructures based on the mouse polyomavirus for development of a recombinant vaccine against porcine circovirus 2

“…All these vaccines are directed against the PCV2a subtype. Although an improvement in the expression of self-contained Cap protein in insect cells has been achieved [ 73 , 74 ], in our hands, the production and isolation of VarC chimeric structures carrying the fused Cap protein of PCV2b subtype was more efficient and easy. Another advantage of the VarC chimeric vaccine is that it represents a so-called DIVA (differentiating infected from vaccinated animals) vaccine, which also induces an immune response that differs from the response induced by natural infection, in this case, antibodies against the mouse polyoma VP1 protein.…”

Harnessing Recent Advances in Synthetic DNA and Electroporation Technologies for Rapid Vaccine Development Against COVID-19 and Other Emerging Infectious Diseases

“…As compared to monomeric antigens, nanoparticle vaccines have been demonstrated to induce significantly stronger humoral responses to various targets including HIV, influenza, RSV, and malaria (126)(127)(128)(129)(130). However, assembly of these nano-vaccines is technologically cumbersome and costly with the conventional techniques (131). Xu et al recently demonstrated that DNA/EP can enable direct de novo assembly of nanoparticle vaccines in the hosts to bypass such complex production processes (27,132).…”

Synthetic biology for bioengineering virus‐like particle vaccines

“…Synthetic engineering of baculovirus vectors using combinations of transcriptional or translational elements can increase yield in this system (Gómez‐Sebastián, López‐Vidal, & Escribano, ; Liu, Zhang, et al, 2015). Similarly, a synthetically designed expression cassette, containing rearranged genetic regulatory elements, transcription factors IE1 and IE0 and a transcription enhancer sequence linked to differential promoters, increased both expression and cell viability of porcine circovirus VLPs and rabbit hemorrhagic disease VLPs in IC‐BEVS (López‐Vidal et al, ).…”