Characterization of rVSVΔG-ZEBOV-GP glycoproteins using automated capillary western blotting.

Ebolavirus (EBOV) entry to host cells requires membrane-associated glycoprotein (GP). A recombinant vesicular stomatitis virus vector carrying Zaire Ebola virus glycoprotein (rVSV-ZEBOV) was developed as a vaccine against ebolaviruses. The VSV glycoprotein gene was deleted (rVSV Delta G) and ZEBOV glycoprotein (GP) was inserted into the deleted VSV glycoprotein open reading frame (ORF) resulting in a live, replication-competent vector (rVSV Delta G-ZEBOV-GP). Automated capillary westerns were used to characterize the rVSV Delta G-ZEBOV-GP vaccine (ERVEBO (R)) manufacturing process with regards to glycoprotein (GP) structure and variants. The method shows a unique electropherogram profile for each process step which could be used to monitor process robustness. rVSV Delta G-ZEBOV-GP encodes GP (GP1-GP2), secreted GP (sGP), and small secreted GP (ssGP) variants. Furthermore, a TACE-like activity was observed indirectly by detecting soluble GP2 Delta after virus precipitation by ultracentrifugation. Capillary western blotting techniques can guide process development by evaluating process steps such as enzyme treatment. In addition, the technique can assess GP stability and process lot-to-lot consistency. Finally, capillary western-based technology was used to identify a unique biochemical profile of the rVSV Delta G-ZEBOV-GP vaccine strain in final product. Virion membrane-bound GP1-GP2 is critical to vaccine-elicited protection by providing both neutralizing antibodies and T-cell response. (C) 2020 The Authors. Published by Elsevier Ltd.