12/11/2022 0 Comments Multipass vaccineProtease degradation and codon bias can also be a source of reduced manufacturing precision, contributing to lower yields and possibly to nonhomogeneity of the final VLP architecture. Even in downstream processing of soluble fractions, the VLP precursors often require separation of HSPs and molecular chaperone proteins (eg, GroEL) that can remain attached to the capsomeres, creating a significant bioseparation problem. Consequently, the process route becomes potentially more expensive than the eukaryotic route. Since limited solubility of recombinant viral proteins promotes the formation of inclusion bodies, the downstream processing is significantly compromised. MULTIPASS VACCINE FREEAnother common difficulty of these cells is the expression of a soluble and full-length product free of toxins, heat shock proteins (HSPs), and chaperone proteins. This is due to the inability of the proteins expressed in prokaryotic cells to undergo PTM such as protein glycosylation, a key feature in most VLP-derived vaccines. In fact, little or no immunogenic information is available for HBV-VLP, HPV-VLP, HCV-VLP, Ebola-VLP, SV40-VLP, RSV-VLP, infectious hypodermal and hematopoietic necrosis virus-VLP, No-VLP, and Indian peanut clump virus-VLP. VLPs produced in bacteria (ie, Escherichia coli) have not yet reached the market. Other VLPs produced in yeast, either in S. cerevisiae or in Pichia pastoris, namely the HIV-VLP, polyomavirus-VLP, norovirus (No)-VLP, and HCV-VLP, are under investigation. A different species of yeast, Hansenula polymorpha, has been used for the production of a licensed HBV-VLP (Hepavax-Gene, Berna Biotech Korea Corp). and Engerix-B, GlaxoSmithKline) and one HPV-VLP (Gardasil, Merck & Co.). Three licensed VLPs are currently produced in Saccharomyces cerevisiae: two HBV-VLPs (Recombivax HB, Merck & Co. VLPs of structurally simple viruses are usually produced in bacteria or yeast. Carrondo, in Comprehensive Biotechnology (Third Edition), 2017 1.47.4.2.1 Bacteria and yeast cells
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