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Boselli D, Panigada M, Di Terlizzi S, Romanò M, Canonico E, Villa C, Minici C, van Anken E, Soprana E, Siccardi AG. Time- and cost-effective production of untagged recombinant MVA by flow virometry and direct virus sorting. J Transl Med 2023; 21:495. [PMID: 37482614 PMCID: PMC10364397 DOI: 10.1186/s12967-023-04353-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2023] [Accepted: 07/11/2023] [Indexed: 07/25/2023] Open
Abstract
BACKGROUND Recombinant MVAs (rMVAs) are widely used both in basic and clinical research. Our previously developed Red-to-Green Gene Swapping Method (RGGSM), a cytometry-based Cell-Sorting protocol, revolves around the transient expression of a green fluorescent cytoplasmic marker, to subsequently obtain purified untagged rMVA upon loss of that marker by site-specific recombination. The standard RGSSM is quite costly in terms of bench work, reagents, and Sorting Facility fees. Although faster than other methods to obtain recombinant MVAs, the standard RGSSM still is time-consuming, taking at least 25 days to yield the final product. METHODS The direct sorting of fluorescent virions is made amenable by the marker HAG, a flu hemagglutinin/EGFP fusion protein, integrated into the external envelope of extracellular enveloped virions (EEVs). Fluorescent EEVs-containing supernatants of infected cultures are used instead of purified virus. Direct Virus-Sorting was performed on BD FACSAria Fusion cell sorter equipped with 4 lasers and a 100-mm nozzle, with 20 psi pressure and a minimal flow rate, validated using Megamix beads. RESULTS Upon infection of cells with recombinant EEVs, at the first sorting step virions that contain HAG are harvested and cloned, while the second sorting step yields EEVs that have lost HAG, allowing to clone untagged rMVA. Because only virion-containing supernatants are used, no virus purification steps and fewer sortings are necessary. Therefore, the final untagged rMVA product can be obtained in a mere 8 days. CONCLUSIONS Altogether, we report that the original RGSSM has been markedly improved in terms of time- and cost efficiency by substituting Cell-Sorting with direct Virus-Sorting from the supernatants of infected cells. The improved virometry-based RGGSM may find wide applicability, considering that rMVAs hold great promise to serve as personalized vaccines for therapeutic intervention against cancer and various types of infectious diseases.
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Affiliation(s)
| | - Maddalena Panigada
- Division of Genetics and Cell Biology, San Raffaele Scientific Institute, Milan, Italy
| | | | - Monica Romanò
- FRACTAL - San Raffaele Scientific Institute, Milan, Italy
| | | | - Chiara Villa
- FRACTAL - San Raffaele Scientific Institute, Milan, Italy
| | - Claudia Minici
- Division of Genetics and Cell Biology, San Raffaele Scientific Institute, Milan, Italy
| | | | - Elisa Soprana
- Division of Genetics and Cell Biology, San Raffaele Scientific Institute, Milan, Italy
| | - Antonio G Siccardi
- Division of Genetics and Cell Biology, San Raffaele Scientific Institute, Milan, Italy.
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2
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RNA helicase DDX3X modulates herpes simplex virus 1 nuclear egress. Commun Biol 2023; 6:134. [PMID: 36725983 PMCID: PMC9892522 DOI: 10.1038/s42003-023-04522-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2022] [Accepted: 01/23/2023] [Indexed: 02/03/2023] Open
Abstract
DDX3X is a mammalian RNA helicase that regulates RNA metabolism, cancers, innate immunity and several RNA viruses. We discovered that herpes simplex virus 1, a nuclear DNA replicating virus, redirects DDX3X to the nuclear envelope where it surprisingly modulates the exit of newly assembled viral particles. DDX3X depletion also leads to an accumulation of virions in intranuclear herniations. Mechanistically, we show that DDX3X physically and functionally interacts with the virally encoded nuclear egress complex at the inner nuclear membrane. DDX3X also binds to and stimulates the incorporation in mature particles of pUs3, a herpes kinase that promotes viral nuclear release across the outer nuclear membrane. Overall, the data highlights two unexpected roles for an RNA helicase during the passage of herpes simplex viral particles through the nuclear envelope. This reveals a highly complex interaction between DDX3X and viruses and provides new opportunities to target viral propagation.
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Ricci G, Minsker K, Kapish A, Osborn J, Ha S, Davide J, Califano JP, Sehlin D, Rustandi RR, Dick LW, Vlasak J, Culp TD, Baudy A, Bell E, Mukherjee M. Flow virometry for process monitoring of live virus vaccines-lessons learned from ERVEBO. Sci Rep 2021; 11:7432. [PMID: 33795759 PMCID: PMC8016999 DOI: 10.1038/s41598-021-86688-z] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2020] [Accepted: 03/04/2021] [Indexed: 12/19/2022] Open
Abstract
Direct at line monitoring of live virus particles in commercial manufacturing of vaccines is challenging due to their small size. Detection of malformed or damaged virions with reduced potency is rate-limited by release potency assays with long turnaround times. Thus, preempting batch failures caused by out of specification potency results is almost impossible. Much needed are in-process tools that can monitor and detect compromised viral particles in live-virus vaccines (LVVs) manufacturing based on changes in their biophysical properties to provide timely measures to rectify process stresses leading to such damage. Using ERVEBO, MSD's Ebola virus vaccine as an example, here we describe a flow virometry assay that can quickly detect damaged virus particles and provide mechanistic insight into process parameters contributing to the damage. Furthermore, we describe a 24-h high throughput infectivity assay that can be used to correlate damaged particles directly to loss in viral infectivity (potency) in-process. Collectively, we provide a set of innovative tools to enable rapid process development, process monitoring, and control strategy implementation in large scale LVV manufacturing.
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Affiliation(s)
- Geoffri Ricci
- Vaccines Process Development and Commercialization, Merck & Co., Inc., 770 Sumneytown Pike, WP 42-3, West Point, PA, 19486, USA
| | - Kevin Minsker
- Vaccines Process Development and Commercialization, Merck & Co., Inc., 770 Sumneytown Pike, WP 42-3, West Point, PA, 19486, USA
| | - Austin Kapish
- Vaccines Process Development and Commercialization, Merck & Co., Inc., 770 Sumneytown Pike, WP 42-3, West Point, PA, 19486, USA
| | - James Osborn
- Vaccines Process Development and Commercialization, Merck & Co., Inc., 770 Sumneytown Pike, WP 42-3, West Point, PA, 19486, USA
| | - Sha Ha
- Vaccines Process Development and Commercialization, Merck & Co., Inc., 770 Sumneytown Pike, WP 42-3, West Point, PA, 19486, USA
| | - Joseph Davide
- Vaccines Process Development and Commercialization, Merck & Co., Inc., 770 Sumneytown Pike, WP 42-3, West Point, PA, 19486, USA
| | - Joseph P Califano
- Vaccines Process Development and Commercialization, Merck & Co., Inc., 770 Sumneytown Pike, WP 42-3, West Point, PA, 19486, USA
| | - Darrell Sehlin
- Vaccines Process Development and Commercialization, Merck & Co., Inc., 770 Sumneytown Pike, WP 42-3, West Point, PA, 19486, USA
| | - Richard R Rustandi
- Vaccines Analytical Research and Development, Merck & Co., Inc., West Point, PA, USA
| | - Lawrence W Dick
- Vaccines Analytical Research and Development, Merck & Co., Inc., West Point, PA, USA
| | - Josef Vlasak
- Vaccines Analytical Research and Development, Merck & Co., Inc., West Point, PA, USA
| | - Timothy D Culp
- Vaccines Process Development, Merck & Co., Inc., West Point, PA, USA
| | - Andreas Baudy
- Safety Assessment and Laboratory Animal Resources, Merck & Co., Inc., West Point, PA, USA
| | - Edward Bell
- Vaccines Process Development and Commercialization, Merck & Co., Inc., 770 Sumneytown Pike, WP 42-3, West Point, PA, 19486, USA
| | - Malini Mukherjee
- Vaccines Process Development and Commercialization, Merck & Co., Inc., 770 Sumneytown Pike, WP 42-3, West Point, PA, 19486, USA.
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Abstract
Herpes simplex virus replicates in the nucleus, where new capsids are assembled. It produces procapsids devoid of nucleic acid but containing the preVP22a scaffold protein. These thermo-unstable particles then mature into A-, B- or C-nuclear icosahedral capsids, depending on their ability to shed the proteolytically processed scaffold and incorporation of the viral genome. To study how these viral capsids differ, we performed proteomics studies of highly enriched HSV-1 A-, B- and C-nuclear capsids, relying in part on a novel and powerful flow virometry approach to purify C-capsids. We found that the viral particles contained the expected capsid components and identified several tegument proteins in the C-capsid fraction (pUL21, pUL36, pUL46, pUL48, pUL49, pUL50, pUL51 and pUS10). Moreover, numerous ribosomal, hnRNPs and other host proteins, absent from the uninfected controls, were detected on the capsids with some of them seemingly specific to C-capsids (glycogen synthase, four different keratin-related proteins, fibronectin 1 and PCBP1). A subsequent proteomics analysis was performed to rule out the presence of protein complexes that may share similar density as the viral capsids but do not otherwise interact with them. Using pUL25 or VP5 mutant viruses incapable of assembling C-nuclear or all nuclear capsids, respectively, we confirmed the bulk of our initial findings. Naturally, it will next be important to address the functional relevance of these proteins.IMPORTANCE Much is known about the biology of herpesviruses. This includes their unique ability to traverse the two nuclear envelopes by sequential budding and fusion steps. For HSV-1, this implies the pUL31/pUL34 and pUL17/pUL25 complexes that may favor C-capsid egress. However, this selection process is not clear, nor are all the differences that distinguish A-, B- and C-capsids. The present study probes what proteins compose these capsids, including host proteins. This should open up new research avenues to clarify the biology of this most interesting family of viruses. It also reiterates the use of flow virometry as an innovative tool to purify viral particles.
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