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Hickey JM, Jacob SI, Tait AS, Vahid FD, Barritt J, Rouse S, Douglas A, Joshi SB, Volkin DB, Bracewell DG. Measurement of Adenovirus-Based Vector Heterogeneity. J Pharm Sci 2023; 112:974-984. [PMID: 36563855 PMCID: PMC9767660 DOI: 10.1016/j.xphs.2022.12.012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2022] [Revised: 12/14/2022] [Accepted: 12/14/2022] [Indexed: 12/25/2022]
Abstract
Adenovirus vectors have become an important class of vaccines with the recent approval of Ebola and COVID-19 products. In-process quality attribute data collected during Adenovirus vector manufacturing has focused on particle concentration and infectivity ratios (based on viral genome: cell-based infectivity), and data suggest only a fraction of viral particles present in the final vaccine product are efficacious. To better understand this product heterogeneity, lab-scale preparations of two Adenovirus viral vectors, (Chimpanzee adenovirus (ChAdOx1) and Human adenovirus Type 5 (Ad5), were studied using transmission electron microscopy (TEM). Different adenovirus morphologies were characterized, and the proportion of empty and full viral particles were quantified. These proportions showed a qualitative correlation with the sample's infectivity values. Liquid chromatography-mass spectrometry (LC-MS) peptide mapping was used to identify key adenovirus proteins involved in viral maturation. Using peptide abundance analysis, a ∼5-fold change in L1 52/55k abundance was observed between low-(empty) and high-density (full) fractions taken from CsCl ultracentrifugation preparations of ChAdOx1 virus. The L1 52/55k viral protein is associated with DNA packaging and is cleaved during viral maturation, so it may be a marker for infective particles. TEM and LC-MS peptide mapping are promising higher-resolution analytical characterization tools to help differentiate between relative proportions of empty, non-infectious, and infectious viral particles as part of Adenovirus vector in-process monitoring, and these results are an encouraging initial step to better differentiate between the different product-related impurities.
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Affiliation(s)
- John M Hickey
- Department of Pharmaceutical Chemistry, Vaccine Analytics and Formulation Center, University of Kansas, Lawrence, KS 66047, USA
| | - Shaleem I Jacob
- Department of Biochemical Engineering, University College London, London, UK
| | - Andrew S Tait
- Department of Biochemical Engineering, University College London, London, UK
| | | | - Joseph Barritt
- Department of Life Sciences, Imperial College London, London, UK
| | - Sarah Rouse
- Department of Life Sciences, Imperial College London, London, UK
| | | | - Sangeeta B Joshi
- Department of Pharmaceutical Chemistry, Vaccine Analytics and Formulation Center, University of Kansas, Lawrence, KS 66047, USA
| | - David B Volkin
- Department of Pharmaceutical Chemistry, Vaccine Analytics and Formulation Center, University of Kansas, Lawrence, KS 66047, USA
| | - Daniel G Bracewell
- Department of Biochemical Engineering, University College London, London, UK.
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Miller LM, Jarrold MF. Charge detection mass spectrometry for the analysis of viruses and virus-like particles. Essays Biochem 2023; 67:315-323. [PMID: 36062529 PMCID: PMC10842916 DOI: 10.1042/ebc20220101] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2022] [Revised: 08/11/2022] [Accepted: 08/19/2022] [Indexed: 11/17/2022]
Abstract
Heterogeneity usually restricts conventional mass spectrometry to molecular weights less than around a megadalton. As a single-particle technique, charge detection mass spectrometry (CDMS) overcomes this limitation. In CDMS, the mass-to-charge (m/z) ratio and charge are measured simultaneously for individual ions, giving a direct mass measurement for each ion. Recent applications include the analysis of viruses, virus-like particles, vaccines, heavily glycosylated proteins, and gene therapy vectors.
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Affiliation(s)
- Lohra M Miller
- Department of Chemistry, Indiana University, 800 E Kirkwood Ave, Bloomington 47401, Indiana
| | - Martin F Jarrold
- Department of Chemistry, Indiana University, 800 E Kirkwood Ave, Bloomington 47401, Indiana
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Jarrold MF. Charge Detection Mass Spectrometry: Analysis of Gene Therapy Vectors. LCGC NORTH AMERICA 2022. [DOI: 10.56530/lcgc.na.wh5987h4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Conventional mass spectrometry is limited by heterogeneity to relatively small molecular weights from a biologics perspective. Charge detection mass spectrometry—where masses of individual ions are directly measured—overcomes this limitation and allows measurements into the gigadalton (GDa) range. An important application of this emerging technology is the analysis of gene therapy vectors. Their large size and complexity present analytical challenges that must be addressed for this promising therapeutic approach to reach its full potential.
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Powers TW, Mullins EK, Zhang K, Binder JJ, Friese O, Runnels HA, Thompson LC. Identification of Recombinant Chimpanzee Adenovirus C68 Degradation Products Detected by AEX-HPLC. Front Bioeng Biotechnol 2022; 10:753481. [PMID: 35449595 PMCID: PMC9017566 DOI: 10.3389/fbioe.2022.753481] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2021] [Accepted: 03/09/2022] [Indexed: 12/01/2022] Open
Abstract
Physicochemical tests represent important tools for the analytical control strategy of biotherapeutics. For adenoviral modalities, anion-exchange high performance liquid chromatography (AEX-HPLC) represents an important methodology, as it is able to simultaneously provide information on viral particle concentration, product purity and surface charge in a high-throughput manner. During product development of an adenoviral-based therapeutic, an accelerated stability study was performed and showed changes in each of the AEX-HPLC reportable attributes. These changes also correlated with a decrease in product infectivity prompting a detailed characterization of the impurity and mechanism of the surface charge change. Characterization experiments identified the impurity to be free hexon trimer, suggesting that capsid degradation could be contributing to both the impurity and reduced particle concentration. Additional mass spectrometry characterization identified deamidation of specific hexon residues to be associated with the external surface charge modification observed upon thermal stress conditions. To demonstrate a causal relationship between deamidation and surface charge changes observed by AEX-HPLC, site-directed mutagenesis experiments were performed. Through this effort, it was concluded that deamidation of asparagine 414 was responsible for the surface charge alteration observed in the AEX-HPLC profile but was not associated with the reduction in infectivity. Overall, this manuscript details critical characterization efforts conducted to enable understanding of a pivotal physicochemical test for adenoviral based therapeutics.
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Affiliation(s)
- Thomas W. Powers
- Analytical Research and Development, Biotherapeutic Pharmaceutical Sciences, Pfizer Inc., Chesterfield, MO, United States
| | - Elise K. Mullins
- Analytical Research and Development, Biotherapeutic Pharmaceutical Sciences, Pfizer Inc., Chesterfield, MO, United States
| | - Kun Zhang
- Analytical Research and Development, Biotherapeutic Pharmaceutical Sciences, Pfizer Inc., Chesterfield, MO, United States
| | - Joseph J. Binder
- Cancer Vaccines and Immunotherapeutics, Pfizer Inc., San Diego, CA, United States
| | - Olga Friese
- Analytical Research and Development, Biotherapeutic Pharmaceutical Sciences, Pfizer Inc., Chesterfield, MO, United States
| | - Herbert A. Runnels
- Analytical Research and Development, Biotherapeutic Pharmaceutical Sciences, Pfizer Inc., Chesterfield, MO, United States
| | - Lawrence C. Thompson
- Analytical Research and Development, Biotherapeutic Pharmaceutical Sciences, Pfizer Inc., Chesterfield, MO, United States
- *Correspondence: Lawrence C. Thompson,
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Barnes LF, Draper BE, Jarrold MF. Analysis of Recombinant Adenovirus Vectors by Ion Trap Charge Detection Mass Spectrometry: Accurate Molecular Weight Measurements beyond 150 MDa. Anal Chem 2022; 94:1543-1551. [PMID: 35023731 DOI: 10.1021/acs.analchem.1c02439] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Adenovirus is one of the largest nonenveloped, double-stranded DNA viruses. It is widely used as a gene therapy vector and has recently received a lot of attention as a novel vaccine platform for SARS-CoV-2. Human adenovirus 5 (HAdV5) contains over 2500 protein molecules and has a 36 kbp genome. Adenovirus is well beyond the range of conventional mass spectrometry, and it was unclear how well such a large complex could be desolvated. Here, we report molecular weight (MW) distributions measured for HAdV5 and for 11 recombinant AdV vectors with genomes of varying lengths. The MW distributions were recorded using ion trap charge detection mass spectrometry (CDMS), a single-particle technique where m/z and charge are measured for individual ions. The results show that ions as large as 150 MDa can be effectively desolvated and accurate MW distributions obtained. The MW distribution for HAdV5 contains a narrow peak at 156.1 MDa, assigned to the infectious virus. A smaller peak at 129.6 MDa is attributed to incomplete particles that have not packaged a genome. The ions in the 129.6 MDa peak have a much lower average charge than those in the peak at 156.1 MDa. This is attributed to the empty particles missing some or all of the fibers that decorate the surface of the virion. The MW measured for the mature virus (156.1 MDa) is much larger than that predicted from sequence masses and copy numbers of the constituents (142.5 MDa). Measurements performed for recombinant AdV as a function of genome length show that for every 1 MDa increase in the genome MW, the MW of the mature virus increases by around 2.3 MDa. The additional 1.3 MDa is attributed to core proteins that are copackaged with the DNA. This observation suggests that the discrepancy between the measured and expected MWs for mature HAdV5 is due to an underestimate in the copy numbers of the core proteins.
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Affiliation(s)
- Lauren F Barnes
- Chemistry Department, Indiana University, 800 E Kirkwood Avenue, Bloomington, Indiana 47405, United States
| | - Benjamin E Draper
- Megadalton Solutions, Inc., 3750 E Bluebird Lane, Bloomington, Indiana 47401, United States
| | - Martin F Jarrold
- Chemistry Department, Indiana University, 800 E Kirkwood Avenue, Bloomington, Indiana 47405, United States
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