Development of analytical characterization tools for process monitoring of adenovirus-based vaccines (ChAdOx and Ad5)

Product quality understanding is a critical part of viral vector vaccine manufacturing and regulation. Mass spectrometry is a technique that has widely been applied to protein-based therapeutics and could be used as a characterisation tool to monitor viral vector vaccine product quality. The ultimate objective of this Bill and Melinda Gates Foundation funded project is to enable vaccine manufacturing in Low and Middle-income countries (LMIC) through increased scientific understanding of viral vector vaccine manufacturing bottlenecks and therefore de-risking of vaccine development and manufacturing. Please click Download on the upper right corner to see the full abstract

Measurement of Adenovirus-Based Vector Heterogeneity

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

Transverse boundaries in the embryonic cerebellar cortex of the mouse

Bibliography: p. 118-139Some pages are in colour

Zoning of Isfahan Drinking Water Distribution Network Corrosion Potential in Summer and Autumn of 2011 Using Geographic Information System (GIS)

This cross-sectional study has been conducted to determine the corrosion potential of water in Isfahan drinking water distribution system in 2011. Eighty samples during summer and fall 2011(40 samples for each season) were collected from different parts of the Isfahan drinking water distribution system. The temperature, calcium hardness, alkalinity, total dissolved solids, and pH were measured. Values of Langelier, Ryznar, Corrosiveness, and Puckorius indexes were calculated. Zoning maps were prepared using ArcGIS 9.3 software. The calculated mean values of Langelier, Ryznar, Corrosiveness, and Puckorius indexes in the summer and fall were (-0.52), 8.83, 10.37, 10.84 and (-0.71), 9.27, 10.94, 10.88, respectively. These results indicated that the Isfahan drinking water based on Langelier, Ryznar, and Puckorius indexes had a corrosive tendency and based on aggressiveness index had a moderate corrosivity potential. The corrosiveness of water may be as a basis for gradual deterioration of water distribution and transmission pipeline systems or as a route for contaminant entrance and finally can cause unhealthy impacts. Therefore, remedial measures are necessary to corrosion control of Isfahan drinking wate