Adenoviral vectors have been widely used in gene therapy clinical trials and subjected to rigorous testing to ensure safety and efficacy. Like therapeutic proteins, aggregation of adenoviral vectors needs to be quantified for process consistency and stability monitoring. The sucrose gradient sedimentation method of adenovirus particles using disc centrifugation, which is a modification of a method described by Bondoc and Fitzpatrick, was used. It proved to be quantitative and reproducible in evaluating a variety of samples including deliberately cross-linked adenovirus particles and process development lots of various ages. This aggregation assay revealed that most aggregates detected in the production lots were dimers, trimers, and tetramers; and the number of these small oligomers was easily reduced with the addition of 300 mM salt, thus demonstrating the reversible nature of a portion of the aggregate population. This method was validated to demonstrate that it was appropriate for final product lot release and stability monitoring…
Tag: <span>biologics production</span>
The evaluation of bacteriocin cytotoxicity is a critical first step in guaranteeing its safe use in food and therapeutic applications. In this study, the bacteriocins nisin, pediocin, and colicin ([Col] E1, E3, E6, E7, and K) were evaluated for cytotoxicity against cultured mammalian cells. Cellular membrane potential (delta psi) changes of bacteriocin-treated cells were used as an index of cytotoxicity. Simian virus 40-transfected human colon (SV40-HC) cells and African green monkey kidney epithelial cells (Vero) cells were cultured (35°C, 10% CO2, humidified air) as monolayers on tissue culture plates. Log phase cells (~104 cells/mL) were treated with partially purified, individual bacteriocin preparations at 170, 350, and 700 activity units (AU)/mL…
Cell therapy products derived from adipose tissue have some unique processing issues with regard to obtaining accurate cell counts. This is because processing methods may not only show us the nucleated stromal vascular fraction (SVF) cells but also the micellular and microvesicle particles. This is true for both veterinary and human clinical products, and poses special concerns for in-clinic processing where the cell therapy dose is correlated with cell numbers and other QC data is not especially useful. In this study, multiple cell counting methods were compared for SVF cell preparation that were derived from canine adipose tissue using commercially-available processing kits. The data clearly showed that many non-nucleated particles appear cell-like by size and shape, and can lead to counting errors with automated counters. In addition, certain reagents important to processing can have properties wherein the reagents alone (e.g., lecithin) may be counted as cells. The most accurate cell numbers were from hemocytometer-counting of cells stained with 4´,6-diamidino-2-phenylindole (DAPI) which shows the nuclei in concert with a viability stain such as trypan blue. The data clearly showed that care must be taken when counting cells used as a therapeutic dose…
Efficient bioprocess characterization is essential for both regulatory compliance and commercial viability of biologics. Traditional approaches using resolution III/IV screening designs followed by response surface methodology are time-consuming, costly, and not always effective in identifying the important experimental effects. Definitive screening designs (DSDs) represent a novel class of three-level screening designs that can simultaneously evaluate main effects and quadratic relationships. While DSDs are increasingly used in bioprocess development, practical implementation guidelines remain limited. This case study bridges this gap by introducing a model-based framework to identify critical process parameters (CPPs) and optimize operating ranges for robust biologics production using plasmid DNA (pDNA). Minimal 14-run DSDs evaluated six input parameters and successfully identified CPPs and optimal operating ranges. This approach reduces experimental requirement by >50% compared to traditional designs, providing an efficient and economical strategy for bioprocess characterization and optimization.