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>gene therapy</span>
An emerging application of viruses involves engineering them to treat diseases using a number of approaches. Broadly defined under the “virotherapy” umbrella, these include viral vectors used for gene therapy, oncolytic viruses, and viral immunotherapy. Although a majority of these products are in various stages of clinical development, the diversity of the therapeutic targets and wealth of future opportunities is encouraging. A significant challenge, as it is for any virus-based technology, is gaining a clear picture of the quality of a sample at any given point—from early research and development through manufacturing and product release. Of prime concern is the quantification of viruses, which in the past, has relied on slow, labor-intensive, subjective methods such as plaque titer assays and electron microscopic imaging. However, the diversity of new viral technologies now being used as the basis for innovative drugs and vaccines requires advanced, sophisticated analytical systems. In this white paper, we discuss how the real-time enumeration of viruses made possible by the ViroCyt® Virus Counter® 3100 can significantly enhance the pace of virotherapy product development…
While playing an integral role in biotechnology and medicine, cryopreservation (CP) is often viewed as a “simple tool” and is overlooked as a critical and evolving component of cell and tissue bioprocessing. Despite this, cryopreservation serves as an enabling technology in numerous areas including the latest cell therapies. For example, over one third of the cells used in clinical trials are cryopreserved using the traditional methods, which in many cases yield suboptimal outcomes. Further, researchers still rely on the assessment of cell survival immediately post-thaw (within a few hours), and fail to account for the impact of cryopreservation-induced delayed-onset cell death (CIDOCD) which continues to impact survival from hours to days post-thaw.
An astonishing range of viruses has provided building blocks for gene delivery systems, from the simple adeno-associated virus with a 5 kb genome to the complex poxviruses with 300 kb. This review focuses on non-replicating viral vectors that infect host cells just once, without producing infections virus. Viral vectors are generally characterized by several criteria, including their ability to integrate into the host genome, coding capacity, titer, toxicity, immunogenicity, host range, duration of gene expression, and transient or stable production systems. These are precisely the features that need to be carefully studied in the context of the application when deciding which vector to use…