Adenoviruses manufacture

One cornerstone provision of cGMPs is validation, a concept introduced to assure product consistency [84], The validation of downstream processing operations aims to prove that they are capable of consistently removing impurities (e.g., host cell components, process-related materials, adventitious agents) to acceptable levels. Additionally, acceptance limits and operating ranges for each step must be determined [84]. Validation studies usually lead to optimized processes with reduced variability and, as a consequence, to a decrease in the number of failed batches. Thus, the development of adenovirus manufacturing processes (and associated facility) should be undertaken with validation in mind, not only to improve quality assurance and accelerate approval, but also to reduce costs [85, 86]. 

Ostrove, J.M., Iyer, P., Marshall, J., and Va-cante, D. (1998) Comparison of manufacturing techniques for Adenovirus production. 

Manufacture Scale-Up. The adenovirus harvest process consisted of three general steps concentration, lysis, and clarification. In the small-scale process, the intact adenovirus-infected cells in culture medium were aliquoted and batch centrifuged to achieve a 30-fold concentration, and the supernatant was manually removed and replaced with a smaller volume of the freeze buffer. Although sufficing for harvest volumes of no more than lOL, such a manual process would prove to be inadequate on a larger manufacturing scale. 

Most El-deficient recombinant adenoviruses are propagated in the HEK-293 and PER.C6 cell lines (and derivatives thereof) as discussed in Section 10.1.2.3. The generation of RCAs is minimal in PER.C6 but remains a concern for HEK-293. Both cell lines have been documented for GMP manufacturing [110]. The production of these cells can be accomplished by a variety of methods, which depend on whether adherent or suspension cell lines are being used. 

Iyer P, Ostrove J M, Vacante D (1999). Comparison of manufacturing techniques for adenovirus poduction. Cytotechnol. 30 169-172. 

However, a reporter gene needs to be introduced into the cells to be imaged. Viral gene vectors (retrovirus, adenovirus, Herpes simplex virus, etc.) have a high transfection efficiency, but may lead to immunogenic response, whereas nonviral systems (naked DNA, liposomes, etc.) are less immunogenic and easier to manufacture, but lead to a less efficient transfection (3). 

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