Need to Test Viral Products for Adventitious Viruses?

by Katherine Marotte, Principal Scientist, Group Leader, Viral Safety Testing Services

Biopharmaceutical products used for gene therapy applications are manufactured in living systems, such as animal or human cells or tissues. As such, they are at risk of being contaminated with adventitious viruses (foreign viruses that are introduced into a product accidentally during the manufacturing process). Many of the viral assays used to detect adventitious viruses employ live cell cultures, which can often present challenges in products that contain viruses. Eurofins Lancaster Laboratories, Inc. has experience working with these products as well as overcoming the challenges that accompany them.

Oncolytic viruses are designed to kill tumor cells while sparing normal cells. These viruses may be able to infect and kill the indicator cells used for the assays. The virus may need to be neutralized with an antibody before testing for the presence of adventitious viruses, and it may be challenging to achieve complete neutralization depending on the concentration of the virus. Viral vectors for gene therapy are engineered to produce a therapeutic product using a viral particle that is unable to replicate and produce new virus. Most viral vectors exhibit some degree of toxicity in the indicator cells used in assays, so the products may need to be diluted before testing. Viral vectors also have the potential to generate a false positive result in cell-based assays. The vector may be able to initiate an infection in certain cell types. Even though the infection may not be productive, it can produce signs that can be mistaken for a true viral infection. Additional testing will be needed to determine if the result is due to the vector or a true infection.

Eurofins has extensive expertise in dealing with challenging, but novel viral products in cell-based viral assays. Please contact Eurofins for further information regarding your oncolytic or gene therapy product testing.