Adapting the power of density gradient separations for characterizing viral vector fullness

Abstract

A prominent hurdle in gene therapy is the inefficient packaging of nucleic acids into delivery vehicles. Depending on the type of viral vector used and the size of the transgene, the result is often a heterogenous population of capsids including empty, partially full, and full capsids. Only full capsids produce the intended therapeutic effect, with empty and partial capsids possibly causing adverse reactions and contributing to undesirable safety profiles. Capsid loading is therefore scrutinized rigorously by regulatory agencies such as the Food and Drug Administration (FDA), European Medicines Agency (EMA), or National Medical Products Administration NMPA (NMPA). There is a need within the industry for robust, serotype-independent purification and characterization schemes. Two such methods are density gradient ultracentrifugation (DGUC) and analytical ultracentrifugation (AUC).