Type of cell line used to produce viruses or viral components, typically for the purpose of gene therapy...

Here is a general example of how this concept is used:
Gene Therapy Production: In the method described, a packaging cell line is created to stably express all the necessary components for adeno-associated virus (AAV) particle production. This includes the required viral proteins and genetic material that allow for the generation of viral vectors used in gene therapy applications.

Please go through these references for an in-depth clarification:
Precision NanoSystems: Discusses cell therapy and uses of lipid nanoparticles (LNPs) as an alternative to traditional viral vector-based systems, which often rely on packaging cells for gene delivery. This highlights the role of alternative delivery systems in gene therapy.
https://www.precisionnanosystems.com/workflows/genomic-medic...

Journal of Nuclear Medicine: Provides a scientific article that mentions the use of packaging cells in the context of gene therapy, specifically referencing the creation of specific types of cells for medical research and therapeutic purposes.
https://jnm.snmjournals.org/content/52/1/123