Enhanced production of herpes simplex virus 1 (HSV-1) amplicon vectors by gene modification and optimization of packaging cell growth medium

Iván Fernández-Frías, Sara Pérez-Luz, Javier Díaz-Nido, Molecular Therapy - Methods & Clinical Development, 2020, doi:10.1016/j.omtm.2020.03.005.

This work improved HSV-1 amplicons by genetic modification of the packaging cell line and optimization of the culture medium. A stably-transfected Vero 2-2 cell line overexpressing the anti-apoptotic Bcl-2 protein was generated, exhibiting an increased resistance to apoptosis, prolonged culture duration and a significant improvement in viral vector production. Additionally, supplementation of the growth medium with antioxidants, polyamines, amino acids and reduced glutathione further increased the yield of packaged amplicon vectors. With these modifications, HSV-1 amplicons could be isolated from culture supernatants instead of cell lysates, leading to vector preparations with higher titer and purity and paving the way for generation of stable cell lines that are capable of continuous herpesviral vector production.