Viral vectors for gene therapy, such as recombinant Adeno-Associated
Viruses (rAAV), are produced in Human Embryonic Kidney (HEK) 293 cells.
However, the presence of the SV40 T-antigen-encoding CDS SV40GP6
and SV40GP7 in the HEK293T genome raises safety issues when these
cells are used in manufacturing for clinical purposes. We developed a
new T-antigen-negative HEK cell line from ExcellGene’s proprietary
HEKExpress®, using the CRISPR-Cas9 strategy. We obtained a high number
of clonally-derived cell populations and all of them were demonstrated
T-antigen negative. Stability study and AAV production evaluation showed
that the deletion of the T-antigen-encoding locus did not impact neither
cell growth nor viability nor productivity. The resulting CMC-compliant
cell line, named HEKzeroT®, is able to produce high AAV titers, from
small to large scale.