{Reference Type}: Journal Article
{Title}: Engineering an Autonucleolytic Mammalian Suspension Host Cell Line to Reduce DNA Impurity Levels in Serum-Free Lentiviral Process Streams.
{Author}: Howe G;Wasmuth M;Emanuelle P;Massaro G;Rahim AA;Ali S;Rivera M;Ward J;Keshavarz-Moore E;Mason C;Nesbeth DN;
{Journal}: ACS Synth Biol
{Volume}: 13
{Issue}: 2
{Year}: 2024 02 16
{Factor}: 5.249
{DOI}: 10.1021/acssynbio.3c00682
{Abstract}: We engineered HEK293T cells with a transgene encoding tetracycline-inducible expression of a Staphylococcus aureus nuclease incorporating a translocation signal. We adapted the unmodified and nuclease-engineered cell lines to grow in suspension in serum-free media, generating the HEK293TS and NuPro-2S cell lines, respectively. Transient transfection yielded 1.19 × 106 lentiviral transducing units per milliliter (TU/mL) from NuPro-2S cells and 1.45 × 106 TU/mL from HEK293TS cells. DNA ladder disappearance revealed medium-resident nuclease activity arising from NuPro-2S cells in a tetracycline-inducible manner. DNA impurity levels in lentiviral material arising from NuPro-2S and HEK293TS cells were undetectable by SYBR Safe agarose gel staining. Direct measurement by PicoGreen reagent revealed DNA to be present at 636 ng/mL in lentiviral material from HEK293TS cells, an impurity level reduced by 89% to 70 ng/mL in lentiviral material from NuPro-2S cells. This reduction was comparable to the 23 ng/mL achieved by treating HEK293TS-derived lentiviral material with 50 units/mL Benzonase.