Tissue culture
HEK 293F (HEK) cells (Thermo Fisher Scientific) were cultured in
FreeStyle 293 Expression Medium (Thermo Fisher Scientific) supplemented
with penicillin-streptomycin (0.2 U/mL) (Thermo Fisher Scientific).
CHO-S cells (Thermo Fisher Scientific) were cultured in FreeStyle CHO
Expression Medium (Thermo Fisher Scientific) supplemented with
L-glutamine (8 mM, Thermo Fisher Scientific) and penicillin-streptomycin
(0.2 U/mL). All cells were grown at 37°C and 5% CO2with rotation at 125 rpm in a humidified atmosphere. Transfections were
incubated in the same growth conditions. HEK cells were not subject to
more than 25 passages, whereas CHO cells were studied below 10 passages
to mitigate cell clumping. All cells were grown to a density of
1.2×106 cells/mL and diluted to
1.0×106 cells/mL on the day of transfection.