Are differences in cell viability levels from one transfection method to another large enough to actually affect protein titers?

Answer

Yes, high cell viability is critical for achieving high titers. Of course, it is essential to use cells that exhibit high viability pre-transfection (>95%), but it should also be emphasized that if cell viability is impacted by the transfection process, then cells will also exhibit reduced productivity. We consistently observed that post transfection viability >90% leads to titers that are significantly higher compared to cells that show viability <90% post transfection.