Development of a safe and high-quality Chinese hamster ovary (CHO) cell line is of paramount importance for the chemistry, manufacturing, and controls (CMC) portion of studies that support investigational new drug (IND) applications (1, 2). Desirable attributes of a CHO cell line include its ability to produce high titers of biotherapeutic proteins facilitate quick recoveries and selection processes maintain phenotypic and genetic stability throughout in-vitro aging of a culture. A CHO cell line also should be scalable to high-capacity culture…