CHO Cell Culture and Maintenance

CHO K1 cells were obtained from ATCC (Manassas, VA, USA), and CHO DG44 cells were obtained from Dr. Lawrence Chasin of Columbia University and Dr. Motonobu Katoh of our laboratory. These cells were maintained in Ham’s F-12 nutrient mixture (Invitrogen, Carlsbad, CA, USA) plus 10% fetal bovine serum (FBS) (JRH Biosciences, Lenexa, KS, USA). CHO K1 hybrids carrying the HAC (21HAC4) were cultured with 8 μg/ml blasticidin S hydrochloride (Wako, Tokyo, Japan) as previously described^{24 (link)}. In antibody purification analysis, CHO K1 and CHO DG44 cells were maintained in Ham’s F-12 nutrient mixture (Invitrogen) 10% plus IgG free fetal bovine serum (FBS) (GE Healthcare, Piscataway, NJ, USA).