The effects of microcarrier culture on recombinant CHO cells under biphasic hypothermic culture conditions

Abstract

A Chinese hamster ovary (CHO) cell line, producing recombinant secreted human placental alkaline phosphatase (SEAP) was investigated under three different culture conditions (suspension cells, cells attached to Cytodex 3 and Cytopore 1 microcarriers) in a biphasic culture mode using a temperature shift to mild hypothermic conditions (33 degrees C) in a fed-batch bioreactor. The cell viability in both the suspension and the Cytodex 3 cultures was maintained for significantly longer periods under hypothermic conditions than in the single-temperature cultures, leading to higher integrated viable cell densities. For all culture conditions, the specific productivity of SEAP increased after the temperature reduction; the specific productivities of the microcarrier cultures increased approximately threefold while the specific productivity of the suspension culture increased nearly eightfold. The glucose and glutamine consumption rates and lactate and ammonia production rates were significantly lowered after the temperature reduction, as were the yields of lactate from glucose. However, the yield of ammonia from glutamine increased in response to the temperature shift.

Fig. 1

Comparison of growth and viability between single-temperature and biphasic cultures. a Suspension cultures. b Cytodex 3 cultures. c Cytopore 1 cultures. Solid symbols [suspension (▲), Cytodex 3 (▼), Cytopore 1(■)] represent single-temperature cultures. Open symbols [suspension (○), Cytodex 3 (□), Cytopore 1 (△)] represent biphasic cultures. Solid lines indicate viable cell density; dashed lines indicate percent viability. Vertical dashed line indicates the temperature reduction from 37 °C to 33 °C

Fig. 2

Comparison of the productivities of SEAP-producing CHO cells under three different culture conditions in biphasic culture mode. Accumulated activity of SEAP in different culture conditions. [suspension (▲), Cytodex 3 (▼), Cytopore 1(■)]. Vertical dashed arrows at 95 and 133 h indicate the time of temperature reduction from 37 °C to 33 °C for suspension and microcarrier cultures, respectively

Fig. 3

Comparison of the accumulated productivities of SEAP-producing CHO cells between single-temperature and biphasic culture mode in different culture conditions. a Suspension cultures. b Cytodex 3 cultures. c Cytopore 1 cultures. Solid symbols [suspension (▲), Cytodex 3 (▼), Cytopore 1(■)] represent single-temperature cultures. Open symbols [suspension (○), Cytodex 3 (□), Cytopore 1 (△)] represent biphasic cultures

Fig. 4

Comparison of the metabolic activities of SEAP-producing CHO cells under three different culture conditions. a Glucose consumption. b Glutamine consumption. c Lactate production. d Ammonia production. Vertical dashed arrows at 95 and 133 h indicate the time of temperature reduction from 37 °C to 33 °C for suspension and microcarrier cultures, respectively. [suspension (▲), Cytodex 3 (▼), Cytopore 1(■)]