Zinc supplementation increases protein titer of recombinant CHO cells

  • Berta Capella RocaEmail author
  • Antonio Alarcón Miguez
  • Joanne Keenan
  • Srinivas Suda
  • Niall Barron
  • Donal O’Gorman
  • Padraig Doolan
  • Martin Clynes
Original Article


In order to study the impact of zinc and copper on the titer levels of mAb and recombinant protein in CHO cells, the IgG-expressing (DP12) and EPO-expressing (SK15) cell lines were cultured in chemically defined media with increasing concentrations of either metal. Supplementation with 25 mg/l in CDM media resulted in a significant increase in EPO (1.7-fold) and IgG (2.6-fold) titers compared to control (no added zinc). Titers at this Zn concentration in CDM containing the insulin replacing agent aurintricarboxylic acid (ATA) (CDM + A) showed a 1.8-fold (EPO) and 1.2-fold (IgG) titers increase compared to control. ATA appeared to also reduce the specific productivity (Qp) enhancement induced by Zn-25, with up to 4.9-fold (DP12) and 1.9-fold (SK15) Qp increase in CDM compared to the 1.6-fold (DP12) and 1.5-fold (SK15) Qp increase observed in CDM + A. A 31% reduced Viable Cell Density (VCD) in DP12 was observed in both Zn-supplemented media (3 × 106 cells/ml vs 4.2 × 106 cells/ml, day 5), whereas SK15 Zn-25 cultures displayed a 24% lower peak only in CDM + A (2.2 × 106 cells/ml vs 3.2 × 106 cells/ml, day 5). Supplementation with copper at 13.7–20 mg/l resulted in less significant cell line/product-type dependent effects on titer, VCD and Viability. Analysis of the energetic phenotype of both cell lines in 25 mg/l Zn-supplemented CDM media revealed a twofold increase in the oxygen consumption rate (OCR) compared to non-supplemented cells. Together, these data suggest that high zinc supplementation may induce an increase in oxidative respiration metabolism that results in increased Qp and titers in suspension CHO cultures.


Zinc Copper Titer Chinese Hamster Ovary cells (CHO) Erythropoietin (EPO) IgG 



This work was conducted with the financial support of Scientific Foundation of Ireland (SFI) Grant No. [13/IA/1841] and Science Foundation Ireland co-funded by ERDF, Grant No. [12/RC/2275_P2].

Compliance with ethical standards

Conflict of interest

The authors declare that they have no conflict of interest.

Supplementary material

10616_2019_334_MOESM1_ESM.docx (42 kb)
Supplementary material 1 (DOCX 42 kb). Supplementary Fig. 1. Titer (a, b), VCD (c, d) and Viability (e, f) of SK15 (a, c, e) and DP12 (b, d, f) cells grown in suspension in in-house chemically-defined medium CDM + A supplemented with copper at: 1 mg/l (Cu-1), 7.5 mg/l (Cu-7.5), 13.7 mg/l (Cu-13.7) and 20 mg/l (Cu-20). Statistical differences in titer data compared to the control (CDM + A) are represented as: p-value < 0.05 (*) and < 0.01 (**)


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Copyright information

© Springer Nature B.V. 2019

Authors and Affiliations

  1. 1.National Institute for Cellular BiotechnologyDublin City UniversityDublin 9Ireland
  2. 2.SSPC-SFI, Centre for PharmaceuticalsDublin City UniversityDublin 9Ireland
  3. 3.National Institute for Bioprocessing Research and TrainingUniversity College DublinDublinIreland

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