Recombinant LONG R3IGF‐1 and rTransferrin Improved Growth and Productivity of Two Suspension Chinese Hamster Ovary Cell lines

Jinghui Qian, Rina Gandhi, Ariane Marolewski
Repligen Corporation


LONG®R3IGF‐1 is a human IGF‐1 analog containing a 13 amino acid N‐terminal extension and a mutation at position 3. It activates the Type 1 IGF receptor, which is responsible for growth‐promoting and protein synthesis effects in CHO cells. A common growth factor supplement used in CHO media, insulin, acts primarily through the IGF‐R.

LONG®R3IGF‐1 has previously been shown to increase CHO productivity. However, past characterization studies used primarily DMEM/F12 media. As serum‐free media development has progressed, media have become richer and more complex. To establish the effect of LONG®R3IGF‐1 in media that meet today’s industry standards, the effect of LONG®R3IGF‐1 on the productivity of two antibody‐expressing cell lines was compared to that of insulin and no growth factor supplemented media. The studies were carried out in TPP Tubespin50mL bioreactor tubes. Media with LONG®R3IGF‐1 gave superior titers versus no growth factor or insulin in several instances. In addition, it was demonstrated that combination of LONG®R3IGF‐1 and rTransferrin gave higher titer than commercial ITS (rInsulin, rTransferrin, Selenium) solution in several modern commercial media types.

LONG®R3IGF‐1 is used at low, 10 –100 ng/mL, concentrations in cell culture and is currently used in several commercial antibody manufacturing processes. It represents a regulatory‐friendly method of enhancing serum‐free cell culture performance. LONG®R3IGF‐1 should, therefore, be considered as a media supplement to further optimize a protein‐free process or to replace insulin in existing processes.

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