Conclusions
- Low concentrations of insulin supplemented into the basal media enhances cell proliferation
and IgG productivity by 1.5-fold in CHO-K1 cells. - Supplementation of Recombinant Insulin into feeding media enhances IgG productivity by
1.5-fold, without impacting cell proliferation. - Optimizing the Recombinant Insulin concentration in cell culture media is crucial to identify the
optimal conditions for maximizing cell culture media performance.
Background
The CHO cell line is widely recognized for its role in producing recombinant proteins, owing toits high growth capacity and productivity. Customizing cell culture media for specific cell lines is essential to leverage these characteristics for cost-effective and optimized performance. This study shows the beneficial effects of supplementing animal-free Recombinant Insulin in the basal or in the feeding media of a CHO-K1 fed-batch cell culture, specifically focusing on its impact on cell proliferation and IgG protein productivity.
Study description
The study comprised two parts. Firstly, varying concentrations (0, 2, 5, 10 mg/L) of Recombinant Insulin were added to the basal chemically defined medium (in house-developed) at the beginning of the CHO-K1 fed-batch cell culture. In the second part, different concentrations of Recombinant Insulin (0, 8, 20, 40 mg/L) were added into the feeding medium.
In both parts, 5% feed was supplemented to the culture every second day, beginning from day 3, and cell count and viability were determined daily. Additionally, the concentration of IgG in the supernatant was assessed on days 9, 11, and 13.
Results
In the initial experiment, when Recombinant Insulin was added to the basal media, the control group without insulin reached maximum density on the 9th day. Among the insulin concentrations tested, only 2 mg/L increased cell proliferation and resulted in a 1.2-fold increase in maximum cell density (Fig. 1A).
Consistent with these findings, 2 mg/L led to the highest increase (1.5-fold) in IgG expression. Despite having no effect on growth, 5 mg/L insulin noticeably increased IgG expression, whereas 10 mg/L did not show an increase compared to the control (Fig. 1B).
In the second part of the experiment, when Recombinant Insulin was added in the feeding media, there was no discernible effect of insulin on cell growth (Fig. 1C). However, IgG production increased with varying insulin concentrations, with the lowest concentration (8 mg/L) leading to the highest increase (1.5-fold) in IgG productivity (Fig. 1D).
Figure 1: Insulin supplementation in basal or feeding media improves IgG production in CHO-K1.
Recombinant Insulin was supplemented to the basal (A and B) or to the feeding media (C and D) in a fed-batch culture of CHO-K1 cells. When insulin was added to the basal media, cell proliferation was increased by 1.2-fold (A) and IgG production increased by 1.5-fold (B). When insulin was supplemented to the feeding media, cell proliferation was not markedly affected (C) but IgG production was increased by 1.5-fold (D).
