ExpiCHO-S™ Cells
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ExpiCHO-S™ Cells
Gibco™

ExpiCHO-S™ Cells

ExpiCHO-S Cells are derived from a non-engineered subclone that has been screened and isolated from CHO-S Chinese hamster ovary (CHO) cells.
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货号Format
A29127
A29132
货号 A29127
价格(CNY)
17,480.00
Each
添加至购物车
价格(CNY)
17,480.00
Each
添加至购物车
ExpiCHO-S Cells are derived from a non-engineered subclone that has been screened and isolated from CHO-S Chinese hamster ovary (CHO) cells (1). They are a core component of the ExpiCHO Expression System Kit (Cat. No. A29133). ExpiCHO-S Cells are maintained in suspension culture, have minimal tendency to clump, and grow to high density in ExpiCHO Expression Medium (Cat. No. A2910001). As part of the ExpiCHO Expression System Kit, the cells generate superior protein yields by transient transfection compared to standard CHO and 293 cells.

Features of ExpiCHO-S Cells include:

  • Suspension culture cells adapted in ExpiCHO Expression Medium
  • Demonstrated yields of up to 3 g of protein per L of transfected culture as part of the ExpiCHO expression system
  • Rapid doubling times of approximately 17 hours
  • Consistent transient expression performance for over 20 passages after thaw
  • High cell viability and productivity for greater than 10 days post-transfection as part of the ExpiCHO expression system
  • Enable rapid, high-yield transient protein production, allowing labs developing protein biotherapeutics to work with CHO-expressed proteins from start to finish in the drug development process

Frozen cells are supplied in a vial containing 1 mL of cells at 1 x 107 viable cells per mL in ExpiCHO Expression Medium and 10% DMSO. The cells should be thawed directly into ExpiCHO Expression Medium. The 6-vial multipack eliminates the need to expand and bank the cells in the lab.

Cells are typically grown in flasks on a shaker platform in a humidified, CO2 cell culture incubator. However, cultures are scalable from volumes of <1 mL up to 5 L when using a Nalgene 5-L angled-bottom flask. Protein harvest can be performed at 5 to 14 days post-transfection, depending on the protein expressed.

Reference

1. Wurm, FM. CHO Quasispecies—Implications for Manufacturing Processes (2013) Processes 1:296-311.

For Research Use Only. Not for use in diagnostic procedures.
规格
数量1 mL
Unit SizeEach

常见问题解答 (FAQ)

采用高滴度或最高滴度操作规程时,我发现有时细胞存活率在转染后大约第 7–8 天时会突然下降。该如何解决这个问题?

这种细胞存活率的突然降低往往提示蛋白表达过程中某些细胞培养条件不在最佳状态。发现这种问题时,应确认摇床速度在操作规程规定范围内;培养体积与培养瓶尺寸应相配;开始蛋白表达前操作 ExpiCHO-S 细胞时应小心,确保细胞不会因剧烈混匀动作而发生应激,等等。

有时,按照高滴度或最高滴度操作规程使用 125 mL 培养瓶培养时,不同瓶之间会有差异。此时,建议将 25 mm 摇床和19 mm 摇床的摇床速度分别提高到 130 rpm 和 140 rpm。

另外,我们发现如果使用 125 mL 培养瓶,那么有挡板培养瓶(baffled flask) 的效果更好,可消除不同瓶之间的差异——此时,考虑到挡板的影响,应将转染的细胞悬液量从 25 mL 增加到 35–40 mL,使其在挡板上达到最佳流动效果,同时其他试剂量也应相应调整。

使用有挡板培养瓶时也可使用较少的转染体积 (即 30–35mL);但此时考虑到挡板的影响,应稍微降低摇床速度 (即:将19 mm 摇床和 25 mm 摇床的速度分别设为 115 rpm 和 110rpm)。我们发现对于其他尺寸的培养瓶,使用有挡板培养瓶既无必要,也无益处。

ExpiCHO 蛋白表达可减少规模至比摇瓶更小的体积吗?

可以。如果使用 24 和 96 孔深孔板以及 50 mL 迷你生物反应管进行蛋白表达,请参照以下在线操作规程(https://www.thermofisher.com/content/dam/LifeTech/global/life-sciences/Protein%20Bio%20-%20Thermo/pdf/ExpiCHO-Protocols-Deep-Well-Blocks-Mini-Bioreactor-Tubes.pdf)。

澄清过程中有时ExpiCHO细胞上清液难以过滤。该如何解决这个问题?

由于 ExpiCHO 系统所用组分不同于以 HEK 293为基础的表达系统 (如:Gibco Expi293 系统),因此有时上清液可能较难通过普通的瓶顶过滤器进行处理。 解决这一问题时,我们建议首先将上清液以大约 5,000 x g 的离心力离心 30 分钟,然后再用 0.22 μm 过滤器过滤。其他过滤器 (如深层过滤器) 能提供更出色的上清液过滤性能,尤其是对较大的培养规模,因为此类过滤器专为处理 CHO 类表达系统的上清液而设计。

对于ExpiCHO表达系统的操作规程,应什么时候收集上清液?

收集时间高度取决于蛋白的性质。对于抗体等稳定蛋白,如果采用标准操作规程我们一般建议在转染后第 7–8 天收集,如果采用高滴度操作规程建议在第 9–10 天收集,如果采用最高滴度操作规程建议在第 11–12 天收集。此时细胞存活率应该仍然很高,理想状况下可达 70–80% 或更高。细胞内蛋白可能需要提早在第 4–7 天时收集。对于易于降解的蛋白,应该考虑设置不同的时间点收集,以确定最佳的收集时间。任何情况下,保持收集时细胞高存活率对蛋白质量和纯化都有好处。

对于高滴度和最高滴度操作规程有什么特殊说明吗?

按照高滴度和最高滴度操作规程调整温度时,建议使用一台专用的 32°C 培养箱,因为将 37°C 培养箱的温度改为 32°C后,培养箱的温度需要很长时间才能降下来,从而影响温度调整的效果。打开培养箱门降温可能会导致污染。