ExpiCHO is a highly efficient transient expression system that provides an expression level comparable to stable cell lines within two weeks. While CHO cells have been widely used in the industry for a long time, stable cell lines must be constructed to obtain CHO-expressed proteins, a time-consuming and labor-intensive procedure that requires experienced R&D personnel. In the drug development phase, it is necessary to produce a large quantity of proteins in a relatively short period of time, which makes the 293-transient expression system the only choice in most cases. This system, however, expresses at low levels with inconsistencies in the quality of the yielded proteins compared with the CHO system. In contrast, ExpiCHO, as an efficient transient expression system, can reach a yield of at least 1 g/L in just two weeks. In 2017, we used this system for the production of multiple fusion proteins and monoclonal antibodies. The expression levels were maintained at 1 g/L or more, exceeding 2 g/L and up to 3 g/L in some cases. When comparing the expression levels of the transient expression platform with those of stable CHO-S cell lines, we found that the two systems were  similar. In addition, while expressing a large amount of a protein, the transient system could also evaluate the expression level of the molecule in stable cell lines. ExpiCHO therefore provides an excellent tool for users who need to prepare a high volume of proteins rapidly.

ExpiCHO是一种高效的瞬时表达系统，可以在2周内获得与稳定细胞株相当的表达量。 CHO细胞长期以来一直在工业界广泛使用，获得CHO表达蛋白必须构建稳定的细胞株，这一过程不仅耗时耗力，而且需要经验丰富的研发人员。在药物开发阶段需要在较短时间获得大量蛋白，往往只能采用293细胞的瞬转表达系统，但该系统产量低，表达蛋白与CHO系统存在质量差异。ExpiCHO作为高效的瞬时表达系统能够在2周时间内获得克级每升表达量。2017年，我们采用该系统进行了多种融合蛋白及单抗的生产，表达量均维持在1g/L以上，部分超过2g/L，接近3g/L水平。同时，我们对比了瞬转表达水平与基于CHO-S的稳定细胞株表达水平，发现瞬转表达系统的产量与稳转细胞株的产量类似，瞬转系统在制备大量蛋白的同时也能评估该分子在稳定细胞株的表达水平。因此，ExpiCHO为需要快速制备大量蛋白的用户提供了一种极好的工具。