CHO cells were first developed by Dr. Theodore Puck in 1957 for research purposes (Puck, 1957, Puck et al., 1958), resulting in limited productivity and the need to improve their performance. Therefore, we established our original CHO host cells from Chinese hamster ovaries, CHO-MK cells, that are compatible with industrial purposes. Having been screened and selected for high growth and high productivity, CHO-MK cells were successfully developed and are capable of meeting industrial needs such as for large-scale biopharmaceutical manufacturing (Masuda et al., 2024).

CHO-MK host cells have unique characteristics with an excellent growth rate, showing a short doubling time of less than 10 hours (Masuda et al., 2024). CHO-MK cells have a high metabolic rate and excellent viability, even at high culture densities. Consequently, CHO-MK cells can achieve high protein expression resulting in a high titer production of therapeutic proteins, which is unsurpassed by the conventional CHO cells.

CHO-MK host cells were established in our facilities by our experienced and expert scientists. At the beginning, we initiated the primary culture from isolated Chinese hamster ovary tissues. The immortalized cells were generated by spontaneous immortalization through continuous passaging and observation of cell morphology. The immortalized cells were then adapted to serum-free suspension culture. Finally, the fastest growing cells with high productivity were selected at a certain population doubling level (PDL) and used to produce host cell banks (HCBs) (Masuda et al., 2024). Documentation regarding the origin of Chinese hamsters, the culture history, etc., is available for Common Technical Document (CTD) submission.

Our vector system was designed to work optimally with CHO-MK cells throughout the Cell Line Development (CLD) process. For monoclonal antibody (mAb) production, we use a dual expression vector system with heavy and light chain regions. The vector selection system works efficiently for stable pool enrichment and cell sorting based on flow cytometry (FCM). Please get in touch with us to discuss your needs.

We use commercially available culture media. We have evaluated CHO-MK expression cells using several commercially available and chemically defined culture media. The results showed that the productivities were comparable, suggesting that CHO-MK cells are applicable to various culture media.

We monitor passage stability by culturing the cells for 15 passages, resulting in around 60 generations, and measure the cell productivity. The expression clones could show >90% of productivity level.

We mainly perform high-expression clone screening and assurance of clonality using digital and visual technology platforms i.e., fluorescence-activated cell sorting (FACS) and cell imaging (Jia, 2016). We developed our original gating method for FACS, which efficiently sorts the most highly productive cells.

We select one (1) to five (5) expression clones to produce PCBs. The number of clones is negotiable. Please contact us to discuss your needs.

The CHO-MK cell line has demonstrated top productivity, showing more than twice the production of Trastuzumab than the conventional CHO cell line in one third the usual culture period, i.e., 10 g/L in only 5 days. The average specific productivity was calculated at 60 pg/cell/day, which is greater than for the conventional CHO cells (Schulze et al., 2022; Xu et al., 2017). The potential impact on protein manufacturing and the economy is enormous. For example, such a high productivity should enable the production of more than twice the usual number of batches annually.

We provide Cell Line Development (CLD) services for antibody drugs, recombinant proteins, and biosimilars. Our CLD service platform begins with vector construction and produces a pre-master cell bank (PCB). We have expressed multiple antibodies including human, humanized, and chimeric (human-mouse) antibodies using CHO-MK cells. The average titer varies depending on the type of protein but can reach around 7-10 g/L using the common fed-batch culture method.

The potential impact on protein manufacturing and the economy is enormous. Thanks to the cells’ high productivity, the shorter culture period will allow manufacturers to produce more than twice the usual number of batches annually, and limit the cost of medium, labour-intensive processes, etc. Furthermore, a short culture period will also reduce the amount of residual protein expression and increase the purification efficiency.

Multicolor fluorescence in situ hybridization (mFISH) analysis suggests that the karyotype of CHO-MK cells is similar to that of the Chinese hamster (Masuda et al., 2024). Further, the Whole Genome Sequencing analysis (WGS) and sequencing of the expression cassette showed no genetic instabilities in CHO-MK cells (unpublished data).

No, we currently do not provide any service for biosimilarity and immunogenicity analysis. However, we can introduce you to professional Contract Research Organizations (CROs).

We have passed the safety tests for viral and other microorganism contamination and received the Certificate of Analysis (CoA) issued by BioReliance® which is recognized by the United States Food and Drug Administration (FDA). Notably, viruses, fungi, yeasts, bacteria, and mycoplasmas were not detected in CHO-MK host cells. The complete documentation can also be provided for Common Technical Document (CTD) submission.

Our client’s needs are our priority. We will customize the service and provide you with accurate estimates according to your protein (or biotherapeutic or therapeutic protein) products and requirements. Quotations will be issued under a non-disclosure agreement (NDA). Please get in touch with us to discuss your needs.

Several license packages are available. Discounts, free licenses, and free royalty packages are also available. Please get in touch with us to discuss your needs.

Yes, we have CDMO partners in Japan and overseas, including in the USA and Europe.