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Introducing the CHO-MK Platform

CHITOSE’s proprietary CHO-MK* is a host cell line developed from a primary culture of Chinese hamster ovary tissue and is fully banked for biopharmaceutical production.


In performance testing, CHO-MK has demonstrated remarkably higher productivity compared to conventional CHO cell lines.

  • Naturally established without viral vectors or genetic engineering.

  • Yielding high titers in serum-free suspension culture.

  • A stable chromosomal foundation for consistent, long-term manufacturing.

*CHO-MK cells were developed under the support of AMED (Grant Number JP18ae101054)

CHO-MK Characteristics & Performance

The CHO-MK platform redefines bioprocess efficiency, consistently achieving antibody titers exceeding 10 g/L* within a condensed 5 – 7 day production cycle. This high productivity maximizes facility throughput and significantly lowers operational costs.

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Our lead clones exhibit excellent phenotypic stability and have been proven for robust performance at the 2,000 L manufacturing scale, ensuring a seamless transition from development to commercial production.

  • High Titers: Deliver consistently high yields of 10 – 13 g/L.

  • Industry Speed: Rapid 5 – 7 day production cycles.

  • Scalable Growth: Optimized for high-density suspension.

  • Proven Stability: Scalable manufacturing.

  • Fully banked industrial cell lines.

10 – 13 g/L 

ANTIBODY YIELDS*

5 – 7 Days

PRODUCTION CYCLE

>2,000 L

BIOREACTOR SCALE

*Enhancing monoclonal antibody production efficiency using CHO-MK cells and specific media in a conventional fed-batch culture, Hisashi Saeki, et al, Cytotechnology (2025) Volume 77 (1)

In fed-batch culture, the CHO-MK cell line produces 10 g/L of antibody in just 5 days, significantly faster than the conventional CHO cell line.

CS CHO Expression Vector

Created with Biorender.com

Developed through over a decade of protein expression research, the CHITOSE Super CHO (CS CHO) Expression Vector is our proprietary system engineered for high-performance biopharmaceutical production.

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By integrating the optimized signal sequences and nucleotide designs, this vector ensures robust protein expression specifically fine-tuned for the CHO-MK host platform.

  • CHITOSE's original expression vector system.

  • Contains optimized signal sequences to ensure high-level protein expression.

  • Features expertly designed nucleotide sequences for maximizing expression in CHO-MK cells.

Cell Line Development Service

FROM DNA TO PCB WITH HIGH‑TITER, STABLE CHO-MK CELL LINES

Built on over a decade of expertise, CHITOSE has established a high-performance protein expression platform integrating our productive CHO-MK host cell line and proprietary CS CHO expression vector system.

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We deliver robust, flexible solutions that shorten production timelines and reduce costs for biologics development, providing a reliable expression system for your protein through high-performance Research Cell Banks (RCBs) and Pre-Master Cell Banks (PCBs).

  • CHO-MK Cell Line and CS CHO expression vector system.

  • FCM-based enrichment of highly producing stable pools.

  • High-fidelity cloning by single-cell sorting.

  • Clonality assurance by high-resolution imaging.

  • Early process development using bioreactors.

Cell Line Development Process

STEP

1

STEP

2

STEP

3

STEP

4

VECTOR CONSTRUCTION

~ STABLE POOL

CLONING ~ RCB

PASSAGE STABILITY

~ PCB

PROCESS DEV.

CHARACTERIZATION

  • DNA & Vector Synthesis

  • Vector Construction

  • Stable Pool Enrichment

  • Single-Cell Cloning

  • Clonality Assurance

  • High Expression Clone  Selection

  • Passage Stability Testing

  • PCB Candidate Selection​

  • Early Process Development

  • Technology Transfer

Speedy Cell Line Development Timeline

Vector Construction

Clone Production

PCB Production

PCB Characteristic Analysis

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1

2

3

4

Months

REDUCED COST OF GOODS • HIGH-PRODUCTIVITY • SCALABLE AND EFFICIENT • SHORT PRODUCTION TIME • STREAMLINED PROCESS • CONSISTENT APPROACH •

Business Process

STEP

1

STEP

2

STEP

3

STEP

4

STEP

5

Initial Inquiry

NDA Signing

Technical Consultation, Commercial Terms
& Quotation

Contract Execution

Service
Implementation &
Support

How We Support You

Comprehensive Partner Network

Integrated connectivity with media manufacturers, CROs, and equipment suppliers through a robust, expert-led network.

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One-Stop Solution

A unified hub delivering end-to-end support for pharmaceutical and biotech companies, simplifying complex bioprocesses.

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Single Point of Contact

Acting as your lead coordinator to ensure seamless transitions from initial development to commercial-scale manufacturing.

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Technical Documentation

Providing comprehensive documentation upon request.

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