The Chinese hamster ovary (CHO) cell line is widely used for the production of therapeutic antibodies. In a typical cell line development workflow, CHO cells are transfected with an IgG expressing vector. Single transfected CHO cells are isolated for clonal expansion and high titer clones are identified via ELISA following outgrowth. These high producing cell lines are then expanded for large scale antibody production.
Generating cell lines for therapeutic antibodies requires clonal cell populations. Isolation of single cells for CHO cloning has traditionally been done with either FACS or limiting dilutions, each of which have inherent drawbacks.
Fluorescence-Activated Cell Sorters (FACS) instruments sort cells at very high pressure (up to 70 psi), which is harsh on the cells and results in reduced cell viability. These machines are also very difficult to use and prone to cross-contamination and clogging.
Limiting dilution, while gentler than FACS, limiting dilution is time-consuming, labor-intensive, and has very poor single cell isolation efficiency (by the Poisson distribution, empty wells and doublets are guaranteed). Therefore, this approach is extremely inefficient and costly.
CHO cells are transfected with a plasmid encoding the desired protein for mass production. Following selection, transfected cells in suspension are loaded into one of Namocell’s proprietary microfluidic cell cartridges and dispensed with Namocell’s Single Cell Dispenser into 96- or 384-well plates for clonal outgrowth. Following clonal expansion, colonies are analyzed via ELISA to determine antibody titers.
- Gentle sorting (<2 psi) preserves cell viability
- Higher clonality
- Better outgrowth
- 96-well plate in 1 min
- 384-well plate in 6 min
- Easily isolate high titer CHO clones
- Fit inside a cell culture hood for sterile sorting
- No clogging, no cross-contamination
- Easy to use, zero maintenance
Namocell Single Cell Dispensers are highly efficient and consistent at dispensing single cells (80-90% with mammalian cells) compared to manual pipetting (~30%).
Namocell’s Namo Single Cell Dispenser was used to sort CHO cells for clonal outgrowth alongside both limiting dilution (LDC) and a FACS. Cells sorted with Namo showed higher cloning efficiencies than LDC and FACS.
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