Home » Therapeutic Antibody » Antibody Engineering & Characterization » In vitro Pharmacology » Conventional Assay Cell Line Engineering Service

Major Challenges for Stable Cell Line Generation

Major Challenges Resolution
Lengthy development hindering the downstream applications One-stop service: gene synthesis, plasmid construction and preparation, lentivirus packaging in one service package.
Low efficiency in gene delivery to cells such as suspension cells and primary cells using conventional transfection methods

Lentivirus infection: Lentivirus can infect suspension cells and primary cells.

Non-lentivirus infection: Electro-transfection and nuclear-transfection are utilized for lentivirus-sensitive cell lines

Difficulty in delivery of genes longer than 3 kb into the target cells Lentivirus, electro-transfection and nuclear-transfection are great methods for improved transfection efficiency

Assay cell line at GenScript ProBio

GenScript ProBio has successfully constructed more than 500 assay cell lines, of which more than 100 can be used for antibody development, such as PD-1, PD-L1, Tim3, CTLA4, Lag3, Siglec15 as well as GPCR cell lines.

Part of the assay cell lines developed and available for antibody drug development

  • Type Cell Line
    Antigen CHO-K1/siglec 15
    Antigen CHO-K1/mouse siglec 15
    Antigen CHO-K1/cyno siglec 15
    Antigen CHO-K1/CD73
    Antigen CHO-K1/Mouse CD73
    Antigen CHO-K1/Cyno CD73
    Antigen CHO-K1/NKG2D
    Antigen CHO-K1/cyno NKG2D
    Antigen CHO-K1/LAG3
    Antigen CHO-K1/Claudin18.2
    Antigen HEK293/Claudin18.2
    Antigen BxPc-3/Claudin18.2
    Antigen HEK293/mouse Claudin18.2
    Antigen HEK293/Claudin18.1
    Antigen CHO-K1/cyno CD40
    Antigen CHO-K1/cyno CXCR4
    Antigen CHO-K1/CD70
  • Type Cell Line
    Immune Checkpoint CHO-K1/PD-1
    Immune Checkpoint CHO-K1/mouse PD-1
    Immune Checkpoint CHO-K1/cyno PD-1
    Immune Checkpoint Daudi/PD-1
    Immune Checkpoint CHO-K1/PD-L1
    Immune Checkpoint CHO-K1/mouse PD-L1
    Immune Checkpoint CHO-K1/cyno PD-L1
    Immune Checkpoint Raji/PD-L1
    Immune Checkpoint CHO-K1/CD47
    Immune Checkpoint CHO-K1/Mouse CD47
    Immune Checkpoint CHO-K1/Cyno CD47
    Immune Checkpoint CHO-K1/CTLA4
    Immune Checkpoint CHO-K1/mouse CTLA4
    Immune Checkpoint CHO-K1/cyno CTLA4
    Immune Checkpoint CHO-K1/4-1BB
    Immune Checkpoint CHO-K1/mouse 4-1BB
    Immune Checkpoint CHO-K1/cyno 4-1BB

Service Highlights

1.One-stop service: Service package including gene synthesis, vector construction, lentivirus packaging, and host cell characterization to ensure the delivery of cell lines with stable expression of genes inserted. All we need is your gene name of interest.

2.Proof of single cell clonality: Molecular Devices CloneSelect Imager imaging system verifies the monoclonality of cells.

3.Customized construction of expression vectors: Multiple promoters or co-expression of two or more genes in one plasmid. Various promoters and tags are available for your choice.

4.Multiple choices of expression validation methods: qPCR, RT-PCR, ELISA, Immunofluorescence, FACS and Western Blot.

5.Quality check: Delivered cell line free of fungus, bacteria and mycoplasma with viability over 90%.

6.Quality assurance: traceable experiment records.

7.Short turnaround time: Single cell clones delivered in 10-15 weeks.

Case study 1: Expression of unstable proteins

A common problem when developing assay cell lines is that the protein expression level is relatively low but mRNA level is high. We tackled this problem by co-expressing suitable co-factor or chaperone proteins which had the potential improve the expression level by 1000 folds.

Case study 2: Discriminative isoform-specific antibody development

Targeting a specific protein isoform is challenging in antibody development due to high sequence identity between these isoforms. By generating assay cells expressing different protein isoforms, antibodies’ specificity can be validated using FACS binding assay. For instance, anti-Claudin 18.2 antibody screening was incorporated with a counter-screen against Claudin 18.1, which is ubiquitously expressed in normal tissue.

Case study 3: Expression of secreted proteins on cell membrane

Anchoring secreted proteins on a cellular surface is a common way to enable antibody screening. One example is to construct an assay cell line expressing pro-inflammatory cytokine, tumor necrosis factor-α (TNF-α), which is usually secreted by macrophages.

The Stable Cell Line Service

Milestone Service Detail TAT (weeks)*
1 Host cell characterization Testing the single cell growth, killing curve 3~4
2 Expression vector construction Codon optimization, promoter selection, gene synthesis, plasmid preparation
3 Lentivirus generation Lentivirus packaging (optional) 1~2
4 Stable pool generation Cell pool with selection marker 3
5 Single cell clone generation and Screening Limited dilution to generate a single clone 3~4
6 Clone expansion, cryopreservation and QC Expanding the clone and preparing cryopreservation Check for bacteria, fungi and mycoplasma contamination 2~3
total 11~15

*The timeline is for estimation only, the actual delivery time may vary due to the complexity of biological process.