Landing Pad cells with targeted integration for rapid cell line generation and library integration

Benefits of landing pad stable cells

Rapid timelines

Thanks to our landing pad technology, we can drastically limit the number of clones screened resulting in short timelines. From DNA to research cell banks in:

8-10 weeks for CHO cells
10-12 weeks for HEK293 cells

Difficult-to-express targets

The landing pad sites in our master cells are strategically selected to ensure stable and high expression across a diverse range of target classes.

Combined with expression from different promoters, we consistently find expression setups that show stable expression even for targets that are typically challenging to express.

Varied expression levels

By combining different master cell lines with expression driven by multiple promoters, we create a range of expression setups. This allows us to provide you with sets of cell lines with varying expression levels of the target.

Library integration

The single-copy integration technology enables variant library integration approaches to simultaneously test thousands of genetic variants. This is useful for mammalian display for biologics hit discovery, or knockdown and knockout screenings.

License free

No royalties, no license fees, no hidden costs. We only charge for the service we provide.

Our landing pad technology

We offer a variety of master cell lines, each featuring a landing pad located at a distinct genomic locus. These loci are all chosen for their capacity to support stable expression of a diverse range of targets.

Our approach utilizes directional DNA integration, where a recombinase specifically cuts a segment of the genomic landing pad and inserts the target sequence, supplied on a plasmid, in its place.

Since all resulting cell lines are genetically identical, extensive clone screening becomes unnecessary, saving both time and costs.

By combining different master cell lines with expression driven by multiple promoters, we create a range of expression setups. This maximizes the likelihood of successful expression for even the most challenging targets and allows the generation of cell line sets with varied target expression levels.

Features and Applications

Landing pad stable cells project workflow

-> We provide you with an honest feasibility assessment

Based on your project idea, we draft a project proposal including:

a feasibility assessment
suggested project structure and milestones
timeline and cost estimates

Thanks to our extensive experience generating thousands of stable cell lines, we will tell you if your project is a low-, mid-, or high-risk project.

-> We design and organize the gene synthesis

We design the ideal expression construct for your target – all we need is a target name, Gene ID or amino acid sequence. Together with you, we work on improving and modifying the sequence. For example. We may suggest adding a leader sequences or tags to improve protein expression and detection.

We then initiate, monitor and organize the gene synthesis together with our trusted partners.

This usually takes between 1 and 3 weeks depending on the sequence length and complexity.

-> Rapid cloning into our optimized in-house vectors

We design all synthesized genes ready for integration into our molecular biology workflow minimizing the time required for cloning.

We clone your target into our in-house plasmids that we have optimized for robust transfection into our landing pad cells.

Molecular cloning usually takes between 1 and 2 weeks.

-> We use optimized transfection protocols for high-efficiency into our master cells

We use our optimized transfection protocols to co-transfect your target together with the recombinase, which provides the directional DNA integration. We only use non-viral methods for gene delivery, either electroporation or lipofection.

Thanks to our optimized protocols, we routinely achieve high transfection efficiency further minimizing timelines.

We use an antibiotic selection marker, together with counter-selection to provide you with 100% positive cells. The selection marker only becomes functional if your target is correctly integrated providing another level of reassurance of correct transgene integration.

Transfection and expansion usually takes between 2-4 weeks depending on the cell type.

-> We make sure the cell line fits your requirements

We analyze target expression levels and provide additional characterization as necessary. Our default assays are: flow cytometry, qPCR or ELISA. In addition we offer a range of different assays to characterize the cell line.

Here is a non-exhaustive list of characterisation methods we offer in house or via subcontractors:

DNA/RNA level

RT-qPCR
NGS
RNASeq

Protein level

IF/ICC
ELISA
Flow cytometry
WB

Functional assays

second messenger assays (calcium, cAMP etc.) by fluorescence or luminescence
live cell imaging (fluorescence or brightfield) for short- or long-term assays (Cellcyte X, Zeiss CD7)
barrier formation via TEER
plate reader-based assays
Electrophysiology

-> We make sure everything looks good before we ship the cells

We perform extensive quality control to ensure you receive the best possible cell line. We offer a range of QC options, some of which are included as standard in our projects, others are optional:

contaminations (bacteria, mycoplasma, fungi)
human pathogens
STR profiling, species identification
cell numbers and viability
karyotyping

As part of our QC, we can also prepare cell banks ranging from research cell banks (<50Mio cells) up to small master cell banks (up to 1000Mio cells).

We provide all protocols and results generated within the project to you in a comprehensive written report.

Pricing

-> Our cell line packages can be further customized according to your requirements

Basic

For when you just need a cell line, for easy targets

from

8 500 €

8–10 weeks

CHO or HEK293
1 expression setup
Low-risk targets
Mid- to High-risk targets
Different expression levels
Intermediate reports
Final report
Monoclonal cells
Flow Cy, qPCR, ELISA
Basic cell bank

Optional add-ons

Standard

For difficult targets and if different expression levels are required

from

13 000 €

10–14 weeks

CHO or HEK293
> 6 expression setups
Low-risk targets
Mid- to High-risk targets
Different expression levels
Intermediate reports
Final report
Monoclonal cells
Flow Cy, qPCR, ELISA
Research cell bank

Optional add-ons

Both cell backgrounds +6 000 €
Long-term stability +1 500€
Receptor density +1 500€
Master cell bank +6 000€
Inducible expression +3 000€
Other characterization assays

Llama

Immortalized Llama cells with a landing pad

5 000–15 000 €

6–10 weeks

Immortalized Llama cells
Multiple expression setups
Any target possible
Different expression levels
Pool or monoclonal cells
Intermediate report
Final report
Flow Cy, qPCR, ELISA
Research Cell Bank

Optional add-ons

Stable landing pad cells Frequently Asked Questions (FAQ)

How are the cells generated?

We use our landing pad technology to generate stable cell lines.

Each of our master cell lines feature a landing pad located at a distinct genomic locus. These loci are all chosen for their capacity to support stable expression of a diverse range of targets.

We then use a recombinase for directional DNA integration, essentially cutting out a part of the landing pad and inserting your target in place. Both, the recombinase and the target are delivered by co-transfection using plasmids.

For a detailed discussion of our landing pad technology, schedule an introductory call, or have a look at our methodology paper: Schucht et al. J Biomol Screen (2011).

Can I use your stable cell lines for production of biologics?

While our landing pad cell lines are optimized for high and stable expression, the single-copy integration approach leads to lower titers compared to multi-copy approaches making our landing pad cells best suited for use in drug discovery.

Please also note that the cell culture conditions and protocols are not optimized for production, for example in fed-batch processes.

For which cell types do you offer landing pad technology?

Currently we have established our landing pad technology in:

CHO
HEK293
Immortalized Llama cells

Please contact us, if you would like us to establish our landing pad technology in your preferred cell line.

We also offer the generation of stable cell lines in any cell background using viral and non-viral random integration.

Can you establish landing pads in other cell lines as well?

Yes, we also offer the establishment of our landing pads in other cell backgrounds as a service. Please contact us to discuss your project idea.

We also offer the generation of stable cell lines in any cell background using viral and non-viral random integration.

What cell line package do I need, Basic or Standard?

The different packages provide a framework for our projects and can be further customized even during an ongoing project. We will provide you with a package recommendation during our feasibility assessment.

Generally, we recommend the Basic package if you just need a cell line and the target is low-risk meaning it has no know toxicity and has already been successfully overexpressed in stable recombinant cells – either by us or by others.

With the Standard package, we will use multiple expression setups (combination of master cell line and promoter) to find the ideal combination for your target. This increases the chances of generating a cell line even for difficult-to-express targets and opens up the possibility to obtain sets of cell lines with different expression levels of the target.

Llama...??

That’s right. We have previously immortalized a Llama cell line, also known as CellVacc-Llama. It is a fibroblastoid cell line derived from a male Llama. We then established our landing pad technology in this cell line.

This is especially useful for cell-based immunizations as you can very quickly generate large numbers of stable recombinant llama cells overexpression your immunogen for immunization campaigns. Ideal for complex targets, such as T-cell receptors that need a membrane-bound configuration for stability.

The llama cell background minimizes background epitopes in cell-based immunizations compared to a xeno cell line such as CHO or HEK293.

Can I use the landing pad cells for commercial purposes?

Generally, most commercial research applications are allowed and you receive a royalty-free license to our IP to use the cells for your research with completion of the service project.

Any other commercial uses may be possible as well (offering research services, release assays, incorporation into your products) but they may require separate licenses.

Please contact for more information.

What is the BSL of the stable cell lines?

The cell lines are BSL1.

What are the lead times for your stable cell services?

We do not have any lead times and can start your project immediately.

How do I order your cell services?

The first step is to get in touch with us and tell us about your project idea. We will then provide you with a quote, which you can use for generating a purchase order.

You can then submit this PO to and we will start the project.

If we need to be registered as a supplier in your database, please contact .

In addition, we are listed on multiple digital purchasing platforms.