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HEK293 / hPD-L1 Expression Stable Cells


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Clonal HEK293 cells stably expressing full-length human PD-L1 (CD274) under a CMV promoter. Untagged expression for native conformation. Suitable for PD-1/PD-L1 interaction studies, immune checkpoint screening, and anti-PD-L1 antibody validation.

Storage and Shipping: Cells are shipped as a frozen vial on dry ice. 

Upon Receipt: Frozen Vial: Transfer immediately to liquid nitrogen for long-term storage. 

⚠️ FOR RESEARCH USE ONLY This product is intended for laboratory research purposes only and is not suitable for human or veterinary diagnostic or therapeutic use.
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For Research Use Only
Return & Refund Policy

Internal Reference: KCL-ENG-102

Description
Characterization
Receipt Protocol
Catalog
Storage & Handling
Safety
FAQs
Product Description

⚠ FOR RESEARCH USE ONLY — Not for diagnostic or therapeutic procedures

KCL-ENG-102 is a clonal, antibiotic-selected HEK293 cell line engineered to stably express full-length human Programmed Death Ligand 1 (hPD-L1, also known as CD274) under a CMV promoter. The PD-L1 transgene is expressed untagged, preserving native protein conformation for antibody binding and functional assay work.

The line was generated by lentiviral transduction or piggyBac transposon integration and selected using puromycin resistance to ensure stable, clonal integration of the transgene. Expression is maintained under continuous puromycin selection for over 20 passages with greater than 95% of cells expressing hPD-L1 by flow cytometry.

This cell line is well-suited for studies of PD-1/PD-L1 checkpoint biology, screening of immune checkpoint modulators, and validation of anti-PD-L1 antibodies and small molecules. All lots are quality-tested prior to release for expression level, post-thaw viability, mycoplasma, and STR identity.

Recommended Medium

DMEM supplemented with 10% heat-inactivated FBS and 1% Pen/Strep. For routine maintenance under selection, add Puromycin at 0.5 to 1.0 μg/mL. Allow cells to recover in selection-free medium for 48 hours after thawing before reintroducing Puromycin.

Applications
PD-1/PD-L1 Interaction Studies Immune Checkpoint Research Antibody Validation Small Molecule Screening Flow Cytometry Reporter Assays Co-culture Assays Drug Discovery
Characterization

All lots are quality tested prior to release. The following characterization data is generated for each production lot.

Expression & Identity
Parameter Result Specification
hPD-L1 / CD274 expression ✓ Positive >95% by flow cytometry; MFI ~12,000
Expression stability ✓ Stable Stable for >20 passages under Puromycin selection
Post-thaw viability ✓ Pass >80% by trypan blue exclusion
Cell line identity (STR profiling) ✓ Confirmed Matches HEK293 reference profile
Transgene ✓ Confirmed Full-length hPD-L1 / CD274 (NCBI RefSeq: NP_054862.1), untagged
Selection marker ✓ Confirmed Puromycin resistance (PAC gene)
Contaminant Testing
Test Result
Mycoplasma ✗ Negative
Bacteria ✗ Negative
Fungi ✗ Negative

Certificates of Analysis with complete QC data, including flow cytometry histograms and STR profile, are available upon request. Contact Kulture Scientific with your lot number.

Receipt Protocol

KCL-ENG-102 is shipped as a cryopreserved vial on dry ice. Follow the steps below upon receipt. Detailed thawing, plating, and subculture protocols are available on the Kulture Scientific protocol page.

❄  Immediate receipt (same day)
1
Inspect the vial upon receipt. Confirm dry ice is present and vial cap is intact. Do not allow cells to thaw.
2
For long-term storage, transfer immediately to liquid nitrogen vapor phase (−150°C to −196°C).
⚠ Do not allow cells to thaw during transit or before intended use. Repeated freeze-thaw cycles will compromise viability and expression stability.
⚗  Thawing & recovery
1
Thaw vial rapidly in a 37°C water bath with gentle agitation. Remove when a small ice crystal remains.
2
Transfer cells dropwise into 9 mL of pre-warmed DMEM + 10% FBS + 1% Pen/Strep. Centrifuge at 200 x g for 5 minutes.
3
Aspirate supernatant and resuspend in selection-free DMEM + 10% FBS. Seed into a T-25 flask and place at 37°C, 5% CO₂.
4
Allow 48 hours recovery in selection-free medium before adding Puromycin (0.5 to 1.0 μg/mL) for maintenance.
⚠ Do not add Puromycin immediately after thaw. A 48-hour recovery window is required to avoid unnecessary cell stress and loss.
Subculture Guidelines

Subculture at 80 to 90% confluence using 0.25% Trypsin-EDTA. Split 1:4 to 1:6 every 2 to 3 days. Maintain under Puromycin selection (0.5 to 1.0 μg/mL) to preserve stable expression. Full subculture and cryopreservation protocols are available on the Kulture Scientific protocol page.

Product Catalog

KCL-ENG-102 is available as a cryopreserved vial containing at least 5×10&sup5; viable cells in cryoprotective medium containing DMSO.

Product Cat. No. Format Cell Number
HEK293 / hPD-L1 Expression Stable Cells KCL-ENG-102 Cryopreserved Vial ≥5×105 cells/vial
Storage & Handling
❄ Long-Term: Liquid Nitrogen Vapor Phase Ships on Dry Ice ⚠ Do Not Store at −20°C or −80°C
  • Long-term storage — store in liquid nitrogen vapor phase (−150°C to −196°C); cells are stable until the expiry date on the vial label when maintained under correct cryogenic conditions
  • Do not store at −80°C or −20°C — neither temperature is suitable for long-term cell storage; ice crystal formation at these temperatures will irreversibly damage cell membranes and compromise viability
  • Temperature sensitivity — minimize time outside cryogenic storage; cells are sensitive to temperature fluctuations
  • Freeze-thaw cycles — repeated freeze-thaw cycles compromise cell viability and expression stability; thaw only what is needed for immediate use
  • Shipping condition — cryopreserved vials are shipped on dry ice; inspect dry ice upon receipt and transfer vials promptly
  • DMSO content — cryoprotective medium contains DMSO; wear nitrile gloves during thaw procedures and avoid contact with skin
  • Certificate of Analysis — lot-specific QC documentation including flow cytometry data, viability, and STR profile available upon request
Health & Safety Information
⚠ WARNING! This product is of human origin. Handle all human-derived biological materials using Universal Precautions in accordance with local biosafety regulations. Appropriate personal protective equipment (PPE) must be worn at all times, including gloves, lab coat, and eye protection. Refer to your institutional biosafety guidelines for proper handling and disposal. Safety Data Sheet available at kulturesci.com.
Regulatory Status

For research purposes only. Not for use in diagnostic or therapeutic procedures. This product has not been tested or validated for clinical use. Not for direct administration into humans or animals.

Biosafety Level

This cell line should be handled under Biosafety Level 2 (BSL-2) conditions based on the following characteristics:

  • Human-derived origin — all human-derived cell lines require BSL-2 containment under Universal Precautions regardless of donor screening status
  • Lentiviral transduction history — the line was generated using lentiviral vectors; replication-incompetent lentivirally transduced lines are classified as BSL-2 by most institutional biosafety committees
  • Stable transgene integration — integrated transgene expression warrants appropriate institutional review and containment

Users must consult their institutional biosafety committee (IBC) prior to use. Individual institutions may impose additional requirements based on local policy.

Biosafety Considerations
  • Human-derived material — treat as potentially infectious; follow BSL-2 guidelines for handling human-derived cell lines
  • Lentiviral transduction history — handle in accordance with your IBC guidelines for lentivirally transduced cell lines; verify institutional requirements before use
  • DMSO (cryoprotectant) — cryopreserved vials contain DMSO, a skin-penetrating solvent; wear nitrile gloves at all times during thawing
  • Puromycin — handle antibiotic selection reagents in accordance with institutional chemical safety guidelines
  • Disposal — decontaminate all cell culture waste with an appropriate disinfectant (e.g., 10% bleach) prior to disposal in accordance with local biohazardous waste regulations
Frequently Asked Questions
Why is PD-L1 expressed untagged?
The hPD-L1 transgene in KCL-ENG-102 is expressed without an epitope tag to preserve native protein conformation. This is important for applications where tag-mediated steric interference could affect PD-1 binding, antibody recognition, or downstream signaling. If a tagged variant is required for your application, contact Kulture Scientific to discuss options.
When should I add Puromycin after thawing?
Allow 48 hours of recovery in selection-free medium after thawing before reintroducing Puromycin. Cells recovering from cryopreservation are under metabolic stress, and adding selection antibiotic immediately after thaw causes unnecessary cell death and reduces expansion efficiency. After the recovery window, maintain under 0.5 to 1.0 μg/mL Puromycin to preserve stable expression.
How do I confirm PD-L1 expression in my lab?
Expression is most readily confirmed by flow cytometry using an anti-human CD274 (PD-L1) antibody. Greater than 95% of cells should be positive with a mean fluorescence intensity of approximately 12,000 under continuous Puromycin selection. Western blot and immunofluorescence are also suitable detection methods. Kulture Scientific's Certificate of Analysis includes representative flow cytometry data for your lot.
How long is PD-L1 expression stable?
Expression has been validated as stable for more than 20 passages under continuous Puromycin selection. If cells are maintained without selection, transgene silencing or loss may occur over time. Always maintain KCL-ENG-102 under Puromycin pressure and verify expression periodically if extended culture is planned.
What is the parental cell line?
The parental line is HEK293 (human embryonic kidney, female, adherent), a widely used research cell line with well-characterized biology. Cell line identity is confirmed by STR profiling for each production lot. STR data is available on the Certificate of Analysis.
Can I use this cell line for clinical or therapeutic purposes?
No. KCL-ENG-102 is for research use only and is not validated for diagnostic or therapeutic procedures. This product has not undergone the regulatory review, manufacturing controls, or safety testing required for clinical-grade cell products. Do not administer to humans or animals.
Where can I find the Certificate of Analysis for my lot?
Certificates of Analysis are available upon request. Contact Kulture Scientific at info@kulturesci.com with the lot number printed on your vial label to receive the corresponding QC documentation, including flow cytometry data, viability, contaminant testing, and STR profile.