Tumor killing assays
Antibody-Dependent Cellular Cytotoxicity (ADCC) Assay
Does your tumor-targeting antibody trigger NK cells to kill antibody-coated cancer cells?
Explicyte measures ADCC directly in primary human NK-cell co-cultures, combining real-time tumor-cell apoptosis imaging with IFN-γ release as a functional readout of NK-cell activation.
ADCC assay format and readouts
- Format
- 96- or 384-well plates
- Model
- Human tumor cell lines co-cultured with primary NK cells
- Readouts
- Real-time tumor cell apoptosis and count (live-cell imaging), NK cell response via IFNγ release
- Reference antibodies
- Trastuzumab (anti-HER2), cetuximab (anti-EGFR)
- On request
- Cytokine release profiling, NK cytotoxic factor assessment (perforin/granzymes), proteomics, transcriptomics
Treated – 24h post-coculture
Control – 24h post-coculture
SKOV3 ovarian tumor cells co-cultured with stimulated NK cells for 24 hours. Cetuximab exposure triggers ADCC, driving apoptotic death of antibody-coated tumor cells.
The ADCC assay tells us whether an antibody can genuinely recruit NK cells to kill its target — not just bind it. By imaging tumor cell death in real time alongside IFNγ release, we separate true antibody-dependent killing from background NK activity, on the exact tumor model that matters for your program.
Imane Nafia, PhD
Chief Scientific Officer, Explicyte
Assay principle
How the ADCC assay works
1
Challenge tumor cells with candidate antibodies
Human tumor cell lines are exposed to test antibodies targeting a specific tumor antigen, then co-cultured with primary NK cells.
2
Track the tumor and immune response in parallel
Real-time live-cell imaging monitors tumor cell count and death using a nuclear probe and a caspase 3/7 apoptosis reagent. IFNγ release is quantified in parallel as a surrogate marker of NK cell activation.
3
Segment and analyze automatically
Automated image segmentation extracts kinetic apoptosis and proliferation curves across the full time course.
illustrative ADCC data
NK cell-mediated killing: example results
Target and effector cell characterization
Flow cytometry confirms CD16 expression on primary NK cells isolated from PBMCs (A), and HER2/EGFR expression levels on ovarian SKOV3 (B) and lung A549 (C) tumor cell lines used in the assay.
IFN-γ release reveals target-dependent NK-cell activation
SKOV3 (HER2+/EGFR+) and A549 (EGFR+/HER2−) tumor cells were treated with trastuzumab or cetuximab, then co-cultured with activated NK cells at increasing E:T ratios. IFNγ release, measured in supernatants 24 hours later, rose with NK ratio in all conditions — but cetuximab boosted it further on both cell lines, while trastuzumab did so only on HER2+ SKOV3. The target- and antibody-dependent IFN-γ response distinguishes specific NK-cell activation from basal NK activity.
Avelumab drives NK-mediated killing of triple-negative breast cancer cells
MDA-MB-231 (TNBC) cells were treated with atezolizumab or avelumab, then co-cultured with activated NK cells at increasing E:T ratios. IFNγ release rose with NK ratio in all conditions, but only avelumab drove a further increase. Live-cell imaging confirmed the effect functionally, with avelumab-treated cells showing a corresponding rise in tumor cell apoptosis following NK addition. The assay distinguishes antibody-specific ADCC from basal NK activity, with cytokine and functional readouts in agreement.
Making a difference as a preclinical CRO in oncology
Why work with Explicyte
Proven experience
>10 years in preclinical immuno-oncology, deep expertise in NK- and antibody-mediated killing, over 100 in vitro campaigns delivered.
Built around your program
A PhD-level study director designs your study around your antibody, target antigen, and tumor model (over 100 tumor cell lines available).
Beyond functional readouts
A multiomic platform to resolve mechanism of action, alongside the core killing data — flow cytometry, proteomics, scRNA-seq, Xenium-STAMP.
Reports you can act on
Progress reports let you adjust the plan as the study runs; final reports arrive with ready-to-publish data for scientific and partner review.
Paul Marteau, PharmD (study director), Imane Nafia, PhD (CSO), Loïc Cerf, MSc (COO), Alban Bessede, PhD (founder, CEO), Jean-Philippe Guégan, PhD (CTO)
Contact our team
Discuss your ADCC assay
Tell us about your antibody, its target antigen, and the tumor models you're considering — we'll scope the right assay design, readouts, and reporting, and send a fit-for-purpose proposal.
Frequently asked questions
Answers about ADCC assay services
What is an ADCC assay used for?
It measures whether a candidate antibody can direct NK cells to kill antibody-coated tumor cells — a core mechanism behind several approved monoclonal antibody therapies, including trastuzumab and cetuximab.
How is NK cell activity measured in this assay?
Two ways in parallel: real-time live-cell imaging tracks tumor cell death and proliferation directly, while IFNγ release in the culture supernatant serves as a functional readout of NK cell activation.
Can I test my own antibody and target antigen?
Yes. The assay is built around your candidate antibody and the tumor antigen it targets, using a tumor cell line expressing that antigen at appropriate levels.
Which tumor cell lines and NK cell sources are used?
Cell lines are selected according to target-antigen expression. For example, the assays shown here use HER2+/EGFR+ SKOV3 cells and EGFR+/HER2− A549 cells. Primary NK cells are purified from human PBMCs rather than using an immortalized effector-cell line.
Can ADCC studies be performed across multiple NK-cell donors?
Yes. Studies can be designed with multiple independent primary NK-cell donors to assess reproducibility and inter-donor variability. Donor number, E:T ratios, antibody concentrations and replication are defined according to the study objective.
Can additional readouts be added to the assay?
Yes — cytokine release profiling, NK cytotoxic factor assessment (perforin/granzymes), proteomics, and transcriptomics are all available on request, alongside the core apoptosis and IFNγ readouts.
What deliverables do I receive from an ADCC assay?
Each study provides kinetic tumor-cell apoptosis and count curves, IFN-γ quantification as a functional NK-cell readout, and dose-response and/or E:T-ratio analyses as defined in the study design. A full study report includes raw data, figures, statistical analyses and experimental methods.
