Immune function & modulation
Immune cell activation assay
Does your compound switch immune cells on — driving proliferation and cytokine release — or hold that response back?
This in vitro assay reads immune cell activation directly: primary human PBMCs or purified T cells are stimulated through the TCR, proliferation is tracked by live-cell imaging, and effector cytokines (IFN-γ, IL-2, TNF-α) are quantified by HTRF — benchmarked against anti-PD-1 and anti-PD-L1 standards.
Immune cell activation assay: format & readouts
- Format
- 96-well plate
- Model
- Primary human PBMCs, or a purified subset such as T cells
- Activator
- Anti-CD3 (TCR ligation), or another defined immune stimulus
- Readouts
- Proliferation by automated live-cell imaging; effector cytokine release (IFN-γ, IL-2, TNF-α) by HTRF or LEGENDplex
- Standards
- Anti-PD-1 (nivolumab, pembrolizumab) and anti-PD-L1 (atezolizumab)
- On request
- Flow cytometry immunophenotyping (checkpoint and activation markers), cytokine array, proteomics, transcriptomics
Anti-CD3 activated – 120h
Control – Inactivated PBMCs
The activation of immune cells is the first step in almost any response to immunotherapy, and it can be pushed in either direction. This assay measures that step directly in human primary cells: partners can read whether their compound raises or lowers proliferation and cytokine output, and interpret the effect against reference checkpoint inhibitors run in the same system.
Imane Nafia, PhD
Chief Scientific Officer, Explicyte
Assay principle
From TCR stimulation to a quantified cytokine readout
1
Stimulate through the TCR
PBMCs or purified T cells are incubated with an anti-CD3 activator cocktail for TCR ligation — or another defined immune stimulus.
2
Track proliferation live
Immune cell proliferation and clustering are visualized and measured over time by automated live-cell imaging.
3
Quantify cytokine release
Effector cytokines (IFN-γ, IL-2, TNF-α) are quantified by HTRF or LEGENDplex, functionally confirming the activation state.
illustrative immune cell activation data
The assay reads activation in both directions
Anti-CD3 drives a dose- and time-dependent release of inflammatory cytokines
TNF-α is induced by 24 h, while IFN-γ and IL-2 rise with both anti-CD3 concentration and time. IL-2 and IFN-γ track PBMC activation closely, making them the primary surrogates for activation state.
Anti-PD-1 antibodies raise anti-CD3-induced IFN-γ
Adding increasing concentrations of nivolumab or pembrolizumab to anti-CD3-activated PBMCs produces a dose-dependent increase in IFN-γ release, resolving a checkpoint inhibitor's effect on activation.
L-kynurenine suppresses the activated T-cell response
In anti-CD3-stimulated primary CD4+ T cells, TNF-α and IFN-γ (HTRF, 72 h) fall dose-dependently with concomitant L-kynurenine — the assay reads immunosuppression as clearly as it reads activation.
Making a difference as a preclinical CRO in oncology
Human-primary data, read in both directions and in depth
Ten years of in vitro campaigns
100+ in vitro immuno-oncology campaigns over the past decade, each run by a PhD-level study director from experimental plan through final report.
Human primary cells, not lines
Benchmarked in both directions
Reference checkpoint inhibitors — nivolumab, pembrolizumab, atezolizumab — run in the same system as your compound, so a potentiating or suppressive effect is read against a known scale rather than in isolation.
More than one readout per sample
Beyond proliferation and cytokine release, the same cultures support flow immunophenotyping, cytokine array, proteomics, and transcriptomics — turning an activation screen into a mechanism-of-action study.
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 immune cell activation project
Tell us the question you need the immune cell activation assay to answer, and we'll come back with a fit-for-purpose plan. Whether you're screening a single compound or benchmarking against checkpoint standards, a PhD-level study director will scope it with you before anything runs.
Immune cell activation assay: common questions
Frequently asked questions
What does the immune cell activation assay measure?
It measures whether a compound modulates the activation of primary human immune cells — reading both proliferation and effector cytokine release after stimulation through the T-cell receptor. It resolves potentiation and suppression on the same scale.
Which cells does the assay use?
Primary human PBMCs, or a purified subset such as T cells, depending on the question. Working in primary cells means the response reflects donor biology rather than an immortalized line.
How is activation read out?
Two readouts run in parallel: proliferation and clustering by automated live-cell imaging over time, and effector cytokine release quantified by HTRF or LEGENDplex at defined timepoints.
Which cytokines are quantified?
IFN-γ, IL-2, and TNF-α as standard. IL-2 and IFN-γ track activation most closely and serve as the primary surrogates; TNF-α is induced earliest, by around 24 hours.
What reference standards are included?
Anti-PD-1 (nivolumab, pembrolizumab) and anti-PD-L1 (atezolizumab), run in the same system as your compound so its effect is benchmarked against a known checkpoint response rather than read in isolation.
Can the assay detect immunosuppression as well as activation?
Yes. The readout moves in both directions: checkpoint inhibitors raise IFN-γ output, while an immunosuppressor such as L-kynurenine lowers anti-CD3-induced cytokine release dose-dependently.
What add-on readouts are available on request?
The same cultures support flow cytometry immunophenotyping (checkpoint and activation markers), cytokine array, proteomics, and transcriptomics — extending an activation screen into a mechanism-of-action study.
Can you test a compound in combination?
Yes. Compounds and antibodies can be run alone and in combination with anti-CD3, which is how checkpoint inhibitors are profiled — reading the added effect on proliferation and cytokine output against the anti-CD3 baseline.