Effective T-cell engagers (TCEs) can transform patient outcomes, but only if you can confidently balance efficacy with safety. Our mouse models enable you to predict cytokine release syndrome (CRS) before clinical studies.

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Powerful TCEs Carry Significant, Often Unpredictable Risks

Whether you're developing bispecifics, trispecifics, Fc engineered molecules, or costimulatory CD28 based TCEs, genOway provide human relevant mouse models validated with biopharma partners and TAA-expressing cell lines that help you generate more predictive efficacy data:

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Despite strong anti-tumor potential, TCEs can generate severe, dose limiting-toxicity:

On-target, off-tumor toxicity occurs when tumor-associated antigens (TAAs) are expressed in healthy tissues, narrowing the therapeutic window.
Strong T-cell activation, which is central to efficacy, can escalate into cytokine release syndrome (CRS), especially when myeloid and dendritic cells amplify immune signaling.

To prioritize safe candidates, researchers need preclinical systems that reflect human immune drivers of CRS, not oversimplified models that underpredict risk.

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Solution: Human-Relevant Models that Capture CRS Biology

Our mouse models are engineered to help you confidently assess TCE safety, define therapeutic windows, and identify CRS-prone constructs early.

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A mouse model with humanized CD3εδγ

The genO-panhCD3 model provides a robust foundation for TCE safety assessment because it reproduces human CD3 biology with high fidelity:

The physiological human CD3 expression preserves natural receptor density
Unaltered CD3/TCR interactions ensure that T-cell activation occurs through native signaling pathways
Functional T/B cell cooperation and intact immune homeostasis help generate immune responses that closely mirror human physiology

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These features allow for evaluation of TCE-induced activation and cytokine release under conditions that are truly predictive of clinical safety risks, including CRS, as shown in figure 1:

Multi‑panel graphs showing serum cytokine levels over time (CCL4/MIP‑1β, CXCL9 (MIG), IL‑4, IL‑6, IFN‑γ, TNF‑α, CXCL10 (IP‑10), and CCL2 (MCP‑1)) following anti‑CD3 OKT3 treatment compared with untreated controls. — **Figure 1** – cytokine release measured in genO-panhCD3 mice upon treatment with OKT3. This shows that CRS is induced upon OKT3 stimulation and that the model can be used to predict safety issues. Adapted from Martin-Jeantet, *et al.*, 2022.

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genO-hCD28 for safety assessment

As part of our portfolio of mouse models for evaluating the toxicity of TCEs, we also make available the genO-hCD28 model, which enables the evaluation of next generation TCEs that rely on CD28 co-stimulation thanks to the physiological regulation and expression pattern of hCD28 and the expression of different hCD28 isoforms. This model has been shown to reproduce the CRS-like features induced by TGN1412 as shown in figure 2, as presented at the AACR 2024:

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Multi‑panel graphs showing time‑dependent serum cytokine levels (IL‑4, IFN‑γ, CCL4, IL‑10, CXCL9, CXCL10, TNF‑α, IL‑6, CCL3, CCL2, GM‑CSF, and IFN‑α) after treatment, comparing multiple doses of TGN1412 and anti‑mouse CD3 with untreated controls. — **Figure 2** – Cytokine release measured in genO-hCD28 mice upon treatment with increasing concentrations of TGN1412. This demonstrates that the genO-hCD28 model can be used to predict safety issues, mimicking the CRS response observed in the TGN1412 clinical trial.

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Mice with a human immune system (HIS)

Additionally, we have also developed a mouse model with a human immune system, the genO-BRGSF-HIS, that contains a functional human myeloid and lymphoid cell compartment following reconstitution with CD34⁺ hematopoietic stem cells. A functional myeloid compartment is essential for measuring CRS-like features since CRS is not driven by T cells alone. Clinical evidence shows that myeloid and dendritic cells play central roles in amplifying cytokine cascades.

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This is why models such as the genO-BRGSF-HIS, provide a more reliable foundation for safety evaluation. It demonstrates:

Improved representation of immune cross talk essential for evaluating TCE activity
A more predictive environment for assessing cytokine release and toxicity risk, as shown in the paper by Martin et al., and summarized in figure 3:

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Multi‑panel graphs showing time‑dependent human cytokine release (TNF‑α, IL‑2, IFN‑γ, IL‑10, IL‑6, IL‑1RA, CCL2, and CXCL10) after OKT3 stimulation in PBMCs and CD34+ reconstituted mice, compared with vehicle controls. — **Figure 3** – genO-BRGSF-HIS (CBC) or BRGSF mice reconstituted with PBMCs were treated with OKT3. Cytokine release was measured over 48 hours. This shows that CRS is induced upon OKT3 stimulation in both PBMC- and hCD34+-reconstituted models, and the contribution of the myeloid cells for the profile of cytokines that are produced. Adapted from Martin *et al.*, 2024.

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These features make the model particularly suited for understanding how TCE designs translate into CRS propensity, helping teams prioritize safer constructs before submitting their investigational new drug application (IND).

If you’d like to know more about how this model helps you assess the safety of therapeutics, watch our webinar.

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genOway’s catalog models for safety assessment of TCEs

Below you can find a summary of key differences between our mouse models (table 1), which may help you choose the most appropriate model for your study.

Additionally, if you’d like to know more about our model portfolio for TCE assessment, you can find more information here.

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Comparative table summarizing syngeneic and humanized mouse models, highlighting differences in immune system composition, clinical signs, therapeutic window, CRS features, and price across genO‑panhCD3, genO‑hCD28, genO‑BRGSF‑PBMC, and genO‑BRGSF‑HIS models. — **Table 1** - Model comparison for safety studies

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List of references

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Scientific papers:

Martin et al., 2024, "Myeloid and dendritic cells enhance therapeutics-induced cytokine release syndrome features in humanized BRGSF-HIS preclinical model" - https://www.genoway.com/science/publications/scientific-publications/myeloid-and-dendritic-cells-enhance-therapeutics-induced-cytokine-release-syndrome-features-in-humanized-brgsf-his-preclinical-model

Posters

Martin-Jeantet et al., 2022, SITC, “CD3 humanized mouse models asvalidated tools to assess immune-related adverse events of T-cell engagers” - CD3 humanized mouse models as validated tools to assess immune-related adverse events of T-cell engagers | Poster | genOway
Sônego et al., 2024, AACR, “CD28 humanized mouse model for efficacy and safety assessment of CD28-targeting therapies” - CD28 humanized mouse model for efficacy and safety assessment of CD28-targeting therapies | Poster | genOway

Webinars

“Safety assessment of biologics in genO-BRGSF HIS: a highly predictive and translational mouse model” - Safety assessment in humanized mice｜Webinar genO-BRGSF-HIS｜genOway

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