Focused on peptide immunogenicity assessment, precisely empowering tumor neoantigens.
Release Date:
2026-06-02 16:42
In the field of cancer immunotherapy, tumor neoantigen–specific T-cell responses serve as a key metric for assessing peptide immunogenicity. Leveraging its well-established in vitro assay platform, Hycells Biotechnology offers end-to-end services—ranging from initial screening of peptide immunogenicity and antigen‑specific T-cell expansion to validation of tumor cell‑killing activity—thereby supporting the efficient and reliable discovery and validation of neoantigens.
Comprehensive In Vitro Protocol for Assessing Peptide Immunogenicity
1. Core Experimental Objectives
1) Positive Peptides and Donor Screening
The peptide to be tested is co-incubated with PBMCs from HLA‑A‑matched healthy donors, and hIFN‑γ release is assessed by ELISpot assay, while T‑cell proliferation is analyzed by CFSE‑based flow cytometry, enabling systematic evaluation and identification of positive peptide–donor pairs.
2) Acquisition and Expansion of Antigen-Specific T Cells
The selected positive combinations were used to re‑stimulate PBMCs, and CD137⁺ T cells were sorted and expanded to sufficient numbers under the action of an activator for downstream functional assays.
3) DC load induction
Dendritic cells (DCs) from the same donor are pulsed with the target peptide (using HLA‑tetramer technology) to mimic the in vivo antigen‑presentation process.
4) Peptide-based authentication
Cells were collected for liquid-phase mass spectrometry analysis and peptide amino acid sequencing; the results were compared with the target peptide sequence, confirming its identity as a specific immunogen.
2. Standardized Experimental Procedure
1) Assay 1: Initial Screening Phase (approximately 2 weeks)
Prepare those with clearly defined HLA-A typing. X Peripheral blood mononuclear cells from a healthy donor;
Primary stage: PBMCs are pre-incubated with the peptide to be tested.
Boost phase: Cells are collected and seeded onto an ELISpot (IFN-γ) plate, followed by a second round of peptide stimulation.
ELISpot assay;
Proliferation assay: PBMCs after primary‑stage incubation are stained with CFSE, seeded in plates, and then subjected to peptide stimulation again.
Flow cytometric analysis of CD3⁺ T-cell proliferation (CFSE fluorescence decay).
2) Assay 2: Validation and Functional Phase (approximately 1 month in duration)
The positive peptide–donor pairs identified in Assay 1 were subjected to a second round of incubation.
Sort CD137⁺ T cells and expand them in the presence of an activator;
According to E:T specific ratio T cells were co-cultured with target cells, and the cytotoxic activity against tumor cells was assessed using the CTG/LDH assay.
Key Questions and Answers (Frequently Asked by Customers)
1. Why are multiple donors needed?
Enhance screening efficiency to ensure identification of the highest‑expressing peptide–donor matching combinations across different HLA‑A subtypes, thereby minimizing false negatives arising from donor‑specific variability.
2. What are the requirements for peptides provided by the customer?
Endotoxin: <10 EU (to avoid non-specific immune activation);
Solvent: If dissolved in DMSO, the stock solution concentration must be greater than 1 mg/mL.
Purity (HPLC): ≥95%;
TFA content: <1% (TFA exhibits strong immunogenicity); it is recommended to convert to the acetate form, which offers improved biocompatibility;
Sample submission format: Either lyophilized powder or solution is acceptable, with a total peptide amount of ≥100 μg per single peptide.
3. What positive control is used?
CEF peptides (a broad T-cell epitope library) and PHA (phytohemagglutinin).
4. Why does Primary use long peptides, while Boost uses short peptides?
Long peptide (Primary, 7–14 days): APC processing and presentation are required to mimic the in vivo natural process, prevent non-specific binding, and more accurately reflect immunogenicity; IL‑2 is added during this period to maintain T‑cell activity.
Short Peptide (Boost) : Directly and efficiently binds to HLA, rapidly induces T cells to secrete IFN-γ, facilitating ELISpot assays.
5. Was the wild-type (WT) peptide used as a control?
Yes, the CEF peptide and PHA were used as controls to rule out non-specific activation by the peptide itself.
6. How should individuals who test positive on the initial screening be managed?
ELISpot-positive → undergo proliferation assay → proliferation also positive → match the corresponding tumor cells and perform cytotoxicity validation.
Delivery cycle
Assay 1: Approximately 2 weeks (from the date of receipt of the peptide)
Assay 2: Approximately 1 month (including cell expansion)
Total: approximately 1.5 months
Advantages of the Hycells Bio Peptide Immunogenicity Assessment Platform
Advantages of Hycells Bio’s peptide immunogenicity platform:
A systematic donor–peptide matching screening strategy to prevent the omission of high-risk positive combinations.
A segmented stimulation protocol combining long and short peptides balances physiological relevance with assay sensitivity.
Stringent quality control standards (endotoxin levels, purity, and TFA content) eliminate background interference.
From immunogenicity assays to cytotoxicity validation, we offer end-to-end services, ensuring more closed-loop and reliable results.
The scope of in vitro immunogenicity assessment now extensively encompasses a wide range of fields, including antibody therapeutics, mRNA therapeutics, peptide therapeutics and their generic‑drug impurities, adjuvant screening, small nucleic acid therapeutics, as well as allogeneic cell‑based therapies.
Among these, impurities in peptide drugs and their generic counterparts have become the most critical and rigorously standardized assessment focus, driven by explicit regulatory requirements—particularly those outlined in the FDA’s ANDA guidance. Moreover, this evaluation framework provides robust support for tumor immunotherapy and personalized vaccine development, enabling clients to efficiently identify novel antigens with genuine functional activity from vast pools of predicted sequences. It also helps innovative pharmaceutical companies—working in areas such as peptides, proteins, and cell therapies—proactively mitigate clinical immunogenicity risks during the IND‑stage review process.
Hycells Bio—ensuring that the immunogenicity of every peptide progresses from “prediction” to “validation,” and from “activation” to “cytotoxicity,” with full-process controllability and traceability.
Another representative case comes from the Phase I clinical trial of the in vivo CAR product ESO‑T01, whose safety and immune profile warrant close attention. Among five patients, three experienced Grade 3 or higher cytokine release syndrome (CRS), with an incidence of 60%, and the CRS exhibited a “biphasic” pattern: an early phase driven by the viral vector–induced innate immune response, followed by a later phase triggered by CAR‑T cell expansion and the ensuing adaptive immune response—distinct from the dynamics observed in autologous CAR‑T therapies. This finding is highly significant, suggesting that we may have underestimated the intrinsic immunogenicity of lentiviral vectors, a factor that will pose a critical challenge to realizing the vision of “off‑the‑shelf” in vivo CAR therapies. Hycells will continue to advance the development of innovative in vitro immunogenicity assessment platforms, helping to mitigate safety risks for an expanding array of drug candidates.
For inquiries regarding in vitro immunogenicity assessment of pharmaceuticals, please contact the Business Manager of the Technical Service Platform: Manager Liu, at 13917511641.
Scan the QR code to obtain contact information.

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