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| 1mg |
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| 5mg |
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| 10mg |
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| Targets |
OVA G4 peptide TFA targets the H-2Kb MHC class I molecule on antigen-presenting cells. After being loaded onto H-2Kb, the peptide-MHC complex is recognized by the T cell receptor (TCR) on ovalbumin-specific CD8+ T cells (OT-I T cells). This recognition triggers T cell activation, proliferation, and effector functions, including cytokine production and cytotoxic activity. The G4 variant may alter TCR recognition affinity compared to the native SIINFEKL sequence, making it useful for studying TCR-peptide-MHC interactions. This peptide is a fundamental tool for studying T cell biology, vaccine development, and immune responses.
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| ln Vitro |
In vitro, the parent peptide SIINFEKL is a potent activator of OT-I T cells. At concentrations of 0.01-10 nM, SIINFEKL induces T cell proliferation, IFN-gamma production, and granzyme B expression. The G4 peptide variant (SIIGFEKL) is likely to possess similar but potentially altered immunogenicity. In T cell activation assays, the peptide (1-100 nM) is incubated with OT-I CD8+ T cells and antigen-presenting cells (APCs) expressing H-2Kb, or with T2-Kb cells loaded with the peptide. Activation is measured by CD69 upregulation, proliferation (CFSE dilution), or cytokine release (IFN-gamma ELISA). The peptide's activity is critical for immunological assays. SIINFEKL is used to test new vaccine adjuvants and evaluate stable hydrogel formulations.
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| ln Vivo |
The in vivo activity of OVA G4 peptide TFA is not specifically detailed, but the parent peptide SIINFEKL is extensively used in mouse immunization models. In C57BL/6 mice, intravenous or subcutaneous injection of SIINFEKL peptide (10-100 microg) along with an adjuvant (e.g., CpG, poly I:C, or Complete Freund‘s Adjuvant, CFA) induces a robust antigen-specific CD8+ T cell response. Alternatively, peptide-pulsed dendritic cells are adoptively transferred into mice to prime T cell responses. The G4 variant can be used similarly to study antigen presentation and T cell activation in vivo. It may also be utilized to test the stability of vaccine adjuvants or delivery systems, such as hydrogels.
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| Enzyme Assay |
OVA peptides are not used in cell-free enzyme assays. For receptor binding assays, a T2-Kb cell-based assay measures peptide-MHC binding affinity. T2-Kb cells (H-2Kb-expressing) are deficient in the TAP transporter, so they require exogenous peptide loading. T2-Kb cells are incubated with varying concentrations of OVA G4 peptide TFA (0.1 nM to 100 microM) and 1 microg/mL human beta2-microglobulin in serum-free medium at 37degC for 4 hours. Cells are washed and stained with an antibody specific for the peptide-loaded H-2Kb conformation (e.g., 25-D1.16 monoclonal antibody) followed by flow cytometry. The mean fluorescence intensity (MFI) is plotted against peptide concentration, and the EC50 is determined. The assay compares the binding affinity of the G4 variant to that of the native SIINFEKL peptide.
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| Cell Assay |
For T cell activation assays, CD8+ T cells are isolated from OT-I transgenic mice (which express a TCR specific for SIINFEKL/H-2Kb). Splenocytes from OT-I mice are enriched for CD8+ T cells using magnetic beads. For proliferation assays, CD8+ T cells are labeled with CFSE (5 microM, 10 min, 37degC) and cocultured with irradiated (2000 rad) C57BL/6 splenocytes (as APCs) at a 1:1 ratio in 96-well plates. OVA G4 peptide TFA (0.001-100 nM) is added, and cells are cultured for 72 hours. Proliferation is measured by CFSE dilution using flow cytometry. For cytokine production, supernatants are collected at 24-48 hours and analyzed for IFN-gamma, IL-2, and TNF-alpha by ELISA. For cytotoxicity assays, OT-I T cells are activated with peptide (10 nM) for 5 days. Activated T cells are then cocultured with 51Cr-labeled EL4 target cells pulsed with peptide (10 nM) at various effector-to-target ratios. 51Cr release is measured after 4 hours to determine specific lysis.
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| Animal Protocol |
C57BL/6 mice (6-8 weeks, female) are used for in vivo immunization studies. Mice are injected subcutaneously or intraperitoneally with OVA G4 peptide TFA (10-100 microg per mouse) emulsified in Complete Freund's Adjuvant (CFA) or mixed with other adjuvants (e.g., 50 microg CpG ODN). A control group receives adjuvant alone or SIINFEKL peptide. On day 7-14 post-immunization, spleens are harvested. Splenocytes are restimulated ex vivo with the peptide (10 microg/mL) for 5-6 hours in the presence of GolgiPlug (Brefeldin A). Intracellular cytokine staining for IFN-gamma and TNF-alpha is performed, followed by flow cytometry. Alternatively, an in vivo cytotoxicity assay is performed: target splenocytes are labeled with high (2.5 microM) or low (0.25 microM) CFSE, pulsed with peptide (10 microM), and adoptively transferred into immunized mice. After 16 hours, the ratio of high to low CFSE-labeled cells in the spleen is analyzed by flow cytometry to calculate specific killing. For vaccine adjuvant studies, peptide alone or peptide + adjuvant is administered, and the ability of the adjuvant to form a stable hydrogel or depot is evaluated by measuring the persistence of antigen at the injection site.
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| ADME/Pharmacokinetics |
The TFA salt form has a molecular formula of C40H59N8O13 (from the peptide component). The lyophilized powder should be stored at -20degC, protected from moisture, where it is stable for up to 3 years. For solution storage, it should be kept at -80degC for 6 months or -20degC for 1 month in sealed, moisture-protected vials. The compound is soluble in DMSO (typically 20-30 mg/mL) and water (5-10 mg/mL). The TFA counterion accounts for approximately 10-20% of the total mass. Avoid repeated freeze-thaw cycles and prolonged storage in solution to prevent degradation. Working solutions in culture media should be used within 24-48 hours.
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| Toxicity/Toxicokinetics |
This product is for research use only and is not for human therapeutic use. No specific toxicity data is available for the peptide. At concentrations used in T cell activation assays (0.1-100 nM), the peptide is non-toxic. The TFA counterion may be cytotoxic at high concentrations (>0.1% in culture) but is safely diluted in standard assays. Standard laboratory safety practices should be followed. The immunogenicity of the peptide may vary depending on mouse strain (C57BL/6 mice are H-2b and respond to SIINFEKL; BALB/c mice are H-2d and generally do not respond). Unintended exposure may cause an immune response in sensitized individuals. Avoid inhalation of powder. The compound is not an FDA-approved drug.
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| References |
[1]. François P, et al. Phenotypic model for early T-cell activation displaying sensitivity, specificity, and antagonism. Proc Natl Acad Sci U S A. 2013 Mar 5;110(10):E888-97.
[2]. Kamalov M,et al. Ovalbumin Epitope SIINFEKL Self-Assembles into a Supramolecular Hydrogel. Sci Rep. 2019 Feb 25;9(1):2696. |
| Additional Infomation |
The OVA (257-264) SIINFEKL peptide is one of the most extensively studied MHC class I-restricted epitopes in immunology. It has become a gold-standard tool for studying CD8+ T cell responses, antigen cross-presentation, and vaccine development. The G4 variant (SIIGFEKL) contains a glycine insertion or substitution that can alter MHC binding and TCR recognition kinetics, making it useful for studying the structural requirements for T cell activation. This peptide is used to test new vaccine adjuvants, evaluate nanoparticle-based vaccine delivery systems, and investigate T cell tolerance, exhaustion, and memory formation. The TFA salt is the standard research form. This product is not a clinical drug. Supplier information must not be included.
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| Molecular Formula |
C45H72F3N9O14
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| Related CAS # |
OVA G4 peptide;148274-82-2
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| Appearance |
Typically exists as solid at room temperature
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| HS Tariff Code |
2934.99.9001
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| Storage |
Powder -20°C 3 years 4°C 2 years In solvent -80°C 6 months -20°C 1 month Note: Please store this product in a sealed and protected environment, avoid exposure to moisture. |
| Shipping Condition |
Room temperature (This product is stable at ambient temperature for a few days during ordinary shipping and time spent in Customs)
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| Solubility (In Vitro) |
H2O :~6.67 mg/mL (~6.54 mM)
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| Solubility (In Vivo) |
Note: Listed below are some common formulations that may be used to formulate products with low water solubility (e.g. < 1 mg/mL), you may test these formulations using a minute amount of products to avoid loss of samples.
Injection Formulations
Injection Formulation 1: DMSO : Tween 80： Saline = 10 : 5 : 85 (i.e. 100 μL DMSO stock solution → 50 μL Tween 80 → 850 μL Saline)(e.g. IP/IV/IM/SC) *Preparation of saline: Dissolve 0.9 g of sodium chloride in 100 mL ddH ₂ O to obtain a clear solution. Injection Formulation 2: DMSO : PEG300 ：Tween 80 : Saline = 10 : 40 : 5 : 45 (i.e. 100 μL DMSO → 400 μLPEG300 → 50 μL Tween 80 → 450 μL Saline) Injection Formulation 3: DMSO : Corn oil = 10 : 90 (i.e. 100 μL DMSO → 900 μL Corn oil) Example: Take the Injection Formulation 3 (DMSO : Corn oil = 10 : 90) as an example, if 1 mL of 2.5 mg/mL working solution is to be prepared, you can take 100 μL 25 mg/mL DMSO stock solution and add to 900 μL corn oil, mix well to obtain a clear or suspension solution (2.5 mg/mL, ready for use in animals). View More
Injection Formulation 4: DMSO : 20% SBE-β-CD in saline = 10 : 90 [i.e. 100 μL DMSO → 900 μL (20% SBE-β-CD in saline)] Oral Formulations
Oral Formulation 1: Suspend in 0.5% CMC Na (carboxymethylcellulose sodium) Oral Formulation 2: Suspend in 0.5% Carboxymethyl cellulose Example: Take the Oral Formulation 1 (Suspend in 0.5% CMC Na) as an example, if 100 mL of 2.5 mg/mL working solution is to be prepared, you can first prepare 0.5% CMC Na solution by measuring 0.5 g CMC Na and dissolve it in 100 mL ddH2O to obtain a clear solution; then add 250 mg of the product to 100 mL 0.5% CMC Na solution, to make the suspension solution (2.5 mg/mL, ready for use in animals). View More
Oral Formulation 3: Dissolved in PEG400 (Please use freshly prepared in vivo formulations for optimal results.) |
Calculation results
Working concentration： mg/mL；
Method for preparing DMSO stock solution： mg drug pre-dissolved in μL DMSO (stock solution concentration mg/mL). Please contact us first if the concentration exceeds the DMSO solubility of the batch of drug.
Method for preparing in vivo formulation:：Take μL DMSO stock solution, next add μL PEG300, mix and clarify, next addμL Tween 80, mix and clarify, next add μL ddH2O，mix and clarify.
(1) Please be sure that the solution is clear before the addition of next solvent. Dissolution methods like vortex, ultrasound or warming and heat may be used to aid dissolving.
(2) Be sure to add the solvent(s) in order.
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