| Size | Price | Stock | Qty |
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| 1mg |
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| 5mg |
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| 10mg |
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| Other Sizes |
| Targets |
QL9 TFA targets the 2C T cell receptor (TCR) via presentation by the MHC class I molecule Ld. It is a high-affinity alloantigen that is recognized by the 2C TCR. The peptide forms a complex with MHC Ld, and this complex is specifically recognized by the 2C TCR. The binding of QL9 to MHC Ld involves almost all peptide side chains, which are dispersed across the whole length of the peptide. This system is a model for studying TCR-pMHC interactions.
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| ln Vitro |
Major Histocompatibility Complex (MHC) ligands self (MHC Kb) and allogeneic (MHC Ld) are recognized by mouse T cell clone 2C. SIY (SIYRYYGL) and QL9 (QLSPFPFDL), two different peptides, bind to Kb and Ld, respectively, and function as potent and selective agonists. Almost all of the side chains in a peptide are involved in QL9 binding to MHC Ld, and they are dispersed across its length. Findings with both systems, but QL9-Ld in particular, point to the possibility that numerous single-residue changes added to peptides to enhance their MHC binding and, hence, their vaccination potential, may also have the unintended effect of decreasing T cell reactivity through TCR binding sensitivity. To determine how peptide SIY and QL9 residues affect T cell activity, T cell activation experiments are used[2].
In vitro, QL9 TFA is a high-affinity alloantigen that exhibits high affinity for the 2C T cell receptor (TCR). The mouse T cell clone 2C recognizes both the self MHC molecule Kb and the allogeneic MHC molecule Ld. QL9 binds to Ld and is presented to the 2C TCR, leading to T cell activation. It is used to study TCR-pMHC interactions, T cell activation, and immune recognition. |
| Enzyme Assay |
A cell-free binding assay for QL9 can be performed using surface plasmon resonance (SPR). Recombinant MHC Ld protein is biotinylated and immobilized on a streptavidin sensor chip. Increasing concentrations (0.1-1000 nM) of QL9 peptide are flowed over the chip. Association and dissociation rates are measured. The Kd value is calculated. Alternatively, a competition binding assay can be performed using a fluorescently labeled QL9 peptide and soluble MHC Ld.
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| Cell Assay |
QL9 TFA is used in T cell activation assays. 2C TCR-transfected T cell hybridomas (or primary 2C CD8+ T cells) are seeded in 96-well plates. Antigen-presenting cells (e.g., T2-Ld cells) are loaded with QL9 peptide (0.1-1000 nM) for 2-4 h. The peptide-loaded APCs are then co-cultured with T cells for 24 h. T cell activation is measured by IL-2 production (ELISA) or by detecting CD69 expression via flow cytometry. The EC50 for T cell activation is calculated.
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| Animal Protocol |
QL9 TFA can be studied in mouse models to evaluate T cell responses. Female BALB/c mice (6-8 weeks, n=5 per group) are immunized subcutaneously with QL9 peptide (50-100 ug) emulsified in complete Freund's adjuvant (CFA). After 7-14 days, splenocytes are harvested. T cell responses are assessed by IFN-gamma ELISpot or by intracellular cytokine staining for IFN-gamma and TNF-alpha. The peptide is used to expand specific CD8+ T cell populations. It is also used in adoptive transfer models to study T cell function in vivo.
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| ADME/Pharmacokinetics |
QL9 TFA has a molecular formula of C52H74N10O14 and a molecular weight of approximately 1065. The TFA salt has a higher molecular weight. The powder should be stored at -80degC for up to 2 years or at -20degC for 1 year, sealed and away from moisture. In solvent, it is stable for 6 months at -80degC or 1 month at -20degC. Specific PK parameters have not been reported. The TFA salt enhances solubility.
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| Toxicity/Toxicokinetics |
No detailed toxicity data for QL9 TFA are available. As a research-grade peptide, it is expected to have low inherent toxicity. In animal studies, the peptide was well-tolerated at the doses used for immunization (50-100 microg). Standard safety precautions for handling peptides should be followed. The compound is not intended for human use.
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| References |
[1]. Bowerman NA, et al. Different strategies adopted by K(b) and L(d) to generate T cell specificity directed against their respective bound peptides. J Biol Chem. 2009 Nov 20;284(47):32551-61.
[2]. Speir JA, et al. Structural basis of 2C TCR allorecognition of H-2Ld peptide complexes. Immunity. 1998 May;8(5):553-62. |
| Additional Infomation |
QL9 TFA is a research-grade peptide and is not approved for clinical use. It is a high-affinity alloantigen for the 2C T cell receptor, used to study T cell activation and TCR recognition. This product is for research use only and not for human therapeutic applications. Store as a lyophilized powder at -20degC or -80degC.
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| Molecular Formula |
C52H74N10O14.XC2HF3O2
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| Related CAS # |
QL9;159646-83-0
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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) |
DMSO :~100 mg/mL
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| Solubility (In Vivo) |
Solubility in Formulation 1: ≥ 2.5 mg/mL (Infinity mM) (saturation unknown) in 10% DMSO + 40% PEG300 + 5% Tween80 + 45% Saline (add these co-solvents sequentially from left to right, and one by one), clear solution.
For example, if 1 mL of working solution is to be prepared, you can add 100 μL of 25.0 mg/mL clear DMSO stock solution to 400 μL PEG300 and mix evenly; then add 50 μL Tween-80 to the above solution and mix evenly; then add 450 μL normal saline to adjust the volume to 1 mL. Preparation of saline: Dissolve 0.9 g of sodium chloride in 100 mL ddH₂ O to obtain a clear solution. Solubility in Formulation 2: ≥ 2.5 mg/mL (Infinity mM) (saturation unknown) in 10% DMSO + 90% (20% SBE-β-CD in Saline) (add these co-solvents sequentially from left to right, and one by one), clear solution. For example, if 1 mL of working solution is to be prepared, you can add 100 μL of 25.0 mg/mL clear DMSO stock solution to 900 μL of 20% SBE-β-CD physiological saline solution and mix evenly. Preparation of 20% SBE-β-CD in Saline (4°C，1 week): Dissolve 2 g SBE-β-CD in 10 mL saline to obtain a clear solution. View More
Solubility in Formulation 3: ≥ 2.5 mg/mL (Infinity mM) (saturation unknown) in 10% DMSO + 90% Corn Oil (add these co-solvents sequentially from left to right, and one by one), clear solution. |
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.
Products are for research use only; We do not sell to patients
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