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| 1mg |
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| 5mg |
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| 10mg |
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| Other Sizes |
| Targets |
KSPWFTTL TFA targets the immune system, specifically serving as an antigen that binds to MHC class I molecules (Kb-restricted). It is recognized by cytotoxic T lymphocytes (CTLs) specific to the p15E epitope, facilitating T-cell activation and target cell lysis. The peptide is presented by the H-2Kb MHC molecule on antigen-presenting cells, leading to CTL-mediated killing.
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| ln Vitro |
From the retroviral p15 TM envelope protein, KSPWFTTL TFA is produced. After being pulsed with the KSPWFTTL TFA peptide, the cytolytic T-lymphocyte (CTL)-insusceptible variation cl.18-5 clonal line becomes susceptible to lysis by antiviral CTL[2].
KSPWFTTL TFA is derived from the retroviral p15 TM envelope protein. In cell-free assays, its binding affinity to purified H-2Kb MHC molecules is determined by surface plasmon resonance or ELISA, typically exhibiting high nanomolar to low micromolar affinity. The peptide forms stable complexes with MHC, enabling recognition by specific T-cell receptors. |
| ln Vivo |
In cell-based assays, the cytolytic T-lymphocyte (CTL)-insusceptible variant cl.18-5 clonal line is pulsed with KSPWFTTL TFA peptide. After pulsing, the cells become susceptible to lysis by antiviral CTLs specific for the p15E epitope. This peptide restores susceptibility to CTL-mediated killing, as measured by standard chromium-51 release assays or flow cytometry-based cytotoxicity assays.
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| Enzyme Assay |
The binding affinity of KSPWFTTL TFA to H-2Kb is measured using a cell-free MHC-peptide binding assay. Purified soluble H-2Kb molecules are incubated with a fluorescent reference peptide and varying concentrations (1-100 uM) of KSPWFTTL TFA. After overnight incubation, bound and free peptides are separated by size exclusion chromatography or anti-MHC capture, and fluorescence is measured to calculate IC50 values.
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| Cell Assay |
The murine tumor line cl.18-5 (a variant of Rauscher virus-induced RBL-5 leukemia) is cultured in RPMI-1640 with 10% FBS. Cells are pulsed with KSPWFTTL TFA (1-100 uM) for 2-4 hours at 37degC, then washed. These peptide-pulsed target cells are co-incubated with antiviral CTLs at various effector-to-target ratios (e.g., 10:1 to 100:1) for 4 hours. Specific lysis is measured by a standard chromium-51 release assay or europium release assay.
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| Animal Protocol |
In vivo experiments are performed in C57BL/6 mice. Mice are immunized subcutaneously with KSPWFTTL TFA (50-100 ug) emulsified in complete Freund's adjuvant. After 7-10 days, splenocytes are harvested and re-stimulated in vitro with the peptide. For challenge studies, peptide-pulsed target cells (e.g., splenocytes labeled with CFSE or chromium-51) are injected intravenously, and in vivo cytotoxicity is measured after 18-24 hours by analyzing target cell recovery.
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| ADME/Pharmacokinetics |
KSPWFTTL TFA has a molecular weight of 1093.15 Da (free base) and molecular formula C50H71N10O14. The TFA counterion improves aqueous solubility, with reported solubility in water of 66.67 mg/mL. The peptide is stable as a powder at -80degC for 2 years or at -20degC for 1 year. In solution, it should be stored at -80degC for 6 months or -20degC for 1 month, sealed and away from moisture.
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| Toxicity/Toxicokinetics |
KSPWFTTL TFA is used in small quantities for immunological research and is generally non-toxic at typical experimental concentrations (1-100 uM in vitro, 50-100 ug per mouse in vivo). No significant acute or chronic toxicity has been reported. Standard laboratory safety precautions (gloves, lab coat, safety glasses) should be followed when handling this peptide.
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| References |
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| Additional Infomation |
KSPWFTTL TFA is a research-use-only peptide not approved for clinical use. The KSPWFTTL sequence represents an immunodominant epitope recognized by CD8+ T cells in the context of H-2Kb MHC class I. It is widely used as a model antigen for studying cytotoxic T lymphocyte responses, viral immunology, and cancer immunotherapy in murine models. The peptide is derived from the p15E protein of the AKR/Gross murine leukemia virus (MuLV).
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| Molecular Formula |
C50H71F3N10O14
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| Related CAS # |
KSPWFTTL;153049-05-9
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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 :~66.67 mg/mL (~60.99 mM)
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| Solubility (In Vivo) |
Solubility in Formulation 1: 100 mg/mL (91.48 mM) in PBS (add these co-solvents sequentially from left to right, and one by one), clear solution; with sonication.
(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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