| Size | Price | Stock | Qty |
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| 5mg |
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| 10mg |
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| Other Sizes |
| Targets |
IRBP derived peptide R16 targets the immune system, specifically T-cell receptors (TCRs) on CD4+ T cells that recognize the peptide presented by MHC class II molecules (e.g., I-Ak or I-Ab in mice). This recognition triggers an autoimmune response against retinal antigens, leading to uveitis. The peptide is used to model autoimmune ocular inflammatory diseases.
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| ln Vitro |
In cell-free assays, R16 peptide binds to purified MHC class II molecules (e.g., I-Ak). Binding affinity is measured by competitive ELISA or SPR. The peptide has a moderate to high affinity for its restricting MHC allele (Kd in the nanomolar to micromolar range). This binding is necessary for T-cell activation. No enzymatic activity is involved; it is a receptor-ligand interaction.
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| ln Vivo |
In vitro, R16 peptide (0.1-10 uM) stimulates proliferation and cytokine production (IFN-gamma, IL-17) from T cells isolated from IRBP-immunized mice or from T-cell hybridomas specific for this epitope. Activation is measured by [3H]-thymidine incorporation or by cytokine ELISA. The peptide is specific for the R16 epitope; scrambled peptides do not induce responses. The acetate salt does not affect activity.
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| Enzyme Assay |
MHC binding is determined using a cell-free competition assay. Purified I-Ak MHC class II molecules are incubated with a fluorescent reference peptide and varying concentrations (0.01-100 uM) of unlabeled R16 peptide. After incubation, bound and free peptides are separated by size-exclusion chromatography or captured with an anti-MHC antibody. Fluorescence is measured, and the IC50 is calculated. Alternatively, a cell-free SPR assay is used.
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| Cell Assay |
Splenocytes or lymph node cells from R16-immunized B10.A or C57BL/6 mice are cultured in 96-well plates with R16 peptide (0.001-10 uM) for 48-72 hours. Proliferation is measured by [3H]-thymidine incorporation during the last 16-18 hours. Supernatants are collected for cytokine measurement (IFN-gamma, IL-17, IL-2) by ELISA. T-cell activation is also assessed by flow cytometry for CD25 and CD69 expression. Controls include no peptide or an irrelevant peptide.
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| Animal Protocol |
To induce EAU, mice (e.g., B10.RIII or C57BL/6) are immunized subcutaneously with R16 peptide (50-200 ug) emulsified in complete Freund's adjuvant (CFA) supplemented with Mycobacterium tuberculosis. A pertussis toxin injection (0.5-1 ug) is given intraperitoneally on the day of immunization and/or 48 hours later. Mice are monitored daily for clinical signs of uveitis (e.g., eye redness, discharge, fundus changes). Eyes are harvested for histological grading of inflammation at day 14-21.
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| ADME/Pharmacokinetics |
As a peptide, R16 acetate has a short half-life in vivo (minutes) due to proteolysis. When emulsified in CFA, it forms a depot at the injection site, providing sustained antigen release over days. The peptide alone without adjuvant is rapidly cleared. The acetate salt improves water solubility. For EAU induction, the peptide is mixed with CFA to create a stable emulsion. The peptide's MW is approximately 2000 Da.
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| Toxicity/Toxicokinetics |
R16 peptide is well-tolerated at EAU-inducing doses (50-200 ug/mouse). The disease itself is the intended outcome; the peptide is not toxic to the animal. No off-target organ toxicity has been reported. The adjuvant (CFA) may cause local granulomas and systemic inflammation. The peptide alone without adjuvant is non-toxic. Standard handling precautions apply. Not for human use.
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| Additional Infomation |
The R16 peptide (IRBP161-180) is a standard antigen for inducing experimental autoimmune uveitis (EAU), an animal model of human autoimmune uveitis. It is widely used to study the pathogenesis of ocular inflammatory diseases and to test immunomodulatory therapies. The acetate salt form is common for peptide stability. The peptide is for research use only, not for therapeutic or diagnostic applications in humans.
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| Molecular Formula |
C64H96N16O24.XC2H4O2
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| Molecular Weight |
1473.54 (free acid)
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| Related CAS # |
IRBP derived peptide, R16;145821-83-6
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| Appearance |
White to off-white solid powder
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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 (e.g. under nitrogen), avoid exposure to moisture and light. |
| 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 :~7.69 mg/mL
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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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