Biological Description

Specificity

Von Willebrand Factor Antibody (Rabbit mAb) [L10F8] detects endogenous levels of total Von Willebrand Factor protein.

Background

Von Willebrand factor (VWF) is a large multimeric plasma glycoprotein produced by endothelial cells and megakaryocytes that occupies a central position in primary hemostasis by linking subendothelial collagen to platelets and by serving as the specific carrier and stabilizer of coagulation factor VIII. The protein is synthesized as pro‑VWF, dimerized in the endoplasmic reticulum and further multimerized in the Golgi into ultra‑large multimers, which are stored in Weibel–Palade bodies and platelet α‑granules or secreted to plasma and subendothelial matrix; its modular domain organization includes A1, A2 and A3 domains that mediate key ligand interactions. At sites of vascular injury, VWF immobilizes on fibrillar collagen via its A3 domain and acts as a molecular bridge between the collagen matrix and platelet glycoprotein Ib-IX-V, with the A1 domain engaging GPIbα to support rapid platelet tethering and rolling under high shear conditions where direct collagen–platelet binding is insufficient. Initial binding through A1–GPIbα triggers intracellular signaling in platelets that activates integrin αIIbβ3 and other receptors, allowing additional interactions with VWF and fibrinogen to stabilize adhesion, promote platelet spreading and build multilayered aggregates that seal the defect. Soluble VWF in plasma also uncoils under shear, binds to adherent platelets and recruits further platelets, amplifying plug growth, while proteolytic regulation by ADAMTS13 limits ultra‑large multimer size and prevents uncontrolled VWF‑rich microthrombi in the microcirculation. Beyond its adhesive role, VWF binds factor VIII through specific sites in its D′D3 region, protects factor VIII from proteolytic degradation and premature clearance, and delivers it to activated platelets and the site of injury, thereby linking primary hemostasis to the intrinsic coagulation cascade. Quantitative or qualitative defects in VWF underlie von Willebrand disease, characterized by impaired platelet adhesion, reduced factor VIII carriage and variable bleeding phenotypes, whereas excessive or dysregulated VWF activity, particularly in the setting of reduced ADAMTS13, contributes to thrombosis such as thrombotic thrombocytopenic purpura and to arterial thrombus formation in high-shear vascular beds.

Usage Information

Application WB, IHC, FCM Dilution
WB IHC FCM
1:1000-1:5000 1:50 1:500
Reactivity Mouse, Rat
Source Rabbit Monoclonal Antibody MW 309 kDa
Storage Buffer PBS, pH 7.2+50% Glycerol+0.05% BSA+0.01% NaN3
Storage
(from the date of receipt)
-20°C (avoid freeze-thaw cycles), 2 years
WB
Experimental Protocol:
 
Sample preparation
1. Tissue: Lyse the tissue sample by adding an appropriate volume of ice-cold RIPA/NP-40 Lysis Buffer (containing Protease Inhibitor Cocktail),and homogenize the tissue at a low temperature or lyse it by sonication on ice, then incubate on ice for 30 minutes.
2. Adherent cell: Aspirate the culture medium and wash the cells with ice-cold PBS twice. Lyse the cells by adding an appropriate volume of RIPA/NP-40 Lysis Buffer (containing Protease Inhibitor Cocktail) , sonicate to lyse the cells, and incubate on ice for 30 minutes.
3. Suspension cell: Transfer the culture medium to a pre-cooled centrifuge tube. Centrifuge and aspirate the supernatant. Wash the cells with ice-cold PBS twice. Lyse the cells by adding an appropriate volume of RIPA/NP-40 Lysis Buffer (containing Protease Inhibitor Cocktail) , sonicate to lyse the cells, and incubate on ice for 30 minutes.
4. Place the lysate into a pre-cooled microcentrifuge tube. Centrifuge at 4°C for 15 min. Collect the supernatant;
5. Remove a small volume of lysate to determine the protein concentration;
6. Combine the lysate with protein loading buffer. Boil 20 µL sample under 95-100°C for 5 min. Centrifuge for 5 min after cool down on ice.
 
Electrophoretic separation
1. According to the concentration of extracted protein, load appropriate amount of protein sample and marker onto SDS-PAGE gels for electrophoresis. Recommended separating gel (lower gel) concentration: 5%. Reference Table for Selecting SDS-PAGE Separation Gel Concentrations
2. Power up 80V for 30 minutes. Then the power supply is adjusted (110 V~150 V), the Marker is observed, and the electrophoresis can be stopped when the indicator band of the predyed protein Marker where the protein is located is properly separated. (Note that the current should not be too large when electrophoresis, too large current (more than 150 mA) will cause the temperature to rise, affecting the result of running glue. If high currents cannot be avoided, an ice bath can be used to cool the bath.)
 
Transfer membrane
1. Take out the converter, soak the clip and consumables in the pre-cooled converter;
2. Activate PVDF membrane with methanol for 1 min and rinse with transfer buffer;
3. Install it in the order of "black edge of clip - sponge - filter paper - filter paper - glue -PVDF membrane - filter paper - filter paper - sponge - white edge of clip";
4. The protein was electrotransferred to PVDF membrane. ( 0.45 µm PVDF membrane is recommended ) Reference Table for Selecting PVDF Membrane Pore Size Specifications
Recommended conditions for wet transfer: 250 mA, 180 min.
( Note that the transfer conditions can be adjusted according to the protein size. For high-molecular-weight proteins, a higher current and longer transfer time are recommended. However, ensure that the transfer tank remains at a low temperature to prevent gel melting.)
 
Block
1. After electrotransfer, wash the film with TBST at room temperature for 5 minutes;
2. Incubate the film in the blocking solution for 1 hour at room temperature;
3. Wash the film with TBST for 3 times, 5 minutes each time.
 
Antibody incubation
1. Use primary antibody dilution buffer to prepare the primary antibody working liquid (recommended dilution ratio for primary antibody 1:5000), gently shake and incubate with the film at 4°C overnight;
2. Wash the film with TBST 3 times, 5 minutes each time;
3. Add the secondary antibody to the blocking solution and incubate with the film gently at room temperature for 1 hour;
4. After incubation, wash the film with TBST 3 times for 5 minutes each time.
 
Antibody staining
1. Add the prepared ECL luminescent substrate (or select other color developing substrate according to the second antibody) and mix evenly;
2. Incubate with the film for 1 minute, remove excess substrate (keep the film moist), wrap with plastic film, and expose in the imaging system.
IHC
Experimental Protocol:
 
Deparaffinization/Rehydration
1. Deparaffinize/hydrate sections:
2. Incubate sections in three washes of xylene for 5 min each.
3. Incubate sections in two washes of 100% ethanol for 10 min each.
4. Incubate sections in two washes of 95% ethanol for 10 min each.
5. Wash sections two times in dH2O for 5 min each.
6.Antigen retrieval: For Citrate: Heat slides in a microwave submersed in 1X citrate unmasking solution until boiling is initiated; continue with 10 min at a sub-boiling temperature (95°-98°C). Cool slides on bench top for 30 min.
 
Staining
1. Wash sections in dH2O three times for 5 min each.
2. Incubate sections in 3% hydrogen peroxide for 10 min.
3. Wash sections in dH2O two times for 5 min each.
4. Wash sections in wash buffer for 5 min.
5. Block each section with 100–400 µl of blocking solution for 1 hr at room temperature.
6. Remove blocking solution and add 100–400 µl primary antibody diluent in to each section. Incubate overnight at 4°C.
7. Remove antibody solution and wash sections with wash buffer three times for 5 min each.
8. Cover section with 1–3 drops HRPas needed. Incubate in a humidified chamber for 30 min at room temperature.
9. Wash sections three times with wash buffer for 5 min each.
10. Add DAB Chromogen Concentrate to DAB Diluent and mix well before use.
11. Apply 100–400 µl DAB to each section and monitor closely. 1–10 min generally provides an acceptable staining intensity.
12. Immerse slides in dH2O.
13. If desired, counterstain sections with hematoxylin.
14. Wash sections in dH2O two times for 5 min each.
15. Dehydrate sections: Incubate sections in 95% ethanol two times for 10 sec each; Repeat in 100% ethanol, incubating sections two times for 10 sec each; Repeat in xylene, incubating sections two times for 10 sec each.
16. Mount sections with coverslips and mounting medium.
 

References

  • https://pubmed.ncbi.nlm.nih.gov/22477538/
  • https://pubmed.ncbi.nlm.nih.gov/18786007/

Application Data

WB

Validated by Selleck

  • F7213-wb
    Lane 1: Mouse spleen