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4097S 100 µl (50 µg)

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Concentration SENSITIVITY Isotype
0.5 mg/ml Endogenous Mouse IgG1
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Immunoprecipitation

Immunoprecipitation of extracts from Jurkat cells treated with either LY294002 #9901 (1) or Calyculin A #9902 (2), using Akt (pan) (40D4) Mouse mAb (Biotinylated) #4821 and Mouse (MOPC-21) mAb IgG1 Isotype Control (Biotinylated). Immunocomplexes were pulled down using Immobilized Streptavidin (Bead Conjugate) #3419. Western blotting analysis was performed using Akt (pan) (C67E7) Rabbit mAb #4691.

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Immunoprecipitation

Immunoprecipitation of extracts from Jurkat cells treated with either LY294002 #9901 (1) or Calyculin A #9902 (2), using Phospho-Akt (Ser473) (587F11) Mouse mAb (Biotinylated) #5102 and Mouse (MOPC-21) mAb IgG1 Isotype Control (Biotinylated). Immunocomplexes were pulled down using Immobilized Streptavidin (Bead Conjugate) #3419. Western blotting analysis was performed using Phospho-Akt (Ser473) (D9E) Rabbit mAb #4060.

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Flow Cytometry

Flow cytometric analysis of Jurkat cells using Akt (pan) (40D4) Mouse mAb (Biotinylated) #4821 (blue) compared to Mouse (MOPC-21) mAb IgG1 Isotype Control (Biotinylated) (red).

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Immunoprecipitation for Native Proteins

This protocol is intended for immunoprecipitation of native proteins for analysis by western immunoblot or kinase activity.

A. Solutions and Reagents

NOTE: Prepare solutions with reverse osmosis deionized (RODI) or equivalent grade water.

  1. 20X Phosphate Buffered Saline (PBS): (#9808) To prepare 1 L of 1X PBS, add 50 ml 20X PBS to 950 ml dH2O, mix.
  2. 10X Cell Lysis Buffer: (#9803) To prepare 10 ml of 1X cell lysis buffer, add 1 ml cell lysis buffer to 9 ml dH2O, mix.

    NOTE: Add 1 mM PMSF (#8553) immediately prior to use.

  3. 3X SDS Sample Buffer: Blue Loading Pack (#7722) or Red Loading Pack (#7723) Prepare fresh 3X reducing loading buffer by adding 1/10 volume 30X DTT to 1 volume of 3X SDS loading buffer.
  4. Streptavidin (Sepharose® Bead Conjugate) (For biotinylated antibodies): (#3419) Gently vortex vial and use 10 µl per immunoprecipitation.
  5. 10X Kinase Buffer (for kinase assays): (#9802) To Prepare 1 ml of 1X kinase buffer, add 100 µl 10X kinase buffer to 900 µl dH2O, mix.
  6. ATP (10 mM) (for kinase assays): (#9804) To prepare 0.5 ml of ATP (200 µM), add 10 µl ATP (10 mM) to 490 µl 1X kinase buffer.

B. Preparing Cell Lysates

  1. Aspirate media. Treat cells by adding fresh media containing regulator for desired time.
  2. To harvest cells under nondenaturing conditions, remove media and rinse cells once with ice-cold 1X PBS.
  3. Remove PBS and add 0.5 ml ice-cold 1X cell lysis buffer to each plate (10 cm) and incubate on ice for 5 min.
  4. Scrape cells off the plate and transfer to microcentrifuge tubes. Keep on ice.
  5. Sonicate on ice three times for 5 sec each.
  6. Microcentrifuge for 10 min at 4°C, 14,000 x g and transfer the supernatant to a new tube. The supernatant is the cell lysate. If necessary, lysate can be stored at -80°C.

C. Immunoprecipitation

Cell Lysate Pre-Clearing (Optional)

  1. Add 10 µl Streptavidin (Sepharose® Bead Conjugate) (#3419; for biotinylated antibodies), to 200 µl cell lysate at 1 mg/ml.
  2. Incubate with rotation at 4°C for 30–60 min.
  3. Microcentrifuge for 10 min at 4°C. Transfer the supernatant to a fresh tube.
  4. Proceed to immunoprecipitation below.

Immunoprecipitation

  1. Add biotinylated antibody (at the appropriate dilution as recommended in the product datasheet) to 200 µl cell lysate at 1 mg/ml. Incubate with rotation overnight at 4°C.
  2. Gently mix Streptavidin (Sepharose® Bead Conjugate) (#3419) and add 10 µl of slurry. Incubate with rotation for 2 hr at 4°C.
  3. Microcentrifuge for 30 sec at 4°C. Wash pellet five times with 500 µl of 1X cell lysis buffer. Keep on ice during washes.
  4. Proceed to sample analysis by western immunoblotting or kinase activity (section D).

D. Sample Analysis

Proceed to one of the following specific set of steps.

For Analysis by Western Immunoblotting

  1. Resuspend the pellet with 20 µl 3X SDS sample buffer. Vortex, then microcentrifuge for 30 sec at 14,000 x g.
  2. Heat the sample to 95–100°C for 2-5 min and microcentrifuge for 1 min at 14,000 x g.
  3. Load the sample (15–30 µl) on a 4–20% gel for SDS-PAGE.
  4. Analyze sample by western blot (see Western Immunoblotting Protocol).

NOTE: To minimize masking caused by denatured IgG heavy chains (~50 kDa), we recommend using Mouse Anti-Rabbit IgG (Light-Chain Specific) (L57A3) mAb (#3677) or Mouse Anti-Rabbit IgG (Conformation Specific) (L27A9) mAb (#3678) (or HRP conjugate #5127). To minimize masking caused by denatured IgG light chains (~25 kDa), we recommend using Mouse Anti-Rabbit IgG (Conformation Specific) (L27A9) mAb (#3678) (or HRP conjugate #5127).

For Analysis by Kinase Assay

  1. Wash pellet twice with 500 µl 1X kinase buffer. Keep on ice.
  2. Suspend pellet in 40 µl 1X kinase buffer supplemented with 200 µM ATP and appropriate substrate.
  3. Incubate for 30 min at 30°C.
  4. Terminate reaction with 20 µl 3X SDS sample buffer. Vortex, then microcentrifuge for 30 sec.
  5. Transfer supernatant containing phosphorylated substrate to another tube.
  6. Heat the sample to 95–100°C for 2–5 min and microcentrifuge for 1 min at 14,000 x g.
  7. Load the sample (15–30 µl) on SDS-PAGE (4–20%).

posted December 2008

revised November 2013

protocol id: 412

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Flow Cytometry

A. Solutions and Reagents

NOTE: Prepare solutions with reverse osmosis deionized (RODI) or equivalent grade water.

  1. 20X Phosphate Buffered Saline (PBS): (#9808) To prepare 1 L 1X PBS: add 50 ml 20X PBS to 950 ml dH2O, mix.
  2. 16% Formaldehyde (methanol free).
  3. 100% methanol.
  4. Incubation Buffer: Dissolve 0.5 g Bovine Serum Albumin (BSA) (#9998) in 100 ml 1X PBS. Store at 4°C.
  5. Streptavidin conjugated.

B. Fixation

  1. Collect cells by centrifugation and aspirate supernatant.
  2. Resuspend cells in 0.5–1 ml 1X PBS. Add formaldehyde to obtain a final concentration of 4%.
  3. Fix for 10 min at 37°C.
  4. Chill tubes on ice for 1 min.
  5. For extracellular staining with antibodies that do not require permeabilization, proceed to immunostaining (Section D) or store cells in PBS with 0.1% sodium azide at 4°C; for intracellular staining, proceed to permeabilization (Section C).

C. Permeabilization

NOTE: This step is critical for many CST antibodies.

  1. Permeabilize cells by adding ice-cold 100% methanol slowly to pre-chilled cells, while gently vortexing, to a final concentration of 90% methanol. Alternatively, remove fix prior to permeabilization by centrifugation and resuspend in 90% methanol as described above.
  2. Incubate 30 min on ice.
  3. Proceed with immunostaining (Section D) or store cells at -20°C in 90% methanol.

D. Immunostaining

NOTE: Account for isotype matched controls for monoclonal antibodies or species matched IgG for polyclonal antibodies. Count cells using a hemocytometer or alternative method.

  1. Aliquot 0.5–1 x 106 cells into each assay tube (by volume).
  2. Add 2–3 ml incubation buffer to each tube and wash by centrifugation. Repeat.
  3. Resuspend cells in 100 µl of diluted, biontinylated primary antibody (prepared in incubation buffer at the recommended dilution).
  4. Incubate for 1 hr at room temperature.
  5. Wash by centrifugation in 2–3 ml incubation buffer.
  6. Resuspend cells in Streptavidin, diluted in incubation buffer at the recommended dilution.
  7. Incubate for 30 min at room temperature.
  8. Wash by centrifugation in 2–3 ml incubation buffer.
  9. Resuspend cells in 0.5 ml PBS and analyze on flow cytometer; alternatively, for DNA staining, proceed to optional DNA stain (Section E).

E. Optional DNA Dye

  1. Resuspend cells in 0.5 ml of DNA dye (e.g. Propidium Iodide (PI)/RNase Staining Solution #4087).
  2. Incubate for at least 30 min at room temperature.
  3. Analyze cells in DNA staining solution on flow cytometer.

posted July 2009

revised September 2013

protocol id: 160

Product Usage Information

Note: This control antibody must be diluted to the same concentration (not dilution) as the specific antibody in analysis.


Storage: Supplied in 136 mM NaCl, 2.6 mM KCI, 12 mM sodium phosphate (pH 7.4) dibasic, 2 mg/ml BSA, and 50% glycerol. Store at –20°C. Do not aliquot the antibodies.

Specificity / Sensitivity

Mouse (MOPC-21) mAb IgG1 Isotype Control (Biotinylated) has unknown specificity and was chosen as an isotype control after screening on a variety of resting, activated, live, and fixed rat and human tissues.


Source / Purification

Mouse (MOPC-21) mAb IgG1 Isotype Control (Biotinylated) was purified by affinity chromatography.

Product Description

This Cell Signaling Technology monoclonal antibody is conjugated to biotin under optimal conditions.


Isotype control antibodies are used to estimate the nonspecific binding of target primary antibodies due to Fc receptor binding or other protein-protein interactions. An isotype control antibody should have the same immunoglobulin type and be used at the same concentration as the test antibody.



For Research Use Only. Not For Use In Diagnostic Procedures.
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