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p16 INK4A (D7C1M) Rabbit mAb (PE Conjugate)
Antibody Conjugates

p16 INK4A (D7C1M) Rabbit mAb (PE Conjugate) #82548


H Endogenous Rabbit IgG
Flow Cytometry

Flow cytometric analysis of MCF7 cells (blue) and HeLa cells (green) using p16 INK4A (D7C1M) Rabbit mAb (PE Conjugate) (solid lines) or a concentration-matched Rabbit (DA1E) mAb IgG XP® Isotype Control (PE Conjugate) #5742 (dashed lines).

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Flow Cytometry, Methanol Permeabilization Protocol for Direct Conjugates

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.

B. Fixation

NOTE: If using whole blood, lyse red blood cells and wash by centrifugation prior to 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 15 min at room temperature.
  4. Wash by centrifugation with excess 1X PBS. Discard supernatant in appropriate waste container. Resuspend cells in 0.5-1 ml 1X PBS.

C. Permeabilization

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

D. Immunostaining

  1. Aliquot desired number of cells into tubes or wells.
  2. Wash cells by centrifugation in excess 1X PBS to remove methanol. Discard supernatant in appropriate waste container. Repeat if necessary.
  3. Resuspend cells in 100 µl of diluted antibody conjugate (prepared in incubation buffer at the recommended dilution).
  4. Incubate for 1 hr at room temperature. Protect from light.
  5. Wash by centrifugation in incubation buffer. Discard supernatant. Repeat.
  6. Resuspend cells in 1X 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 5 min at room temperature.
  3. Analyze cells in DNA staining solution on flow cytometer.

posted July 2009

revised June 2017

Protocol Id: 407

Application Dilutions
Flow Cytometry 1:50

Supplied in PBS (pH 7.2), less than 0.1% sodium azide and 2 mg/ml BSA. Store at 4°C. Do not aliquot the antibody. Protect from light. Do not freeze.

p16 INK4A (D7C1M) Rabbit mAb (PE Conjugate) recognizes endogenous levels of total p16 INK4A protein. This antibody does not cross-react with p15 INK4B. This antibody is not recommended for use in immunohistochemistry.

Species Reactivity:


Monoclonal antibody is produced by immunizing animals with a synthetic peptide corresponding to residues surrounding Ala143 of human p16 INK4A protein.

This Cell Signaling Technology antibody is conjugated to phycoerythrin (PE) and tested in-house for direct flow cytometric analysis in human cells. This antibody is expected to exhibit the same species cross-reactivity as the unconjugated p16 INK4A (D7C1M) Rabbit mAb #80772.

Members of the INK4 family of cyclin dependent kinase inhibitors include p16INK4A, p15INK4B, p18INK4C and p19INK4D. The INK4 family members inhibit cyclin dependent kinases 4 and 6 (CDK4 and CDK6), causing cell cycle arrest in G1 phase. The INK4A-ARF-INK4B locus on chromosome 9p21, frequently lost in human cancer, encodes the INK4 family members p16INK5A and p15INK4B, as well as the unrelated protein, ARF (1).

p16 INK4A expression, typically repressed in the absence of stress, is thought to drive cells into senescence, and p16 INK4A expression is a commonly used marker of senescent cells (2). p16INK4A protein expression is often altered in human cancer (3,4), and high expression is currently used as a predictive biomarker in cervical cancer (5).

  1. Kim, W.Y. and Sharpless, N.E. (2006) Cell 127, 265-75.
  2. LaPak, K.M. and Burd, C.E. (2014) Mol Cancer Res 12, 167-83.
  3. Ishikawa, M. et al. Int J Gynecol Cancer 16, 347-53.
  4. Queiroz, C. et al. (2006) Pathol Res Pract 202, 77-83.
  5. Romagosa, C. et al. (2011) Oncogene 30, 2087-97.
Entrez-Gene Id
Swiss-Prot Acc.
For Research Use Only. Not For Use In Diagnostic Procedures.

Cell Signaling Technology is a trademark of Cell Signaling Technology, Inc.
XP is a registered trademark of Cell Signaling Technology, Inc.

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To Purchase # 82548S

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Product # Size Price
100 µl  (50 tests) $ 305

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