Anti-Platelet Factor 4 Antibody, clone 197.2

Platelet factor 4 (UniProt P02776; also known as C-X-C motif chemokine 4, Iroplact, Oncostatin-A, PF-4) is encoded by the PF4 (also known as CXCL4, SCYB4) gene (Gene ID 5196) in human. Platelet factor 4 (PF4) is a small CXC chemokine family cytokine released from alpha-granules of activated platelets during platelet aggregation to promote blood coagulation. PF4 binds heparin with high affinity (Kd ~4-20 nM) via its heparin-binding domain (a.a. 92-98) and neutralizes the anti-thrombin activity of heparin-like molecules. PF4 is chemotactic for neutrophils, fibroblasts and monocytes, and interacts with the chemokine receptor CXCR3 splice variant CXCR3B. In individuals suffering from heparin-induced thrombocytopenia (HIT), PF4-heparin complexes can trigger an immune response and the generation of anti-PF4 antibodies, resulting in the foramtion of macromolecular antibody-heparin-PF4 immune complexes that bind Fc RIIa (CD32a) on platelets and induce platelet activation. Platelet activation in turn results in more PF4 release into circulation, enhanced immune-complex formation, exaggerated platelet activation, and cell clearance. PF4 is synthesized with a signal peptide sequence (a.a. 1-31) that is removed posttranslationally to produce the mature PF4 (a.a. 32-101), additional proteolytic cleavage yields the PF4 short form (a.a. 48-101).

Clone 197.2 targets a linear epitope sensitive to heparin binding, but insensitive to reducing agent or denaturation by SDS (Xiao, Z., et al. (2008). Blood. 112(4):1091-1100).

Purified human platelet PF4 (Xiao, Z., et al. (2008). Blood. 112(4):1091-1100).

Detect PF4 using this mouse monoclonal Anti-Platelet Factor 4, clone 197.2, Cat. No. MABS1255, validated for use in ELISA, Flow Cytometry, Function Analysis, Immunocytochemistry. and Western Blotting.

Western Blotting Analysis: A representative lot detected E. coli expressed recombinant mature human PF4 (a.a. 32-101) under both reduced and non-reduced condition (Courtesy of Dr. Richard H. Aster, MD, PhD, Blood Center of Wisconsin, U. S. A.).

ELISA Analysis: A representative lot detected PF4 in the absence of heparin by ELISA. Decreased immunoreactivity of clone 197.2 was seen toward heparin-complexed PF4 (Xiao, Z., et al. (2008). Blood. 112(4):1091-1100).

Function Analysis: A representative lot and PF4, but not clone 197.2 or PF4 alone, activated human neutrophils as indicated by Mac-1 upregulation (Xiao, Z., et al. (2008). Blood. 112(4):1091-1100).

Immunocytochemistry Analysis: A representative lot, preconjugated with Alexa Fluor^™ 488, immunolabeled the co-administered PF4 on human neutrophils. CD32a (Fc gamma RIIA) was seen co-localized with the PF4 anti-PF4 immune complexes on the surface of activated neutrophils (Xiao, Z., et al. (2008). Blood. 112(4):1091-1100).

Western Blotting Analysis: A representative lot detected PF4 under both reduced and non-reduced condition by recognizing a linear epitope (Xiao, Z., et al. (2008). Blood. 112(4):1091-1100).

Evaluated by Flow Cytometry in human platelets.

Flow Cytometry Analysis: 1 µg of this antibody detected PF4 in one million 4% paraformaldehyde-fixed, 0.2% Triton X-100-permeabilized human platelets.

~8 kDa (recombinant mature hPF4) observed. 10.84 kDa (pro-form), 7.769 kDa (mature; a.a. 32-101), 6.033 kDa (cleaved short form; a.a. 48-101) calculated. Uncharacterized bands may be observed in some lysate(s).

Format: Purified

Purified mouse IgG1 in buffer containing PBS without preservatives.

Concentration: Please refer to lot specific datasheet.

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