Anti-Glycoprotein GPIIb/IIIa complex mAbs [314.1](MABL-1718)

MABL-1718

crystallization, in vitro, in vivo, SPR, FC

Engineer antibody

Human

314.10000000000002

Recombinant Antibody

The antibody recognizes the N terminus of the GPIIb beta propeller domain only when soluble quinine is present.

Integrin beta-3; Platelet membrane glycoprotein IIIa; GPIIIa; CD61

P05106

The original antibody was generated by immunizing BALB/c mice with a mixture of quinine- linked GPIIb/IIIa, unlinked GPIIb/IIIa, and soluble quinine.

The antibody reacted with normal human platelets in the presence of quinine, as shown by flow cytometry. The reactions of the antibody with CHO cells expressing all-human GPIIb/IIIa (H/H), all-rat GPIIb/IIIa (R/R), or human/rat mixed GPIIb/IIIa integrins (H/R, R/H) were studied by flow cytometry. Quinine dependent antibody binding occurred with constructs H/H and H/R, but not with R/R or R/H (Bougie et al., 2009; PMID: 18948570). Nonobese diabetic/severe combined immunodeficient (NOD/scid) mouse was used as a model to study drug-dependent clearance of platelets in vivo. Mice were first infused with human platelets and then injected with the antibody and quinine or buffer; platelets were cleared from the circulation when the antibody and quinine were injected, whereas the antibody alone was without effect. (Bougie et al., 2010; PMID: 20587782) GPIIb/IIIa bound monovalently to the immobilized antibody with low affinity in the absence of quinine and with fivefold greater affinity when quinine was present (KD ≈ 2.2*10^- 6), as shown by SPR analysis. Measurements of quinine-dependent binding of intact antibody and Fab fragment to platelets showed that affinity is increased 10 000- to 100 000-fold by bivalent interaction between antibody and its target, as determined by flow cytometry (Bougie et al., 2015; PMID: 26353910). The crystal structures of the Fab fragment and its complex with quinine were determined. Quinine induced structural modifications of the Fab fragment; the authors propose that quinine remodels the Fab paratope and enables binding to the platelet GPIIb/IIIa. The monovalent KD values for quinine binding to the IgG fragment measured was 58 nM (Zhu et al., 2015; PMID: 26282540).

Bougie et al. Quinine-dependent, platelet-reactive monoclonals mimic antibodies found in patients with quinine-induced immune thrombocytopenia. Blood. 2009 Jan 29; 113(5): 1105–1111. PMID:18948570

The paper describes the generation and characterization of the antibody. The antibody is employed in studies to define the molecular basis for drug-dependent antibody binding and platelet destruction in DITP.

100 μg Purified antibody.

1 mg/ml.

Protein A affinity purified

PBS with 0.02% Proclin 300.

Store at 4⁰C for up to 3 months. For longer storage, aliquot and store at - 20⁰C.