Anti-Glycoprotein GPIIb/IIIa complex [314.1]

Absolute Antibody

Anti-Glycoprotein GPIIb/IIIa complex [314.1]

7

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).

Flow Cytometry, Other Application

FC; Crystallization; in vivo; in vitro; SPR

Research Use Only

Integrin beta-3

This chimeric rabbit antibody was made using the variable domain sequences of the original Mouse IgG1 format for improved compatibility with existing reagents assays and techniques.

-20°C,2°C to 8°C

12352203