Faculty Collaboration Database

Interaction of AP-2, a monoclonal antibody specific for the human platelet glycoprotein IIb-IIIa complex, with intact platelets. J Biol Chem 1983 Oct 25;258(20):12582-6

Date

10/25/1983

Pubmed ID

6226659

Scopus ID

2-s2.0-0021027332 (requires institutional sign-in at Scopus site)   268 Citations

Abstract

A murine monoclonal antibody, designated AP-2, reacts specifically with the complex formed by human platelet membrane glycoproteins IIb and IIIa, but does not react at all with the individual glycoproteins. Purified AP-2 covalently coupled to Sepharose CL4B was used as an immunoadsorbent column to purify the IIb-IIIa complex from a preparation of Triton X-100-solubilized human platelet proteins. Radioiodinated AP-2 was shown to bind to a single class of sites, with 57,400 +/- 9,700 molecules bound per cell (mean +/- S.D.) at saturation and a dissociation constant (Kd) of 0.64 +/- 0.15 nM (mean +/- S.D.). Binding could not be readily reversed even after a 1-h incubation with a 100-fold excess of cold antibody. AP-2 inhibits ADP-induced binding of radiolabeled fibrinogen to gel-filtered platelets in a noncompetitive fashion, consistent with the previous observation that AP-2 also inhibits the aggregation of platelets in plasma induced by a number of physiologic agonists, including adenosine diphosphate, epinephrine, collagen, thrombin, and arachidonic acid. Using AP-2, we have obtained evidence that the IIb-IIIa complex exists in the membrane of intact nonstimulated platelets and that complex integrity is not affected by external calcium ion concentration.

Author List

Pidard D, Montgomery RR, Bennett JS, Kunicki TJ

MESH terms used to index this publication - Major topics in bold

Antibodies, Monoclonal
Antigen-Antibody Complex
Blood Platelets
Cell Membrane
Chromatography, Affinity
Glycoproteins
Humans
Immunoelectrophoresis, Two-Dimensional
Kinetics
Molecular Weight
Platelet Membrane Glycoproteins