Characterization of an antibody raised against reduced glycoprotein IIIa of human platelets.
A polyclonal antibody against reduced and vinylpyridylethylated human glycoprotein IIIa was raised in rabbits. Its reactivity with reduced GPIIIa was about 500 times higher than that of the antibody against native GPIIIa. The lowest amounts of purified reduced and native GPIIIa recognized by the antibody against reduced GPIIIa were 25 and 400 ng, respectively. The antibody did not recognize native GPIIIa (about 1-2 micrograms) in platelet extracts and chymotryptic degradation products of GPIIIa. It inhibited ADP-induced platelet aggregation but it did not inhibit fibrinogen binding to ADP-stimulated platelets. Our experiments suggest that the antigenicity of GPIIIa (beta 3 integrin) depends on the conformation of the molecule determined by numerous S-S bridges between cysteine residues.
Eckardt
A J
AJ
Department of Physiology, Temple University School of Medicine, Philadelphia, PA 19140.
Cook
J J
JJ
Niewiarowski
S
S
D000906:Antibodies / Q000276:immunology*; D015153:Blotting, Western; D002918:Chymotrypsin; D004591:Electrophoresis, Polyacrylamide Gel; D004797:Enzyme-Linked Immunosorbent Assay; D005340:Fibrinogen / Q000378:metabolism; D006801:Humans; D010084:Oxidation-Reduction; D010980:Platelet Membrane Glycoproteins / Q000032:analysis / Q000276:immunology*; D011485:Protein Binding; D011487:Protein Conformation; D013329:Structure-Activity Relationship
D000906:Antibodies; D010980:Platelet Membrane Glycoproteins; D005340:Fibrinogen; D002918:Chymotrypsin