Methods of detecting disorders involving defective p-selectin glycoprotein ligand or defective p-selectin

Abstract

P-selectin has been demonstrated to bind primarily to a single major glycoprotein ligand on neutrophils and HL-60 cells, when assessed by blotting assays and by affinity chromatography of [ 3 H]glucosamine-labeled HL-60 cell extracts on immobilized P-selectin. This molecule was characterized and distinguished from other well-characterized neutrophil membrane proteins with similar apparent molecular mass. The purified ligand, or fragments thereof (including both the carbohydrate and protein components), or antibodies to the ligand, or fragments thereof, can be used as inhibitors of binding of P-selectin to cells, and to treat various conditions involving leukocyte binding via P-selectin glycoprotein ligand.

What is claimed is:  
     
         1 . A method of detecting a disorder involving defective P-selectin in a patient comprising: 
 providing a quantity of P-selectin glycoprotein ligand, or a P-selectin binding portion thereof, the P-selectin glycoprotein ligand comprising a fucosylated sialylated glycoprotein containing sialyl Lewis x  antigen and the glycoprotein ligand having an apparent relative molecular weight of about 120,000 D as assessed by SDS-PAGE under reducing conditions and having binding specific for P-selectin; and    testing the binding of the P-selectin glycoprotein ligand, or the P-selectin binding portion thereof, to activated platelets or activated endothelial cells derived from the patient.    
     
     
         2 . A method of detecting a disorder involving defective binding of P-selectin glycoprotein ligand in a patient, comprising: 
 providing an antibody to a protein component or to a carbohydrate-protein component of P-selectin glycoprotein ligand, the glycoprotein ligand comprising a fucosylated sialylated glycoprotein containing sialyl Lewisx antigen and the glycoprotein ligand having an apparent relative molecular weight of about 120,000 D as assessed by SDS-PAGE under reducing conditions and wherein the antibody has binding specific for P-selectin glycoprotein ligand and wherein the antibody inhibits binding of P-selectin glycoprotein ligand to P-selectin; and    testing the binding of the antibody to leukocytes obtained from the patient.