Expression vectors encoding alloantigens of glycoprotein ib.alpha.

Abstract

A method of inhibiting platelet transfusion refractoriness comprising administering third-party platelets to a patient whose platelet glycoprotein Ib.alpha. polypeptides expressed from the patient's DNA have been determined to have either threonine or methionine residues, or both, at amino acid residue position 145 thereof, said third-party platelets having expressed at residue position 145 of the glycoprotein Ib.alpha. polypeptide thereof amino acids that are the same as those expressed on the glycoprotein Ib.alpha. polypeptides of the patient's platelets. Also, an antibody, or a fragment thereof, in substantially pure form having as its target epitope a domain of glycoprotein Ib.alpha., the affinity of said antibody, or fragment thereof, for said epitope being dependent on the identity of the amino acid residue at position 145 of said glycoprotein. In addition, in a process for storing a supply of platelets for therapeutic use in a patient, the improvement comprising segregating said platelets into three stocks dependent upon whether residue 145 of glycoprotein Ib.alpha. polypeptides of said platelets includes: (A) threonine; (B) methionine; or (C) both threonine and methionine. Also, a method of immunoassay comprising contacting a sample of blood, or a composition derived therefrom, with alloantigenic Thr or Met.sup.145 form of glycoprotein Ib.alpha., or a fragment thereof, containing said Thr/Met.sup.145 locus, and determining whether there is present a complex of antibody and a form of said glycoprotein or a fragment thereof.