Development of a monoclonal antibody capable of differentiating platelet PLA1/PLA1, PLA1/PLA2 and PLA2/PLA2 genotypes

A monoclonal antibody, LK-4, has been developed which distinguishes platelet PLA1/PLA1, PLA1/PLA2 and PLA2/PLA2 genotypes on platelet glycoprotein GPIIIa of Triton-solubilized platelet extracts. An ELISA assay has been developed which traps GPIIIa with Concanavalin A, enriching the platelet extract for the PLA antigens. A second monoclonal antibody, DEK-10, which reacts equally with GPIIIa of PLA1/PLA1 and PLA2/PLA2 platelet extracts is employed as an internal standard to correct for individual differences in GPIIIa content, GPIIIa extracted by Triton X-100 and GPIIIa trapped with Concanavalin A. This ELISA assay clearly differentiated 11 different PLA1/PLA1 subjects from eight PLA2/PLA2 women with a history of neonatal alloimmune thrombocytopenia as well as six unrelated obligate heterozygotes and should be useful in evaluating the PLA genotype of pregnant women and their families.