Immunoprecipitation analysis of the GPIb-Ibβ-IX complex of Iy^a-phenotyped platelets after trypsin treatment.

Aliquots of 10⁹ biotinylated platelets from an Iy^a-positive individual were treated with trypsin, washed, lysed, and immunoprecipitated with MAB SZ2 (lane 1), MAB Gi10 (lane 2), MAB Gi27 (lane 3), and anti-Iy^a antibodies (lane 4). Immunoprecipitates were analyzed with 7.5% SDS-PAGE under nonreducing conditions.