Figure 3.

Giant platelet from patient with May-Hegglin anomaly. The frozen thin section has been stained with a polyclonal antibody to the glycocalicin portion of GPIb and protein A coupled to 5-nm gold particles. Immunogold particles indicating sites of GPIb cover the exterior surface (S) of the large cell and line channels of the dilated OCS. Densities of labeling for immunogold detecting GPIb are comparable on the external surface or on membranes lining channels of the OCS. Original magnification, ×80,000.