Immunostaining of Stx receptors. Immunohistochemical detection of the Stx receptor Gb3/CD77 on 5 single endothelial cells (HUVEC) immobilized onto glass slides by cytocentrifugation was performed with avidin biotin complex technique using a monoclonal rat antihuman CD77 primary antibody. Binding of the antibody is pictured as a red linear membrane stain (arrows, × 630).