Sialidase pretreatment of splenic cryostat sections enhances sialoadhesin-mediated adhesion of sheep erythrocytes. (A) Murine splenic cryostat section (untreated). (B) Murine splenic cryostat section pretreated with VC-sialidase; arrow denotes adherent sheep erythrocytes in the splenic marginal zones. (C) VC-sialidase treated splenic cryostat section pretreated with the antisialoadhesin blocking MoAb, 3D6.