M. Mitsuo Yokoyama

Detection of Platelet Antibody Using Rosette Technique with Anti-IgG Antibody-Coated Polyacrylamide Gel

Abstract. Paraformaldehyde‐fixed platelets from normal donors were used for detection of antibody to platelet by in vitro sensitization (indirect method) utilizing rabbit anti‐human IgG heavy chain specific antibody‐coated polyacrylamide gels (Immunobeads). The sensitized platelets formed rosettes with Immunobeads and the positive rosette count was over 30%, while control showed less than 8% when normal sera were used. This method was also applicable for detecting antibody‐sensitized platelets in vivo (direct method) in patients with autoimmune thrombocytopenia. This method is simple, rapid and reproducible for clinical use. Direct and indirect immunofluorescent antibody tests and a blocking test with anti‐human serum also supported the results of Immunobead rosetting technique.

Species-Specific Glycoproteins of the Human Red Cell Membrane

Abstract. Specific antiserum of human red cells was prepared from rabbit anti‐human red cell serum by absorption with red cells of horse, hog, dog and Japanese monkey. This antiserum proved specific for human red cells regardless of blood types ABO and MN as demonstrated by the hemagglutination test. Sialoglycoproteins were extracted with lithium diiodosalicylate and isolated through chromatographic procedures from human red cell membranes, and showed inhibitory activity for the specific antiserum as well as for anti‐M and anti‐N sera. The isolated glycoproteins corresponded to the sialoglycoproteins on the basis of SDS‐PAG electrophoresis. The inhibitory activity of the sialoglycoproteins for the specific antiserum was lost after the substance was treated with sialidase for 24 h. A moderate reduction of the inhibitory activity for anti‐M and anti‐N sera but not for the specific antiserum was seen after treatment for 1 h. These results showed that the receptors for the species‐specific antiserum were more resistant towards sialidase treatment.