モノクローナル抗体を用いたＭａｔｕｈａｓｉ‐Ｏｇａｔａ ｐｈｅｎｏｍｅｎｏｎの解析

Abstract

Monoclonal antibodies specific to human group A red blood cells (A-116, A-251 and A-361) and group B red cells (B-218, B-299 and B-361) were obtained through murine hybridomas. Three of these monoclonal antibodies, A-251, B-218 and B-361, were used for the present analysis. This study aimed for further immunological characterization whether the Matuhasi-Ogata phenomenon is truely exist and if it is true event in immunological basis.The analysis was carried out by absorption and elution of the mixture of monoclonal anti-A and anti-B antibodies with human group A group B red blood cells. The resulting antibody activity was measured by saline and papain methods. The phenomenon was also studied using sera from group O, and the mixture of group A and group B sera from healthy donors. A commercial blood typing anti-A and anti-B and commercially obtained monoclonal anti-A antibodies were simultaneously used for a comparative study.In absorption experiment, the mixture of monoclonal anti-A and anti-B antibodies was markedly absorved by the red blood cells processing corresponding antigen without affecting the titer for reciprocal red cells, respectively. In group O serum, the absorption with group A red cells markedly abolished the titer against group A red cells, while anti-B was also moderately reduced. A similar but reciprocal phenomenon was observed when the serum was absorbed by group B red cells. In the case of the mixture of group A and group B normal sera the mixture of commercial anti-A and inti-B sera, absoption of antibody with red cells was type specific.In elution experiment, only corresponding antibody was recovered from the red cells after mixting with the monoclonal anti-A and anti-B mixed antibodies, respectively. No cross reaction with red cells was observed, while the eluates from group A and group B red cells absorbed group O serum agglutinated both A and B red cells. However, the eluates from the mixture of group A and group B normal sera agglutinated only corresponding red cells, respectively, and no cross reaction with both red cells was observed. Furthermore, the eluates from the mixture of commerical anti-A and anti-B sera also showed type specific agglutination, respectively, and no cross reaction with both red cells was observed.From these results, it is suggested that non-specific adhesion of antibody molecules to antigen-antibody complex known as Matuhasi-Ogata phenomenon was not confirmed when the mixture of monoclonal and normal anti-A and anti-B antibodies, and the phenomenon was only observed when group O serum was used. The phenomenon was therefore implicated due to the presence of cross-reactive antibody only in group O serum reactive with a nature of chemical structures of group A and group B antigens on the red cells.It was clarified by the present investigation that Matsuhasi-Ogata phenomenon seems to be a false phenomenon presented by non-specific adhesion of serum proteins to the membrance when red blood cells were used in the experiment after a day for storage. No Matsuhasi-Ogata phenomenon was observed when the mixture of both type-specific antibodies was used for fresh group A or group B red cells.