Distribution of ABH blood group epitopes on inner surface of dental hard tissue: serological, immunohistochemical and ultrastructural study on odontoblasts.

This study was designed to investigate localization of ABH antigens on the inner surface of human tooth hard tissues. The tooth samples, extracted therapeutically, were cut and dried at room temperature for a few weeks. Scanning electron microscopic observation disclosed that the inner surface was exclusively covered with the odontoblastic zone and virtually no blood vessels remained in the samples. Blood group activities of the tooth fragments, which were detected with absorption-elution test, were markedly decreased when the odontoblastic zone was scraped off. To visualize the activity, the avidin-biotin-peroxidase complex immunostaining was performed on the odontoblasts of fresh teeth followed by embedding. Decalcification process was omitted to preserve the antigenicity. Group specific colorization was successfully developed on the cell surface of the odontoblasts. Immunoreactivity of the cell membrane of the odontoblast including the odontoblastic process was also confirmed by immunotransmission microscopic observation. On the other hand, localization of epitopes on intrinsic dentine without cell components could not be visualized. The results of these experiments indicate that the odontoblasts are one of potent sources of blood group antigenicity for blood grouping of the human teeth.