一般演題

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NK細胞の標的細胞認識障害機構におけるCD44の役割：神吉和重^１,鳥越俊彦^１,平井到^１,佐藤昇志^１,菊地浩吉^１,２（^１札幌医大第１病理,^２札幌IDL）

CD44 plays an significant role in target cell recognition and lysis of NK cells ：Kazushige KANKI^１, Toshihiko TORIGOE^１, Itaru HIRAI^１, Noriyuki SATO^１, Kokichi KIKUCHI^１,２（^１Dept. of 1st Path. Sapporo Medical Univ.,^２Sapporo IDL）

We previously reported one of tumor-associated antigens as a candidate for a target structure of NK cell-mediated cytolysis. Monoclonal antibody(mAb)#109 recognized a glycoprotein with a molecular weight of 86,000 dalton composed of a single plypeptide chain . #109 antigen was expressed on the surface of W31 cells, which is transformant of WFB(rat fibroblast cell line) with H-ras oncogene. mAb#109 inhibited NK cell lysis against W31. In this study, expression cDNA cloning was performed using mAb#109 and W31 cDNA library, revealing that the #109 antigen was identical to rat CD44. CD44 is a widely expressed cell surface protein that recognizes multiple ligands and is involved in extra- and intercellular adhesion. Though the role of CD44 in tumor metastasis has been documented,NK-mediated killing mechanism is currently unknown. Our data suggest that it may be involved in target cell recognition and lysis of NK cells. A significant role of CD44 expression in an immune survaillance will be discussed.