347회 mT-20: A Novel Thymocyte Differentiation Antigen and its Role in …

347회

연사 :  배 영 미, 강원대학교 의과대학 병리학교실

제목: mT-20: A Novel Thymocyte Differentiation Antigen and its Role in Thymic Education

Abstract

A monoclonal antibody was produced by immunizing mouse thymocytes and named as anti-mT-20 antibody.  According to the expression profile in mouse tissues, anti-mT-20 mAb seems to recognize a novel antigen expressed in various cell types.  In order to investigate the role of mT-20 antigen in T cell development, biochemical and functional analysis was performed.  The mT-20 antigen is a 32 KDa molecule whose expression on mouse thymocytes varies according to the differentiation stage: high density on immature CD3-/low thymocytes and reduced density on CD3high single positive thymocytes and circulating T cells. Engagement of anti-mT-20 mAb on mouse thymocytes induced homotypic aggregation and subpopulation of thymocytes underwent apoptosis.  To study the mechanism of apoptosis further, we induced apoptosis in mouse thymocytes and thymocyte cell lines.  Interestingly, one of mouse thymocyte cell lines, Scid-Adh, is susceptible for apoptosis upon mT-20 ligation.  In addition, apoptotic signal is appeared to be independent from caspase activity.  As the electron microscopic configuration shows typical apoptotic configurations by mT-20 signaling in Scid-Adh cells, other molecule(s) such as BAX or/and BAD could be involved in this pathway. In conclusion, a novel thymic differentiation antigen, mT-20, might play a critical role in negative selection in T cell development.