Terminal Transferase Positive Rat Thymocytes are Resistant to Steroid-induced Apoptosis

Cell Structure and Function

Oriana Trubiani³  F.J. Bollum¹  Roberto Di Primio² 

[1] Supertechs, 96100 Medical Center Drive;Istituto di Morfologia Umana Normale, Università di Ancona, Monte D'Ago;Istituto di Morfologia Umana Normale, Università di Chieti

关键词: apoptosis;    steroids;    terminal deoxynucleotidyl transferase;    Bcl-2;    thymocytes;   

DOI  :  10.1247/csf.20.455

学科分类：分子生物学，细胞生物学和基因

来源: Japan Society for Cell Biology

【 摘 要 】

References(41)Apoptosis is a prominent mechanism of programmed cell death in the immune system. In the thymus apoptosis is responsible for the deletion of autoreactive T-cells during thymic differentiation. The typical features of apoptosis are characterized by nuclear and cytoplasmic morphologic changes, along with cleavage of chromatin at regularly spaced sites. Terminal deoxynucleotidyl transferase (TdT) is a DNA polymerizing enzyme found at an early stage of T and B lymphocyte differentiation, which generates diversity in the DNA sequence of immunoglobulin (Ig) or T cell receptor (TCR). The combined evaluations of thymocyte morphological features, immune phenotype and thymic topography associated to TdT expression allow the recognition of three different thymocyte subpopulations, characterized by small-size, intermediate-size and large-size. The results of this study show that dexamethasone (Dx)-treatment induces cell death via apoptosis involving distinct transformations related to differentiation stages of thymic subpopulations. Intermediate and small-size thymocytes that are TdT-negative or weakly positive at nuclear level are Dx sensitive. In contrast the large-size thymocytes, highly TdT positive, corresponding to the undifferentiated cells, do not show significant morphological modifications and TdT positivity to Dx-treatment. Immunocytochemical analysis shows that Dx-treatment does not affect TdT synthesis but morphological changes, occurring during apoptotic process, are responsive to intracellular movement and intranuclear arrangement of the TdT.

【 授权许可】

Unknown