2002 Fiscal Year Final Research Report Summary

Signal transduction of negative selection in human thymus

Research Project

Project/Area Number	13671399
Research Category	Grant-in-Aid for Scientific Research (C)
Allocation Type	Single-year Grants
Section	一般
Research Field	Thoracic surgery
Research Institution	Nagoya City University
Principal Investigator	FUKAI Ichiro Nagoya City University, Graduate School of Medical Sciences, Assistant professor, 大学院・医学研究科, 講師 (10244550)
Co-Investigator(Kenkyū-buntansha)	FUJII Yoshitaka Nagoya City University, Graduate School of Medical Sciences, Professor and Chair, 大学院・医学研究科, 教授 (40156831)
Project Period (FY)	2001 – 2002
Keywords	negative selection / apoptosis / mitochondria / cytochrome C / AIF
Research Abstract	The negative selection ; the elimination of auto reactive T cell, is executed against CD4+CD8+ : double positive (DP) cells. The apoptotic factors were induced following the strong signal through T cell receptor (TCR) and finally the targeted cells were killed and eliminated We set up the in vitro negative selection model using anti-CD3 antibody and anti-CD28 antibody to human DP cell. The DP cell that was trated by anti-CD3 and anti-CD28 antibody falled to death showing the characteristic feature of apoptois such as the Annexin V was proved to positive and Caspase 3 was activated. In this process, the loss of mitochondrial delta-psi was obsereved. We investigated that the mitochondria act the key role in T cell negative selection. In the apoptotic signal transduction, various protein such as cytochrome c, AIF, Smac, Endonuclease G, and HtrA2 was released from mitochondrial intermembrane space into cytoplasm. We studied the change of the intracellular distribution of these proteins using the flowcytometry in anti-CD3 and anti-CD28 antibody treated DP cell. Cytochrome c or AIF is not localysed in cytoplasm, but the elevation of the cytoplasmic concentration of cytochrome c or AIF was observed in treated DP cell. From these result, we consider that the mitochondria is act in the apoptotic signal transduction of the negative selection in human thymus.