MEK Activity Regulates Negative Selection of Immature CD4+CD8+ Thymocytes

MEK activity regulates negative selection of immature CD4+CD8+ thymocytes.

CD4+CD8+ thymocytes are either positively selected and subsequently mature to CD4 single positive (SP) or CD8 SP T cells, or they die by apoptosis due to neglect or negative selection. This clonal selection is essential for establishing a functional self-restricted T cell repertoire. Intracellular signals through the three known mitogen-activated protein (MAP) kinase pathways have been shown to...

Transcription Factor Activation during Signal-induced Apoptosis of Immature CD4CD8 Thymocytes

Many signals that cause apoptotic cell death operate by inducing transcription and translation of other (presumably death effector) mediators, and it is well established that stimulus-induced apoptosis can often be blocked by inhibiting transcription and translation. Transcriptional regulation of apoptosis, however, is incompletely understood. To gain insight into nuclear events associated with...

T cell receptor-mediated recognition of self-ligand induces signaling in immature thymocytes before negative selection

Shaping of the T cell repertoire by selection during intrathymic maturation involves T cell receptor (TCR) recognition of major histocompatibility complex/self-antigen complexes. In this communication, we studied the ability of minor lymphocyte stimulating (Mls) determinants to act as self-tolerogens in the selection of the T cell repertoire. We demonstrate that unprimed T cells from normal as ...

Human Immature Thymocytes as Target Cells of the Leukemogenic Activity

The risk of developing adult T-cell leukemia (ATL) associated with neonatal infection by human T-cell leukemia virus type I (HTLV-I) suggests that early events triggered by HTLV-I might be of crucial importance in initiating the multistep lymphoproliferative process leading several decades later to the development of leukemic disease. Thus, infection of thymocytes early in life might be directl...

Immature and Mature T Cells Complexes: Differential Sensitivity of Thymocytes by a Few Peptide-MHC Cutting Edge: Negative Selection of Immature