Conditional deletion reveals a cell-autonomous requirement of SLP-76 for thymocyte selection.
The SH2 domain containing leukocyte phosphoprotein of 76 kD (SLP-76) is critical for pre-TCR-mediated maturation to the CD4+CD8+ double positive (DP) stage in the thymus. The absolute block in SLP-76null mice at the CD4-CD8-CD44-CD25+ (double-negative 3, DN3) stage has hindered our understanding of the role of this adaptor in alphabeta TCR-mediated signal transduction in primary thymocytes and peripheral T lymphocytes. To evaluate the requirements for SLP-76 in these events, we used a cre-loxP approach to generate mice that conditionally delete SLP-76 after the DN3 checkpoint. These mice develop DP thymocytes that express the alphabeta TCR on the surface, but lack SLP-76 at the genomic DNA and protein levels. The DP compartment has reduced cellularity in young mice and fails to undergo positive selection to CD4+ or CD8+ single positive (SP) cells in vivo or activation-induced cell death in vitro. A small number of CD4+SP thymocytes are generated, but these cells fail to flux calcium in response to an alphabeta TCR-generated signal. Peripheral T cells are reduced in number, lack SLP-76 protein, and have an abnormal surface phenotype. These studies show for the first time that SLP-76 is required for signal transduction through the mature alphabeta TCR in primary cells of the T lineage.
Maltzman
Jonathan S
JS
Department of Medicine, University of Pennsylvania School of Medicine, Philadelphia, PA 19104, USA.
Kovoor
Lisa
L
Clements
James L
JL
Koretzky
Gary A
GA
D048868:Adaptor Proteins, Signal Transducing; D000818:Animals; D015139:Blotting, Southern; D015153:Blotting, Western; D002118:Calcium / Q000378:metabolism; D002454:Cell Differentiation / Q000276:immunology*; D019070:Cell Lineage / Q000276:immunology*; D005260:Female; D005434:Flow Cytometry; D017353:Gene Deletion; D051379:Mice; D008810:Mice, Inbred C57BL; D010750:Phosphoproteins / Q000235:genetics*; D015398:Signal Transduction / Q000276:immunology*; D013234:Stem Cells / Q000276:immunology; D016176:T-Lymphocyte Subsets / Q000166:cytology / Q000276:immunology*; D013950:Thymus Gland / Q000166:cytology*
D048868:Adaptor Proteins, Signal Transducing; D010750:Phosphoproteins; C092947:SLP-76 signal Transducing adaptor proteins; D002118:Calcium