Two opposite signaling outputs are driven by the KIR2DL1 receptor in human CD4+ T cells.
Inhibitory killer Ig-like receptors (KIR), expressed by human natural killer cells and effector memory CD8(+) T-cell subsets, bind HLA-C molecules and suppress cell activation through recruitment of the Src homology 2 domain-containing protein tyrosine phosphatase 1 (SHP-1). To further analyze the still largely unclear role of inhibitory KIR receptors on CD4(+) T cells, KIR2DL1 transfectants were obtained from a CD4(+) T-cell line and primary cells. Transfection of CD4(+) T cells with KIR2DL1 dramatically increased the T-cell receptor (TCR)-induced production of interleukin-2 independently of ligand binding but inhibited TCR-induced activation after ligation. KIR-mediated costimulation of TCR activation involves intact KIR2DL1-ITIM phosphorylation, SHP-2 recruitment, and PKC- phosphorylation. Synapses leading to activation were characterized by an increase in the recruitment of p-Tyr, SHP-2, and p-PKC-, but not of SHP-1. Interaction of KIR2DL1 with its ligand led to a strong synaptic accumulation of KIR2DL1 and the recruitment of SHP-1/2, inhibiting TCR-induced interleukin-2 production. KIR2DL1 may induce 2 opposite signaling outputs in CD4(+) T cells, depending on whether the KIR receptor is bound to its ligand. These data highlight unexpected aspects of the regulation of T cells by KIR2DL1 receptors, the therapeutic manipulation of which is currently being evaluated.
Fourmentraux-Neves
Emmanuelle
E
Inserm U753, Institut Gustave Roussy, Villejuif, France.
Jalil
Abdelali
A
Da Rocha
Sylvie
S
Pichon
Christophe
C
Chouaib
Salem
S
Bismuth
Georges
G
Caignard
Anne
A
D015496:CD4-Positive T-Lymphocytes / Q000276:immunology*; D002478:Cells, Cultured; D006801:Humans; D007376:Interleukin-2 / Q000096:biosynthesis; D007527:Isoenzymes / Q000378:metabolism; D011493:Protein Kinase C / Q000378:metabolism; D000074121:Protein Kinase C-theta; D054592:Protein Tyrosine Phosphatase, Non-Receptor Type 11 / Q000378:metabolism; D053824:Protein Tyrosine Phosphatase, Non-Receptor Type 6 / Q000378:metabolism; D011948:Receptors, Antigen, T-Cell / Q000378:metabolism; D054342:Receptors, KIR2DL1 / Q000235:genetics / Q000378:metabolism*; D015398:Signal Transduction / Q000276:immunology*; D014162:Transfection
D007376:Interleukin-2; D007527:Isoenzymes; D011948:Receptors, Antigen, T-Cell; D054342:Receptors, KIR2DL1; C076233:PRKCQ protein, human; D011493:Protein Kinase C; D000074121:Protein Kinase C-theta; C516724:PTPN11 protein, human; C509249:PTPN6 protein, human; D054592:Protein Tyrosine Phosphatase, Non-Receptor Type 11; D053824:Protein Tyrosine Phosphatase, Non-Receptor Type 6