ABSTRACT
T cell antigen receptor (TCR)-mediated activation of T cells requires the interaction of dozens of proteins. Here we used quantitative mass spectrometry and activated primary CD4(+) T cells from mice in which a tag for affinity purification was knocked into several genes to determine the composition and dynamics of multiprotein complexes that formed around the kinase Zap70 and the adaptors Lat and SLP-76. Most of the 112 high-confidence time-resolved protein interactions we observed were previously unknown. The surface receptor CD6 was able to initiate its own signaling pathway by recruiting SLP-76 and the guanine nucleotide-exchange factor Vav1 regardless of the presence of Lat. Our findings provide a more complete model of TCR signaling in which CD6 constitutes a signaling hub that contributes to the diversification of TCR signaling.
Subject(s)
Adaptor Proteins, Signal Transducing/metabolism , Antigens, CD/metabolism , Antigens, Differentiation, T-Lymphocyte/metabolism , CD4-Positive T-Lymphocytes/immunology , Membrane Proteins/metabolism , Phosphoproteins/metabolism , T-Lymphocyte Subsets/immunology , Adaptor Proteins, Signal Transducing/genetics , Animals , Calcium Signaling/genetics , Cells, Cultured , Membrane Proteins/genetics , Mice , Mice, Inbred C57BL , Mice, Transgenic , Multiprotein Complexes/metabolism , Phosphoproteins/genetics , Protein Binding/genetics , Proteomics , Proto-Oncogene Proteins c-vav/metabolism , Receptors, Antigen, T-Cell/metabolism , ZAP-70 Protein-Tyrosine Kinase/metabolismABSTRACT
Advanced cutaneous T-cell lymphoma (CTCL) remains an unmet medical need, which lacks effective targeted therapies. In this study, we report the development of IPH4102, a humanized monoclonal antibody that targets the immune receptor KIR3DL2, which is widely expressed on CTCL cells but few normal immune cells. Potent antitumor properties of IPH4102 were documented in allogeneic human CTCL cells and a mouse model of KIR3DL2(+) disease. IPH4102 antitumor activity was mediated by antibody-dependent cell cytotoxicity and phagocytosis. IPH4102 improved survival and reduced tumor growth in mice inoculated with KIR3DL2(+) tumors. Ex vivo efficacy was further evaluated in primary Sézary patient cells, sorted natural killer-based autologous assays, and direct spiking into Sézary patient peripheral blood mononuclear cells. In these settings, IPH4102 selectively and efficiently killed primary Sézary cells, including at unfavorable effector-to-target ratios characteristic of unsorted PBMC. Together, our results offer preclinical proof of concept for the clinical development of IPH4102 to treat patients with advanced CTCL.