InVivoMAb anti-mouse CD3ε/BE00

in vivo T cell depletion

Glasner, A., et al. (2018). "NKp46 Receptor-Mediated Interferon-gamma Production by Natural Killer Cells Increases Fibronectin 1 to Alter Tumor Architecture and Control Metastasis" Immunity 48(1): 107-119 e104. 

Natural killer (NK) cells are innate lymphoid cells, and their presence within human tumors correlates with better prognosis. However, the mechanisms by which NK cells control tumors in vivo are unclear. Here, we used reflectance confocal microscopy (RCM) imaging in humans and in mice to visualize tumor architecture in vivo. We demonstrated that signaling via the NK cell receptor NKp46 (human) and Ncr1 (mouse) induced interferon-gamma (IFN-gamma) secretion from intratumoral NK cells. NKp46- and Ncr1-mediated IFN-gamma production led to the increased expression of the extracellular matrix protein fibronectin 1 (FN1) in the tumors, which altered primary tumor architecture and resulted in decreased metastases formation. Injection of IFN-gamma into tumor-bearing mice or transgenic overexpression of Ncr1 in NK cells in mice resulted in decreased metastasis formation. Thus, we have defined a mechanism of NK cell-mediated control of metastases in vivo that may help develop NK cell-dependent cancer therapies.

in vitro T cell stimulation/activation

Wendland, K., et al. (2018). "Retinoic Acid Signaling in Thymic Epithelial Cells Regulates Thymopoiesis" J Immunol 201(2): 524-532. 

Despite the essential role of thymic epithelial cells (TEC) in T cell development, the signals regulating TEC differentiation and homeostasis remain incompletely understood. In this study, we show a key in vivo role for the vitamin A metabolite, retinoic acid (RA), in TEC homeostasis. In the ab-sence of RA signaling in TEC, cortical TEC (cTEC) and CD80(lo)MHC class II(lo) medullary TEC displayed sub-set-specific alterations in gene expression, which in cTEC included genes involved in epithelial proliferation, development, and differentiation. Mice whose TEC were unable to respond to RA showed increased cTEC proliferation, an accumulation of stem cell Ag-1(hi) cTEC, and, in early life, a decrease in medullary TEC numbers. These alterations resulted in reduced thymic cellularity in early life, a reduction in CD4 single-positive and CD8 single-positive numbers in both young and adult mice, and enhanced peripheral CD8(+) T cell survival upon TCR stimulation. Collectively, our results identify RA as a regulator of TEC homeostasis that is essential for TEC function and normal thymopoiesis.

in vitro T cell stimulation/activation

Lacher, S. M., et al. (2018). "NF-kappaB inducing kinase (NIK) is an essential post-transcriptional regulator of T-cell activation affecting F-actin dynamics and TCR signaling" J Autoimmun 94: 110-121. 

NF-kappaB inducing kinase (NIK) is the key protein of the non-canonical NF-kappaB pathway and is important for the development of lymph nodes and other secondary immune organs. We elucidated the specific role of NIK in T cells using T-cell specific NIK-deficient (NIK(DeltaT)) mice. Despite showing normal development of lymphoid organs, NIK(DeltaT) mice were resistant to induction of CNS autoimmunity. T cells from NIK(DeltaT) mice were deficient in late priming, failed to up-regulate T-bet and to transmigrate into the CNS. Proteomic analysis of activated NIK(-/-) T cells showed de-regulated expression of proteins involved in the formation of the immunological synapse: in particular, proteins involved in cytoskeleton dynamics. In line with this we found that NIK-deficient T cells were hampered in phosphorylation of Zap70, LAT, AKT, ERK1/2 and PLCgamma upon TCR engagement. Hence, our data disclose a hitherto unknown function of NIK in T-cell priming and differentiation.

in vitro T cell stimulation/activation

Ron-Harel, N., et al. (2016). "Mitochondrial Biogenesis and Proteome Remodeling Promote One-Carbon Metabolism for T Cell Activation" Cell Metab 24(1): 104-117. 

Naive T cell stimulation activates anabolic metabolism to fuel the transition from quiescence to growth and proliferation. Here we show that naive CD4(+) T cell activation induces a unique program of mitochondrial biogenesis and remodeling. Using mass spectrometry, we quantified protein dynamics during T cell activation. We identified substantial remodeling of the mitochondrial proteome over the first 24 hr of T cell activation to generate mitochondria with a distinct metabolic signature, with one-carbon metabolism as the most induced pathway. Salvage pathways and mitochondrial one-carbon metabolism, fed by serine, contribute to purine and thymidine synthesis to enable T cell proliferation and survival. Genetic inhibition of the mitochondrial serine catabolic enzyme SHMT2 impaired T cell survival in culture and antigen-specific T cell abundance in vivo. Thus, during T cell activation, mitochondrial proteome remodeling generates specialized mitochondria with enhanced one-carbon metabolism that is critical for T cell activation and survival.

in vitro T cell stimulation/activation

Liu, H., et al. (2015). "The Immune Adaptor SLP-76 Binds to SUMO-RANGAP1 at Nuclear Pore Complex Filaments to Regulate Nuclear Import of Transcription Factors in T Cells" Mol Cell 59(5): 840-849. 

While immune cell adaptors regulate proximal T cell signaling, direct regulation of the nuclear pore complex (NPC) has not been reported. NPC has cytoplasmic filaments composed of RanGAP1 and RanBP2 with the potential to interact with cytoplasmic mediators. Here, we show that the immune cell adaptor SLP-76 binds directly to SUMO-RanGAP1 of cytoplasmic fibrils of the NPC, and that this interaction is needed for optimal NFATc1 and NF-kappaB p65 nuclear entry in T cells. Transmission electron microscopy showed anti-SLP-76 cytoplasmic labeling of the majority of NPCs in anti-CD3 activated T cells. Further, SUMO-RanGAP1 bound to the N-terminal lysine 56 of SLP-76 where the interaction was needed for optimal RanGAP1-NPC localization and GAP exchange activity. While the SLP-76-RanGAP1 (K56E) mutant had no effect on proximal signaling, it impaired NF-ATc1 and p65/RelA nuclear entry and in vivo responses to OVA peptide. Overall, we have identified SLP-76 as a direct regulator of nuclear pore function in T cells.