@article{RhodesChenWilliamsonetal.2018,
  author    = {Rhodes, David A. and Chen, Hung-Chang and Williamson, James C. and Hill, Alfred and Yuan, Jack and Smith, Sam and Rhodes, Harriet and Trowsdale, John and Lehner, Paul J. and Herrmann, Thomas and Eberl, Matthias},
  title     = {Regulation of Human γδ T Cells by BTN3A1 Protein Stability and ATP-Binding Cassette Transporters},
  series = {Frontiers in Immunology},
  volume    = {9},
  journal   = {Frontiers in Immunology},
  number    = {662},
  issn      = {1664-3224},
  doi       = {10.3389/fimmu.2018.00662},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-197054},
  year      = {2018},
  abstract  = {Activation of human Vγ9/Vδ2 T cells by "phosphoantigens" (pAg), the microbial metabolite (E)-4-hydroxy-3-methyl-but-2-enyl pyrophosphate (HMB-PP) and the endogenous isoprenoid intermediate isopentenyl pyrophosphate, requires expression of butyrophilin BTN3A molecules by presenting cells. However, the precise mechanism of activation of Vγ9/Vδ2 T cells by BTN3A molecules remains elusive. It is not clear what conformation of the three BTN3A isoforms transmits activation signals nor how externally delivered pAg accesses the cytosolic B30.2 domain of BTN3A1. To approach these problems, we studied two HLA haplo-identical HeLa cell lines, termed HeLa-L and HeLa-M, which showed marked differences in pAg-dependent stimulation of Vγ9/Vδ2 T cells. Levels of IFN-γ secretion by Vγ9/Vδ2 T cells were profoundly increased by pAg loading, or by binding of the pan-BTN3A specific agonist antibody CD277 20.1, in HeLa-M compared to HeLa-L cells. IL-2 production from a murine hybridoma T cell line expressing human Vγ9/Vδ2 T cell receptor (TCR) transgenes confirmed that the differential responsiveness to HeLa-L and HeLa-M was TCR dependent. By tissue typing, both HeLa lines were shown to be genetically identical and full-length transcripts of the three BTN3A isoforms were detected in equal abundance with no sequence variation. Expression of BTN3A and interacting molecules, such as periplakin or RhoB, did not account for the functional variation between HeLa-L and HeLa-M cells. Instead, the data implicate a checkpoint controlling BTN3A1 stability and protein trafficking, acting at an early time point in its maturation. In addition, plasma membrane profiling was used to identify proteins upregulated in HMB-PP-treated HeLa-M. ABCG2, a member of the ATP-binding cassette (ABC) transporter family was the most significant candidate, which crucially showed reduced expression in HeLa-L. Expression of a subset of ABC transporters, including ABCA1 and ABCG1, correlated with efficiency of T cell activation by cytokine secretion, although direct evidence of a functional role was not obtained by knockdown experiments. Our findings indicate a link between members of the ABC protein superfamily and the BTN3A-dependent activation of γδ T cells by endogenous and exogenous pAg.},
  language  = {en}
}
@article{RauSchmittBergetal.2018,
  author    = {Rau, Monika and Schmitt, Johannes and Berg, Thomas and Kremer, Andreas E. and Stieger, Bruno and Spanaus, Katharina and Bengsch, Bertram and Romero, Marta R. and Marin, Jose J. and Keitel, Verena and Klinker, Hartwig and Tony, Hans-Peter and M{\"u}llhaupt, Beat and Geier, Andreas},
  title     = {Serum IP-10 levels and increased DPPIV activity are linked to circulating CXCR3+ T cells in cholestatic HCV patients},
  series = {PLoS ONE},
  volume    = {13},
  journal   = {PLoS ONE},
  number    = {12},
  doi       = {10.1371/journal.pone.0208225},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-177674},
  pages     = {e0208225},
  year      = {2018},
  abstract  = {Background \& aims Serum interferon-gamma-inducible protein-10 (IP-10) is elevated in cholestatic liver diseases and predicts response to antiviral therapy in patients with chronic hepatitis C virus (HCV) infection. Dipeptidylpeptidase 4 (DPPIV) cleaves active IP-10 into an inactive form, which inhibits recruitment of CXCR3+ T cells to the liver. In this study the link between IP-10 levels, DPPIV activity in serum and CXCR3+ T cells is analysed in cholestatic and non-cholestatic liver patients. Methods In serum DPPIV activity (by enzymatic assay), IP-10 (by ELISA) and bile acids (BA) (by enzymatic assay) were analysed in 229 naive HCV genotype (GT) 1 patients and in 16 patients with cholestatic liver disease. In a prospective follow-up (FU) cohort of 27 HCV GT 1 patients peripheral CD3+CXCR3+, CD4+CXCR3+ and CD8+CXCR3+ cells were measured by FACS. Results In 229 HCV patients serum IP-10 levels correlated positively to DPPIV serum activity. Higher IP-10 levels and DPPIV activity were detected in cholestatic and in cirrhotic HCV patients. Increased IP-10 serum levels were associated with therapeutic non-response to antiviral treatment with pegylated-interferon and ribavirin. In the HCV FU cohort elevated IP-10 serum levels and increased BA were associated with higher frequencies of peripheral CD3+CXCR3+, CD4+CXCR3+ and CD8+CXCR3+ T cells. Positive correlation between serum IP-10 levels and DPPIV activity was likewise validated in patients with cholestatic liver diseases. Conclusions A strong correlation between elevated serum levels of IP-10 and DPPIV activity was seen in different cholestatic patient groups. Furthermore, in cholestatic HCV patients a functional link to increased numbers of peripheral CXCR3+ immune cells could be observed. The source of DPPIV release in cholestatic patients remains open.},
  language  = {en}
}
@article{BoertleinDraegerSchoenaueretal.2018,
  author    = {B{\"o}rtlein, Charlene and Draeger, Annette and Schoenauer, Roman and Kuhlemann, Alexander and Sauer, Markus and Schneider-Schaulies, Sybille and Avota, Elita},
  title     = {The neutral sphingomyelinase 2 is required to polarize and sustain T Cell receptor signaling},
  series = {Frontiers in Immunology},
  volume    = {9},
  journal   = {Frontiers in Immunology},
  number    = {815},
  doi       = {10.3389/fimmu.2018.00815},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-176572},
  year      = {2018},
  abstract  = {By promoting ceramide release at the cytosolic membrane leaflet, the neutral sphingomyelinase 2 (NSM) is capable of organizing receptor and signalosome segregation. Its role in T cell receptor (TCR) signaling remained so far unknown. We now show that TCR-driven NSM activation is dispensable for TCR clustering and initial phosphorylation, but of crucial importance for further signal amplification. In particular, at low doses of TCR stimulatory antibodies, NSM is required for Ca\(^{2+}\) mobilization and T cell proliferation. NSM-deficient T cells lack sustained CD3ζ and ZAP-70 phosphorylation and are unable to polarize and stabilize their microtubular system. We identified PKCζ as the key NSM downstream effector in this second wave of TCR signaling supporting dynamics of microtubule-organizing center (MTOC). Ceramide supplementation rescued PKCζ membrane recruitment and MTOC translocation in NSM-deficient cells. These findings identify the NSM as essential in TCR signaling when dynamic cytoskeletal reorganization promotes continued lateral and vertical supply of TCR signaling components: CD3ζ, Zap70, and PKCζ, and functional immune synapses are organized and stabilized via MTOC polarization.},
  language  = {en}
}