bluuebunny/crossref_metadata_2025_split huggingface dataset:
LAMP5 distribution in and on plasmacytoid dendritic cells (P5019)
Authors: Zhang Hong , Pahuja A. , Lin Xiao , Li Sky , Ransom John , Yang Xi Feng 
Published: January 2023

Abstract
The brain and dendritic cell (BAD)-associated lysosome-associated membrane protein (LAMP)-like molecule, also known as BAD-LAMP, c20orf103, UNC-46, is a newly identified LAMP family member, which has been recently officially designated as LAMP5. It is a transmembrane glycosylated protein localized in the ER-Golgi intermediate compartment (ERGIC). LAMP5 shares sequence and structural homology with other LAMP family members. In mouse, LAMP5 is expressed in postnatal cortical neurons of particular layers, where it is enriched in defined zones along neuronal projections. In human, like its murine homolog, LAMP5 is principally expressed in brain, and it was recently found in primary plasmacytoid dendritic cells (pDCs). However, LAMP5 expression profile and function have not been extensively studied in pDCs. By using anti-human LAMP5 monoclonal antibody (clone 124-40B), we report that LAMP5 is specifically expressed in peripheral blood pDCs which are characterized by surface expression of CD303+/CD304+/CD123+/HLA-DR+/CXCR3+/CD11c-/CD14-/CD209-, but is not expressed by GM-CSF plus FL3 or IL-4 induced monocyte-derived CD303+/CD123+/HLA-DR+/CD209+/CD14+/CXCR3dim pDCs or CD209+/CD123dim/CXCR3dim/HLA-DR+/CD11c+/CD14+ mDCs. Like other LAMP members, LAMP5 is rapidly relocated on the cell surface of peripheral blood pDCs after 24 hours stimulation by IL-3. These data suggest that LAMP5 may be a useful marker for studying pDC development and activation.
Inhibition of the CD8 T cell response and cytotoxicity by human intravenous immunoglobulin. (P5023)
Authors: Trepanier Patrick , Bazin Renée 
Published: January 2023

Abstract
Intravenous immunoglobulin (IVIg) is made of plasma-derived human IgG and exerts anti-inflammatory effects in several autoimmune disorders when administered at high doses. The constant increase in its use exposes providers and patients to considerable risks of shortage. Understanding its complex mechanisms of action is required in order to develop potent substitutes. Our group previously demonstrated that IVIg inhibits the in vitro and in vivo activation of CD4 T cells (Aubin et al, Blood 2010), as well as the in vitro CD8 T cell activation (Trépanier et al, Blood 2012). In the present work, we investigated whether IVIg could also interfere with the CD8 T cell response, which contribute to the persistence and severity of many autoimmune conditions. Bone marrow-derived DC from C57BL/6 mice were treated with IVIg and used to cross-present ovalbumin to OVA-specific OT-I CD8 T cells. Proliferation and cytokine production were measured after 72 hours. Cytotoxicity was measured using SIINFEKL-pulsed EL-4 target cells in presence of therapeutic doses of IVIg. Results showed a reduced (50%) CD8 T cells activation in the presence of IVIg and a concomitant decrease in IL-2 and IFN-gamma secretion. In addition, IVIg-treated CD8 T cells are less cytotoxic, as measured by specific lysis of target cells. These results support a novel immunomodulatory mechanism by which IVIg decrease CD8 T cell response. The importance of these results in vivo are currently being investigated.
Effect of cellular activation on the antigen processing machinery of primary CD4 T cells. (P5029)
Authors: Boucau Julie , Madouasse Julien , Carlin Christopher , Zhu Tom , Xu Yang , Shimada Mariko , Le Gall Sylvie 
Published: January 2023

Abstract
The killing of HIV-infected CD4 T cells by specific CD8 T cells (CTL) requires the presentation of peptide-MHC-I complexes produced during the intracellular degradation of viral proteins by the proteasome and other peptidases, to their cognate T cell receptors. HIV infection induces general cellular activation, which renders cells more susceptible to infection. Whether the activation state of cells alters the expression and activity of the antigen processing machinery and the kinetics and nature of epitopes displayed by MHC-I is not known despite its potential role in altering the efficiency of recognition of infected cells by CTL. We compared the expression and peptidase activities of the antigen processing machinery of primary CD4 T cells upon activation with anti-CD3/CD28 beads or with phytohemagglutinin. In primary CD4 T cells from HIV seronegative individuals, the hydrolytic activities of the proteasome, the expression of several of its subunits and of the peptidase TPP2 significantly increased upon activation. The mass spectrometry analysis of in vitro degradation of 2 long epitope-containing HIV peptides in extracts from CD3/CD28-activated CD4 T cells showed production of smaller and less antigenic peptides than in the non-activated samples. Reduced presentation of peptides by activated cells might lead to reduced recognition and slower clearance of activated infected cells by CTL thus allowing more time for viral replication and spread.
Immunodominant and subdominant WNV epitopes are differentially presented (P5005)
Authors: McMurtrey Curtis , Kim Sojung , Bardet Wilfried , Schafer Fredda , Diamond Michael , Weidanz Jon , Hansen Ted , Hildebrand William 
Published: January 2023

Abstract
There are many factors that are thought to contribute to T-cell immunodominance hierarchies including timing and levels of antigen presentation to T-cells. One of the most potent tools for studying antigen presentation for a specific determinant are monoclonal antibodies that are specific for not only MHC but a specific ligand, similar to a T cell receptor. In this study we utilize these antibodies to study levels and timing of antigen presentation of immunodominant (SVG9), sub-dominant (SLF9), and super sub-dominant (YTM9) T-cell epitopes during West Nile virus (WNV) infection. In this study, we demonstrate that these ligands are differentially expressed on the surface of a cell infected with WNV. Specifically, the super sub-dominant ligand (YTM9) was presented earlier and at 20 times the levels of the immunodominant (SVG9) and subdominant (SLF9) ligands. Transfection of ICP47 in the infected cells show that all three epitopes are TAP dependent. Using these highly specific reagents we show that there is differential ligand presentation within the restrictive allele. High levels of peptide HLA complexes on the surface of an infected do not correspond with immunodominance hierarchies as the super subdominant epitope YTM9 was presented at higher levels than the most dominant epitope SVG9. This differential in presentation was not due the TAP dependence of the ligands.
Initiation of TCR phosphorylation and signal transduction. (P5041)
Authors: Casas Javier , Brzostek Joanna , Hoerter John , Fu Guo , Ampudia Jeanette , Gascoigne Nicholas 
Published: January 2023

Abstract
Recognition of antigen by the T cell receptor (TCR) is the key event for the T cell activation. The earliest molecular events in T cell recognition have not yet been fully described, and the TCR triggering mechanism remains a subject of controversy. By using supported lipid bilayers to present peptide MHC class I complexes to CD8+ cells, we can monitor the molecular events occurring at the immune synapse. The lipid bilayer technology mimics the signaling environment for T cell activation as judged by Ca2+ flux, total phospho-Tyr levels, and IL-2 secretion. Using TIRF/FRET microscopy we have observed an early (&gt; 1 min) interaction between CD3ζ and the coreceptor CD8 that is independent of the MHC-CD8 binding, but requires CD8 association with Lck. Later (&lt; 10 min) CD3ζ-CD8 interactions require CD8-MHC binding. This suggests that, upon antigen recognition, TCR may be initially phosphorylated by Lck not associated with coreceptor, followed by MHC dependent recruitment of CD8-Lck complexes. We have now additional evidences that free Lck is the responsible for the initial TCR phosphorylation. We are currently working on elucidating the proposed different roles of unbound and coreceptor associated Lck during the early stages of antigen recognition.
MAIT cell recognition of MR1 bound by non-peptide antigen on bacterially infected and uninfected cells. (P5053)
Authors: Young Mary , U'Ren Lance , Kappler John , Marrack Philippa , Gapin Laurent 
Published: January 2023

Abstract
Mucosal-associated invariant T cells are a unique population of T cells that express a semi-invariant αβ TCR and are restricted by the MHC class I-related molecule MR1. MAIT cells recognize uncharacterized ligand(s) presented by MR1 through the cognate interaction between their TCR and MR1. To understand how the MAIT TCR recognizes MR1 at the surface of APCs cultured both with and without bacteria, we undertook extensive mutational analysis of both the MAIT TCR and MR1 molecule. We found differential contribution of particular amino acids to the MAIT TCR-MR1 interaction based upon the presence of bacteria or bacterially-derived compounds, supporting the hypothesis that the structure of the MR1 molecules with the microbial-derived ligand(s) differs from the one with the endogenous ligand(s). Furthermore, we demonstrate that microbial-derived ligand(s) is unlikely proteinaceous or lipidaceous, arguing that a new class of antigen(s) is most likely recognized by this unique lymphocyte population.
Satiated-efferocytosis: A novel functional property for resolution-phase macrophages regulated by glucocorticoids, resolvins, galectin-1 and the chemokine-scavenging receptor D6 (P4157)
Authors: Ariel Amiram , Serhan Charles , Rabinovich Gabriel , Pashover-Schallinger Ester , Gross Nufar , Aswad Miran , Rostoker Ran , Assi Simaan , Yaseen Hiba , Schiff-Zuck Sagie 
Published: January 2023

Abstract
The engulfment of apoptotic leukocytes (efferocytosis) by macrophages during the resolution of inflammation is essential for homeostasis and results in macrophage reprogramming/immune-silencing. Here, we show CD11bhigh macrophages convert to CD11blow ones and stop efferocytosing apoptotic PMN after reaching an engulfment threshold in vivo. In addition, CD11blow macrophages are distinct from either M1 or M2 in their protein expression profile and display pro-resolving properties, such as diminished responses to different TLR ligands ex vivo and propensity to emigrate from resolving inflammation sites to lymphoid organs. Of interest, we found the pro-resolving lipid mediators resolvin E1 and D1, as well as the glucocorticoid dexamethasone (Dex) and the lectin galectin-1 enhance satiated-efferocytosis and consequently CD11blow macrophage conversion from their CD11bhigh counterparts. Deficiency in the atypical chemokine receptor D6 resulted in delayed satiation and reduced immune-silencing of macrophages, and inhibits their departure from resolving inflammation sites. In sum, satiated-efferocytosis is a novel phagocyte property of CD11blow macrophages that is regulated by pro-resolving mediators. Moreover, satiated-efferocytosis is required for CD11blow macrophage emigration from resolving inflammation sites and the return of tissue homeostasis. Thus, satiated-efferocytosis is essential for the completion of timely- and spatially-coordinated resolution of acute inflammation.
Adenylyl cyclase 6 activation negatively regulates TLR4 signaling through lipid raft-mediated endocytosis (P4169)
Authors: Xu Congfeng , Cai Wei , Feng Kuan , Zhao Xiaonan , Jin Min , Qian Liu , Ostrom Rennolds , Zhang Yanyun 
Published: January 2023

Abstract
Proper intracellular localization of Toll-like receptors is essential for their signaling and biological functions. Endocytosis constitutes a key step in protein turnover as well as maintenance of localization, and thus provides important points to regulate their signaling. Here we demonstrated that adenylyl cyclase activation attenuated membrane Toll-like receptor 4-dependent NF-κB signaling and IRF activation in the murine macrophage cell line RAW264.7 and in bone marrow-derived macrophages stimulated with lipopolysaccharide. We further showed that the adenylyl cyclase 6 isoform distributed in lipid raft-enriched domains played key roles in the negative regulation of Toll-like receptor 4 signaling by promoting its degradation. Toll-like receptor 4 is normally endocytosed through the clathrin-mediated pathway, which is a critical step in signal transduction, while adenylyl cyclase 6 activation initiated its colocalization with Toll-like receptor 4 and their interaction, and shifted clathrin-mediated endocytosis of Toll-like receptor 4 to lipid raft-mediated endocytosis, leading to accelerated degradation of Toll-like receptor 4 and consequently suppressed downstream signaling. Our studies have unveiled a new mechanism of negative regulation of Toll-like receptor 4 signaling through adenylyl cyclase 6-mediated endocytosis. Adenylyl cyclase 6-specific activation might provide a novel therapeutic approach for limiting inflammatory and autoimmune diseases.
SIRPα-dependent phagocytosis of tissue cells by macrophages (P4171)
Authors: Bian Zhen , Liu Yuan 
Published: January 2023

Abstract
Macrophage surface SIRPα, a ITIMs-containing inhibitory signaling receptor, plays a pivotal role in controlling macrophage phagocytosis of host cells, including healthy self-cells, cancerous and apoptotic cells, through interactions with CD47 expressed on target cells. Utilizing SIRPα-/- and CD47-/- mice, we further investigated SIRPα-dependent macrophage phagocytosis and found that, while ligation of macrophage SIRPα by CD47 triggering inhibitory signaling prohibits phagocytosis, depletion of SIRPα does not immediately render/enhance macrophage phagocytosis. In contrast, SIRPα-/- mice, and also CD47-/- mice, display no signs of macrophage-mediated tissue-destruction or anemia. In adoptive transfer experiments, SIRPα-/- mice demonstrated phagocytic suppression and failure of clearance of CD47-/- RBC, while WT mice hastily cleared CD47-/- RBC in the spleen. We found that treating SIRPα-/- macrophages or mice with inflammatory cytokines especially IL-17, but not IFNγ, releases such functional suppression resulting in significantly augmented macrophage phagocytosis (splenomegaly) and anemia in vivo. IL-17 also largely promotes SIRPα-dependent phagocytosis of macrophages derived from WT mice. Remarkably, we observed that IL-17-treated SIRPα-/- macrophages aggressively ingest cancer cells in vitro, and IL-17-adminitrated SIRPα-/- and WT mice completely cleared and largely delayed, respectively, implanted Lewis lung tumors and B16 melanoma in vivo.
Human P2X7 receptor activation induces ADAM10-mediated shedding of CD23 and CXCL16 (P4137)
Authors: Pupovac Aleta , Wang Bin , Foster Christopher , Sluyter Ronald 
Published: January 2023

Abstract
Activation of the damage-associated molecular pattern receptor P2X7 by extracellular ATP induces the shedding of cell surface molecules, including CD23, from leukocytes. The mechanisms involved in this process however remain poorly understood. Using a flow cytometric assay, we demonstrated that ATP-induces the rapid shedding of CD23 from the surface of human multiple myeloma RPMI 8226 and peripheral blood B cells with a t1/2 of 7 min. The P2X7 antagonist, AZ10606120, impaired ATP-induced CD23 shedding by 89%. Moreover, P2X7-induced CD23 shedding was impaired by a broad-spectrum metalloprotease inhibitor, BB-94, by 63% and the ADAM10 inhibitor, GI254023X, by 67%. RT-PCR confirmed the expression of ADAM10 in B cells. P2X7-induced CD23 shedding was not dependent on changes in extracellular Na+, K+ and Ca2+ concentrations, and was unaffected by a panel of enzyme inhibitors targeting various kinases and phospholipases previously implicated in P2X7-mediated signaling events. ATP also induced the rapid shedding of the ADAM10 substrate, CXCL16, with a t1/2 of 1 min. AZ10606120 impaired ATP-induced CXCL16 shedding by 86%. Moreover, P2X7-induced CXCL16 shedding was impaired by BB-94 by 77% and GI254023X by 87%. This data indicates that human P2X7 activation induces the rapid shedding of CD23 and CXCL16, and that this process involves ADAM10. Thus, P2X7 may represent a novel target in disorders involving CD23 or CXCL16.
CD40L induces networks of branching tunneling nanotube-like structures exclusively in type 1 polarized dendritic cells (P4187)
Authors: Zaccard Colleen , Mailliard Robbie , Kalinski Pawel , Ayyavoo Velpandi , Salter Russel , Watkins Simon , Rinaldo Charles 
Published: January 2023

Abstract
The ability of dendritic cells to mediate CD40L-dependent CD4+ T cell help for the induction and support of effector CD8+ cytotoxic T lymphocyte responses greatly depends on activation signals they received during maturation. In addition to being 'programmed' to produce high levels of IL-12p70, we found that DC matured under type 1 polarizing conditions also form intricately branched tunneling nanotube-like structures upon CD40L stimulation. These formations can create extensive interconnected networks between cells, a process we termed 'reticulation'. Importantly, this response was found to occur exclusively in mature type 1 polarized DC and was uniquely induced by recombinant CD40L or CD40L-expressing cells. Using live-cell time-lapse confocal imaging, we were able to determine that these structures can support the transfer of endosomes, HIV-1 virus-like particles, and nano-beads representing antigen from 'donor' to 'recipient' type 1 polarized DC. This induction of the process of DC reticulation potentially represents a novel helper function of CD40L, as it likely enhances intercellular communication and contributes to the superior capacity of type 1 polarized DC to induce cellular immune responses. This active immune cell process may also be utilized by viruses such as HIV-1 for cell-to-cell spread.
p62/SQSTM1 enhances NOD2-mediated signaling and cytokine production through stabilizing NOD2 oligomers (P4189)
Authors: Kim Sung Ouk , Park Sangwook , Ha Soon-Duck , Coleman Macon , Meshkibaf Shahab 
Published: January 2023

Abstract
NOD2 is a cytosolic pattern-recognition receptor that senses muramyl dipeptide of peptidoglycan that constitutes the bacterial cell wall, and plays an important role in maintaining immunological homeostasis in the intestine. To date, multiple molecules have shown to be involved in regulating NOD2 signaling cascades. p62 (sequestosome-1; SQSTM1) is a multifaceted scaffolding protein involved in trafficking molecules to autophagy, and regulating signal cascades activated by Toll-like receptors, inflammasomes and several cytokine receptors. Here, we show that p62 positively regulates NOD2-induced NF-kB activation and subsequent production of cytokines (IL-1b and TNF-a). p62 associated with the nucleotide binding domain of NOD2 through a bi-directional interaction mediated by either TRAF6-binding or ubiquitin-associated domains. NOD2 formed a large complex with p62 in an electron-dense area of the cytoplasm, which increased its signaling cascade likely through preventing its degradation. This study for the first time demonstrates a novel role of p62 in enhancing NOD2 signaling effects.
DAP12 inhibition of LPS signaling in macrophages is mediated by DOK3 (P4147)
Authors: Long Courtney , Peng Qisheng , Malhotra Shikha , Humphrey Mary 
Published: January 2023

Abstract
Toll like receptors serve as sentinels to the innate immune system by binding common pathological antigens and initiating host responses. These responses can be deleterious to the host if unchecked leading to chronic diseases including autoimmunity. DNAX-activating protein 12 (DAP12) is an adaptor protein containing an immunoreceptor tyrosine-based activation motif expressed in myeloid cells, NK cells, osteoclasts and microglia. In macrophages, DAP12 can couple with immunoreceptor triggering receptor expressed on myeloid cells 2 (TREM2) to negatively regulate TLR signaling through an as yet undefined mechanism. We have shown that downstream of kinase 3 (DOK3), through its phosphotyrosine domain, associates with DAP12 after low down LPS stimulation of bone marrow macrophages (BMM). DOK3-/- BMMs stimulated with LPS show increased phospoERK signaling at 20 and 40 minutes indicative of enhanced activation. Supernatants taken from these cells show significantly increased levels of proinflammatory cytokines TNFα, IL-6, and IL-12p40 compared to wild type cells. Upon LPS stimulation, DOK3 is phosphorylated in a DAP12- and Src kinase- dependent manner leading to DOK3 translocation to the plasma membrane. Despite the recruitment of SHIP1 to DOK3 and DAP12 after LPS stimulation; SHIP1 is not required for DAP12-dependent inhibition of LPS-induced ERK activation. These results reveal a new mechanism underlying DAP12 and TREM2 inhibition of TLR responses in macrophages.
Induction of CD70 is essential for TGF-β-mediated inhibition of T cells (P1019)
Authors: Yang Zhi-Zhang , Grote Deanna , Xiu Bing , Price-Troska Tammy , Ziesmer Steven , Hodge Lucy , Witzig Thomas , Novak Anne , Ansell Stephen 
Published: January 2023

Abstract
Although extensively studied, the exact mechanism by which TGF-β mediates T-cell inhibition is not entirely clear. When we examined the effect of TGF-β on the phenotype and function of T cells, we noted that CD70 was significantly up-regulated by TGF-β. This surprising finding led us to explore the underlying mechanism by which TGF-β upregulates CD70 expression on T cells and to define the function of CD70+ cells in B-cell NHL. Interestingly, we observed that TGF-β preferentially induced CD70 expression on effector memory T cells while it predominantly up-regulated Foxp3 on naïve T cells. CD70 induction is Smad3-dependent and involves Stat5 signaling. CD70+ T cells were highly susceptible to TGF-β-mediated apoptosis and that transfection of Jurkat cells with the CD70 gene led to a significantly reduced survival. TGF-β-induced CD70+ T cells had a diminished response to immune stimulation associated with downregulation of co-stimulatory molecules CD27 and CD28. CD70-expressing T cells from biopsy specimens of patients with B-cell NHL failed to produce cytokines and displayed no signal transduction when stimulated. CD70-expressing T cells were highly represented in follicular NHL biopsy specimens and increased numbers of CD70+ cells correlated with an inferior patient outcome. These novel findings not only revealed a biological role for a TGF-β/CD70 axis in mediating immune inhibition, but also may lead to therapeutic approaches in patients with B-cell NHL.
TL1A-Ig induces transplantation tolerance (P1003)
Authors: Khan Samia , Tsai Matthew , Schreiber Taylor , Wolf Dietlinde , Deyev Vadim , Podack Eckhard 
Published: January 2023

Abstract
Tumor necrosis factor (TNF) superfamily member 15 (TL1A) is the natural ligand for TNFRSF25. We previously reported that TNFRSF25 stimulation with an agonist antibody 4C12 selectively expands pre-existing Tregs in vivo. To compare TL1A to 4C12, we generated a soluble mouse hexameric TL1A-Ig fusion protein. TL1A-Ig mediates proliferation of Foxp3+ Treg in vitro. TNFRSF25 stimulation by TL1A-Ig in vivo induces expansion of Tregs to 30-35% of all CD4+ T cells in the peripheral blood within 5 days of treatment. With daily injections of TL1A-Ig elevated levels of Tregs can be maintained for at least 20 days. TL1A-Ig expanded Tregs express high levels of the activation/memory markers KLRG1 and CD103 and are highly suppressive ex vivo. TL1A-Ig mediated Treg expansion in vivo is protective against allergic lung inflammation by reversing the ratio of Tconvs:Tregs in the lung and blocking eosinophil exudation into the bronchoaveolar fluid. We tested the potential of TNFRSF25 agonists in transplant tolerance in several models. (1) TL1A-Ig injections 12 days after injection of allogeneic splenocytes caused diminished alloantigen-specific T cell responses in mixed lymphocyte reactions as compared to mice treated with allogeneic splenocytes only. (2) TNFRSF25 mediated Treg expansion in vivo significantly prolonged allogeneic skin graft survival. Thus, TL1A-Ig fusion proteins are potent and tightly controllable agents that may provide therapeutic benefit in asthma and transplant tolerance.