bluuebunny/crossref_metadata_2025_split huggingface dataset:
SLAM family receptors 2B4 and CD48 are key drivers of CD8 T cell priming by B cells
Authors: Huang Yu-Hsuan , Tsai Kevin , Kang Sohyeong , Wang Xiaoxia , Ford Mandy L , Harder Kenneth W , Tan Rusung , Priatel John J 
Published: January 2023

Abstract
Mutations in SH2D1A gene that encodes SAP (SLAM-associated protein) result in X-linked lymphoproliferative disease (XLP), a rare primary immunodeficiency defined by exquisite sensitivity to the B-lymphotropic Epstein-Barr virus (EBV) and B cell lymphomas. However, the precise mechanism of how the loss of SAP function contributes to extreme vulnerability to EBV and the development of B cell lymphomas remains unclear. Here, we utilized SAP-deficient (Sh2d1a−/−) mice to investigate the hypothesis that SAP is critical for CD8 T cell immune surveillance of antigen-expressing B cells or B lymphoma cells. Sh2d1a−/− CD8 T cells exhibited greatly diminished proliferation relative to wild type when antigen-presenting-B cells or -B lymphoma cells served as the primary APC. By contrast, Sh2d1a−/− CD8 T cells responded equivalently to wild type CD8 T cells when B cell-depleted splenocytes, melanoma cells or breast carcinoma cells performed antigen presentation. Through application of SLAM family receptor blocking antibodies or SLAM family receptor-deficient CD8 T cells and APCs, we found that CD48 engagement on the B cell surface by 2B4 is crucial for initiating SAP-dependent signaling required for the antigen-driven CD8 T cell proliferation and differentiation. Altogether, a pivotal role for SAP in promoting the expansion and differentiation of B cell-primed viral-specific naïve CD8 T cells may explain the selective immune deficiency of XLP patients to EBV and B cell lymphomas.
ECM remodelling by ADAMTS5 regulates influenza-specific immunity following acute infection
Authors: Stambas John , Ye Siying , Izzard Leonard , Tripp Ralph A , McCulloch Daniel , McMahon Meagan 
Published: January 2023

Abstract
Members of the ADAMTS (A disintegrin-like and metalloproteinase with thrombospondin-1 motifs) metalloproteinase family remodel the extracellular matrix (ECM) to facilitate immune cell migration and cell adhesion. In this current study, we infected Adamts5−/− mice with X31 influenza virus (104pfu/mouse)and measured weight loss, viraemia and T cell immunity following acute infection. Adamts5−/− mice showed greater weight loss and increased viraemia when compared to WT counterparts. Furthermore, we observed reduced NP366 and PA224 influenza specific CD8+ T cells in the spleen and lungs of Adamts5−/− mice with a corresponding accumulation of these T cell specificities in the mediastinal lymph node (MLN) 10 days post infection. Critically, these responses correlated with increased expression of a key ADAMTS5 substrate; versican, in the MLNs of Adamts5−/− mice. We therefore hypothesize that versican accumulation in the MLNs of Adamts5−/− mice results in T cell accumulation and that ADAMTS5 is a key enzyme involved in facilitating T cell migration from the MLN to the periphery following acute influenza virus infection.
The role of bone marrow promiscuous gene expression in peripheral tolerance
Authors: Chen Chih-Yeh , Klein Michelle , Klug Felix , Pinto Sheena , Kyewski Bruno , Beckhove Philipp 
Published: January 2023

Abstract
For the negative selection of autoreactive T cells, peripheral tissue-restricted antigens (TRAs) are ectopically expressed and presented by medullary thymic epithelial cells (mTECs). This physiological property of mTECs, termed promiscuous gene expression (pGE), is predominantly regulated by the transcription factor, autoimmune regulator (AIRE). In the periphery, pGE was also found in secondary lymphoid organs and can induce peripheral immune tolerance. Bone marrow is an important organ known to prime naïve conventional T cells, as well as being a reservoir of regulatory T cells. However, the occurrence of pGE in the bone marrow is hitherto unknown. We hypothesize that a repertoire of auto-antigens is ectopically expressed and presented in the bone marrow, which maintains the peripheral tolerance of T cells. We investigated the presence of AIRE-expressing cells in bone marrow using a transgenic reporter mouse model in which GFP is expressed under the control of the AIRE promoter. AIRE expression was detected at both the RNA and protein levels. The bone marrow-resident AIRE-expressing cells (BMACs) anatomically locate adjacent to clusters of CD4+ T cells and express high levels of CD45, MHC-II and EpCAM. Their tolerogenic characteristic was conferred by the expression of PD-L1 and lack of costimulatory molecules CD80 and CD86. Gene expression analysis showed the AIRE-dependent TRA genes expressed in BMACs differ from those expressed in mTECs. BMACs were also detected at various frequencies in patients carrying different tumor entities. Our result demonstrates that the AIRE-expressing cells which ectopically express TRAs in the bone marrow could comprise the cellular basis for the induction of peripheral T-cell tolerance.
TGF-β1 produced by alternatively activated macrophages synchronizes a tolerogenic iTreg-Th17 cell axis
Authors: Haribhai Dipica , Ziegelbauer Jennifer , Williams Calvin B 
Published: January 2023

Abstract
Induced regulatory T (iTreg) cells and T helper 17 (Th17) cells develop at mucosal interfaces. While iTreg cells are required for the maintenance of mucosal tolerance, Th17 cells can play divergent roles. Both iTreg and Th17 cells require TGF-β1 for their differentiation. Importantly, the primary source of TGF-β1 in vivo is unknown. Here, we investigate the mechanisms that control iTreg and Th17 cell development. We hypothesize that alternatively activated M2a macrophages support mucosal tolerance through TGF-β1 mediated expansion of both iTreg and Th17 cells.
We pretreat Rag1­­−/− C57BL/6 mice prior to colitis induction or treat mice with established disease with polarized macrophages. In some experiments the macrophages lacked the capacity to produce TGF-β1. Weight loss, colitis disease scores, and FACS analysis of mesenteric lymph nodes and gut infiltrates were used to evaluate the impact of macrophage therapy on the expansion and function of the iTreg-Th17 cell axis.
Pre-conditioning mice with M2a but not M1 macrophages resulted in a 16-fold increase in the number of iTreg cells and a 8-fold increase in the number of Th17 cells when compared to control mice. This expansion required TGF-β1 produced by both the transferred M2a cells and by host myeloid cells. Established colitis was successfully treated by concomitant M2a and nTreg cell transfers, but not by nTreg cell transfers alone.
In conclusion, M2a macrophages that produce TGF-β1 regulate development of a tolerogenic iTreg-Th17 cell axis. The change in iTreg and Th17 cells numbers linked to M2a macrophage polarization is directionally concordant and dependent on T cell produced IL17A, confirming that both iTreg and Th17 cells are required to mediate intestinal homeostasis.
NFIL3 and Ets1 co-regulate a cluster of genes, including Tim-3, that is associated with T cell tolerance
Authors: Zhu Chen , Gu Guangxiang , Zhang Huiyuan , Xiao Sheng , Wang Chao , Xiong Huabao , Garrett-Sinha Lee Ann , Ho I-Cheng , Kuchroo Vijay 
Published: January 2023

Abstract
Inhibitory receptor Tim-3 has critical roles in the suppression of effector T cell function. Here we demonstrate that the expression of Tim-3 is highly associated with T cell tolerance induction. TCR other than CD28 co-stimulatory signal is required for its induction. This process is accompanied with inhibition of IL-2 but upregulation of IL-10. Among the downstream pathways of TCR signaling, the calcium-calmodulin-dependent Kinase II (CaMKII) pathway is essential for Tim-3, IL-10 induction and IL-2 inhibition. CaMKII directly regulates transcription factors Ets1 and NFIL3. While NFIL3 induces Tim-3, IL-10 and suppresses IL-2 expression, Ets1 plays an opposite role for their expression. Accordingly, functional analyses suggest that NFIL3 is required, but Ets1 actually has an opposite role, in maintaining T cell tolerance/anergy. ChIP-Seq results reveal that NFIL3 and Ets1 co-localize in the loci of Tim-3, IL-2 and IL-10, suggesting a functional cooperation between NFIL3 and Ets1 in the regulation of these genes. We further identified a cluster of genes that has direct binding with both NFIL3 and Ets1. RNA-seq analysis reveals that the expression of these genes is associated with ionomycin-mediated T cell anergy induction. Collectively, our study suggests that NFIL3 and Ets1 cooperatively regulate a transcriptional network to control the expression of a cluster of genes, including Tim-3, IL-10, and IL-2, that is functionally important for T cell tolerance/anergy induction.
Separating RORgammat function in Th17 differentiation and T cell development
Authors: Sun Zuoming , Ma Jian , He Zhiheng 
Published: January 2023

Abstract
RORgammat regulates two equally important T cell function: Th17 differentiation and development of thymocytes, and lymph node genesis. By ex vitro structure-function analysis, we identified two amino acid mutations in RORgammat (RORgammatM) that specifically disrupt Th17 differentiation but allow normal T cell development. Mice expressing RORgammatM lack Th17 differentiation and resist to Th17-mediated autoimmune EAE similar to RORgammat−/− mice, however, have almost normal thymic T cell development and lymph node genesis. RORgammatM mice are thus a better model for specifically evaluating RORgammat-regulated Th17 immunity in vivo. Global analysis of RORgammat-DNA binding sites and target genes demonstrated that RORgammatM selectively affected the DNA binding and activating critical RORgammat target genes in Th17 cells. Therefore, our study distinguishes two critical RORgammat functions, which will facilitate the development of RORgammat-based treatments that selectively target Th17-mediated autoimmunity while avoid interfering with RORgammat-regulated development of T cells and lymph nodes.
c-FLIP suppresses p38 MAPK signaling and inhibits dendritic cell activation
Authors: Lai Ming-Zong , Wu Yu-Jung , Wu Yung-Hsuan , Mo Shu-Ting , He You-Wen 
Published: January 2023

Abstract
c-FLIP is reported to transmit activation signals but the nature of the signaling remains controversial. Here we report a novel function of c-FLIP involving inhibition of myeloid cell activation. Conditional knockout of c-FLIP in dendritic cells (DCs) led to neutrophilia and splenomegaly. Peripheral dendritic cell and macrophage populations were not affected by c-FLIP deficiency in dendritic cells. c-FLIP-knockout conventional DC (cDC), plasmacytoid DC (pDC), and bone marrow-derived DC (BMDC) displayed enhanced production of TNF-α, IL-2, or G-CSF in response to stimulation of TLR2, TLR4, and dectin-1. The enhanced activation of c-FLIP-deficient BMDCs could be partly linked to an elevated activation of p38 MAPK. In contrast, the activation of ERK, JNK, and NF-κB was not affected by c-FLIP-deficiency in BMDCs. In addition, the increased activation in c-FLIP-deficient dendritic cells was independent of caspase-8. Our results reveal a novel inhibitory role of c-FLIP in myeloid cell activation and demonstrate the unexpected anti-inflammatory activity of c-FLIP. In addition, our observations suggest that cancer therapy target c-FLIP downregulation may facilitate DC activation and increase T cell immunity.
Signal regulatory protein α suppresses macrophage inflammatory responses via reducing PKM2 tyrosine phosphorylation
Authors: Zhu Dihan , Pan Chaoyun , Shi Lei , Bian Zhen , Liu Yuan , Ke Zen 
Published: January 2023

Abstract
Signal regulatory protein α (SIRPα) plays an important part to restrain macrophage chemotaxis, secretion and phagocytosis. However, the signals involved in SIRPα-mediated control of macrophage inflammatory responses are poorly defined. Here we report that the inhibitory effect of SIRPα is mainly due to its suppression on macrophage aerobic glycolysis (Warburg effect). Upon ligation by CD47, SIRPα recruits/activates SHP-1 to dephosphorylate pyruvate kinase M2 (PKM2), a rate limiting enzyme of glycolysis. Compared to wild-type mice, SIRPα-deficiency mice (SIRPα−/−) develop a faster and severer macrophage-mediated insulitis induced by multiple low-dose streptozotocin. SIRPα−/− macrophages are M1-preferential and have higher level of phosphorylated PKM2 (p-PKM2) compared to their WT littermates. In addition, activation of macrophages to M1 phenotype, accompanying with reduction of SIRPα but increase of p-PKM2 and aerobic glycolysis level, can be abolished by SIRPα overexpression, as well as glycolysis inhibitors. Overexpression of SIRPα also strongly reduces the levels of macrophage aerobic glycolysis and p-PKM2. Finally, substrate-trapping and mutagenesis study clearly shows the binding of p-PKM2 with SIRPα-recruited SHP-1 complex and identifies PKM2 Tyr105 as a key site mediating SHP-1-PKM2 interaction. In summary, our findings identify SIRPα as a critical molecule that controls both metabolic switch and inflammatory responses in macrophages
Cell culture oxygen and signaling: Supraphysiologic in vitro oxygen signals through the HIF-CXCR4 pathway in human B cells
Authors: Henn Alicia D. , Hilchey Shannon P. , Garigen Jessica , Cipolla Valentina , Perry Sheldon , Farovitch Lorne , Yerden Randy , Zand Martin Stuart 
Published: January 2023

Abstract
Current understanding of B lymphocyte function relies heavily upon in vitro assays. However, standard incubators maintain cells at supraphysiologic oxygen (16–19% oxygen). Physiologic oxygen is far lower (blood 5–10%, secondary lymphoid tissues 1–5%, regions of inflammation, tumor, and bone marrow 0–1%). Previously, we showed that transcripts for hypoxia-induced factor 1 alpha (HIF-1a), an oxygen-sensing transcription factor, are upregulated in peripheral B cells after vaccination1. HIF-1a is also a therapeutic target in multiple myeloma2. Downstream of HIF-1a are genes tied to metabolism, proliferation, and the unfolded protein response. One gene downstream of HIF1a that is critical for B cell migration and function is CXCR4. We set out to determine if room air incubation might affect B cells in vitro, our null hypothesis being that physiologic oxygen would not affect B cell HIF-1a levels or CXCR4 function. We used C-chamber incubator sub-chambers and Pro-Ox 110 gas controllers to control the incubation oxygen and carbon dioxide levels. Setting the reference frame to a range relevant to secondary lymphoid organs (1–5% oxygen), we set the chambers to 5% CO2 and 1% (hypoxic), 4% (physioxic), or 19% (supraphysioxic) oxygen. In primary human B cells and myeloma cell lines, HIF-1a protein levels stabilized at 24 hrs of culture at 1% and 4% oxygen, but not at 19% oxygen. More importantly, B cell migration in response to the CXCR4 ligand, CXCL12, was significantly decreased at low oxygen levels, without affecting cell proliferation or viability, disproving our null hypothesis. This has widespread implications for assessments of B cell function in that incubator oxygen drives HIF-1a degradation and CXCR4 responsiveness in vitro.
Adhesion protein Fibulin-7 (Fbln7) regulate differentiation and polarisation of human monocytes and macrophages.
Authors: Sarangi Pranita P , Chakraborty Papiya , Wahl Larry , Yamada Yoshihiko 
Published: January 2023

Abstract
Fibulin-7 (Fbln7) is a member of the fibulin family of secreted glycoproteins, majorly found in developing teeth, bone and cartilage and shows interaction with other ECM proteins. Recently, it was shown that its C-terminal fragment (Fbln7C) and its peptides show anti-angiogenic effects. Fbln7 is also expressed in immune privileged tissues such as eye and placenta but to date very little is known about its functional significance. The results from this study show that human monocytes adhered to Fbln7 full-length (Fbln7-FL) and Fbln7C via integrin α5β1. Interestingly, actin stress fiber formation of monocytes was promoted by Fbln7-FL and not by Fbln7C. Morphological studies and surface expression analysis of CD14, mannose receptor (CD206), MHC-II and CD11b receptors revealed that both Fbln7-FL and Fbln7C inhibited MCSF induced monocyte differentiation with more significant effect with Fbln7C as compared to Fbln7-FL. Similarly, both protein fragments inhibited IFNγ and IL-4 induced M1 and M2 polarization of human blood monocyte derived macrophages. Collectively, these data suggests that Fbln7 and its fragments could negatively regulate immune cell in the expressed tissues.
High avidity TCR-peptide interactions between CD4 lymphocytes and lymph node dendritic cells promote normal lymphocyte arrest, activation, proliferation, and differentiation independently of dendritic cell ICAM-1 and 2
Authors: Feigelson Sara W , Solomon Adam , Biram Adi , Hatzav Miki , Lichtenstein Maria , Regev Ofer , Curato Caterina , Rashkovan Diana , Lefkowitz Dena , Jung Steffen , Shulman Ziv , Alon Ronen 
Published: January 2023

Abstract
The two main LFA-1 ligands ICAM-1 and ICAM-2 are constitutively co-expressed on antigen presenting cells (APCs) and on the lymph node stroma. We find abrogated antigen specific CD4 T cell priming in ICAM-1 and ICAM-2 deficient spleens. Nevertheless, the in vivo contribution of these ligands to lymphocyte activation proliferation and differentiation in lymph nodes has been difficult to dissect in total knockout mice due to their multiple roles in lymphocyte entry and priming in these organs. We therefore constructed lethally irradiated chimeric mice reconstituted with ICAM-1 and 2 double knock out (DKO) APCs in which lymphocyte entry into peripheral lymph nodes was reconstituted. Strikingly, these mice elicited normal antigen specific OT-II T cell activation, proliferation and differentiation into Th1 and Tfh effectors. OT-II T cells could also normally arrest on DCs deficient in ICAM-1 and 2. A compensatory role of VCAM-1 in ICAM deficient DCs was ruled out. Nevertheless, polyclonal T cell proliferation in response to endogenous self-antigens required the presence of ICAM-1 and ICAM-2 on endogenous lymph node DCs. Our results are the first indication that high avidity TCR peptide-MHC-II recognition can bypass integrin-mediated lymphocyte adhesions to DCs under specific settings.
CD11c+ T-bet+ IgM memory B cells provide multi-lineage reconstitution of effector and memory B cells following challenge infection
Authors: Kenderes Kevin J , Papillion Amber M , Cabrera-Martinez Berenice , Winslow Gary 
Published: January 2023

Abstract
IgM memory B cells are now recognized as an important component of immunological memory. These cells have been proposed to act as a reservoir of broadly-reactive B cells that differentiate, in germinal centers, into high affinity class-switched effector B cells following antigen encounter. However, we propose IgM memory cells can differentiate into more than just germinal center and class-switched cells. To address this, we monitored the secondary response of CD11c+ T-bet+ IgM memory cells generated by Ehrlichia muris infection, by monitoring eYFP-labeled, flow cytometrically-purified, IgM memory cells following their transfer to naïve recipient mice and subsequent challenge infection. The IgM memory B cells differentiated into IgM-producing plasmablasts early following infection; this resulted in a 4-fold increase in IgM production, relative to control mice that did not receive memory cells. Other donor memory B cells entered germinal centers, down-regulated CD11c, and underwent class switching, generating switched memory B cells. Finally, some donor B cells were maintained as IgM memory cells. Upon secondary transfer and challenge, purified IgM memory cells underwent the same pattern of self-renewal and differentiation. Additionally, when IgM memory cell recipient mice were challenged with a virulent Ehrlichia strain, a reduction in bacterial burden was observed, indicating that IgM memory cells can provide immunity to challenge infection. Our findings also suggest that T-bet+ IgM memory cells act as a self-renewing population capable of repopulating the entire spectrum of effector and memory B cells during secondary infection, and demonstrate an important role for IgM memory cells in maintaining long-term immunity.
IL-6 induces production of VEGF and MCP-1 from human skin mast cells.
Authors: McHale Cody C , Gomez Gregorio 
Published: January 2023

Abstract
Mast cells are the cell type responsible for IgE-mediated allergic reactions, and are involved in innate immunity against bacteria and pathogens. Interestingly, recent research has implicated mast cells in traditionally non-allergic diseases such as cancer. It has been hypothesized that in these non-allergic diseases mast cells may be activated by stimuli other than antigen, such as pro-inflammatory cytokines. Interleukin-6 (IL-6) is a pleiotropic cytokine that has been implicated in several diseases in which mast cells are also believed to contribute, suggesting that IL-6 could be the link that connects mast cells to non-allergic disease. However, the surface expression of IL-6 receptors, and the effect of IL-6 on human tissue-derived mast cells remained to be determined. Here, we show that human skin mast cells express functional membrane-bound IL-6 receptors, and address the role of IL-6 on the release of allergic and inflammatory mediators. Stimulation of skin mast cells with IL-6 resulted in a dose-dependent increase in Signal Transducer and Activator of Transcription 3 (STAT-3) phosphorylation, and increased expression of Suppressor of Cytokine Signaling 3 (SOCS3) mRNA. IL-6 had no effect on degranulation, but enhanced PGD2 biosynthesis and IL-8 production following FcɛRI crosslinking. In addition, treatment with IL-6 alone was sufficient to induce the production of monocyte chemoattractant protein (MCP-1) and vascular endothelial growth factor (VEGF). Overall, these findings clarify the effect of IL-6 on the allergic response from human tissue-derived mast cells, and reveal a potential role for IL-6 in mast cell-mediated angiogenesis.
MRGPRX2 receptor activation as a rapid, high-throughput mechanistic-based approach for detecting peptide-mediated human mast cell degranulation liabilities.
Authors: Lafleur Marc , Lobenhofer Edward K. , Fort Madeline , Werner Jonathan , Fan Fan , Balazs Mercedesz 
Published: January 2023

Abstract
Mast cells play key roles in allergy, anaphylaxis and pathogen/toxin defense. They contain cytoplasmic granules with a wide spectrum of pleotropic mediators (e.g. histamine, tryptase, serotonin) that are released upon activation. Mast cell degranulation (MCD) occurs upon clustering of the IgE receptor in presence of antigen or via non-IgE mediated mechanisms, one of which is by means of the Mas-related G protein coupled receptor (MRGPRX2). MRGPRX2 is a non-selective, low affinity binding receptor that responds to many basic biogenic amines and peptides. Consequently, MCD is an important potential safety liability for peptide therapeutics. To improve screening of peptides for this liability, we assessed a MRGPRX2-CHO cell-based receptor activation assay using positive (n=30) and negative (n=29) control peptides, which were previously characterized for MCD liability in CD34+ bone marrow-derived human mast cell cultures. MRGPRX2-CHO cells were engineered to selectively activate beta-arrestin upon receptor stimulation. In addition to beta-arrestin, Ca2+ was also measured to determine the potential of ligand bias (selective engagement of G-protein dependent or independent pathways). The MRGPRX2-CHO receptor assay had a sensitivity of 97% (false negative 3%) and specificity of 93% (false positive 7%) against the outcome in human mast cell cultures. No clear evidence of ligand bias was observed. Because MRGPRX2 is overexpressed in CHO cells, the assay may slightly over predict, and does not inform on other mechanisms of MCD not mediated by MRGPRX2. Assessing MRGPRX2 receptor activation provides a rapid, high-throughput and economical mechanism-based approach for detecting peptide-mediated human MCD liabilities.