bluuebunny/crossref_metadata_2025_split huggingface dataset:
Localized, sustained presentation of VEGF-C in mouse dermis alters the local immune microenvironment (IRC5P.628)
Authors: Yu Shann , Fankhauser Manuel , Aigner Petra , Kocher Juliane , Swartz Melody 
Published: January 2023

Abstract
Lymphangiogenesis is induced in areas of chronic inflammation, including in both autoimmunity (associated with immunoreactivity) and in many solid tumors (associated with metastases and immunosuppression). We asked whether and how local VEGF-C-driven lymphangiogenesis alone could affect adaptive immunity to a model antigen. To this end, we designed a hydrogel system for sustained local delivery of the lymphangiogenic protein VEGF-C. These proteins were engineered to express a peptide tag which are covalently crosslinkable onto the hydrogel matrix, and are thus better retained by the hydrogels. Following implantation into healthy mice, local delivery of VEGF-C increased lymphangiogenesis at the implant site as well as at the draining lymph nodes compared to empty hydrogel controls. This promoted increased local expression of CCL21, similar to observations in lymphangiogenic tumors, and associated with increased recruitment of CCR7+ cells, most notably CD4 T cells expressing markers of naïve or memory phenotypes. To further examine the immunological relevance of these observations on antigen-specific T cell populations, hydrogels delivering both VEGF-C and the model antigen OVA were implanted into healthy mice which had previously received an adoptive transfer of OT-II T cells. These hydrogels also recruited CD4 T cells expressing markers of naïve and memory phenotypes. Our studies suggest a role for lymphangiogenesis in the recruitment of immune cells during inflammation.
CD27 costimulation promotes IL-7Rα re-expression in effector CD8+ T cells by transcriptional regulation and enhances memory precursor population during acute viral infection (IRC5P.463)
Authors: Dong Han , Bullock Timothy 
Published: January 2023

Abstract
IL-7 plays a critical role in the generation and maintenance of memory CD8+ T cells, and IL-7Rα has been regarded as a defining marker of long-lived memory precursor effector cells. While IL-7Rα is downreguated acutely upon TCR stimulation, little is known about the stimuli that promote the recovery of IL-7Rα in Ag-activated CD8+ T cells. Using vaccinia virus, we previously demonstrated that CD27 costimulation during primary response is critical for the generation of IL-7Rα-expressing effectors and promotes CD8+ T cell memory. By utilizing agonistic mAb and transgenic models, here we show 1) direct CD27 stimulation on CD8+ T cells is sufficient and necessary to enhance IL-7Rα-expressing effectors; 2) CD27 stimulation neither alleviates the downregulation of IL-7Rα upon TCR signaling nor promotes the expansion/survival of IL-7Rα-expressing effectors, but facilitates IL-7Rα re-expression; 3) CD27 stimulation regulates Il7ra transcription but not protein distribution. Importantly, CD27 stimulation promotes not only IL-7Rα, but also the common γ chain of the receptor and the downstream signaling mediated by pSTAT5. Intriguingly, stimulation of other TNFSF members OX-40 and 4-1BB showed limited ability to promote IL-7Rα. Our results provide insights into the mechanistic basis by which CD27 costimulation influences CD8+ T cell memory differentiation, and highlight the potential of targeting CD27-CD70 axis to enhance IL-7 signaling for antiviral/antitumor immunotherapy.
Splenic MAdCAM-1+ marginal reticular cells deliver antibody-inducing signals and confer gut-homing properties to human marginal zone B cells (IRC5P.622)
Authors: BASCONES GLEAVE SABRINA , Magri Giuliana , Cassis Linda , Comerma Laura , Gentile Maurizio , Barra Carolina , Puga Irene , Cerutti Andrea 
Published: January 2023

Abstract
The splenic marginal zone (MZ) generates prompt antibody responses to blood-borne antigens through a unique subset of innate-like B cells that closely interact with poorly characterized stromal cells. We found that human MZ contained fibroblast-like marginal reticular cells (MRCs) that expressed MAdCAM-1 along with the stromal molecules Thy-1, thrombomodulin, ICAM-1 and VCAM-1, but lacked the endothelial molecules CD31, CD34 and von Willebrand factor. Similar to stromal lymphoid tissue organizers, MRCs up-regulated the adhesion molecules ICAM-1 and VCAM-1 in response to LT and TNF. Moreover, MRCs exposed to microbial TLR ligands, released the B cell-stimulating factors BAFF, APRIL and IL-6, which delivered survival, proliferation, class switching and plasma cell differentiation signals to MZ B cells. Plasma cells emerging from this pathway showed either T cell-dependent or T cell-independent ontogenetic features, and released IgM antibodies to conserved carbohydrate and lipid antigens shared by commensal and pathogenic bacteria. These antibodies decreased in splenectomized individuals. Finally, TLR-primed MRCs produced retinoic acid, which elicited MZ B cell expression of the gut-homing receptors a4b7 and CCR9. These findings indicate that MRCs have unique B cell-helper properties that could be harnessed to enhance vaccine-induced antibody responses systemically and perhaps at mucosal sites of antigen entry.
DNA sensing via STING regulates autoimmunity and tumor immunity. (IRM5P.648)
Authors: Mohamed Eslam , Lemos Henrique , Huang Lei , Ou Rong , Pacholczyk Gabriella , Hayakawa Yoshihrio , Munn David , Mellor Andrew 
Published: January 2023

Abstract
The Stimulator of Interferon Genes (STING) is activated by cytosolic DNA sensors such as cyclic GMP-AMP Synthase (cGAS) to induce interferon type I (IFN-I). Dendritic cells (DCs) that engulf dying tumor cells incite anti-tumor T cell immunity by sensing tumor cell DNA to activate STING/IFN-I signaling. Paradoxically, we find that DNA sensing to activate STING/IFN-I signaling induces DCs to express indoleamine 2, 3 dioxygenase (IDO), which activates regulatory T cells (Tregs). Thus treatment with DNA nanoparticles (DNPs) or cyclic dinucleotides (CDNs) to activate STING attenuated Experimental Autoimmune Encephalomyelitis (EAE), arthritis, and therapeutic responses were dependent on STING/IFN-I signaling to induce IDO. DNP and CDN treatments were also effective in slowing Type I Diabetes (T1D) progression in susceptible female Non-Obese Diabetic (NOD) mice. STING ablation also abolished IDO-dependent regulatory responses to apoptotic cells, suggesting that DNA from dying cells is sensed to activate the STING/IFN-I pathway and induce IDO to suppress autoimmunity. Moreover, cGAS and STING ablation abolished the ability of Lewis Lung carcinoma (LLC) tumor cells to induce local IDO, which suppresses anti-tumor immunity. These findings support the hypothesis that DNA from dying cells is sensed to activate STING/IFN-I in regulatory DCs that suppress T cell immunity and autoimmunity at sites of chronic inflammation associated with autoimmunity and tumor growth.
miR-23a supports survival of activated CD4+ T cells by maintaining reactive oxygen species equilibrium (IRM5P.638)
Authors: Liu Siqi , Zhang Baojun , Lin Regina , Li Chaoran , Li Qi-Jing 
Published: January 2023

Abstract
To identify key miRNAs that regulate CD4+ T cell responses, we profiled miRNA expression in CD4+ T cells at different phases post-antigen stimulation. As miR-23a is a miRNA that correlated strongly with effector CD4+ T cell expansion, we generated a T-cell specific miR-23a knockout mouse line (23T-KO). We found that miR-23a in T cells is essential for effective anti-bacteria protection, as the loss of effector T cells during the early phase of antigen activation rendered 23aT-KO mice susceptible to high-dose listeria infection. As early as a few hours post-activation in vitro, naïve 23T-KO CD4+ T cells exhibit an accelerated death, which is not rescued by caspase inhibition. Further analysis reveal that miR-23a deficiency in CD4+ T cells severely impairs their mitochondrial structural and functional integrity; Consequently, TCR activation of 23T-KO CD4+ T cells induce the rapid loss of mitochondrial potential and accumulation of reactive oxygen species. Forced expression of the antioxidant enzyme GPX1 protects activated naïve 23T-KO T cells from accelerated cell death. Mechanistically, we determine that miR-23a loss results in the accumulation of its direct target, PPIF, a structural component of the mitochondria permeability transition pore complex. Taken together, our results indicate that PPIF-controlled ROS equilibrium is essential for the survival of effector CD4+ T cells, and that miR-23a is indispensable for maintaining ROS homeostasis during early antigen activation.
Essential role of STAT3 in the upregulation of CD28 expression by IL-21 (IRM6P.658)
Authors: Wang Junmei , Frey Amanda , Li Haiyan , Park Jungsun , Lai Ivy , Watowich Stephanie , Lee Dean , Lee Kyung-Mi , Yee Cassian 
Published: January 2023

Abstract
CD28 plays an essential costimulatory role in T cell activation and survival by promoting IL-2 expression. However, the regulation of CD28 expression on CD8 T cells has not been well defined. Our previous studies demonstrated that tumor antigen-specific CD8 T cells generated in the presence of IL-21 stably express high levels of CD28 on the cell surface and exhibit enhanced replicative potential and in vivo persistence following adoptive transfer. The mechanism by which IL-21, a gamma-chain receptor cytokine, known to activate STAT3, and to a lesser degree STAT1 and STAT5, regulates CD28 expression is currently not known. Here we report that IL-21 regulates expression of CD28 at the transcriptional level through pSTAT3 binding to the CD28 promoter region. Using a reported small molecule inhibitor of STAT3, we demonstrate that STAT3 is critical for IL-21-induced expansion of tumor antigen-specific T cells and upregulation of CD28 expression. In addition, using CD8 T cells from Job’s syndrome patients with a sole dominant negative stat3 mutation and T cells transfected with stat3 knockdown shRNAs, we further confirmed that STAT3 is essential for the IL-21 mediated CD28 effect on human CD8 T cells. Moreover, we discovered that STAT3 directly regulates CD28 expression by binding to consensus STAT sites in human CD28 promoter. Taken together, our study demonstrates for the first time a specific role for STAT3 in IL-21-mediated CD28 expression in activated human CD8 T cells.
Evidence for a pivot upon TCR engagement (IRM7P.700)
Authors: Kuhns Michael , Lee Mark , Glassman Caleb , Deshpande Neha , Parrish Heather 
Published: January 2023

Abstract
The T cell receptor (TCR)-CD3 complex is the chief determinant for T cell development, activation, differentiation and the execution of effector functions. The TCR module (TCRα+TCRβ) relays highly specific information about antigenic peptides embedded within major histocompatibility complex molecules (pMHC) to the intracellular signaling domains of the associated CD3γε, CD3δε, and CD3ζζ signaling modules to initiate intracellular signaling. It is unclear how mechanical information is transferred from the TCR-pMHC interface, across the plasma membrane, and on to the intracellular signaling domains of the CD3 subunits. The complexity of this molecular machinery, and the lack of obvious parallels with other receptor systems, has hindered progress in resolving these issues. We tested the hypothesis that the juxtamembrane regions of the CD3 signaling subunits are held in a spatial relationship that keeps the complex ‘off’ until TCR engagement triggers a change in this spatial relationship that converts the complex to an ‘on’ conformation. This would be akin to cytokine receptors, receptor tyrosine kinases, and even integrins. Our data indicate that unengaged TCRs enforce a divaricated conformation of the cytosolic juxtamembrane regions of key TCR-CD3 complex subunits at steady state. We interpret this to represent an off conformation. TCR engagement then triggers the intra-complex apposition of these regions into what we interpret to represent an on conformation.
Cereblon, a molecular target of lenalidomide (IMiDs), negatively regulates T cell activation (IRM7P.715)
Authors: Beatty Matthew , Han Ying , McDaniel Jessica , Mailloux Adam , Painter Jeffrey , Bronk Chrystina , Yoder Sean , Beg Amer , Yu Xue-Zhong , Fu Jianing , Engelman Robert , Liu Chen , Rajadhyaksha Anjali , Epling-Burnette Pearlie 
Published: January 2023

Abstract
Thalidomide analogs classified as immunomodulatory drugs (IMiDs) are rapidly emerging T-cell stimulants for the treatment of cancer. Cereblon, an E3-Ub ligase receptor with no known immune regulatory function, is the first identified target of IMiDs. The drug is hypothesized to have antagonistic properties by interfering with substrate recruitment to the thalidomide-binding domain in cereblon, and agonistic activity through an exposed ring that may recruit new proteins to the Ub complex. To explore this further at the molecular level, we studied immune regulation in cereblon deficient mice (crbn-/-), which exhibited an expanded white blood cell and neutrophil compartment, and higher numbers of peripheral and splenic lymphocytes. Mature crbn-/- T cells were capable of proliferation and IL-2 production following CD3 ligation in the absence of CD28 co-ligation. This positively associates with proximal phosphorylation events including pZap70, pAKT, pro-survival Bcl-XL and Bcl-2 protein expression, and corresponds with decreased pro-apoptotic proteins Bim, Bad, and Bax. Consistent with this data in a lethal graft-versus-host (GVHD) model, MHC-class I mismatched T cells from crbn-/- mice showed shortened post-transplant survival, greater weight-loss, and higher IFN-γ compared to transplanted wild-type T-cells. These data suggest that native targets of cereblon restrain the activation threshold of T-cells and that IMiD-associated blockade of cereblon leads to T-cell potentiation.
Direct interaction between PKCθ and ZAP70 kinases is required for T cell activation (IRM7P.716)
Authors: Xie Jiji , Han Xuemei , Silletti Steven , Lillemeier Bjorn 
Published: January 2023

Abstract
PKCθ plays a key role in T cell activation, but the mechanisms that control its activation are not fully understood. We previously reported that the PKCθ N-terminal C2 region is a novel regulatory phosphotyrosine (pTyr)-binding domain. However, the physiological pTyr-containing C2-binding ligand has remained unknown. Using a GST-PKCθ-C2 recombinant fusion protein in pull-down assays, we detected a ~75-kDa pTyr-containing protein that associated with wild-type PKCθ-C2, but not with a pTyr non-binding PKCθ-C2 mutant after TCR/CD28 costimulation. Mass spectrometry analysis identified this protein as ZAP70 kinase. The stimulation-induced association of ZAP70 with full-length PKCθ or PKCθ-C2 in T cells was confirmed by co-immunoprecipitation assays, and was mediated by residues pY315 and pY319 in interdomain B of ZAP70. This transient association upon T cell activation required Lck kinase, followed by rapid complex dissociation that led to ZAP70 phosphorylation on Y493, resulting in full activation of ZAP70 and downstream signals. Mutation of two PKCθ-C2 residues essential for pTyr binding abolished PKCθ’s ability to rescue TCR- and CD28-induced IL-2 production, proliferation and Th2 differentiation in PKCθ-deficient T cells, without affecting T cell development or Th1 differentiation. These data suggest anchoring of PKCθ-C2 domain to phosphorylated interdomain B of ZAP70 promotes the activation of both kinases, thereby provided a novel pharmaceutical target for immunosuppression.
T cell development is regulated by the coordinated function of two Lck promoters (IRM7P.701)
Authors: Chiang Jeffrey , Hodes Richard 
Published: January 2023

Abstract
Lck is a T cell lineage-specific tyrosine kinase that is critical for T cell development and activation. Expression of an identical Lck protein can be mediated by two promoters, the proximal and distal lck promoters, but the function of these promoters during T cell development has not been directly assessed. We generated mutant mice by inactivating either one of the two lck promoters. Lck-PROX mice, in which only the proximal promoter is functional, had normal levels of Lck protein and thymic development through the CD4-CD8- double negative (DN) stage of T cell development, but reduced levels of Lck later in development and a dramatic reduction of mature single positive thymic T cells. In contrast, Lck-DIST mice, in which only the distal promoter was functional, were deficient in Lck and severely defective in early T cell development, with a block at the DN3 stage equivalent to the defect seen in complete Lck knockouts. Interestingly, the small number of peripheral T cells that developed in Lck-DIST mice expressed Lck protein and proliferated normally in response to TCR/CD3 cross-linking, while those of Lck-PROX mice were deficient in Lck and defective in response to TCR stimulation. These results define the coordinated requirements for proximal and distal lck promoters during T cell development and represent a unique direct demonstration of the requirement for alternative promoters in allowing developmental stage-specific regulation of a single protein product.
MicroRNA-183/96/182 cluster regulates iNKT cell development and function (IRM7P.706)
Authors: Zhou Li , Li Guihua , Zhang Xiling , Xu Shunbin , Mi Qing-Sheng 
Published: January 2023

Abstract
MicroRNAs (miRNAs), a class of non-coding small RNAs. Invariant Natural Killer T (iNKT) cells are potent regulators of diverse immune responses. Our previous study indicated that lack of miRNAs following the deletion of Dicer, a miRNAs-processing enzyme, affect iNKT cell development and function (PNAS, 2009). However, the roles of specific miRNA in iNKT cell development and function remain unclear. The miR-183/96/182 cluster, composed of 3 miRNA genes, is significantly upregulated upon T cell activation. In this study, we investigate the role of miR-183/96/182 cluster on development and function of iNKT cells, using miR-183/96/182 knockout (KO) mice. We found that the frequency of immature iNKT cells significantly increased, while mature iNKT cells significantly decreased in thymus of KO mice compared to littermate control (P&lt;0.05), indicating the blockage of iNKT cell development in thymus. Furthermore, lack of miR-183/96/182 resulted in a substantial reduction of iNKT cell number (p&lt;0.05) in the thymus and in spleen. The mutant iNKT cells displayed defective cytokine production, including IL-4 and IFNγ, compared to iNKT cells from littermate control (P&lt;0.05). Finally, bone marrow chimera transferring experiments further suggested the miR-183/96/182 cluster controlled iNKT cell development and function by cell-intrinsic characteristics. Thus, our data define a specific role of miR-183/96/182 cluster in the development and function of iNKT cells.
Intrahepatic development of liver-resident natural killer cells (LYM2P.739)
Authors: Tian Zhigang , Peng Hui , Tang Ling , Bai Lu , Sun Rui 
Published: January 2023

Abstract
Natural killer (NK) cells are an important component of the innate immune system and play critical roles in host defense against infections and tumors. Accumulating studies have shown that the NK cell pool is highly heterogeneous, consisting of different cell subsets with distinct phenotypic and functional features. Recently, in collaboration with Professor Wayne Yokoyama, we showed that a novel NK cell subset expressing CD49a and lacking DX5 rarely recirculates and selectively resides in the liver, that is, liver-resident NK cells. While bone marrow (BM) cells are efficient in generating conventional (cNK) cells, the frequency of liver-resident NK cells is significantly reduced after BM transplantation. Conversely, lethally irradiated mice adoptively transferred with fetal liver cells exhibit normal frequency of liver-resident NK cells. Further analyses reveal that the adult liver retains hematopoietic potential and contains a few hematopoietic progenitor cells (HPCs), which are phenotypically distinct from BM lineage (Lin)-negative progenitor cells but resemble fetal liver counterparts. Moreover, adoptive transfer of these adult liver HPCs have the capacity to generate liver-resident NK cells, but not cNK cells. Finally, Liver HPCs express higher levels of the transcription factors that are essential for liver-resident NK cell development than their BM counterparts. Thus, our studies suggest an alternative development pathway for liver-resident NK cells.
Exacerbation of human astrocyte inflammatory responses to bacterial pathogens by the neuropeptide substance P (MPF2P.742)
Authors: Young Ada , Marriott Ian 
Published: January 2023

Abstract
The neuropeptide substance P (SP) has increasingly been recognized to augment inflammatory immune responses. We have recently demonstrated that SP can significantly exacerbate the inflammatory responses of isolated murine glial cells to clinically relevant bacterial pathogens. Furthermore, we have shown that SP interactions with its receptor are an essential component in the initiation and/or progression of central nervous system (CNS) inflammation in in vivo mouse models of meningitis. In the present study, we demonstrate that SP similarly alters the inflammatory responses of human astrocytes to clinically relevant bacterial pathogens and their components. Specifically, we show that SP augments the production of inflammatory cytokines and the generation of nitric oxide by human astrocytes in response to Neisseria meningitidis. In addition, we showed that this effect is seen in astrocyte responses to the TLR4 ligand, LPS. However, such SP-mediated increases in inflammatory mediator production are not limited to TLR4 stimuli as human astrocyte responses to the disparate Gram-negative bacterial pathogen Borrelia burgdorferi, that does not express LPS, are also modulated in a dose and time dependent manner. Together, these results suggest that SP could play a significant role in the initiation and/or progression of bacterially induced CNS inflammation in humans in a similar manner to that previously seen in rodent models following infection.
Group 1 CD1-restricted T cells can recognize Staphylococcus aureus lipid antigen (MPF2P.751)
Authors: Visvabharathy Lavanya 
Published: January 2023

Abstract
CD1-restricted T cells are a unique subset of T cells that respond to lipid self- and foreign antigens presented by group 1 CD1 (CD1a, -b, -c) and group 2 CD1 (CD1-d) antigen presenting molecules. Previous studies have shown that group 1 CD1-restricted T cells can respond to lipid antigens derived from Mycobacterium tuberculosis. As group 1 CD1 molecules can accommodate a variety of lipid species, we sought to address whether group 1 CD1-restricted T cells can be activated by Staphylococcus aureus (SA) lipids. Using a transgenic mouse strain that expresses human group 1 CD1 molecules (hCD1Tg), it was found that group 1 CD1-restricted T cell responses against SA lipids can be observed in immunization and infection settings. When DCs coated with total lipid from MRSA strain USA300 were injected into hCD1Tg mice, lymphocytes produced significantly higher amounts of IFN-g in response to SA lipid in a group 1 CD1-dependent manner. Lymphocytes from SA-infected animals also produced more IL-17 in a group 1 CD1- and SA lipid antigen-dependent manner. Finally, long-term cultured CTL clones derived from immunized and infected animals displayed specificity toward SA lipid antigens. These clones produced IL-10 and TNF-α in response to SA lipid, demonstrating that group 1 CD1-restricted T cells isolated from immunized or infected animals can produce multiple cytokines in response to SA lipid.