bluuebunny/crossref_metadata_2025_split huggingface dataset:
Virulence determinants enhance the CD8+ T cell response to a recombinant live virus vaccine (VIR10P.1168)
Authors: Pavelko Kevin , Bell Michael 
Published: January 2023

Abstract
Safe and effective vaccine vectors that drive T-cell responses are critical for the development of immunotherapies that treat cancer and infectious disease. We have developed Theiler’s murine encephalomyelitis virus (TMEV) as a vector for promoting CD8 T-cell responses to epitopes embedded within its genome. Previously, we demonstrated that the site of epitope integration within the viral genome can alter virulence and promote viral clearance. However, its inability to drive complete elimination of tumors suggests that further development is necessary. The TMEV species is comprised of two subspecies, the persisting group Daniel’s (DA) and a non-persistent virulent group GDVII. We introduced a genomic fragment of GDVII into the DA strain that contains the capsid and flanking regions. Virus generated from this vector demonstrates increased virulence and replicative capacity. To determine whether this vector could drive enhanced CD8 T-cell responses to vaccine epitopes we engineered the CD8 epitope SIINFEKL into the leader protein of the GDVII chimeric virus. Infection of B6 mice with this vaccine enhances the number of SIINFEKL specific CD8 T-cells when compared to wild-type vector. Studies to identify the precise determinants that are necessary for this enhancement and how effectively this vaccine can promote anti-tumor immunity will be important for future vector development.
CD44 controls T cell exhaustion and viral persistence during chronic viral infection (VIR10P.1170)
Authors: Carrette Florent , Tinoco Roberto , Barraza Monique , Bradley Linda 
Published: January 2023

Abstract
During a chronic viral infection, inhibitory receptors play a crucial role in controlling viral persistence and T cell exhaustion. However, the role of homing molecules in this process has been poorly investigated. Using the chronic LCMV virus model, Clone 13, we found that expression of CD44, a cell surface glycoprotein broadly used to identify activated T cells, dampens antigen specific T cell responses. In CD44-deficient hosts, we observed a significant increase in antigen specific CD4 and CD8 T cells functions with decreased PD-1 expression and a striking increase in multiple cytokine production. T cell accumulation was not due to increased proliferation based on BrdU incorporation, and the increased CD8 T cell response required CD4 T cell help because CD8 T cell exhaustion was maintained in CD4 depleted CD44-deficient mice. Using a bone marrow chimera approach, we found that restricting the CD44 deficiency in the non-hematopoietic compartment was sufficient to reproduce the observations made in the complete CD44 deficient hosts. Finally CD44-deficiency resulted in viral clearance by d15pi. Importantly, treatment of WT mice with a CD44-blocking antibody increased antigen specific CD4 and CD8 T cell recovery and some aspects of T cell function as early as d9pi. Taken together, these results indicate that CD44 is a novel inhibitory receptor that can be targeted to improve T cell response during chronic viral infections.
Deficiency in the receptor tyrosine kinase EphB2 attenuates experimentally-induced liver fibrosis in mice (CAM1P.156)
Authors: Mimche Patrice , Brady Lauren , Bray Christian , Mimche Sylvie , Thapa Manoj , King Thayer , Quicke Kendra , Lee Choon , Grakoui Arash , Morgan Edward , Lamb Tracey 
Published: January 2023

Abstract
Beyond the well-defined role of Eph receptor tyrosine kinases in biological processes, cell migration, adhesion, nothing is known about their implication in liver pathologies. During blood-stage rodent malaria infection, EphB2 mRNA and proteins are upregulated in the liver, a result likely driven by elevated surface expression on macrophages. This is significant for malaria pathogenesis because EphB2-/- mice are protected from malaria-induced liver fibrosis despite having a similar liver parasite burden compared with littermate mice. This protection is correlated with a defect in inflammatory potential of hepatocytes from EphB2-/- mice resulting in a reduction in adhesion molecules, chemokine/chemokine receptors RNA levels and infiltration of leukocytes including Kupffer cells which mediate liver fibrosis during malaria. These observations are recapitulated in the well-established carbon tetrachloride (CCL4) model of liver fibrosis in which EphB2-/- CCL4-treated mice showed a significant reduction of liver fibrosis compared to CCL4-treated littermate mice. EphB2 is predominantly expressed by Kupffer cells and depletion of macrophages abrogates liver EphB2 mRNA and protein increase in malaria infected mice, as well as fibrosis. Altogether these results reinforce the critical role played by EphB2 in promoting liver inflammation and fibrosis. To our knowledge, this work is the first to reveal the potential profibrotic nature of EphB receptor tyrosine kinases in liver injury.
The middle tyrosine residue of tyrosine-based inhibitory signalling motifs is a key molecule in inhibitory functions of the leukocyte immunoglobulin-like receptor B4 in FcγRI mediated cytokine production and bacterial phagocytosis. (CCR3P.211)
Authors: Park Mijeong , Tedla Nicodemus 
Published: January 2023

Abstract
The leukocyte immunoglobulin-like receptor B4 (LILRB4) is an inhibitory cell surface receptor, primarily expressed on mono-myeloid cells. LILRB4 is a potent inhibitor of FcγRI-mediated pro-inflammatory cytokine production by monocytes and induces tolerogenic dendritic cells in vitro. It is believed that LILRB4 regulates monocyte/macrophage activation through its three intracellular immunoreceptor tyrosine-based inhibitory motifs (ITIMs) by dephosphorylation of non-receptor tyrosine kinases via recruitment of Src homology phosphatase-1 (SHP-1). However, the relative contribution of these ITIMs to LILRB4-mediated inhibition of monocyte/macrophage functions is poorly characterised. To address this, the three functional tyrosine residues of LILRB4 ITIMs at positions 337, 389 and 419 were single, double or triple mutated to non-functional phenylalanine and stably transfected into THP-1 cells. The effects of these mutants on FcγRI-mediated monocyte functions were then assessed. We show that the middle tyrosine residue (Y389) alone maximally inhibited but the proximal tyrosine residue (Y337) enhanced FcγRI-mediated TNF-α production and Fc-dependent bacterial phagocytosis. These results for the first time show that LILRB4 may have variable functions in vitro dependent on the position of the tyrosine residues in its ITIMs. The underlying mechanisms and in vivo implications of these adaptable functions require further investigations.
Signal transduction via CD103 and BAFF-receptor cooperatively play a role in the abnormal activation of T cells. (CCR3P.216)
Authors: Yoshimoto Keiko , Kurasawa Takahiko , Suzuki Katusya , Takeuchi Tsutomu 
Published: January 2023

Abstract
Background and Purpose: It was reported that the expression of CD103 (αEβ7) was elevated in infiltrated T cells in lachrymal glands of patients with Sjögren’s syndrome (SS), suggesting that abnormal expression of CD103 in T cells is involved in the pathogenesis of SS. Our previous study suggests that BAFF plays a role in the development of SS. In this study, we investigated a possible interaction between CD103 and BAFF in T cells. Materials and Methods: Jurkat, a human T cell leukemia cell line, was transfected with both human αE and β7 genes. Stable transfectants were stimulated with anti-CD3 to induce production of IL-2. The cells were further stimulated with anti-CD103, recombinant human soluble BAFF (rhsBAFF) or both. Results and Discussion: It may be noteworthy that the IL-2 production by T cells upon stimulation with ant-CD3 was elevated by the overexpression of CD103. The data suggest that CD103 plays a role in the activation of T cells. Anti-CD103 and rhsBAFF significantly enhanced the effect of anti-CD3 possibly in an additive manner. FACS and quantitative RT-PCR revealed that the expression level of a BAFF receptor (BR3) was increased in the transfectants, suggesting that the effect of CD103 on the response of the cells to rhsBAFF is mediated through the enhancement of BR3 expression. The data collectively suggest that abnormal expression of CD103 in T cells is involved in the development of SS by affecting BAFF signaling pathway.
Runx1 is required for T cell maturation (HEM2P.246)
Authors: Dash Barsha , Hsu Fan-Chi , Belmonte Paul , Constans Megan , Chen Meibo , McWilliams Douglas , Shapiro Virginia 
Published: January 2023

Abstract
T cell development depends on coordinated gene expression changes in order to progress through developmental checkpoints. The loss of transcription factor Runx1 in CD4-cre Runx1 conditional knockout (cKO) mice leads to decreased numbers of CD4 single positive (SP) thymocytes, CD4 peripheral T cells and lower expression of IL-7Rα, a key player of T cell homeostasis, by CD4+ Runx1 deficient T cells . Low IL-7Rα is thought to cause decreased CD4 T cell survival. However, we show that constitutive expression of an IL-7Rα transgene in CD4-cre Runx1 cKO mice does not restore thymic or peripheral CD4 cellularity. We also see similar expression of Bcl-2 and Bcl-xL in WT and Runx1-deficient CD4 T cells, indicating that a Runx1-mediated IL-7Rα-independent mechanism might be responsible. As IL-7Rα expression increases over the course of T cell maturation, we asked if Runx1 is needed for maturation. During thymic maturation, post-positive selection CD4 SP thymocytes migrate from cortex to medulla, changing from CCR7lowCD24high to CCR7highCD24high and finally CCR7highCD24low before thymic egress. We saw a block at the CCR7lowCD24high stage in CD4-cre Runx1 cKO CD4 SP thymocytes. Additionally, other maturation markers including CD55 and Qa2 were also downregulated. Thus, Runx1 is required for thymic maturation of CD4 SP thymocytes.
Retention and tolerance of autoreactive CD4+ recent thymic emigrants in the liver (HEM2P.249)
Authors: Ge Qing , Xu Xi , Zhang Shusong 
Published: January 2023

Abstract
Mechanisms of peripheral tolerance play a critical role in preventing T cells that escape from negative selection in the thymus from initiating autoimmune reactions. To investigate the site of peripheral tolerance induction, we examined migration and activation of recent thymic emigrants (RTEs) in liver, spleen, lymph node and peripheral blood. We show that a fraction of RTE precursors were retained in the liver independent of the secondary lymphoid organs. Compared to RTEs from the lymph nodes, RTEs from the liver proliferated more and many exhibited an activated phenotype with the capability of producing IL-10 upon activation. Liver RTEs also responded poorly to interleukin (IL)-7 and were more prone to apoptosis. Following transfer into RAG-/- recipients, liver RTEs induced more severe inflammation and T cell infiltration in the lung and colon. The extrathymic expression of MHC and Aire is required for the acquisition of tolerogenic phenotype of newly generated thymic emigrants in the liver. These results suggest that the liver is the first checkpoint in the periphery to filter, retain, and enforce tolerance to autoreactive CD4+ thymic emigrants that escape from negative selection.
Interleukin-15 receptor α signaling constrains the development of IL-17-producing γδ T cells (HEM2P.232)
Authors: Colpitts Sara , Puddington Lynn , Lefrançois Leo 
Published: January 2023

Abstract
The development and homeostasis of γδ T cells is highly dependent on distinct cytokine networks. Here we examine the role of interleukin (IL)-15 and its unique receptor, IL-15Rα, in the development of IL-17-producing γδ (γδ-17) T cells. Phenotypic analysis showed that CD44high γδ-17 cells expressed IL-15Rα and the common gamma chain (CD132) yet lacked the IL-2/15Rβ chain (CD122). Surprisingly, we found an enlarged population of γδ-17 cells in the peripheral and mesenteric lymph nodes of adult IL-15Rα KO mice but not IL-15 KO mice. γδ-17 cells were also increased in the peripheral lymph nodes of transgenic knock-in mice where the IL-15Rα intracellular signaling domain was replaced with the intracellular portion of the IL-2Rα chain (that lacks signaling capacity). The generation of mixed chimeras from neonatal thymocytes indicated that cell-intrinsic IL-15Rα expression was required to limit IL-17 production by γδ T cells. Finally, an analysis of neonatal thymi revealed that the CD44low precursors of γδ-17 cells were increased in newborn mice lacking IL-15Rα. Thus, these findings demonstrate that signaling through IL-15Rα regulates the development of γδ-17 cells early in ontogeny with long-term effects on their peripheral homeostasis in the adult.
Themis and the control of SHP1 phosphatase activity in TCR signal strength during thymocyte positive selection (HEM2P.234)
Authors: Gascoigne Nicholas , Brzostek Joanna , Mehta Monika , Zhao Xiang , Fu Guo , Paster Wolfgang , Acuto Oreste , Rybakin Vasily 
Published: January 2023

Abstract
Themis is a T cell-specific protein important for positive selection in the thymus. It associates, through the adaptor GRB2, with the LAT signalosome after stimulation. Recent data show that it acts as a negative regulator of TCR signal strength for positive selecting ligands during thymocyte development, through its interaction with the phosphatase SHP1. A Themis-GRB2-SHP1 complex is recruited to LAT, tuning down the TCR signaling cascade, so that intermediate-strength positive selecting ligands are not recognized as agonists. In Themis-knockout thymocytes, signaling in response to positive selecting ligands is strong, resulting in increased negative selection. In contrast, responses to strong, negative-selecting, ligands are not affected by the absence of Themis. SHP1 is under-phosphorylated in Themis-deficient thymocytes, and its phosphorylation is not significantly increased after TCR stimulation, in contrast to results from Themis-sufficient thymocytes. In concert with phosphorylation, phosphatase activity of SHP1 is increased after TCR stimulation, but this is much reduced in the absence of Themis. We have recently found that phosphatase activity can be coprecipitated with Themis from thymocytes, and this activity increases immediately after TCR stimulation. The amount of phosphatase activity bound to Themis varies with signal strength. These results will be discussed in the context of dynamic control of positive selection signaling during thymocyte development.
An intricate link between autophagy and microRNAs in cystic fibrosis (HUM1P.262)
Authors: Tazi Mia , Dakhlallah Duaa , Khalil Hany , Caution Kyle , Marsh Clay 
Published: January 2023

Abstract
Each year 1,000 children and adults are diagnosed with Cystic Fibrosis (CF), a fatal genetic disorder that critically affects the lungs. Autophagy, a highly-regulated biological process, normally functions to clear dysfunctional CFTR (CF transmembrane conductance regulator) proteins that aggregate within macrophages. However, this process is defective in CF patients and CF mice, as their macrophages express limited autophagy activity thus exacerbating inflammation. Present therapies to improve autophagy are ineffective. MicroRNAs (miRNAs, miRs) are non-coding RNAs that post-transcriptionally regulate targeted mRNA expression. The objective for this study is to elucidate the role of miRNAs in CF macrophages in an effort to restore autophagy. We hypothesize CF macrophages exhibit elevated cluster expression that downregulate autophagy targets thus contributing to autophagy dysfunction. We find that, CF macrophages exhibit decreased autophagy protein expression and elevated cluster expression compared to WT. When cluster expression is absent, autophagy protein expression is restored, suggesting the canonical inverse relationship between miRNA and protein expression. Predicted autophagy targets of specific miRs comprising the cluster were validated. In vivo downregulation of specific miRs comprising the cluster increases autophagy expression. Thus, this data demonstrates, microRNA cluster expression correlates to autophagy expression which modulates the pathophysiology of CF.
Myeloid dendritic cells with elevated CD1c expression in non-infectious uveitis patients exhibited mature phenotype through the regulation of TNFa-p38 MAPK pathway (HUM1P.273)
Authors: Chen Ping , Denniston Alastair , Hannes Susan , tucker william , Wei Lai , Liu Baoying , Hirani Sima , Li Zhiyu , Lee Richard , Sen H. , Nussenblatt Robert 
Published: January 2023

Abstract
Our longitudinal data has shown that the level of CD1c+ myeloid dendritic cells 1 (mDC1) from peripheral blood reflects disease activity in autoimmune non-infectious uveitis patients. However, the role of CD1c+ mDC1 is not clear in autoimmune uveitis patients. Here, we demonstrate that the mDC1 in patients with non-infectious uveitis (n=74) was increased compared to age and gender-matched healthy controls (n=96). The increased CD1c+ mDC1 exhibited high HLADR expression and less antigen uptake. CD1c+ mDC1 were further divided into two subpopulations based on the level of CD1c expression. CD1chi mDC1 subpopulation showed less antigen uptake and higher HLADR expression compared to CD1clo mDC1 subpopulation. Importantly, the CD1chi mDC1 subpopulation was significantly increased in uveitis patients. By utilizing monocyte-derived dendritic cells (MoDCs) for in vitro studies, MoDCs with less antigen uptake and higher levels of CD1c induced more CD4+ T helper cell activation and proliferation. TNFa, increased in uveitis patient sera, reduced the antigen uptake in a dose-dependent manner and increased the phosphorylated p38 expression on MoDCs. A p38 inhibitor significantly inhibited the expression of CD1c during dendritic cell differentiation from monocytes. In conclusion, CD1c is a maturation marker of mDC1, increased in uveitis patients and correlated with disease activity. The high CD1c expression and low antigen uptake are mediated by the TNFa-activated p38 MAPK pathway.
Healthy human pregnancy: inherently inflammatory or anti-inflammatory? (HUM1P.275)
Authors: CHILDStudyTeam . , Graham Caroline , Chooniedass Rishma , Becker Allan , Study Team CHILD 
Published: January 2023

Abstract
Although much is known of immunity at the maternal-fetal interface, the innate immune status of women during healthy pregnancy remains unclear. Whether it exhibits a bias towards inflammatory phenotypes (transiently enhancing host defense) or anti-inflammatory phenotypes (reducing potential responses to the fetus) is controversial. Here, in a longitudinal study of &gt;100 healthy women giving birth to full term healthy infants, systemic innate immune status was examined during the 2nd/3rd trimester and again, one or three years postpartum. Following REB approval and informed consent, pro and anti-inflammatory plasma biomarkers were quantified. Constitutive CCL2, CXCL10 and TNFa levels were sharply reduced (p&lt;0.003 to 0.0001) in pregnancy. Several anti-inflammatory biomarkers were elevated (sTNFRI, sTNFRII, IL-1Ra p&lt;0.0001). Plasma IL-10, expressed in &gt;85% of this population, was not altered during/post pregnancy. Kinetic studies revealed that pro-inflammatory biomarker expression (CXCL10, CCL2, CXCL8, IL-18, TNFa) was independent of gestational age. Conversely, the intensity of anti-inflammatory cytokine antagonist production increased with gestational age (Spearman p&lt;0.0003). In summary, among women experiencing healthy full term pregnancies, basal systemic immunity is characterized by an increasingly intense bias towards an anti-inflammatory innate immune phenotype that is resolved by one year postpartum.
Assessment of the Fc receptor CD16A of NK cells of CFS patients for potential to mediate ADCC activity (HUM1P.303)
Authors: Silvestre Isabel , Peterson Daniel , Redelman Douglas , Anderson Stephen , Hudig Dorothy 
Published: January 2023

Abstract
Natural killer (NK) cytotoxicity of chronic fatigue syndrome (CFS) patients is decreased, as reported by several laboratories. This observation led us to query whether the NK cells also lack antibody-dependent cell-mediated cytotoxicity (ADCC). NK cells have the IgG Fc-receptor CD16A that mediates ADCC. To assess potential ADCC effectors, we examined the peripheral blood of 11 CFS patients from a Lake Tahoe cohort that met the Fukuda standards for CFS and had low SF36 scores. Healthy controls were age- and gender-matched. We stained peripheral blood cells for CD16A with mAb clone 3G8 and for CD3, CD56, and perforin, then assessed the cells by flow cytometry. We found that the percentages of NK cells expressing CD16A were slightly lower for CFS patients 86.0+/-11.5% vs. controls 93.0+/-6.6% (P=0.08). The median fluorescent indices (MFIs) of CD16A were lower,72% of the values for the CFS patients, 9342+/-3233 vs. control 12929+/-4425, though not statistically significant (P&lt;0.17). Intracellular staining for perforin in the CD16Apos cells was similar for patients and controls. Our data indicate that a larger sampling of CFS patients vs. controls is required to determine if the fractions of CD16Apos NK cells and the levels of CD16A on these cells differs. These two observations are both in the direction of compromising ADCC activity of patients. In addition, a bias in F over V allelic variants of CD16A might add to impairment, since the F allele confers reduced ADCC.
Influence of human TLR and NLR genetic variants on colorectal cancer - involvement of commensal bacterial detection, gut immunity or microbiome diversity? (HUM1P.311)
Authors: Weber Alexander , Huhn Stefanie , Klimosch Sascha , da Silva Filho Miguel Inacio , Sanmuganantham Tharmila , Pichulik Tica , Padini Barbara , Naccarati Alessio , Schafmayer Clemens , Vodickova Ludmilla , Vodicka Pavel , Hemminki Kari , Försti Asta 
Published: January 2023

Abstract
Studies on TLR and NLR knock out mice have suggested these pattern recognition receptors (PRRs) drastically affect gut mucosal immunity and composition of the gut microbiome, which may give rise to diseases such as colorectal cancer. We have identified several coding SNPs in TLR5 and different NLR (including the so far enigmatic group of development-associated NLRs) to be associated with different parameters of colorectal cancer, and for TLR5 have observed a functional effect in human blood immune cells. With a view to further elucidating the underlying mechanisms of these SNPs in colorectal cancer, we have begun to investigate the role of these PRR variants on gut immune activation levels and microbiome diversity in humans. Our hypothesis is that functional TLR and NLR variants are associated with different immune potential in the gut, shaping or being shaped by the host microbiome. We have built-up, genotyped and started to assay a cohort of 125 healthy volunteers and established stool assays for sIgA and cytokine levels by ELISA, cellular contents by flow cytometry analysis and PRR stimulating potential. Additionally, a functional characterization of coding NLR SNPs in cellular model systems is being carried out. Our studies dissect the functional impact and relationship of host genetic factors and the microbiome in humans, which may reveal novel targets in the diagnosis or treatment of colorectal cancer or other gut-related diseases.