bluuebunny/crossref_metadata_2025_split huggingface dataset:
Autoimmune susceptibility imposed by public TCRβ chains (BA2P.125)
Authors: Geiger Terrence , Zhao Yunqian , Nguyen Phuong , Vogel Peter 
Published: January 2023

Abstract
The MHC is the largest genetic risk factor for autoimmunity. It imposes risk in association with a complementary autoantigen specific TCR repertoire. How this occurs is unresolved. Each individual’s TCR repertoire is largely unique, and should therefore not contribute to population-wide disease risk. However, due to biases in TCR recombination, a subset of α and β sequences are shared by most individuals, or public. If these public α or β chains modulate a TCRαβ heterodimer’s likelihood of productively engaging autoantigen-MHC, they could influence autoimmune susceptibility. We demonstrate that disease-associated regulatory and effector TCRβ repertoires in autoimmune encephalomyelitis preferentially incorporate public TCR. Some disease-associated public TCRβ, when transgenically expressed, could further endow T cells with autoantigen specificity in the absence of priming, and demonstrate a subordinate role of the non-shared, endogenous TCRα chains in autoantigen specificity. Further, 2 of 7 Tg public and 0 of 7 Tg private TCRβ isolated from high frequency CNS-infiltrating T cells, provoked spontaneous, early-onset autoimmunity when associated with endogenous TCRα. These findings support a disproportionate contribution of public TCR to immunopathology and implicate them, in association with risk-associated MHC, in disease susceptibility. They further suggest that subsets of public sequences may serve as disease-specific biomarkers or therapeutic targets in autoimmunity.
The affinity of MOG specific CD4 + T cells does not predict cross-recognition to NFM in demyelinating autoimmune disease (BA2P.127)
Authors: Blanchfield J. Lori , Evavold Brian 
Published: January 2023

Abstract
TCRs can recognize and cross-react to multiple antigens, but little is known of how cross-reactivity might contribute to the etiology of demyelinating autoimmune disease. Here we extend the analysis of monoclonal 2D2 TCR cross-reactivity for MOG38-49 (myelin oligodendrocyte glycoprotein) and NFM18-30 (neurofilament medium protein) to polyclonal T cells. Utilization of the 2D micropipette adhesion frequency assay allows definition of antigen specificity and affinity of individual T cells for peptide:MHC ex vivo. We show that the frequency of CD4+ T cells from the CNS recognizing MOG, NFM, or both fluctuate during the course of MOG35-55 induced experimental autoimmune encephalomyelitis. Higher affinity T cells are maintained as a rare population within the repertoire yet the frequency of higher affinity, MOG specific T cells increase to a greater extent than NFM specific T cells during disease and MOG specific T cells exhibit higher affinities (10-4 to 10-3) than NFM specific T cells (&lt;10-4). Importantly, cross-recognition is not limited to higher or lower affinity clones. We have cloned an encephalitogenic T cell that is high affinity for MOG and low affinity for NFM, which contrasts the 2D2 TCR exhibiting a medium affinity for NFM and a very low MOG affinity. On a population level, TCR recognition of one or more CNS antigens is dynamic within the chronic autoimmune repertoire warranting future research to understand their individual contributions to disease.
Linker for activation of T cells (LAT) in the regulation of T cell activation and autoimmunity (BA2P.121)
Authors: Zhang Weiguo , Sullivan Sarah , Zhu Minghua , Lewis Catherine 
Published: January 2023

Abstract
The transmembrane adaptor protein LAT (Linker for Activation of T cells) is essential in T cell development, activation, survival, and homeostasis. Upon T cell activation, it is tyrosine phosphorylated and interacts with many signaling proteins, such as Grb2, Gads, and PLC-γ1. The mutation of tyrosine 136 on LAT abrogates its interaction with PLC-γ1, causing defective TCR-mediated signaling. Mice harboring this mutation, LATY136F, have significantly impaired thymocyte development; however, they rapidly develop a severe lymphoproliferative disease marked by the uncontrolled expansion of Th2-skewed CD4+ T cells, high levels of IgE and IgG1, and autoantibody production. In this study, we assessed the contribution of multiple signaling pathways in this disease using mice deficient in Gads and RasGRP1 and mice with constitutive activation of the NFAT and NF-κB pathways. We also examined the role of MHC and CD4 in the development of these pathogenic T cells and further investigated how T follicular helper cells and cytokines contribute to LAT-mediated autoimmunity.
Phenotypic and functional characterization of neutrophils from lupus-prone mice (BA4P.223)
Authors: Cowan Catharine , Dai Rujuan , Heid Bettina , Ahmed S. 
Published: January 2023

Abstract
Neutrophils constitute a critical component of cellular immunity that eliminate infectious organisms through oxidative burst, phagocytosis and the formation of neutrophil extracellular traps (NETs). Recently it has been reported that neutrophils contribute to autoimmunity through NET formation and interactions with auto-reactive immune cells. Our goal is to characterize phenotypic and functional properties of neutrophils in mouse models of systemic lupus (SLE) to determine if and how neutrophil dysregulation occurs. Using flow cytometry we have measured neutrophil populations in healthy control and diseased SLE mouse models. We found neutrophils are consistently increased in the spleen of MRL-Faslpr, C57BL/6-Faslpr and NZBWF1 lupus mice compared to controls. Further characterization of neutrophil functions including phagocytosis, reactive oxygen production, NET formation, protease activity and histone citrullination indicate increased DNA release, increased citrullination and alterations in serine protease activity in lupus neutrophils. Differences in the results between the NZBWF1 and MRL-Faslpr models suggest the background genetics play a role in neutrophil dysregulation in these two models. Ultimately we hope to understand the cause of altered neutrophil function in mouse models of SLE, whether they contribute to lupus disease progression, and hopefully develop newer targeted therapies for lupus.
A higher frequency of anti-EBNA-1 antibodies that cross-react with dsDNA are elicited in BAFF mice than wild type mice (BA4P.224)
Authors: Spatz Linda , Novak Brittany , Samuel Sherin , Paredes Jenny 
Published: January 2023

Abstract
One environmental factor strongly linked to Systemic Lupus Erythematosus (SLE) is the Epstein Barr Virus (EBV). Injecting mice with the major nuclear protein of EBV, EBNA-1, causes some to develop anti-EBNA-1 antibodies that cross-react with double stranded DNA (dsDNA). We hypothesized that autoimmune mice would regulate the development of cross-reactive autoantibodies more poorly than healthy mice. The goal of our study was to examine the potential of using biotin-labeled-EBNA-1 bound to streptavidin-linked magnetic beads (B-EBNA-s-A Dynabeads) to isolate anti-EBNA-1 antibody from sera and to use this method to examine if autoimmune BAFF transgenic mice are more likely to develop antibodies to EBNA-1 that cross-react with dsDNA than wild-type mice. We successfully isolated anti-EBNA-1 antibodies from polyspecific sera obtained from BALB/c, C57BL/6, and BAFF mice injected with EBNA-1, using B-EBNA-s-A-Dynabeads. Eluted antibody was tested by ELISA for binding to EBNA-1 and dsDNA. Anti-EBNA-1 antibody obtained from mice from all three strains was observed to cross-react with dsDNA. However, the frequency of mice producing cross-reactive antibody was greater and the amount of cross-reactive antibody was higher in BAFF than wild type mice. This suggests that a viral protein such as EBNA-1 may trigger the development of antibodies that cross-react with dsDNA and that genetic susceptibility to lupus may enhance the development of cross-reactive antibodies upon viral exposure.
Lymph nodes and Peyer’s patches harbor resident CD4+ T cells that accumulate after prolonged antigen exposure (CAM1P.230)
Authors: Ugur Milas , Schulz Olga , Pabst Oliver 
Published: January 2023

Abstract
CD4+ T cells can acquire various migratory properties after immune responses to provide enhanced immuno-surveillance together with effective protection. However, the comprehensive analysis of these migratory properties has been difficult due to the highly dynamic nature of T cell circulation. We developed two independent methods to analyze the migration of effector/memory CD4+ T cells by long-term in vivo cell tracking. We identified a resident population of effector/memory CD4+ T cells that stays in lymph nodes and Peyer’s patches (PPs) without circulation or proliferation. Resident CD4+ T cells constitute up to 50% of all effector/memory cells, including, but not limited to, follicular helper T cells. This heterogeneous population of resident cells expresses low levels of egress-promoting sphingosine-1-phosphate receptor 1 (S1pr1) and possesses a distinct TCR repertoire. Furthermore, resident cells constituted a significant portion of all CD4+ T cells in PPs and accumulated in these organs after continuous antigen exposure. Our results define a previously unrecognized population of effector/memory CD4+ T cells in lymphoid tissues which might perform similar functions as non-lymphoid tissue-resident memory T cells.
Effective mentoring of undergraduates in an immunology research laboratory (EDU1P.252)
Authors: Chatterjea Devavani , Tonc Elena 
Published: January 2023

Abstract
Rapid turnover, limited time availability, steep learning curve for bench skills, need for close supervision are challenges in the effective engagement of undergraduate students in active research laboratories. We have met this challenge in our immunology research group with early recruitment of first and second year students, year-round research activity and weekly lab meetings, scaffolded transition to independent bench work, peer-to-peer mentoring, an integrated majors’ research methods course, and a “5th year internship” for a selected student to work full-time for a year after graduation. Early recruitment allows motivated students to spend up to 3-4 years in the lab. Year-round journal clubs and lab meetings support a culture of productivity and accountability. Students collaborate, as appropriate, in the entire arc of research from generating preliminary data for grants to submitting manuscripts. In the past 7 years, 30% of 40 students trained have earned co-authorship on five peer-reviewed, published manuscripts to date. A critical outcome of this approach is an authentic ownership of research problems and motivation to contribute to the broader scientific community that is rare among undergraduates. This experience prepares them to pursue their own research careers after college. Of my 26 research students who have graduated, ten (38%) are currently enrolled in PhD programs in the biomedical sciences and 12 (46%) have worked in biomedical research.
Academic civic engagement in the Immunology classroom: from grant proposals to immunology theater (EDU1P.255)
Authors: Walser-Kuntz Debby 
Published: January 2023

Abstract
There is a growing recognition and sense of urgency that scientists need to be better equipped to communicate scientific ideas to the general public. Improved communication is an opportunity with significant policy, behavior, and funding implications. For the past 5 years, I have integrated civic engagement projects into the upper-level Immunology course I teach at Carleton College - a small liberal arts college located in Northfield, MN - in order to provide an opportunity for students to practice translating complex, jargon-rich information into engaging materials for use in the local community. These projects are by nature reciprocal; they provide an authentic learning opportunity for students and a very real benefit for our community partners. Additional student outcomes include increased awareness of local public health issues, enhanced understanding of the connection between immunology and real world problems, and improved scientific communication skills, including in some cases, grant writing skills. Civic engagement projects range from writing grant proposals or research reports for local nonprofit organizations to performing “Immunology Theater” with at-risk high school students or developing comics and videos to teach about sexually transmitted diseases. Assessment of the effectiveness and impact of the civic engagement projects included alumni surveys (2009-2013 graduates; n=192), evaluation of student reflections, and community partner surveys.
Self-renewing HSCs respond directly to TLR4 ligand and are compromised in obesity, a disease linked to chronic TLR4 stimulation (HEM2P.270)
Authors: Liu Ailing , Kumar Rashmi , Stefanovic-Racic Maja , O'Doherty Robert , Ding Ying , Borghesi Lisa 
Published: January 2023

Abstract
Hematopoietic stem cells (HSCs), the sole source of blood cells throughout life, sense and respond to pathogen via toll like receptors (TLRs). Two TLR4 ligands that are persistently elevated in disease include bacterial lipopolysaccharide (LPS) and obesity-associated dietary lipids. Here, we show that CD150+ HSCs and downstream multipotent progenitors express TLR4 at levels comparable to bone marrow derived macrophages. When stimulated with LPS in culture, purified HSCs exhibit a 3-fold increase in myeloid output relative to vehicle controls. Moreover, LPS sensitivity is completely ablated in TLR4 KO HSCs. Thus, HSCs respond directly to LPS in a TLR4-dependent manner. We recently showed that chronic exposure to low-dose LPS drives HSC exhaustion and myeloid bias in vivo. We tested if diet-induced obesity, a disease marked by chronically elevated levels of the TLR4 agonists LPS and dietary fatty acids, compromised HSCs. Mice fed high fat diet for 16-20 weeks but otherwise unmanipulated had a 15-20% reduction in CD150+ self-renewing HSCs. The magnitude of HSC reduction strongly correlated with elevated blood glucose, a metabolic indicator of insulin resistance, and liver triglycerides, a morphometric risk factor for diabetes. This is the first study showing a link between diet-induced obesity and HSC integrity. Our findings imply that blood glucose levels may predict the severity of the HSC defect.
The essential role of Ligase 4 in hematopoietic stem cell homeostasis (HEM2P.257)
Authors: Park Jihye , Welner Robert , Tenen Daniel , Yan Catherine 
Published: January 2023

Abstract
Increased DNA damage is the principal factor that contributes to the functional decline in hematopoietic stem cell (HSC) renewal. Non-homologous DNA end-joining (NHEJ) is critical for the repair of DSBs in all cell types. In recent studies, NHEJ is implicated in the repair of DNA damage in quiescent long-lived HSCs in ex-vivo cell-based assays. However whether NHEJ plays a physiological role in the repair of DNA damage required for maintaining HSC homeostasis remains unclear. Here we assess whether Lig4 is critical role in HSC homeostasis by assaying HSC functions in a knock-in mouse model of the human recessive hypomorphic R278H mutation in Lig4. Whereas long-lived HSCs are quiescent and are continually replenished, we find that these HSCs in R278H mice have a severe defect in quiescence instigated by increased reactive oxygen species ,oxidative DNA damage, cycling and apoptosis. Our studies implicate the attenuation of Sirtuin 1, a NAD+-dependent histone protein deacetylase , as the key causal mechanism. Our preliminary data show treatment with the Sirt1 activating compound resveratrol rescues the survival of Lig4R/R HSC progenitors in long-term cultures. Our hypothesis is that increased ROS caused by impaired Sirt1 activities and autophagy underlies Lig4R/R HSC defects. These observations we have made implicate a critical role for Lig4 in HSC homeostasis, and in regulations impacting the DNA damage response-signaling cascade and anti-oxidant defense system.
Mechanisms of TLR4-mediated impairment of murine and human HSCs (HEM2P.258)
Authors: Borghesi Lisa , Wang Yujuan , Lu Ailing , Santos Patricia , Ding Ying , Payne Kimberly 
Published: January 2023

Abstract
Chronic exposure to toll-like receptor 4 (TLR4) ligand drives murine hematopoietic stem cell (HSC) exhaustion and loss of lymphoid potential. This finding is significant because TLR4 is activated by plasma lipopolysaccharide (LPS) that is elevated in patients with chronic infection as well in obese individuals. For the first time, we show that human HSCs are severely compromised by TLR4 stimulation. Mice engrafted with human cord blood cells and then exposed to low-dose LPS have variably reduced human CD34+ HSCs with near complete ablation of downstream common lymphoid progenitor (CLP) and B cell precursor subsets in bone marrow. By contrast, myeloid precursors are grossly intact. Peripheral tissue subsets similarly exhibit myeloid&gt;lymphoid skewing. We have shown that LPS-exhausted murine HSCs have reduced levels of the major transcription factor E47. Our newly published findings demonstrate a mechanistic link between E47 and the p21 cell cycle regulator. CD150+ HSCs from mice doubly haploinsufficient for E47 and p21 exhibit hyperproliferation, poor self-renewal, and selective myeloid bias. Finally, we show that murine CD150+ HSC and multipotent progenitors (MPP) express TLR4, and directly respond to LPS in a TLR4-dependent manner. Together, our findings suggest that chronic activation of TLR4 damages the functional integrity of not only murine HSC but also human HSC in vivo, via a mechanism linked to disruption of the E47-p21 pathway.
Rpl22 deficiency predisposes to leukemic transformation by blunting DNA damage responses (HEM2P.263)
Authors: Harris Bryan , Perrigoue Jacqueline , Verma Amit , Sykes Stephen , Fahl Shawn , Wiest David 
Published: January 2023

Abstract
Mutations that impair DNA repair mechanisms lead to accumulation of DNA damage within hematopoietic stem cells (HSC), resulting in their functional exhaustion or development into leukemic stem cells (LSC). Surprising, we have found that one such mutation in the ribosomal protein Rpl22 is able to predispose to leukemic transformation and this appears to involve impaired responses to DNA damage. Indeed, Rpl22-defiicency renders lineage negative Sca-1+, c-kit+ (LSK) hematopoietic progenitors resistant to killing by the DNA-damaging agent 5-fluorouricil (5FU), which is used to treat a variety of malignancies. Interestingly, while 5FU treatment increases γH2AX phosphorylation in Rpl22-deficeint LSK, indicating that cellular DNA has been damaged, these cells fail to induce transcriptionally active p53 because of a defect in their DNA-damage response signaling. This leads to an accumulation of LSK harboring damaged DNA, which we hypothesize predisposes them to transformation. Consistent with this viewpoint, we have found that Rpl22-/- LSK do exhibit an enhanced predisposition to transformation by the oncogenic function of MLL-AF9 in mouse models. This also appears to be true in human cancer patients, since AML patients that express less Rpl22 exhibit reduced survival. Taken together, these data support our hypothesis that Rpl22-deficiency impairs the activation of p53 in response to DNA damage and this predisposes cells to transformation and more aggressive leukemias.
Regulation of γδ T cell effector fate specification by ribosomal protein paralogs (HEM3P.285)
Authors: Fahl Shawn , Lee Sang-Yun , Coffey Francis , Perrigoue Jacqueline , Wiest David 
Published: January 2023

Abstract
γδ T cells are key mediators of inflammation that play a crucial role in preserving epithelial barriers and eradicating cutaneous tumors. The molecular mechanisms that control γδ T cell development and function, however, remain poorly understood. We have previously reported that the ribosomal protein paralogs Rpl22 and Rpl22l1 have antagonistic roles during hematopoietic stem cell emergence. Consequently, we sought to determine if Rpl22 and Rpl22l1 might play roles in more differentiated hematopoietic lineages. We have now demonstrated that γδ T cell development is not arrested in the absence of Rpl22 or Rpl22l1, suggesting these proteins are dispensable γδ T cell development; however, Rpl22 and Rpl22l1 do appear to regulate the specification of γδ effector fate during development in the thymus and have opposing roles in this process. Specifically, Rpl22-deficiency enhances the generation of IL-17-producing γδ T cells. In contrast, Rpl22l1-deficiency leads to an expansion of IFN-γ-producing γδ T cells and, in particular, the Vγ1.1+ innate-like γδ T cell subset. Rpl22 and Rpl22l1 are RNA-binding proteins that exert their control over developmental processes extraribosomally (i.e., away from the ribosome) by binding and regulating the expression of cellular RNA targets. Our efforts to identify the key cellular RNAs through which Rpl22 and Rpl22l1 influence γδ T cell effector fate will be presented.
A committed hemopoietic precursor to innate lymphoid cells (HEM3P.277)
Authors: Constantinides Michael , McDonald Benjamin , Verhoef Philip , Bendelac Albert 
Published: January 2023

Abstract
Innate lymphoid cells specialize in the rapid secretion of polarized sets of cytokines and chemokines to combat infection and promote tissue repair at mucosal barriers. Their growing diversity and close similarities with previously characterized NK and LTi cells have prompted a provisional classification of all innate lymphocytes into groups 1, 2 and 3 based solely on cytokine properties. Elucidating their development pathways is essential to resolve their lineage relationships and dissect their respective functions in disease and homeostasis. Using lineage tracing and transfer studies, we identified and characterized a novel subset of lymphoid precursors in fetal liver and adult bone marrow that transiently expressed high amounts of PLZF, a transcription factor previously associated with NKT cell development. PLZF-high precursors were committed ILC progenitors with multiple ILC1, ILC2 and ILC3 lineage differentiation potential at the clonal level. They excluded classical LTi and NK cells, but included a peculiar subset of NK1.1+ DX5- ‘NK-like’ cells residing in the liver. Deletion of PLZF markedly altered the frequency and function of several ILC subsets, but did not affect LTi or NK cells. These findings establish novel lineage relationships between ILC, NK and LTi cells and identify the elusive precursor to ILC, termed ILCP. They also reveal the broad, defining role of PLZF in the differentiation of innate lymphocytes.
mTOR signaling controls iNKT cell differentiation and effector function (HEM3P.278)
Authors: Zhang Lianjun , Rüegg Markus , Hall Michael , Mach Jean-Pierre , Romero Pedro , Donda Alena 
Published: January 2023

Abstract
Invariant natural killer T (iNKT) cells represent a unique T cell lineage that bears NK cell markers and a semi-invariant TCR recognizing glycolipids in the context of CD1d presentation. iNKT cells rapidly produce a variety of cytokines such as IFNg, IL-4, IL-2, IL-10 upon stimulation. Thus, iNKT cells play critical roles in bridging innate and adaptive immunity and have been implicated in multiple physiological and pathological settings. iNKT cells exhibit high proliferative capacity compared with conventional T cells during early stage development in the thymus. The mammalian target of rapamycin (mTOR) is a highly conserved serine/threonine kinase that integrates various environmental cues to regulate cell growth, proliferation and metabolism. Given the significance of mTOR signaling in controlling cell proliferation and metabolism, we have explored the role of mTORC1 and mTORC2 in iNKT cell development and function by using mice with T cell-restricted deletion of Raptor or Rictor. Here, we show, on the one hand, that mTORC1 is selectively required for iNKT cell but not for conventional T cells or Treg thymic development. On the other hand, mTORC2 is required to a lesser extent for thymic development as well as effector function of iNKT cells. In this regard, proper iNKT cell development and acquisition of effector functions is under the control of a dedicated mTOR signaling.