bluuebunny/crossref_metadata_2025_split huggingface dataset:
Intersection of Complement C4 and Interferon Alpha pathways in B cell tolerance (171.32)
Authors: Chatterjee Priyadarshini , Agyemang Amma , Alimzhanov Marat , Degn Soren , Herbst Ronald , Tan Tze , Alicot Elizabeth , Carroll Michael 
Published: January 2023

Abstract
Humoral autoimmunity is an important hallmark of autoimmune diseases like lupus. Factors that allow self-reactive B cells to escape negative selection stages and become activated remain poorly defined. Using a novel B cell receptor knock-in mouse strain 564Igi, we define a complement-dependent pathway by which B cell tolerance is upheld. Interestingly, the 564-autoantibody could bind SSB/La, a common lupus antigen, establishing the physiological relevance of this model. Deficiency in complement C4 caused a breakdown in the elimination of autoreactive B cell clones at the transitional stage, as demonstrated by their continued maturation, their ability to respond to a range of stimuli, entry into follicles (lack of follicular exclusion) and formation of germinal centers with a higher propensity. All results taken together indicate that the complement system must be intact for B cell tolerance to be upheld. Strikingly, the dysregulation of autoreactive B cells in C4-deficient mice was not B cell intrinsic, as a C4-sufficient myeloid compartment could re-establish efficient B cell selection. Our current model holds that poor clearance of apoptotic debris in the absence of C4 chronically activates myeloid cells to release cytokines, like IFNα, in excess and reduce the stringency of tolerance at the transitional stage. In support of our hypothesis, IFNα receptor blockade was found to restore negative selection of B cells in C4-deficient 564Igi mice.
Breaking self-tolerance in MyD88-deficient mice following intracellular bacterial infection (171.35)
Authors: al-Ramadi Basel , Issac Jincy , Rabah Maryem , El-Ojali Samia , Fernandez-Cabezudo Maria , Conca Walter 
Published: January 2023

Abstract
Activation of the innate immune system is a prerequisite for the induction of adaptive immunity to infectious and non-infectious agents. Signaling through TLRs, crucial components of the innate immune system that recognize conserved microbial ligands, takes place mainly through MyD88 and lead to the activation of NF-κB and induction of inflammatory responses. Previously, we demonstrated that MyD88-deficient mice are extremely susceptible to infection by Salmonella typhimurium, succumbing to infection with doses 10,000-fold lower than the LD50 in wild-type counterparts. Curiously, despite their heightened susceptibilities, infected MyD88-/- mice produce elevated serum levels of anti-salmonella antibodies, not only of expected Th1-driven antibody isotypes (IgG2c and IgG3) but also of Th2-associated IgG2b and IgG1 isotypes, suggesting a dysregulation in antibody production. Interestingly, this phenotype was not observed in mice infected with other Gram-negative bacteria, including E. coli and Acinetobacter baumanii. In order to further test this hypothesis, sera from infected mice were tested for reactivity to self antigens by determining titers of anti dsDNA antibodies, thyroglobulin, RF and extent of reactivity to Hep2 cells. Our data revealed the existence of high levels of these autoantibodies in Salmonella-infected but not in normal MyD88-/- mice. These findings suggest that TLR-MyD88 signaling pathway may be critical for maintaining self tolerance in B lymphocytes.
Gene expression and sub-congenic analyses of the Idd9/11 locus that regulates the diabetogenic activity of CD4 T-cells in NOD mice (171.43)
Authors: Chen Yi-Guang , Jia Shuang , Kaldunski Mary , Serreze David , Hessner Martin 
Published: January 2023

Abstract
Despite sharing the H2g7 MHC, the closely NOD-related NOR strain remains type 1 diabetes (T1D) resistant due to the presence of protective Idd5.2, Idd9/11, and Idd13 loci. We previously showed that CD4-T cells isolated from the Idd9/11 congenic strain (NOD.Chr4NOR) were less diabetogenic than those from standard NOD mice. To further determine the underlying mechanism, we asked if CD4-T cells from the NOD.Chr4NOR strain have enhanced suppressive activity compared to those from NOD mice. We used a co-transfer system to show that CD4-T cells isolated from NOD.Chr4NOR but not standard NOD mice (both expressing CD45.1) could actively suppress the diabetogenic activity of those from CD45.2 congenic NOD mice. We further demonstrated that the T1D suppressive activity of the NOR-derived Idd9/11 region was completely lost in the CD28-deficient mice that had greatly reduced numbers of Foxp3+ regulatory T-cells (Tregs). These results suggest that an enhanced T1D suppressive Treg activity contributes to NOR Idd9/11-mediated disease resistance. We have also generated two subcongenic lines carrying distinct intervals of the NOR-derived Idd9/11 region. T1D incidence studies indicated that more than one gene within the NOR-derived Idd9/11 region conferred T1D resistance. The region within the Idd9/11 interval suppressing the diabetogenic activity of CD4 T-cells was further refined from 44.3Mb to 27.1Mb. Microarray gene expression analysis was used to identify Idd9/11 candidate genes.
Genetic control of antibody production during collagen induced arthritis development in heterogeneous stock mice (171.44)
Authors: Foerster Michael , Raposo Bruno , Ekman Diana , Klaczkowska Dorota , Popovic Marjan , Kutty Selva Nandakumar , Lindvall Therese , Hultqvist Malin , Teneva Ivanka , Johannesson Martina , Ahlqvist Emma , Holmdahl Rikard 
Published: January 2023

Abstract
The aim of this study was to identify genetic factors driving pathogenic autoantibody formation in collagen induced arthritis (CIA), a mouse model for rheumatoid arthritis (RA) in order to understand the etiology of the disease and improve possibilities for therapeutic intervention. To this end we made a genome wide analysis of quantitative trait loci (QTL) controlling autoantibodies towards type II collagen (AC2A), anti-citrullinated protein antibodies (ACPA) and rheumatoid factors (RF). To identify loci controlling autoantibody production, we induced CIA in a heterogeneous stock (HS) derived mouse cohort. Serum samples of 1843 mice were collected before onset and at peak of the disease. All antibody concentrations were measured by ELISA and linkage analysis was performed using a linear regression based method. We identified loci controlling formation of AC2A of different IgG isotypes, antibodies to major type II collagen (CII) epitopes, to a citrullinated CII peptide and RF. The AC2A, ACPA and RF responses were all found to be controlled by distinct genes, one of the most important loci being the Immunoglobulin heavy chain (IgH) locus. Here, we provide a comprehensive genetic analysis of autoantibody formation in CIA. Our study demonstrates that not only AC2A, but interestingly also ACPA and RF are associated with arthritis development in mice. These results underscore the importance of non-MHC genes controlling the formation of clinically relevant autoantibodies.
Selenoprotein K interacts with Vav1 in macrophages to inhibit Rac1 activity (172.17)
Authors: Norton Robert , Huang Zhi , Hoffmann Fukun , Hoffmann Peter 
Published: January 2023

Abstract
Selenium is a mineral micronutrient that is essential in a variety of biological systems, including immune responses. Selenium is used for biosynthesis of the amino acid selenocysteine, which is used by selenoproteins to carry out biological functions. In humans, 25 selenoproteins have been identified and Selenoprotein K (SelK) was recently identified as an endoplasmic reticulum transmembrane protein important for calcium flux during the activation of immune cells. Vav1 is a guanine exchange factor that activates Rac1 and leads to actin polymerization and cytoskeletal rearrangement. Implementation of the SH3 hunter software predicted that the SH3-binding domain of SelK associates with one of the two SH3 domains of Vav1. We were able to show that SelK co-immunoprecipitates with Vav1 from mouse bone marrow derived macrophage (BMDM) whole cell lysates. By pull down assay, we saw higher levels of activated, GTP bound Rac1 in KO BMDM’s compared to WT BMDM’s when treated with RANTES. This suggests that SelK could be involved in Rac1 activation. Studies are underway to determine if Vav1 is being sequestered by SelK, preventing it from becoming activated. Macrophage activation might cause SelK to release Vav1, leading ultimately to actin polymerization, cytoskeletal rearrangement and cell motility. Future experiments will determine if this co-immunoprecipitation is abolished when the SH3 binding domain of SelK is deleted or when the SH3 motif of Vav1 is deleted.
Haptoglobin inhibits the pro-inflammatory activity of HMGB1. (172.19)
Authors: Yang Huan , Levine Jacob , Katz David , Lu Ben , Scheinerman Josh , Dancho Meghan , Ochani Mahendar , Li Jianhua , Chavan Sangeeta , Warren Shaw , Tracey Kevin 
Published: January 2023

Abstract
Severe sepsis accounts for over 200,000 deaths in US annually (Angus et al, CCM, 2001). The mechanism involves endogenous molecules that impair organ function. Extracellular hemoglobin is one such factor enhancing tissue damage during sepsis. We designed haptoglobin-coated beads for a perfusion system to remove hemoglobin in an experimental sepsis model. Surprisingly, we observed that in addition to removing hemoglobin, haptoglobin beads also captured large amounts of HMGB1. HMGB1 is a major mediator on the final common pathway to lethality in sepsis (Yang et al, BBA 2009). Addition of haptoglobin suppressed HMGB1-stimulated TNF and IL-8 release in cultured macrophages. Haptoglobin knockout mice subjected to cecal perforation-induced sepsis had significantly higher serum HMGB1 levels and higher mortality compared to wild type animals (75% survival in wild type vs. 34% in haptoglobin knockout mice; n=15/group, P&lt;0.05). Treatment with anti-HMGB1 antibodies significantly reduced the mortality in haptoglobin knockout mice (12% survival in control vs. 56% in animals receiving HMGB1 antibodies; n=16/group, P&lt;0.05). Structure-function analysis revealed that haptoglobin beta subunit alone is sufficient to recapitulate the protective effects observed with haptoglobin. These findings indicate that haptoglobin is an endogenous modulator of HMGB1 that is capable of reducing the toxicity of HMGB1 in sepsis. Supported in part by grants from NIH (RO1GM62508, to KJT and RO1GM098446, to HY).
Particulates induce macrophages to produce lipid mediators via the Syk activation. (172.25)
Authors: Kuroda Etsushi , Ohata Keiichi , Coban Cevayir , Ishii Ken 
Published: January 2023

Abstract
Some particulate such as silica crystal (silica), aluminum salts (alum) and monosodium urate (MSU) can stimulate the innate immune system to induce inflammatory responses. Recently, we found that silica and alum induce macrophages to produce both IL-1β and lipid mediator prostaglandin E2 (PGE2). We also indicated that particulate-induced PGE2 is involved in the production of IgE in vivo. However, the underlying mechanisms involved in the induction of PGE2 by particulate remain to be elucidated. In this study, we show that Syk plays an important role in particulate-induced PGE2 production. Silica and alum induced macrophages to produce IL-1β and PGE2. However, NALP3 inflammasome-deficient macrophages produced higher amounts of PGE2 comparable to WT macrophages. To determine which signaling pathway is involved in the production of PGE2, we analyzed PGE2 production from macrophages treated with various signaling inhibitors. Interestingly, we found a Syk inhibitor markedly suppressed PGE2 production. Similar to inhibitor experiment, knockdown of Syk by siRNA in macrophages significantly reduced both PGE2 and IL-1β production. In conclusion, we have found that particulate silica, alum and MSU stimulate macrophages to produce lipid mediator PGE2 though a pathway that is dependent on Syk but independent of the NALP3 inflammasome.
Bcl-3 is a regulator of dendritic cell functions (172.30)
Authors: Tassi Ilaria , Claudio Estefania , Wang Hongshan , Siebenist Ulrich 
Published: January 2023

Abstract
Bcl-3 is a nuclear member of the family of IκB inhibitors; it can act as an activator or inhibitor of NF-κB activity, depending on the context, and it functions via association with homodimers of the p50 or p52 subunits of NF-κB. In recent years various NF-κB subunits have been implicated in the development and activation of dendritic cells (DCs), which are important effectors in the activation of the innate and adaptive immune system. Here we have explored, for the first time, the role of Bcl-3 in DC-mediated functions. We report that Bcl-3 is required to prime CD4 T cells in vitro. By using an OT-II adoptive transfer model, we were able to demonstrate that Bcl-3 deficient DCs lacked the capacity to prime T cells in vivo. Furthermore, specific ablation of Bcl-3 in DCs in vivo, revealed that Bcl-3 is required for the development of contact hypersensitivity reactions. Mechanistically, Bcl-3 is dispensable for DC maturation and inflammatory cytokine production. In conclusion, we demonstrated for the first time that Bcl-3 expression in DCs is required for the initiation of the adaptive immune response in vitro and in vivo.
CpG ODN treatment in radiation-combined injury (172.31)
Authors: Stoecklein Veit , Osuka Akinori , Lederer James 
Published: January 2023

Abstract
In the scenario of a nuclear event, radiation injury will be accompanied by additional trauma, especially burns. We developed a mouse model to allow us to study the changes in the immune system induced by these injuries. In this study, we tested the potential of using CpG oligodeoxynucleotides (ODN) as treatments in radiation combined injury (RCI). Mice were exposed to 1, 4 and 6 Gy whole body radiation and underwent near simultaneous burn injury. One day after injury, mice were injected with either CpG ODNs or saline. Seven days later, sepsis was induced by cecal ligation and puncture (CLP) and survival was recorded. Spleen immune cell subsets were assessed by FACS and inflammatory cytokine production by splenocytes was determined at 7 days after CLP. To investigate the role of regulatory T cells (Tregs) in this model, mice were Treg depleted after class A CpG treatment. Treatment with class A CpG increased survival after RCI with 1 Gy followed by CLP significantly whereas treatment with class B or C did not. Class A treatment also conferred a survival benefit following RCI with 4 and 6 Gy. Inflammatory cytokine production was decreased with class A treatment but not with class B or C. The effects of class A treatment were not seen in Treg depleted mice. Class A CpG tracking showed increased uptake in Tregs when compared to class B or C. In summary, CpG treatment is effective in enhancing host defense mechanisms following RCI.
Identification and characterization of a protein G-binding intelectin in Japanese lamprey (172.6)
Authors: Li Qingwei , Wu Fenfang , Pang Yue , Xiao Rong , Liu Xin , Xue Zhuang 
Published: January 2023

Abstract
Intelectins are recently identified extracellular animal lectins. They are glycan-binding receptors recognizing glycan epitopes on foreign pathogens and in the host system. In the present study, we report the identification of a new type of serum lectin from Japanese lamprey (Lampetra japonica). Gene expression analysis and Western blots demonstrated that the lamprey intelectin was expressed in blood, intestine, kidney, heart, gill, liver, medulla, and gonad. The recombinant lamprey intelectin protein (Lj-intelectin) appeared as ~34kD, ~44kD, and ~65kD bands on non-reducing SDS-PAGE gels, suggesting that it is consisted of monomers, dimmers and trimers. In addition, direct binding assays demonstrated that Lj-intelectin bind to protein G. Furthermore, Li-intelectin induced by in vivo bacterial stimulation showed agglutination activity against pathogenic Gram-positive and Gram-negative bacteria, indicating that it may play an important role in self-defense against bacteria in the internal circulation system of lamprey. The Lj-intelectin also exhibited a calcium-dependent agglutination to human red blood cells. These results demonstrate that lamprey intelectin plays an important role in immune response.
Antibiotic induced intestinal dysbiosis in infant mice impacts CD8+ T cell anti-viral immune function and control of infection (IRC8P.494)
Authors: Lamouse-Smith Esi , Radens Caleb , Starnbach Michael 
Published: January 2023

Abstract
Infancy and childhood is a critical period for the development of long-term immune function. Normal acquisition of the gastrointestinal (GIT) flora during this period is now appreciated in its role on immune system development and function. Antibiotics cause GIT flora dysbiosis and may alter normal GIT colonization during infancy. Subsequently, immune development and function may also be affected. In this infant mouse model of antibiotic mediated GIT flora dysbiosis, perinatal antibiotic treatment (AT) alters the composition of the GIT flora in mothers and their infants. CD8+ T cells from AT infant mice activated in vitro with cytokines, proliferate, express activation markers, and produce IFN-γ. However, unlike non-antibiotic treated (CTRL) infant mice, AT mice succumb to vaccinia virus infection. AT infant mice survive sub-lethal infection indicating effective primary immune responses to control infection. Interestingly, the expansion of Teff, Tem, and Tcm subsets differs between CTRL and AT sub-lethally infected infant mice. Transfer of OT-I T cells into AT infant mice prior to lethal infection rescues these mice from death. However, expansion of OT-I T cells is limited in AT infant mice and the differential expression of effector and memory cell markers is also recapitulated. These results suggest that dysbiosis during infancy negatively impacts effective adaptive primary immune responses and has potential consequences on memory T cell development.
Defining the minimal signals necessary to generate an encephalitogenic T cell (IRC8P.476)
Authors: Lee Priscilla , Yang Yuhong , Racke Michael , Lovett-Racke Amy 
Published: January 2023

Abstract
While it is generally accepted that Multiple Sclerosis (MS) is a T cell-mediated disease, the factors determining the encephalitogenicity of T cells remains unclear. Myelin-specific T cells generated with antigen presenting cells (APCs) plus myelin peptide are encephalitogenic, whereas T cells generated with anti-CD3/CD28 antibodies are not, suggessting that APCs provide critical signals beyond T cell receptor activation and co-stimulation, contributing to an encephalitogenic phenotype. To recapitulate the signals provided by APCs, naïve myelin-specific CD4+ T cells were activated with anti-CD3/CD28 in the presence of various cytokines. The degree of encephalitogenicity of T cells was examined by the severity of experimental autoimmune encephalomyelitis (EAE). Although no single cytokine was sufficient, the combination of IL-6/IL-23 or IL-12/IL-23 generated highly encephalitogenic T cells. IL-6 and IL-12 induced the initial expression of IL-23R on naïve T cells, and IL-23 further enhanced the expression of its own receptor and the encephalitogenicity. Neutralizing IL-6 or IL-12 with antibodies significantly reduced the severity of EAE, which was induced by APC-generated T cells. We have identified that IL-6/IL-23 or IL-12/IL-23 combination in addition to TCR activation and co-stimulation were the miminal signals necessary to generate encephalitogenic T cells. This provides potential targets that can be manipulated therapeutically, resulting in innovative treatments for MS.
Gut-associated cross-differentiation of T lymphocyte lineages (LYM7P.726)
Authors: Lui Jenbon , Devarajan Priya , Teplicki Sarah , Miska Jason , Chen Zhibin 
Published: January 2023

Abstract
Peripheral regulatory T cells engage in a necessary role in maintaining the volatile balance between the normal flora of the gut and the host immune system. However, the clonal origin of peripheral Treg cells is not well understood and has proven difficult to elucidate in the presence of naturally occurring thymic Treg cells. We hypothesized that the gut-associated environment enables cross differentiation of the CD8 T cell lineage to CD4 Treg cells for the regulation of immune cell homeostasis. Our preliminary examination found evidence for cross-differentiation from the CD8 lineage to CD4 effector and regulatory T cells. Further studies showed that these cross-differentiated CD4 Treg cells were effective in protecting from intestinal inflammatory damage. We found that in transfer experiments mature CD8 T cells were capable of cross-differentiating into CD4 T cells. Results from normal flora depletion studies by broad spectrum antibiotics showed that cross-differentiation of CD8 T cells into CD4 T cells was dependent on the normal flora of the gut. The results that we have obtained suggest that CD8 T cells have the potential to cross-differentiate into CD4 T cells and Treg cells. This pathway may participate in regulating and maintaining the fine balance of tolerance and immunity between normal flora and host immune system.
Nonclassical MHC Ib-restricted CD8+ T cells recognize Mycobacterium tuberculosis-derived protein antigens and contribute to protection against infection (MPF6P.744)
Authors: Shang Shaobin , Bian Yao , Siddiqui Sarah , Zhao Jie , Wang Chyung-Ru 
Published: January 2023

Abstract
MHC Ib-restricted CD8+ T cells have been implicated to contribute to host defense during Mycobacteria tuberculosis (Mtb) infection, but the relative contribution of various MHC Ib-restricted responses has yet to be defined. In this study, we used mice that lack MHC Ia (Kb-/-Db-/-, DKO), MHC Ia/M3 (Kb-/-Db-/-M3-/-, TKO), or β2m (β2m-/-) to study the role of M3-restricted and other MHC Ib-restricted T cells in immunity against Mtb infection. Unlike their role in Listeria infection, we found that M3-restricted CD8+ T cells only represent a small proportion of the CD8+ T cells responding to Mtb infection. This finding highlights the differential role of various MHC Ib-restricted responses in immunity against distinct microbial pathogens. Non-M3, MHC Ib-restricted CD8+ T cells expanded preferentially in the lungs of TKO mice and expressed higher level of KLRG1 compared to MHC Ia-restricted CD8+ T cells. These CD8+ T cells produced IFNγ, TNFα and IL-2 upon stimulation with Mtb-derived protein antigens in a β2m-dependent but TAP-independent manner. TKO mice had similar bacterial loads in tissues as DKO and wildtype mice, but lower bacterial loads than β2m-/- mice. Our findings indicate non-M3, MHC Ib-restricted CD8+ T cells can specifically recognize Mtb protein antigens and contribute to host immune response to Mtb. Targeting these MHC Ib-restricted CD8+ T cells would facilitate the design of better vaccines against Mtb, due to the limited polymorphism of MHC class Ib molecules.