bluuebunny/crossref_metadata_2025_split huggingface dataset:
Decoy FcγR-Ig molecules ameliorate immune-complex induced blood vessel damage by blocking the release of inflammatory mediators from macrophages (INM2P.432)
Authors: Mula Ramanjaneya , Machiah Deepa , Wang Xinyu , Selvaraj Periasmay , Shashidharamurthy Rangaiah 
Published: January 2023

Abstract
Autoimmune vasculitis is an endothelial inflammatory disease that results from deposition of immune-complexes (ICs) in blood vessels. Interaction of FcγRs expressed on inflammatory cells with ICs is known to cause blood vessel damage. Hence, blocking the interaction of ICs and inflammatory cells is prerequisite to prevent the blood vessel damage. Herein, we have shown that dimeric FcγR-Ig (CD16A-Ig and CD32A-Ig) molecules are able to block these interactions using in vitro and in vivo vasculitis models. FcγR-Igs could block 70% of RAW 267.4 cells binding to antibody-coated Human umbilical vein endothelial cells (HUVEC). FcγR-Igs significantly inhibited the IC-mediated expression of inducible nitric oxide synthase (iNOS) and Nitric oxide (NO) release in RAW 264.7 cells. We observed that exogenous NO induced the upregulation of pro-apoptotic genes such as Bax, Bak, caspase-3 and caspase-8 in HUVEC cells. Further, in vivo studies revealed that circulating ICs deposits in the capillaries of various vital organs but not in large arteries. Interestingly, dimeric FcγR-Igs are distributed in the areas where ICs are deposited. The co-localization of ICs and FcγR-Igs revealed that dimeric FcγR-Ig molecules bind specifically to ICs and thus prevent the vascular damage. Taken together, these results suggest that IC-induced NO might be a major factor promoting the blood vessel damage, which can effectively be blocked using recombinant dimeric FcγRs molecules during IC mediated vasculitis.
Adaptor protein Crk-like (CrkL) controls natural killer cell function via regulating the accumulation of activating receptors and phosphorylated Vav-1 molecules at immunological synapses (INM2P.433)
Authors: Zheng Peilin , Hanson Celine , Liu Dongfang 
Published: January 2023

Abstract
Very few studies have addressed how CrkL, a ubiquitous adaptor protein, regulates the immune response, especially in NK cells. Previous studies indicate that CrkL is required for NKG2D-mediated cellular cytotoxicity (NC) and CD16 signaling triggered antibody mediated cellular cytotoxicity (ADCC). However, how CrkL protein controls NK cell cytotoxicity remains unclear. Here we used lentiviral inducible shRNA to silence CrkL in human NK cell line and primary NK cells. Inducible knockdown of CrkL significantly reduced NK-target conjugation, degranulation, and cytotoxicity in both NC- and ADCC-mediated immune responses. Further investigation on the function and signaling transduction at the NK cytotoxic immunological synapse (IS) reveals that polarization of lytic granules, and accumulation of both F-actin and phosphorylated Vav-1 at the IS were greatly reduced in CrkL-silenced NK cells. NK cell activation involves in actin-dependent activating receptor clustering. CrkL silencing resulted in reduced accumulation of ligands for CD16 and NKG2D on the lipid bilayer. Similar results were obtained in NK cells from DiGeorge Syndrome patients (CrkL gene deletion). We thus propose a new model for adaptor protein CrkL function in NK cell activation: CrkL controls NK cell cytotoxicity via promoting F-actin accumulation and lytic granule polarization by modulating the accumulation of activating receptors and phosphorylated Vav-1 molecules at the IS.
Characterizing bone marrow-derived mast cell interaction with electrospun bioresorbable vascular grafts (INM2P.436)
Authors: Abebayehu Daniel , Spence Andrew , Sell Scott , Bowlin Gary , Ryan John 
Published: January 2023

Abstract
Upon implantation, the regenerative potential of a vascular graft will be dependent on the body’s innate immune response. Thus, it is imperative to evaluate and regulate how innate immune cells interact with a vascular graft’s structural architecture. Different pore-sizes and fiber diameters of electrospun grafts should modulate mast cell activation and secretion, thus dictating their innate ability for inflammation or angiogenesis and regeneration. Grafts were electrospun with two different polymer concentrations on a solid mandrel, an air-impedance mandrel (increasing scaffold porosity), and altered by compression (decreasing scaffold porosity). Murine bone marrow-derived mast cells (BMMC) were seeded on scaffolds, and supernatants and cell lysates were collected after LPS and IL-33-mediated activation. ELISA analysis demonstrated that BMMC released TNFα and IL-6 at significantly greater concentrations on grafts with decreased fiber diameter and porosity. This was matched by greater NFκB activation, as measured by western blotting. In contrast, significantly greater VEGF secretion was observed on grafts with the largest fiber diameter and porosity. These results indicate that graft architecture regulates mast cell interactions and subsequent potential for healing, with increased fiber diameter and porosity promoting an anti-inflammatory and angiogenic response.
Regulation of IFN-γ by IL-13 dictates the susceptibility to secondary post-influenza MRSA pneumonia (INM3P.439)
Authors: Rynda-Apple Agnieszka , Harmsen Ann , Erickson Anfin , Harmsen Allen 
Published: January 2023

Abstract
Post-IAV superinfections are the primary cause of deaths during IAV pandemics. The superinfection in mice 7 days after IAV infection results in exacerbated bacterial pneumonia mediated by type I and II IFNs. However, the sequelae of cytokine responses early in IAV infection, that eventually determines the later susceptibility is not understood. Here we examined whether the susceptibility to superinfection with MRSA varies during IAV infection. In the first 3 days of IAV infection mice had increased resistance to MRSA superinfection, which required IFNAR and IL-13 signaling to inhibit IFN-γ. IFN-γ-mediated high susceptibility to MRSA pneumonia 7 days after IAV infection was associated with increased IL-13Rα2 production, and was reversible by treatment with mrIL-13 or anti-IL-13Rα2. Thus, early in IAV infection IFNAR signaling maintained IL-13, which increased resistance to MRSA. Then, as IAV infection progressed, the capacity for IL-13 signaling was inhibited, in part by increased IL-13Rα2, resulting in increased IFN-γ levels and susceptibility to MRSA superinfection. Thus, IAV induces a sequence of cytokine responses where early IFNAR-dependent IL-13 signaling suppresses IFN-γ production resulting in enhanced resistance to MRSA challenge. Understanding these cytokine sequelae is critical to development of immunotherapies for IAV-MRSA coinfection since perturbations in the sequence of these events at the wrong time could increase susceptibility to MRSA and/or IAV.
NLRP3 and AIM2 mediate nitric oxide production and macrophage resistance to T. cruzi infection (INM3P.442)
Authors: Silva Grace , Carneiro Natália , Zamboni Dario , Silva João 
Published: January 2023

Abstract
The Toll-like receptors (TLRs), 2, 4 and 9 are important to immunity against Trypanosoma cruzi, etiologic agent of Chagas disease. Intracellular receptors, including NLRP3 and AIM2, associate to ASC forming a complex that active caspase-1, called inflammasome. This complex is required for cleavage of the active forms of the IL-1β and IL-18. Recently, we show that ASC inflammasome is necessary to control T. cruzi infection, however the receptors that participate in this signalizing are not complete clear. Here, we investigated the participation of NLRP3 and AIM2 in the immune response against T. cruzi. First, we found high IL-1β production and caspase-1 activation in BMMs from WT mice, but not from NLRP3-/- and AIM2-/- mice. To understand the role of the inflammasome pathway during T. cruzi infection, WT, caspase-1-/-, ASC-/-, AIM2-/- and NLRP3-/- mice were infected with Y strain of T.cruzi. Our results showed that ASC-/- and caspase-1-/- mice presented higher mortality, whereas WT, AIM3-/- and NLRP3-/- are resistant to infection, suggesting more than one NLR is necessary to confer resistance for T. cruzi infection. In addition, caspase-1-/-, ASC-/-, AIM2-/- and NLRP3 BMMs presented higher parasitism and reduced amount of Nitric oxide (NO) production. Together, these results suggest that AIM2 and NLRP3 via ASC inflammasome participate of the infection against T. cruzi. Financial Support: FAPESP
Leptin upregulates CRAC channel expression in T lymphocytes (IRC2P.444)
Authors: Ebersbacher Charles , Chimote Ameet , Obici Silvana , Conforti Laura 
Published: January 2023

Abstract
Obesity is a major health problem associated with systemic diseases whose pathogenesis has been linked to inflammation, but the underlying mechanisms are poorly understood. Leptin, an adipokine secreted by adipose tissue, is known to augment the antigen-dependent release of pro-inflammatory cytokines by T lymphocytes. Cytokine production is tightly regulated by cytoplasmic Ca2+ (Cac ) which is under the control of ion channels (Kv1.3, KCa3.1, calcium release activated Ca2+channel [CRAC, formed by Orai1 and Stim1]). We tested the hypothesis that ion channels contribute to the pro-inflammatory effects of leptin. CD3+ T cells isolated from healthy human donors were treated with 100-250 ng/ml leptin and ion channels’ gene expression was measured by RT-qPCR. Leptin induced a dose- and time-dependent increase in Orai1 expression up to 1.53 ± 0.21 (100 ng/ml) and 2.04 ± 0.40 folds (250 ng/ml, n=3) at 12 h. There was no significant difference in Stim1, Kv1.3 and KCa3.1 expression. CRAC channels are important for activation-mediated Ca2+ influx in T cells. Thus, we investigated whether Orai1 regulation by leptin affects Cac using a protocol that bypasses the T cell receptor and allows assessment of ion channel-dependent changes in Cac. Incubation with leptin-depleted serum reduced Ca2+ fluxes, while addition of 250 ng/ml of leptin to the leptin-free serum augmented Ca2+ fluxes. These findings suggest that leptin may promote hyperactivity of T cells via upregulation of ion channels.
Leucine-rich repeat containing 8a (LRRC8A) is a novel T cell co-stimulatory receptor for T cell activation (IRC2P.453)
Authors: Chou Janet , Kumar Lalit , Yee Christina , Fraulino David , Hedayat Mona , Geha Raif 
Published: January 2023

Abstract
LRCC8A is a ubiquitously expressed cell surface receptor necessary for lymphocyte development. The role of LRRC8A in peripheral T cell function is unknown. We now demonstrate that LRRC8A ligation enhances TCR-driven T cell proliferation and cytokine secretion. LRRC8A co-capped with the TCR/CD3 complex after anti-CD3 stimulation, and its ligation led to the phosphorylation of AKT through a Src kinase-Zap-70-PI3K pathway. A GST-LRRC8A fusion protein containing the extracellular leucine-rich region of LRRC8A bound to fibroblasts and keratinocytes, but not dendritic cells or B cells, indicating that non-professional APCs express a ligand for LRRC8A. The LRRC8A receptor-ligand interaction was essential for T cell proliferation to antigen presented by non-professional APCs, and for tissue inflammation induced by contact hypersensitivity to hapten. LRRC8A functions as a co-stimulatory receptor for T cell activation by non-professional APCs. Blocking LRRC8A signaling may be useful in the treatment of T cell-driven inflammatory diseases.
Role of SNX17 in receptor recycling and antigen recognition by T cells. (IRC2P.445)
Authors: Osborne Douglas , Billadeau Daniel 
Published: January 2023

Abstract
A key component in T cell activation is the endosomal recycling of receptors to the cell surface allowing for continual integration of signaling and antigen recognition. Multiple early endosomal associated proteins have been found to interact with T cell surface receptors and play a role in the recycling and transport of these receptors to the cell surface. One endosomal protein possibly involved in T cell receptor transport is sorting nexin 17 (SNX17). SNX17 has been found to bind with receptors involved in T cell activation, but its role in receptor recycling and T cell activation is unknown. Using lentivirus shRNA against SNX17, we have found that the knockdown of the SNX17 protein resulted in fewer T-APC conjugates, lower CD69, TCR, and LFA-1 surface expression, as well as lower overall TCR recycling compared to control T cells. Using immunofluorescence, we have found that SNX17 colocalizes with TCR and localizes to the peripheral-SMAC at the immune synapse in T-APC conjugates. This data suggest that SNX17 plays a synergistic role in the maintenance of normal surface levels of activating receptors and integrins to permit optimum T cell activation at the immune synapse.
Cell-intrinsic TGF-β receptor signaling limits virus-specific CD4 T cell responses and prevents lethal pathology during chronic viral infection. (IRC2P.450)
Authors: Lewis Gavin , Maloveste Sebastian , Streeck Hendrik , Zuniga Elina 
Published: January 2023

Abstract
Persistent viruses create a profound immunosuppressive environment that is conserved in mice and humans. While several pathways suppressing CD8 T cell responses have been identified, much less is known about the immune regulatory molecules restricting the number and helper function of CD4 T cells. By using Lymphocytic Choriomeningitis Virus (LCMV) infection in mice, we observed enhanced signaling of the immunosuppressive cytokine Transforming Growth Factor-β (TGF-β) in virus-specific T cells during chronic infection. Importantly, genetic ablation of TGF-β receptor (R) resulted in rapid mortality upon chronic, but not acute, LCMV infection. While TGF-βR deficient mice showed comparable CD8 T cell responses, CD4 T cell proliferation, terminal differentiation and a cytotoxic program characterized by Granzyme B, Perforin and EOMES expression were significantly enhanced in the absence of TGF-βR signaling. Importantly, EOMES overexpression recapitulated the phenotype of TGF-βR deficient CD4 T cells while EOMES inhibition suppressed it. Finally, preliminary experiments showed TGF-β signaling also suppressed cytotoxic molecules and EOMES in human CD4 T cells. Together these data uncover a novel TGF-βR-dependent axis that restricts EOMES-driven differentiation and cytotoxicity in murine and human CD4 T cells while highlighting a critical role for TGF-βR in limiting anti-viral CD4 T cell responses and mortality upon chronic viral infection.
A new pathway for central B cell tolerance: interaction of AID, MyD88, and BCR (IRC3P.467)
Authors: Kuraoka Masayuki , Snowden Pilar , Kelsoe Garnett 
Published: January 2023

Abstract
Expression of activation-induced cytidine deaminase (AID) in immature and transitional B cells in mice and humans is genetically linked to the first tolerance checkpoint. In the absence of AID, autoreactive immature/transitional-1 (T1) B cells are inefficiently purged and exhibit increased resistant to receptor-induced apoptosis. These substantial effects are surprising given that AID expression in the immature/T1 B cells is only 3% of that in germinal center B cells. We now show that in immature/T1 B cells, but not mature B cells, B-cell antigen receptor and Toll-like receptor (TLR) signaling synergize to elicit high levels of AID expression. This synergy is restricted to intracellular TLR ligands, requires the phospholipase D-dependent compartmentalization of intracellular TLR and activation of the TLR through acidification, and acts to ensure self-tolerance through a process that requires Myd88. In a 3H9 mouse model, we show that suppression of intracellular acidification by administration of chloroquine increased the generation of immature/T1 B cells in proportion to small pre-B cells, suggesting that chloroquine treatment support the survival of autoreactive 3H9 immature/T1 B cells in bone marrow. These findings identify a novel mechanism for central B-cell tolerance and resolve several weaknesses of current models for the first tolerance checkpoint. We suggest that this AID mediated pathway may be the primary mechanism for central B-cell tolerance by deletion.
A temporal switch in the germinal center determines differential output of memory B and plasma cells (IRC3P.468)
Authors: Weisel Florian , Shlomchik Mark 
Published: January 2023

Abstract
Though memory B cells (MBCs) and long-lived plasma cells (LLPCs) are both thought to derive from the germinal center (GC) reaction, there is little insight into or agreement about the signals that control differentiation to one cell type or another. By performing BrdU pulse-labeling studies, GC disruption experiments and V gene sequencing, we found that the generation of these cell types is actually temporally controlled and separated during the immune response. We report that MBCs mainly derive from early GCs (much before GC peak size), while more affinity matured LLPCs are predominantly formed during late GCs - long after its peak in size. Based on these findings, we propose a new model that the GC response undergoes a temporal switch, functioning quite differently at early and late stages. Therefore the generation of MBCs and LLPCs is the consequence of a general shift in GC output over time rather than the result of specific instructive signals that are selectively delivered to GC B cells at any given time during the response. We also present direct evidence that a large fraction of long-lived IgM+ MBC, and even some IgG+ MBC, are formed at very early time points, prior to the existence of detectable GCs. The knowledge of when specific long-lived immune-effector cells are generated during an immune response has strong implications for vaccine design and understanding long-term pathogen immunity.
A novel aging-associate B-cell subset controls antitumor CD8+ T-cell response (IRC3P.469)
Authors: Lee Chang Catalina , Bodogai Monica , Moritoh Kanako , Croft Michael , Gress Ronald , Ferrucci Luigi , Hakim Fran , Biragyn Arya 
Published: January 2023

Abstract
CD8+CD28- T cells are considered an immune risk of mortality and morbidity in elderly. The mechanism of their enrichment and their function in elderly is poorly understood. In the present study we report a novel and evolutionary-conserved B-cell subset expressing 4-1BBL, which accumulates with aging of mammals, such as humans, rhesus macaques and mice. These cells (termed 4BL cells) induce antitumor effector CD8+ T cells by presenting endogenous antigens and utilizing 4-1BBL/4-1BB axis. 4BL cells are also responsible for the expansion of auto-reactive CD8+ T cells in patients treated with high dose chemotherapy and autologous progenitor cell transplantation. Thus, accumulation of antitumor 4BL cells explains the paradox of retarded tumor growth in the elderly, and most likely autoimmune disease outcome in the aged population. However, 4BL cell accumulation and their effects on CD8+ T-cell compartment can be eliminated by inducing B-cell lymphopoiesis in old mice (after B-cell depletion), suggesting that the aging-associated skewed cellular immune responses are reversible. We propose that 4BL cells and their 4-1BBL signaling pathway are useful targets for improved effectiveness of natural antitumor defenses and therapeutic immune manipulations in the elderly. How 4BL are generated, and their impact in the B-cell effector functions homeostasis in elderly will be further discussed.
Disparate regulatory roles for B cells during primary and secondary CD4 T cell responses (IRC3P.470)
Authors: Harrington Laurie , Mollo Sarah , Zajac Allan 
Published: January 2023

Abstract
The generation of CD4 T cell memory is shaped by numerous factors, such as the strength and duration of TCR signaling, as well as the priming environment, all of which can be modified by B cells. Studies using B cell-deficient mice indicate B cells play a critical role in generating effector and memory CD4 T cells; however when and how B cells are acting to promote these responses has not yet been ascertained. Moreover, memory CD4 T cells are documented to have less stringent requirements for activation than their naïve counterparts, yet it remains unknown if B cells influence secondary CD4 T cell responses. In this study, we use anti-CD20 antibody depletion of B cells at different times following Listeria monocytogenes infection to show that B cells are necessary for the induction of optimal CD4 T cell memory, but not for the transition and maintenance of this population. Importantly, the prerequisite of B cells early after infection is partially dependent on their expression of MHC class II. B cells are not only required during the priming phase, but are also necessary for the initiation of robust secondary responses by memory CD4 T cells. Interestingly, the requirement during the recall response is independent of B cell antigen presentation. Overall, these studies demonstrate the temporally and functionally distinct roles for B cells in regulating CD4 T cell responses.
Imbalanced adoptive immunity in the diabetic nephropatic BTBR ob/ob mouse (IRC4P.474)
Authors: Rosendahl Alexander , Pedersen Maiken , Fink Lisbeth 
Published: January 2023

Abstract
Human diabetic nephropathy (DN) has extensive kidney fibrosis and inflammation. The BTBRob/ob mouse model has kidney fibrosis, but the inflammatory status is not known. Herein, we investigated the systemic and local lymphocytic immunity in the BTBRob/ob mouse. The BTBRob/ob mouse developed hyperglycaemia and albuminuria. The diabetic kidney had similar numbers of CD4+, enhanced CD8+ T cells and reduced B cells as the ob+ control. The BTBR ob/ob had moderately enhanced spleen size without significant modulation of the T or B cells numbers. Interestingly, the BTBRob/ob CD4 cells had an activated phenotype while the CD8 T cells seemed naïve. An expanded regulatory T cell population was present in the spleen. BTBR ob/ob splenocytes had significantly enhanced intrinsic proliferation, while signal1/2 proliferation was significantly reduced. No significant modulation of the intrinsic capacity to produce cytokines was present although a marked modulation of the cytokine signature was present upon activation. These data demonstrate that the T2D and DN in the BTBR ob/ob mice is associated with changes in both the local and systemic lymphocyte populations and their functions strengthening that inflammation may contribute to the disease progression.
The role of estrogen in atrazine-mediated inhibition of CD4+ T cell function and induction of CD4+CD25+Foxp3+ regulatory T cells (IRC4P.479)
Authors: Emmons Tiffany , Wetzel Scott 
Published: January 2023

Abstract
The herbicide Atrazine (ATR) is the most common drinking water contaminant in the US. Biochemically, ATR is a phosphodiesterase (PDE) inhibitor and also elevates estrogen via induction of aromatase. Based upon these biochemical activities and several previous studies, ATR is considered potentially immunotoxic. We have previously shown that when activated in the presence of ATR CD4+ T cell proliferation and expression of CD25 and CD69 are significantly reduced. This is accompanied by a 2-5 fold increase in the frequency of Foxp3+ CD25+ Treg. While this phenotype is partially mimicked by treatment with the PDE inhibitor pentoxifylline, the ATR phenotype is more pronounced in cells derived from male mice. This suggests the possibility that estrogen is playing an important role in the observed CD4+ T cell phenotype. To examine the potential role of estrogen in the ATR-associated phenotype, we have investigated the role of the G-protein coupled estrogen receptor, GPER1/GPR-30, in the ATR-mediated inhibition of CD4+ T cell activation and induction of Treg. Treatment with estrogen and the GPER1 agonist G1 mimic the effects of low ATR concentrations. Studies to further define the role of estrogen and GPER1 in the ATR inhibition of T cell activation and iTreg conversion are currently underway.