bluuebunny/crossref_metadata_2025_split huggingface dataset:
Cell types and cell signals important for normal thymic medullary epithelial cell development (HEM7P.231)
Authors: Jeon Hyein , Williams Joy , Hodes Richard 
Published: January 2023

Abstract
Thymic crosstalk between medullary thymic epithelial cells (mTEC) and mature SP thymocytes is critical for tolerance in developing T cells as well as for mTEC development. Several TNF family receptor-ligand pairs, including RANK-RANKL, LTαβ-LTβR and CD40L-CD40, have been shown to be important in thymic crosstalk, in part via RelB mediated non-canonical NFκB pathway. Recently, we identified CD28-CD80/86 as an additional pathway important for mTEC development. CD80/86, LTβR, CD40, RANK, as well as MHCII (also shown to be important for mTEC development) are expressed by both mTEC and by bone marrow (BM) derived cells in the thymus. Thus, it is important to ask which cell types need to express these molecules in order to support mTEC development. To address the question, we have generated and analyzed BM chimeras or conditional knockout mice in which either non-BM-derived cells (including thymic epithelium) or BM-derived cells express the molecule in question. Interestingly, for CD40 and CD80/86, we find that expression on either non-BM or BM-derived cells is sufficient to promote mTEC development. For LTβR, and RANK, we find that expression on radiation-resistant non-BM derived cells is required. The ability of MHCII expression on specific cell populations to drive mTEC development is currently being examined. Our findings suggest that models of thymic crosstalk must consider not only communication between TEC and thymocytes but with other BM derived cell types as well.
MicroRNA-17-92 regulates Tbx1 expression in third pharyngeal pouch endoderm (HEM7P.232)
Authors: Reeh Kaitlin , Bain Virginia , Lorenz Julia , Bai Yan , Martin James , Manley Nancy , Richie Ellen 
Published: January 2023

Abstract
The thymus and parathyroids originate from bilateral 3rd pharyngeal pouch (pp) endoderm. At E11.5, thymus- and parathyroid-fated domains express Foxn1 and Gcm2 respectively, transcription factors that regulate differentiation but do not specify organ fate. Tbx1, which encodes a T-box transcription factor required for segmentation of the pharyngeal endoderm is initially widely expressed in the 3rd pp, but by E10.5 is excluded from the ventral, thymus-fated domain. We recently reported that Tbx1 is a negative regulator of thymus development (Reeh et al. Development 141:2950, 2014). Ectopic expression of Tbx1 in the thymus-fated domain of the 3rd pp suppresses Foxn1 and inhibits thymic epithelial cell proliferation and differentiation. MicroRNAs (miRs) are important regulators of gene expression. We find that members of the miR-17-92 cluster are expressed in the ventral domain of the 3rd pp in wildtype embryos. Moreover, miR-17-92 downregulates Tbx1 in cardiac progenitor cells to promote their differentiation (Wang et al. Developmental Cell 19:903, 2010). Therefore, we proposed that miR-17-92 regulates Tbx1 expression in 3rd pp endoderm. In support of this hypothesis, we find that deletion of miR-17-92 enhances TBX1 and reduces FOXN1 in 3rd pp endoderm. The data support a model in which miR-17-92 plays an essential role in thymus development by regulating Tbx1 expression in the 3rd pp.
Total body sub-lethal irradiation accelerates thymic senescence by reducing lymphoid progenitors in the thymus (HEM7P.236)
Authors: Xiao Shiyan , zhang wen , Manley Nancy 
Published: January 2023

Abstract
Total Body Irradiation (TBI) dramatically damages the BM and thymus organs, however the long-term effects of irradiation and aging on both BM cells and thymocytes are still unclear. In this study, we described that although the kinetics of thymocyte restoration was varied with the sex, dose and exposure age, a long-term and dose dependent reduction of DN1a,b progenitors and a transient over-response peak of thymocytes around 5-6 weeks were shown unanimously in all groups after irradiation, which led to the recovery of thymus maintained in a lower level of total thymocyte number through life. Such events were primarily due to the reduction of functional LSK progenitors in BM rather than the changes to the thymic environment. The damage of irradiation in BM LSK cells was dose dependent and 0.5 Gy was able to result in a significant long-term reduction of LSK progenitors. Responding to the reduction of thymocytes, both DN3 and DN4 subsets played a critical role on the compensation of the reduction of thymocytes with a periodical profile after irradiation, but the recovery potential was dramatically reduced at the age of 12 months. This study provided the evidence that the capability of LSK cells for lymphocyte production in BM is limited and can be dramatically damaged after a single dose of relatively low TBI, which consequently accelerates premature thymic aging and senescence. Our results may also be useful for the evaluation and therapeutic intervention of human TBI events.
LAG-3 modulation of CD4 T cell mediated killing of Mycobacterium tuberculosis infected macrophages (HUM6P.252)
Authors: Phillips Bonnie , Kaushal Deepak 
Published: January 2023

Abstract
Lymphocyte activation gene-3 (LAG-3) is an immunomodulatory protein that decreases Th1-type immune responses in T cells. We believe that this protein is essential during the host immune response to Mycobacterium tuberculosis (Mtb) infections, where the response is dampened to prevent immunopathogenesis within the lungs. Consequently, overproduction of LAG-3 can be detrimental through a greatly reduced response, causing unhampered bacterial replication and activation of tuberculosis (TB) disease. We have demonstrated that LAG-3 expression is significantly induced in the lungs of nonhuman primates (NHPs) with active TB and is directly correlated to bacterial load and level of infection. LAG-3 is primarily expressed in T cells recruited to the lung. To mechanistically assess the effect of LAG-3 production by T cells on the progression of Mtb infection in macrophages, we have developed a co-culture system where differentiated blood monocytes are infected with Mtb, and supplemented with CD4 T cells harvested from blood and lung of NHPs previously infected with Mtb. Utilizing this model, we are silencing the expression of LAG-3 with siRNA to explore the effect it will have on the immune response to Mtb. We hypothesize that the lack of LAG-3 will result in greater bacterial killing, T cell activation, and enhanced production of Th1-type cytokines. This study will allow us to study the exact role of LAG-3 in the modulation of the immune response to Mtb infection within the granuloma.
Chronic alcohol exposure increases viral expression levels in tissue reservoirs of SIV-infected macaques. (HUM6P.243)
Authors: Robichaux Spencer , Nelson Steve , Bagby Gregory , Amedee Angela 
Published: January 2023

Abstract
Chronic alcohol abuse is associated with increased susceptibility to HIV infection and an accelerated disease progression. Using rhesus macaques infected with SIV and exposed to chronic binge alcohol (CBA), our studies have also shown increased susceptibility to mucosal SIV infection. Additionally, higher viral loads and accelerated disease progression were observed in CBA animals, despite the development of comparable humoral and cell-mediated immunity. In our current studies, we sought to evaluate viral replication kinetics by quantifying viral RNA and DNA levels in tissue reservoirs over 10 weeks of SIV followed by treatment with ART for 40 weeks. Viral RNA and DNA burdens in lymph nodes at peak viremia were similar between treatment groups. At viral set point, comparable proviral DNA levels were also found in lymph nodes of both groups, while CBA-treated animals had significantly higher levels of viral RNA (p&gt;0.01). Following ART treatment, similar levels persisted, with comparable proviral DNA burdens found and significantly higher SIV expression levels observed in CBA-animals (p&lt;0.05). Together, these observations show CBA increases viral transcription to increase viremia and accelerate disease progression. Future studies will investigate the immunological mediators affected by CBA and how they influence on viral expression.
Herpes simplex virus type 1 glycoprotein B-specific effector memory CD8+ T cells are associated with asymptomatic ocular herpes disease in both humans and "humanized" HLA transgenic mice (HUM6P.245)
Authors: Benmohamed Lbachir , Khan Arif , Srivastava Ruchi , Wechsler Steven 
Published: January 2023

Abstract
We have dissected the phenotype and the function of HSV-1 glycoprotein B- (gB-) specific CD8+ T cells from HLA-A*02:01 positive, HSV-1 seropositive asymptomatic (ASYMP) individuals (who have never had clinical herpes disease) and symptomatic (SYMP) individuals (with a history of numerous episodes of recurrent ocular herpes disease). We found that: (i) healthy ASYMP individuals maintained a significantly higher proportion of differentiated HSV-1 gB-specific effector memory CD8+ T cells (TEM, CD45RAlowCCR7lowCD44highCD62Llow). In contrast, SYMP patients had frequent less-differentiated central memory CD8+ T cells (TCM, CD45RAlowCCR7highCD44lowCD62Lhigh); (ii) ASYMP individuals had significantly higher proportions of multi-functional effector CD8+ T cells, which responded mainly to gB342-350 and gB561-569 “ASYMP” epitopes, and simultaneously produced IFN-g, CD107a/b, granzyme B and perforin. In contrast, effector CD8+ T cells from SYMP individuals were mostly mono-functional and were directed mainly against non-overlapping gB17-25 and gB183-191 “SYMP” epitopes; (iii) immunization of HLA-A*02:01 transgenic mouse model of ocular herpes with “ASYMP” CD8+ TEM cell epitopes, but not with “SYMP” CD8+ TCM cell epitopes, induced a strong CD8+ T cell-dependent protective immunity against ocular herpes infection and disease. Our findings provide insights into the role of CD8+ TEM cells in protection against herpes and should be considered in the development of an effective vaccine.
Different allergenicity profile of egg white protein extract vs. purified ovalbumin in an adjuvant-free mouse model (HYP7P.267)
Authors: Gangur Venugopal , Ortiz Tina , Parvataneni Sitaram , Gonipeta Babu , He Yingli , Thi San Su , Nolkemper Martha 
Published: January 2023

Abstract
Food allergies are the leading cause of life-threatening allergic reactions with incompletely understood mechanisms. Here we initially evaluated the allergenicity of egg white protein extract (EWPE) in a novel transdermal sensitization model without adjuvants such as alum/cholera toxin/super-antigen that are commonly used in mouse models of egg allergy. Groups of mice received transdermal exposure (TDE) to EWPE (1 mg/exposure/week) for four weeks. Sensitization was measured by specific IgE antibody (SIgE Ab) levels in plasma using ELISA. Systemic anaphylaxis was assessed upon oral challenge (OC) with EWPE using clinical scoring method, and hypothermia reactions. Four TDEs were sufficient to elicit robust SIgE Ab responses. Upon OC (15 mg/mouse), EWPE elicited near-fatal clinical signs of anaphylaxis associated with rapid hypothermia reactions. We then evaluated allergenicity of purified ovalbumin (OVA) using this model. Groups of mice received TDE to OVA at 4 different doses. Robust OVA SpIgE responses were observed upon TDE. Surprisingly, sensitized mice did not exhibit significant clinical symptoms or hypothermia reactions upon OC with a wide dose range. Nevertheless, robust anaphylaxis was evident upon i.p., injection with OVA. These data suggest that mechanisms of oral egg protein-induced reactions in adjuvant-free model likely depends on whether protein extracts or pure protein from the same food source (egg) is used in model development.
TLR7 is required for both plasmacytoid dendritic cell IFN-I production and subsequent exhaustion during chronic viral infection (INC6P.309)
Authors: Macal Monica , Chang Aaron , Zuniga Elina 
Published: January 2023

Abstract
Type I Interferons (IFN-I) are potent cytokines essential for immune surveillance against many pathogens including persistent viruses such as human immunodeficiency virus (HIV) in humans and Lymphocytic Choriomeningitis Virus (LCMV) in mice. Plasmacytoid dendritic cells (pDCs) are specialized to produce IFN-I upon TLR stimulation, but the molecular mechanisms underlying their initial IFN-I production and the subsequent exhaustion that occurs during chronic viral infection remain to be fully elucidated. Using chronic LCMV infection in mice, we demonstrated that pDCs initially sensed and produced abundant IFN-I in a TLR7-dependent manner. Strikingly, cell-intrinsic TLR7 signaling was also essential for the later pDC IFN-I exhaustion observed in chronic LCMV infection and compromised innate responses against secondary opportunistic pathogens. Interestingly, when analyzing pDC bone marrow progenitors, we found that they were reduced in LCMV chronically infected mice, they had compromised developmental potential and only generated exhausted pDCs. Overall, our studies highlight a dual role for TLR7 in contributing to both induction and subsequent exhaustion of innate responses and suggest a pDC progenitor defect underlying IFN-I exhaustion during chronic viral infection.
Lactic acid attenuates LPS-induced cytokine production in mast cells (INC6P.320)
Authors: Caslin Heather , Abebayehu Daniel , Spence Andrew , Abdul Qayum Amina , Ryan John 
Published: January 2023

Abstract
Elevated lactate levels and attenuated lactate clearance following hospital admission have been associated with increased mortality in sepsis patients. While some effects of lactate on LPS stimulation have been examined in monocytes and macrophages, mast cells have not been examined. Therefore, the purpose of this study was to examine the effect of lactic acid on LPS-induced mast cell activation. Methods: Murine bone marrow derived mast cells were cultured in medium with or without lactic acid for 24 hours. Additionally, sodium lactate and formic acid were examined. Following the pre-incubation period, LPS was added and supernatants were collected after 16 hours for cytokine ELISA analysis. Results: Pre-incubation with lactic acid significantly reduced cytokine (TNF, IL-6) and chemokine (MCP-1, MIP-1a) secretion following LPS stimulation. Sodium lactate pre-incubation did not change cytokine production. However formic acid, which has a similar pKa to lactic acid, also reduced cytokine production compared to the control. Discussion: Lactic acid attenuates LPS-induced mast cell activation, an effect that appears to be dependent upon pH rather than acid chemical structure. Our results suggest that lactic acid may play a suppressive role in mast cell activation during sepsis.
Dectin-1 expressed on pDCs and mDCs displays opposing roles in TH2 polarization (INC6P.321)
Authors: Upchurch Katherine , Joo HyeMee , Zhang Wei , Xue Yaming , Li Dapeng , Li Xiao-Hua , Hori Toshiyuk , Zurawski Gerard , Oh SangKon 
Published: January 2023

Abstract
Dendritic cells (DCs) can induce and control host immune responses. DC subset-dependent functional specialties and their ability to display functional plasticity, which is mainly driven by signals via pattern-recognition receptors (PRRs), identify DCs as immune orchestrators. A PRR, Dectin-1 is expressed on myeloid DCs (mDCs) and is known to play an important role in TH17 responses. Here, we demonstrate that human plasmacytoid DCs (pDCs) express Dectin-1. Interestingly, Dectin-1-activated pDCs promote TH2 induction and activation, whereas Dectin-1-activated mDCs decrease both. This counter-regulation of TH2 by the two DC subsets is mainly due to their distinct abilities to control OX40L expression through different mechanisms. This study provides new insights for the regulation of host immune responses by DCs during microbial infections.
Lactic Acid suppresses IL-33-mediated mast cell inflammatory responses while increasing VEGF production: an Akt- and miR-155-dependent pathway (INM6P.336)
Authors: Abebayehu Daniel , Spence Andrew , Abdul-Qayum Amina , Taruselli Marcela , McLeod Jamie , Ndaw Victor , Baker Bianca , Kolawole Elizabeth , Ryan John 
Published: January 2023

Abstract
Lactic acid (LA) is present in tumors, asthma, and wound healing, environments that also include mast cells and IL-33. The goal of this work is to evaluate how LA modifies IL-33 activation in mast cells. Bone marrow derived mast cells (BMMC) were cultured in the presence of LA and activated with IL-33. BMMC cultured in LA had reduced IL-33-mediated cytokine production. However, LA increased IL-33-mediated VEGF production. Using an MCT1 inhibitor or replacing LA with sodium lactate revealed that LA effects are MCT1 and pH-dependent. Examining IL-33 signaling demonstrated that LA decreased TAK1, JNK, and NFkB phosphorylation, yet increased Akt phosphorylation. An Akt inhibitor blocked VEGF production, but surprisingly enhanced IL-33-mediated cytokine production. Because miR-155 has recently been reported to suppress Akt activation in mast cells, we examined LA effects on miR-155. LA decreased miR-155-5p expression in BMMC. Moreover, BMMC transfected with miR-155-5p were resistant to LA-mediated suppression. Our data demonstrate that lactic acid, present in inflammatory and malignant microenvironments, can alter mast cell behavior to suppress inflammation while increasing angiogenesis.
Modulation of immune responses toward Helicobacter pylori infection by NLRs (INM6P.339)
Authors: Washington Philipson Casandra , Bassaganya-Riera Josep , Viladomiu Monica , Kronsteiner-Dobramysl Barbara , Michalak Pawel , Hontecillas Raquel 
Published: January 2023

Abstract
Helicobacter pylori (HP) colonizes 50% of the world’s population resulting in a decades-long gastric infection. Bacterial interaction with host intracellular environment occurs via injection of bacterial components through a TIVSS or intracellular replication. HP has been recognized for its ability to modulate intracellular NOD-like receptors (NLR). Host responses toward the bacterium can result in asymptomatic, pathogenic or even favorable immunity. Mechanisms underlying the dual role of HP as a commensal versus pathogen are not completely understood. We combined computational modeling, bioinformatics and experimental validation to investigate intracellular host-HP interactions. Global transcriptomic analysis on bone marrow-derived macrophages (BMDM) in a gentamycin protection assay unveiled that intracellular colonization of HP upregulated NOD1, NOD2, NLRP3, NLRC5 and inflammasome components (Caspase-1 and -11) but suppressed regulatory NLRX1 which was inversely correlated to TRAF6, NF-B, proinflammatory cytokines and reactive oxygen species. Loss of NLRX1 facilitates bacterial clearance in BMDM and infected mice. Lastly, we constructed a computational model to shed light on complex immune responses and pathway crosstalk regulated by NLRX1 during infection. In conclusion, NLRX1 is associated with chronic bacterial persistence during H. pylori infection and it may represent an immune evasion mechanism employed by the bacterium to facilitate long-term host colonization.
Cell-type specific control of immune responses mediated by inflammasomes in vivo (INM6P.333)
Authors: Nichols Randilea , von Moltke Jakob , Vance Russell 
Published: January 2023

Abstract
Upon pathogen recognition, certain cytosolic nucleotide-binding domain, leucine-rich repeat containing proteins (NLRs) form multi-protein complexes called inflammasomes, which activate CASPASE-1. CASPASE-1 initiates inflammation by processing IL-1beta and -18 into their active forms, and by inducing a rapid, lytic cell death called pyroptosis. The NLRC4 inflammasome responds to the cytosolic presence of specific bacterial proteins, such as flagellin, via NAIPs. A fundamental question is whether and how activation of innate immune responses triggers pathogen-specific adaptive immune responses. We seek to test the hypothesis that cell-type-specific activation of the inflammasome is sufficient to induce inflammation and adaptive immune responses in vivo. To test our hypothesis, we are using a novel ‘knock-in’ mouse strain. This mouse expresses a fusion protein, which selectively activates the NLRC4 inflammasome. Preliminary data indicate extensive NLRC4-dependent inflammatory disease in mice expressing the fusion protein in myeloid-derived cells.
Disabled-2 negatively regulates lipopolysaccharide-stimulated Toll-like receptor 4 signaling and inflammation response in murine macrophage (INM7P.349)
Authors: HUNG WEI-SHAN , Chou Chein-Shen , Tseng Ching-Ping 
Published: January 2023

Abstract
Toll-like receptor 4 (TLR4)-mediated host response to lipopolysaccharide (LPS) stimulation plays a pivotal role in host defense against from Gram-negative bacterial infection. Upon ligand binding, TLR4/MD2 complexes are internalized to form endocytic signalsomes and extend LPS response. However, the underlying mechanism of LPS-stimulated TLR4 internalization and signaling has not yet been completely understood. Here we delineated whether the endocytic adaptor protein Disabled-2 (Dab2) that is highly expressed in macrophage plays a role in TLR4 signaling and trafficking. In vivo analysis of the myeloid lineage-restricted Dab2 knockout (Dab2-/-) mice revealed that the mice were more susceptible to LPS challenge leading to an overproduction of the chemokine RANTES in serum and poor survival. The functional role of Dab2 in TLR4 signaling was investigated further using RAW264.7 macrophage with Dab2 knockdown. We found that attenuation of Dab2 expression increased the basal level of cell surface TLR4/MD2 complexes and accelerated the rate of LPS-induced down-regulation of these complexes from the cell surface. Consequently, TLR4 endocytic pathway-dependent IRF-3 activation was augmented with an increased expression for the subsets of inflammatory cytokine and IFN-inducible genes. These data indicate that Dab2 functions as a negative regulator of TLR4 endocytic pathway and signaling, supporting a novel role of Dab2 in the inflammatory response of macrophage to endotoxin.
Analysis of genes associated with pulmonary mucosal defense against influenza A virus infection (INM8P.402)
Authors: Samarasinghe Amali , Lin Yanyan 
Published: January 2023

Abstract
Influenza A virus infects affect a large population worldwide every year. Antigenic drifts and shifts, and re-assortments in influenza A viruses contribute to reduced host protection. Early host immune defenses may also vary based on the virus strain. A murine model system is one of the best in vivo models to study the host immune defense against Influenza A virus. We hypothesized that host mucosal defenses are initiated in the lung mucosa by expression of antimicrobial peptides. We infected C57BL/6 female mice with 1000 TCID50 A/CA/04/2009 (pH1N1) or A/PR/08/1934 (PR8) strains of influenza A virus and quantified changes in cell recruitment and antimicrobial peptide gene expression at 0, 1, 3, 9, 24, 48, and 120 hours. Both viruses efficiently replicated in mice with peak viral production at 48 hours. However, PR8 caused more damage to the host, marked by increased recruitment of neutrophils, lymphocytes and macrophages and viral burden compared to pH1N1. Genes associated with antimicrobial peptides (RELM, MBD4, CRAMP, PLUNC) were upregulated starting at 3 hours post infection. These genes were more highly expressed in response to PR8 virus. Our data suggest that the proteins encoded by these genes may initiate the immune response against influenza A virus infections and that the host mucosal response varies depending on the strain of virus.