bluuebunny/crossref_metadata_2025_split huggingface dataset:
Filaggrin deficiency in Stat6 transgenic mice exacerbates allergic skin inflammation (HYP4P.310)
Authors: Sehra Sarita , Akhtar Nahid , Nguyen Evelyn , Kaplan Mark 
Published: January 2023

Abstract
Atopic dermatitis (AD) is a chronic inflammatory skin disease induced by a complex interaction between susceptibility genes encoding skin barrier components and environmental antigen exposure. Although genome-wide association studies in AD have identified several susceptibility loci, loss of function mutations in the human filaggrin gene (FLG) is the major predisposing factor for AD. We have previously shown that 40% transgenic mice expressing constitutively active Stat6 (Stat6VT) in T cells spontaneously develop AD due to increased Th2 responses leading to decreased expression of barrier function genes including Flg. Flaky tail mice (FTM) have been widely used as a model of filaggrin deficiency-associated AD pathogenesis in patients. FTM have decreased barrier function, increased Th2 and Th17 responses following sensitization, but do not develop spontaneous allergic inflammation. In order to determine the effects of having both barrier dysfunction and increased Th2 responses, Stat6VT mice were mated to FTM. Our results demonstrate that over 90% of the STAT6VT mice carrying mutant Flg develop severe AD lesions by 3 months of age in comparison to 40% Stat6VT mice that develop disease between 4 to 5 months of age. Histopathological analysis of skin tissues revealed extensive thickening of the dermis with more severe infiltrates as compared to Stat6VT mice. Our studies suggest that skin barrier defects and altered Th2 responses separately contribute to the pathogenesis of AD.
Resistance of subacutely burned mice (SAB-mice) therapeutically treated with CCL1 antisense ODN against infections with MRSA or enterococci (INC4P.344)
Authors: Nishiguchi Tomoki , Lee Jong , Herndon David , Kobayashi Makiko , Suzuki Fujio 
Published: January 2023

Abstract
In previous studies, sepsis stemming for E. faecalis translocation and MRSA local infection has been greatly controlled in SAB-mice prophylactically treated with CCL1 antisense ODN. Effector cells (M1Mφ) in host antibacterial immunities are isolated from the infected SAB-mice after treatment with the ODN. In this study, the antibacterial resistance of SAB-mice therapeutically treated with the ODN was examined against infections with E. faecalis and MRSA. Mice 2 weeks after flame burn injury (3rd degree 25% TBSA) were infected with MRSA (106 CFU/mouse, i.v.). Decontaminated mice 2 weeks after burn injury were infected with E. faecalis (8 x 106 CFU/mouse, p.o.). These mice were therapeutically treated with the ODN (s.c., 10 mg/mouse) at various schedules starting 12 h after the infection. The antibacterial efficacies of the ODN were evaluated by reducing bacterial growth in blood and organs as compared to those of control mice. In the results, bacteria grew in the blood (&gt;105 CFU/ml), liver (&gt;106 CFU/gram), spleen (&gt;105 CFU/gram), and kidneys (&gt;107 CFU/gram) of control mice 3 to 5 days after MRSA infection. However, significant growth of the pathogen in their organs was not demonstrated in SAB-mice treated with the ODN 12, 24, and 36 h after the infection. Similar results were obtained in SAB-mice orally infected with E. faecalis. These results indicate that infections with MRSA and E. faecalis in SAB-mice are controllable by the therapeutic treatment with CCL1 antisense ODN.
Mycobacterial lipid antigen-specific innate T cell responses in TB-naïve macaques (INC4P.328)
Authors: Rout Namita , Tran Dollnovan , Exley Mark , Kaur Amitinder 
Published: January 2023

Abstract
Current tuberculosis (TB) vaccine strategies are targeted mainly towards conventional T cell responses to mycobacterial protein antigens. However, there is growing evidence for the role of mycobacterial lipid specific CD1-restricted T cell responses in anti-mycobacterial immunity. Understanding how the CD1-restricted T cells contribute to TB may provide critical insights into innate mechanisms of resistance to TB and aid the development of new therapies against TB. In this pilot study, we utilized cynomolgus macaques (CM) to characterize innate T cell responses to mycobacterial lipid antigens. PBMC from naïve CM were stimulated with purified mycobacterial lipid antigens, including Lipoarabinomannan (LAM), Phosphatidylinositol mannoside (PIM-1, 2, & 6) and total cellular lipids of MTb H37Rv, presented on CD1-a, -b, -c and -d transfectant C1R B cell lines. T cell responses were measured by IFN-γ, TNF-a and IL-2 ELISA in culture supernatants, and by intracellular cytokine staining for IFN-g, TNF-a, and IL-13. Robust TNF-a and IFN-g production was observed in response to CD1d/PIM and CD1b/LAM in all of the eight CM following 16 hours stimulation. Mainly CD8 positive and CD4/CD8 double negative T cells contributed to the dominant CD1-restricted Th1 cytokine response. The innate Th1-type response of T cells to MTb lipid antigens, particularly LAM and PIM, may be a significant component of the innate immune response in TB and thus promising targets for improved TB vaccines.
Cytosolic sensing of HIV by cGAS (INM2P.350)
Authors: Gao Daxing , Wu Jiaxi , Du Fenghe , Wu Youtong , Sun Lijun , aroh Chukwuemika , nan yan , Chen Zhijian 
Published: January 2023

Abstract
HIV infection abrogates adaptive immunity by the depletion of CD4 T cells. However, innate immune defense mechanisms against HIV is largely unknown. Here we show that pseudotyped HIV can infect human and mouse cell lines, leading to the production of interferons and other antiviral cytokines. Activation of innate immunity by HIV requires viral cDNA synthesis but not cDNA integration. We show that retrotranscribed HIV cDNA is sensed by the cytosolic DNA sensor cGAS, which then produces the second messenger 2'3'cGAMP to activate the adaptor STING. Importantly, wild type HIV also triggers cGAMP production in human primary macrophages, underscoring the key role of cGAS in HIV sensing. Furthermore, cytosolic sensing of other retroviruses such as murine leukemia virus and simian immunodeficiency virus also depends on cGAS. These results further our understanding of immune detection of HIV and can be potentially applied in HIV vaccine and adjuvant designs.
Inhibition of the STING pathway by the AIM2 inflammasome (INM2P.352)
Authors: Corrales Leticia , Woo Seng-Ryong , Gajewski Thomas 
Published: January 2023

Abstract
Tumor-derived DNA triggers the host STING pathway and the subsequent production of IFN-β by antigen-presenting cells, facilitating adaptive immunity against tumors. But cytosolic DNA also activates the AIM2 inflammasome, raising the question of functional impact of this pathway. We found that after DNA stimulation, macrophages or dendritic cells deficient in AIM2, ASC or caspase-1 produce substantially higher IFN-β. This observation suggests possible negative regulation of the STING pathway by the AIM2 inflammasome. We found no evidence for differential delivery of DNA into the cells, increased cell death triggered by activation of the inflammasome, or release of an inhibitory soluble factor. However, biochemical analysis revealed that the AIM2 inflammasome inhibits the early steps of STING pathway activation. Aggregation of STING and phosphorylation of TBK1 and IRF3 were highly enhanced in AIM2 inflammmasome-deficient cells. In addition, pre-treatment with a caspase-1 inhibitor increased the activation of TBK1/IRF3, suggesting that assembly and activation of the inflammasome complex is necessary for the inhibition of the STING pathway. Our data suggest the active AIM2 inflammasome inhibits the STING pathway at or upstream from STING. This crosstalk may have potential consequences for anti-tumor immunity which should be explored in vivo.
A mycobacterial lectin promotes bacilli adhesion to macrophages and influences pathogen growth during infection (INM3P.409)
Authors: Bafica Andre , Morales Stefanny , Eto Carol , Souza Nicole , Nogueira Lucas , Riley Lee , Mansur Daniel 
Published: January 2023

Abstract
Surface and secreted mycobacterial proteins play a major role on the infection process by mediating macrophage-bacteria interactions as well as the fate of cell’s death. We have previously described a secreted 13-kDa lectin (sMTL-13) in Mycobacterium tuberculosis (Mtb), encoded by Rv1419 gene, and although a possible importance for this protein as a major mycobacterial antigen was shown in tuberculosis patients, the importance of such lectin during infection has not been formally addressed. We have generated an Rv1419 knockout Mtb (ΔRv1419) to investigate a possible role of this gene during infection. In silico analysis of the protein as well as its detection on Mtb surface suggest that sMTL-13 may participate during bacteria entry in the host macrophage. This was confirmed by binding experiments performed in either murine or human derived macrophages. In addition, lower levels of TNF were detected in ΔRv1419-infected cells, indicating that this lectin may be important for pathogen recognition. Importantly, ΔRv1419 displays higher intracellular growth than the WT bacteria. Thus, although binding of Mtb to macrophages is decreased in the absence of Rv1419 gene, cells exposed to the knockout Mtb display higher bacterial replication rate and cell death. These data suggest that sMTL-13 expressed on Mtb regulates macrophage entry and perhaps cell fate, which could serve as a pathogen survival strategy, allowing bacterial growth without leading host cells to a premature death.
Population diversity in transcriptional responses of macrophages to TLR7/8 signaling (IRM12P.654)
Authors: SONG RAN , Dozmorov Igor , Liang Chaoying , Zhang Bo , wakeland Benjamin , Arana carlos , Viswanathan Kasthuribai , Riediger Linley , Wakeland Edward 
Published: January 2023

Abstract
The Toll-like receptors (TLR) of the innate immune system play a key role in the recognition of pathogens and the initiation of a robust innate immune response. Although an innate immune response is essential for resistance to pathogen infection, the magnitude and qualities of innate immune responses are quite variable in the human population. Here we performed transcriptome sequencing of monocyte-derived macrophages generated from 78 healthy individuals, including 10 replicates from repeat donors, to profile gene expression patterns in responses to TLR7/8 signaling. Extensive qualitative and quantitative diversity was apparent in the response of individuals in this panel. Cluster analysis discriminated nine distinct clusters of genes expressed in response to the TLR7/8 agonist (R848) with correlated expression variations within this panel. Interestingly, the induction of cytokine and chemokine transcription varied among donors and majority of these genes have very reproducible variability of their expression in 10 replicates. In addition, it was shown that donors with high expression of cytokine and chemokine genes after R848 stimulation were also high responder to Respiratory syncytial virus infection. Thus, there are the variations in gene expression among individuals with TLR7/8 stimulation, indicating that genetic polymorphisms in “master” regulators may correlate expression patterns of multiple genes during innate responses.
Role of interleukin-1 receptor antagonist in regulating specific Hepatitis B antibody production (IRM12P.646)
Authors: Chen Hairong , Zhao Yang , Tang Hong 
Published: January 2023

Abstract
While exogenous interleukin-1 beta was reported to facilitate antibody production, the function and mechanism of its conventional suppressor interleukin-1 receptor antagonist (IL-1Ra) in regulating specific antibody remain largely unknow. We showed that, upon aluminium-conjugated commercial hepatitis B surface antigen vaccination, hepatitis B antibody response was considerably amplified in IL-1Ra-/- mice, demonstrated by higher HBsAb level, increased germinal center and HBsAb secreting B cell numbers in dLN but not spleen. Mechanismly, IL-1 signalling pathway was, unexpectedly, found not to be involved in the process, evident by equivalent HBsAb titre in nalp3-/-, caspase-1-/- and IL-1R-/- mice as in wt. Surprisingly, the IL-17 production was amplified in IL-1Ra-/- mice, demonstrated by higher serum IL-17 level and higher number and frequency of IL-17 secreting cells in dLN of IL-1Ra-/- mice. Moreover, HBsAb level in IL1rn-/- x IL17-/- mice was comparable to that in wt mice, suggesting the essential role of IL-17 in regulating the elevated HBsAb level in IL-1Ra-/- mice. Furthermore, CD4 T cells was identified as the main source of IL-17 production in dLN of IL-1Ra-/- mice, indicating the essential role of IL-17 secreting CD4 T cells in upregulating HbsAb production. Therefore, the increased HBsAb production in IL-1Ra-/- was irrelevant to IL-1 pathway but dependend on evelated IL-17. We have thus proposed a novel mechanism of IL-1Ra in regulating specific antibody production.
Characterization of long-lived human memory CD8 T cells specific to yellow fever virus (LYM5P.707)
Authors: Yang Shu , Akondy Rama , Youngblood Ben , Edupuganti Srilatha , Mulligan Mark , Ahmed Rafi 
Published: January 2023

Abstract
The live yellow fever virus vaccine (YFV-17D) is a safe and effective vaccine that confers long-lasting protection after a single immunization. This vaccine results in the generation of virus memory T and B cells that persist for many years. We have used this vaccine to study the generation and maintenance of human memory CD8 T cells following an acute viral infection. Earlier studies using tetramers targeting an HLA-A2 restricted epitope have shown that YFV-specific CD8 T cells have polyfunctionality and recall potential - two hallmarks associated with effective T cell immunity. To better characterize these long-lived memory CD8 T cells we analyzed the peripheral blood mononuclear cells from HLA-A2+ individuals who had received a single dose of the vaccine 8 to 15 years previously. We will present data on the phenotype, function and epigenetic fingerprint of the YFV-specific memory CD8 T cells. Interestingly, these long-lived memory CD8 T cells had an epigenetic fingerprint that was consistent with their having passed through an effector stage during their differentiation.
OX40 signaling activates epigenetic mechanisms to repress Th17 cells and Th17-related autoimmune diseases (LYM5P.708)
Authors: Xiao Xiang , Shi Xiaomin , Fan Yihui , zhang xiaolong , wu minhao , liu wentao , Zhao Picheng , wu chenglin , Minze Laurie , Ghobrial Rafik , Li Xian 
Published: January 2023

Abstract
Th17 cells produce copious amount of IL-17, which mediates host antimicrobial responses and autoimmune diseases. The exact mechanisms that control Th17 homeostasis, especially those that inhibit Th17 differentiation, remain incompletely defined. Here, we found that the T cell costimulatory molecule OX40 is a potent repressor of Th17 cells and Th17-mediated autoimmune disease. Under Th17-polarizing conditions in vitro, engagement of OX40 strongly inhibited IL-17 production despite enhanced cell survival and proliferation. Mechanistically, OX40 engagement induced sustained activation of both canonical and non-canonical NF-kB pathways, and it is RelB that mediated dominant suppression of Th17 cells that is independent of p52 and p50. RelB directly recruited H3K9 methyltransferases G9a and Setdb1 upon binding to IL-17 locus, and this resulted in di- and tri-methylation of H3K9, which led to a closed epigenetic configuration of IL-17 locus that prevents RORγt binding to IL-17 locus. Conversely, inhibition of histone methyltransferase activity significantly reversed OX40-mediated suppression of Th17 cells. Importantly, in an EAE model, stimulation of OX40 in vivo inhibited the disease process, while RelB-deficient CD4+ T cells induced exacerbated disease. In conclusion, our study identified a new mechanism in the control of Th17 cells, and this mechanism relies on OX40 induced repressive epigenetic process. This finding may have important therapeutic implications in the clinic.
Preventing thymus involution in K5.Cyclin D1 transgenic mice sustains the naïve T cell compartment with age (LYM6P.716)
Authors: Bolner Michelle , Fink Pamela , Richie Ellen 
Published: January 2023

Abstract
The thymus maintains T cell receptor (TCR) repertoire diversity through perpetual release of self-MHC restricted naive T cells. However, thymus involution during the aging process reduces naïve T cell output, leading to defective immune responsiveness to newly encountered antigens. We have shown that age-related thymus involution is prevented in mice expressing a keratin 5 promoter-driven Cyclin D1 (K5.D1) transgene in thymic epithelial cells (TECs). Sustained T cell output from K5.D1 thymi prevents the age-associated decline of naïve T cells in the periphery. We find that K5.D1 recent thymic emigrants (RTEs) undergo typical phenotypic maturation. Competitive adoptive transfer studies with K5.D1 and nontransgenic RTEs indicate that K5.D1 RTEs are incorporated into the peripheral T cell pool comparably to nontransgenic controls. In addition, functional studies show that K5.D1 peripheral T cells are responsive to anti-CD3 and anti-CD28 stimulation in vitro. Collectively, these data show that preventing thymus involution not only sustains T cell output, but also provides functionally competent RTEs during aging.
Toxoplasma gondii gene products involved in the activation of the rat NLRP1 inflammasome (MPF4P.729)
Authors: Cirelli Kimberly , Butty Vincent , Saeij Jeroen 
Published: January 2023

Abstract
Toxoplasma gondii is an intracellular parasite, capable of infecting all warm-blooded animals. Upon infection of a host, Toxoplasma converts into cysts in brain and muscle tissue and establishes a life-long chronic infection. Rats, like humans, are resistant, surviving infection with high doses of mouse-virulent Toxoplasma strains. The Lewis rat is unique in its ability to completely clear infection and prevent cyst formation. We have previously shown that Toxoplasma-infected Lewis rat macrophages undergo rapid NLRP1-mediated pyroptosis. We hypothesize that this rapid cell death is a host mechanism to prevent parasite replication and dissemination to the brain and muscle tissues. Using a chemical mutagenesis screen, we have isolated several independent Toxoplasma mutants that fail to induce macrophage death and identified their mutations using whole genome sequencing. Using CRISPR/Cas9-mediated deletion of candidate genes, we have identified three Toxoplasma genes that contribute to macrophage pyroptosis. Parasites lacking these genes induce significantly less inflammasome activation, as measured by active IL-1β and pyroptosis, and are able to replicate within Lewis macrophages. We are determining if these mutants are able to form cysts in Lewis rats. Using biochemical techniques, we are probing the function of these individual parasite proteins and how they each contribute to NLRP1 activation.
Mycobacterium tuberculosis infection decreases macrophage Tpl-2 protein levels over time which alters responses to TLR agonists (MPF4P.730)
Authors: Ni Bin , Torres Chelsea , Rajaram Murugesan , Schlesinger Larry 
Published: January 2023

Abstract
Mycobacterium tuberculosis (M.tb), the causative agent of tuberculosis, is a host-adapted intracellular pathogen of macrophages. A complex, evolutionally adaptive relationship exists between M.tb and the host during which M.tb evades and subverts the immune response mounted by the macrophage. Understanding the interactions during primary infection between the macrophage and M.tb is important because it can impact the outcomes of infection and course of disease. We show that expression of the MAP3K Tpl-2, which was previously identified as a host defense molecule against M.tb in a murine knockout model, is down-regulated during M.tb infection of human primary macrophages. We observed downstream signaling effects of M.tb-induced suppression of Tpl-2 by studying ERK and MEK activation after stimulation with Toll-like receptor (TLR) ligands. M.tb lipomannan (ErdLM) stimulation of M.tb-infected macrophages showed decreased activation of ERK1/2 and MEK, congruent with decreased Tpl-2 levels after M.tb infection. However, ERK1/2 activation did not decrease significantly in M.tb-infected macrophages after treatment with the pure TLR agonists LPS, Pam3CysSK4, and CpG ODN, although decreased MEK phosphorylation was observed, suggesting that TLR ligands activate ERK1/2-mediated pathways that differ from those activated by ErdLM. These data indicate that M.tb has the capacity to suppress Tpl-2 over time and alter MAPK signaling to promote a survival advantage within the macrophage.
Dependency of TLR4 signaling for the anti-inflammatory effect of exopolysaccharide (EPS) of Bacillus subtilis (MPF4P.731)
Authors: Jones Sara , Paynich Mallory , Knight Katherine 
Published: January 2023

Abstract
Although probiotics offer a promising source of therapeutic compounds, few studies have identified the bacterial molecules or host signaling pathways required for the immunomodulatory effects. We previously demonstrated that exopolysaccharide (EPS) from probiotic Bacillus subtilis is the bacterial molecule that prevents disease induced by the murine pathogen Citrobacter rodentium, a pathogen that shares many similarities to the human pathogen enteropathogenic E. coli. To begin to elucidate how EPS functions, we determined which cells are required for protection and found that mice depleted of macrophages using clodronate loaded liposomes are not protected from the pathogen. Further, transfer of macrophage-rich peritoneal cells from wt, but not TLR4 KO, EPS-treated mice conferred protection from pathogen-induced colitis; these data suggest a role for TLR4 and macrophages. Using flow cytometry and microscopy, we find that EPS binds F4/80+CD11b+ macrophages and co-localizes with TLR4. We also find that EPS binds both wt and TLR4 KO macrophages, suggesting that EPS binds to a component of the TLR4 signaling complex instead of TLR4 directly. We are immunoprecipitating the EPS receptor, predicted to be a co-receptor of the TLR4 signaling complex, and determining if EPS is an agonist or antagonist of TLR4 signaling. Our studies should lead to a new class of bacteria-derived immunomodulatory molecules.
Luminal-GABA promotes inflammation in mouse models of colitis (MUC5P.756)
Authors: Dann Sara , Kelly Hannah , Suarez Diego , Hoppe Daniel , Banks MaChesha , Peniche Alex 
Published: January 2023

Abstract
Background: Inflammatory bowel disease (IBD) results from a dysregulated immune response towards commensal microbiota. Although the etiology of IBD is unclear, there is considerable interest in the role of commensals and their metabolites in regulating pathology. Gamma-aminobutyric acid (GABA) is one metabolite produced by several commensal species that has been reported to have anti-inflammatory effects which could impact severity of IBD. Objective: To determine the physiological role of GABA on intestinal inflammation. Methods & Results: C57BL/6 mice were administered GABA (2mg/ml) in their drinking water 3 days before induction of colitis (3% DSS or Clostridium difficile infection) and for another week thereafter. Intestinal tissue was collected and examined for histopathology, gene expression and cellular responses. In both models, administration of GABA exacerbated intestinal inflammation and damage, whereas inhibition of GABA with the receptor antagonist picrotoxin reduced disease severity. Damage was associated with increased expression of proinflammatory cytokines (IL-6 and IL-1β) and chemokines (CXCL1 and CXCL2) and alterations in macrophages and neutrophils. Conclusion: GABA increases host sensitivity to epithelial damage and inflammation. Identifying the effects of GABA on host immune defenses may reveal new approaches to treating and preventing IBD.