bluuebunny/crossref_metadata_2025_split huggingface dataset:
New mechanism of mucosal immunity in oral candidiasis: insights from Hyper-IgE (STAT3-deficient) patients (56.1)
Authors: Gaffen Sarah , Conti Heather , Freeman Alexandra , Baker Olga , Li Rui , Jang Woong , Holland Steven , Edgerton Mira 
Published: January 2023

Abstract
Oropharyngeal candidiasis (OPC, thrush) is an opportunistic infection caused by the commensal fungus Candida albicans. OPC is an AIDS-defining illness, and is also common in patients on chemotherapy and those with congenital immunodeficiencies. An understanding of immunity to Candida has recently begun to unfold with the identification of fungal pattern recognition receptors such as dectins, which trigger protective Th17 responses in the mucosa. Hyper-IgE syndrome (HIES/Job’s Syndrome) is a rare congenital immunodeficiency characterized by dominant-negative mutations in STAT-3. STAT-3 is downstream of the Th17-inductive cytokines IL-6 and IL-23, and hence HIES patients exhibit dramatic Th17 defects. Striingly, HIES patients develop oral and mucocutaneous candidiasis, supporting a protective role for Th17 cells. However, the Th17-dependent mechanisms of immunity in OPC are poorly defined. An often-unappreciated aspect of oral immunity is saliva, which is rich in anti-microbial proteins (AMPs) and exerts direct antifungal activity. We found that both Th17-deficient mice and HIES patients show significant impairment in salivary candidacidal activity. In HIES, this was linked to reduction in AMPs, such as β-defensin 2 and Histatins. Moreover, IL-17 induces histatins in cultured salivary gland cells. This is the first demonstration that the Th17 axis of immunity is associated with salivary activity, and provides a mechanism for the severe susceptibility of HIES patients to OPC.
Altered activation of neonatal alveolar macrophages affects the immune response to Pneumocystis. (56.10)
Authors: Kurkjian Cathryn , Hollifield Melissa , Murphy Brian , Garvy Beth 
Published: January 2023

Abstract
Postnatal lung development renders a different lung environment and composition in neonates as compared to adults, making the neonatal immune response to lung pathogens, such as Pneumocystis (PC), less efficient than adults. Alveolar macrophages (AMs) are the major effector cells in the immune response to PC, and a proper AM activation phenotype is imperative for clearance of infection. Following peak infection, alternative markers (arginase, mannose receptor and CD23) are increased on adult AMs, suggesting a role for this phenotype in PC resolution. A more robust increase in these alternative markers is observed in neonates following peak infection. Additionally, naïve neonatal AMs constitutively express FIZZ1 and Ym1 at levels comparable to infected counterparts. It is possible that adult AMs develop a classical phenotype in the initial response to PC, and that this phenotype cannot be obtained by neonatal AMs early in infection due to increased expression of alternative markers. Additionally, increases in these alternative markers on neonatal AMs late in infection may suppress an efficient response to PC, thus resulting in delayed clearance as compared to adults. We hypothesize that delayed AM activation and increased expression of alternative markers during resolution results in an insufficient immune response to PC infection in neonates.
Mechanisms of Dectin-1 dependent IL-17A production during invasive fungal infection. (56.14)
Authors: Werner Jessica , Gessner Melissa , Lilly Lauren , Nelson Michael , Metz Allison , Horn Dawn , Deshane Jessy , Chaplin David , Brown Gordon , Weaver Casey , Steele Chad 
Published: January 2023

Abstract
In the current work, we show that mice deficient in the beta-glucan receptor Dectin-1 demonstrate significantly reduced levels of IL-17A in the lungs 48 h after Aspergillus fumigatus (AF) challenge. Culturing cells from enzymatic lung digests ex vivo further demonstrated Dectin-1 dependent IL-17A production, providing a sensitive method to identify mechanisms associated with lung IL-17A production after AF challenge. Neutralization of IL-23, but not IL-1β or IL-6, in WT lung digest cell cultures reduced IL-17A production by 60%. Lung digest cells from AF-challenged Rorc-/- deficient mice had attenuated IL-17A production, however, Rorc and Rora mRNA, and RORγt protein, expression was not impaired in lung digest cells from Dectin-1 KO mice. Ahr, Irf4 and Card9 mRNA expression was also unchanged. Intracellular cytokine staining revealed that CD11b+ and CD11b+ Ly-6G+ cells were sources of IL-17A, although only CD11b+ Ly-6G+ cells produced IL-17A in a Dectin-1 dependent manner. In turn, Ly-6G+ cells purified from the lungs of AF-challenged Dectin-1 KO mice displayed a 2-fold reduction in Il17a mRNA expression, yet increased Rorc and Rora mRNA expression. IL-23R+ cells in lung digest were predominantly CD11b+ Ly-6G+ cells. In summary, Dectin-1 dependent innate IL-17A production in the lungs during invasive fungal infection is mediated in part by CD11b+ Ly-6G+ neutrophils, which is partially dependent on IL-23. Dectin-1 deficiency does not, however, compromise induction of Rorc.
Differential intracellular trafficking of Francisella tularensis strains in human dendritic cells. (56.15)
Authors: El-Etr Sahar , Vergez Lisa , Rasley Amy 
Published: January 2023

Abstract
F. tularensis, the causative agent of tularemia, is an intracellular pathogen that replicates in macrophages and dendritic cells (DCs), where the bacteria escape the endosomal pathway and replicate in the cytoplasm. DCs act as sentries for the immune system and are often the first cells to engulf invading pathogens and trigger the activation of T-cells. F. tularensis inactivates DCs upon entry, but the mechanism of inactivation is not known. We hypothesize that F. tularensis inactivates DCs by disrupting intracellular trafficking and antigen presentation. Using immunofluorescence microscopy, we have performed a detailed characterization of intracellular trafficking of the F. tularensis laboratory strains Schu S4, LVS and novicida and two clinical type A strains in hDCs. Our data indicates that F. tularensis strains colocalize with EEA-1, LAMP-1 and Rab3 endosomal markers as early as 15 min post infection. In addition, we observe a significantly lower number of pathogenic F. tularensis colocalizing with the above markers than the nonpathogenic F. tularensis LVS and novicida strains. Very few bacteria colocalize with the late lysosomal marker Cathepsin D, and we do not observe differences among strains. These data indicate that pathogenic F. tularensis escape the endosomal pathway in hDCs much more rapidly and in greater numbers than nonpathogenic strains, suggesting that pathogenic F. tularensis actively disrupt intracellular trafficking and subsequent antigen presentation.
TCA cycle inactivation in Staphylococcus aureus alters nitric oxide production in RAW 264.7 cells (56.21)
Authors: Massilamany Chandirasegaran , Gangaplara Arunakumar , Gardner Donald , Steffen David , Somerville Greg , Reddy Jay 
Published: January 2023

Abstract
Inactivation of the Staphylococcus aureus tricarboxylic acid (TCA) cycle delays the resolution of cutaneous ulcers in a mouse soft tissue infection model. In the present study, we observed that cutaneous lesions in mice infected with wild-type or isogenic aconitase mutant S. aureus strains contained comparable inflammatory infiltrates, suggesting the delayed resolution was independent of the recruitment of immune cells. These observations led us to hypothesize that staphylococcal metabolism can modulate the host immune response. Using an in vitro model system involving RAW 264.7 cells, we observed that cells cultured with S. aureus aconitase mutant strains produced significantly lower amounts of nitric oxide (NO) and an inducible nitric oxide synthase as compared to those cells exposed to wild-type bacteria. Despite the decrease in NO synthesis, the expression of antigen-presentation and costimulatory molecules was similar in cells cultured with wild-type and those cultured with aconitase mutant bacteria. The data suggest that staphylococci can evade innate immune responses and potentially enhance their ability to survive in infected hosts by altering their metabolism. This may also explain the occurrence of TCA cycle mutants in clinical S. aureus isolates.
ESAT-6 from Mycobacterium tuberculosis inhibits T cell IFN-γ production through p38 MAP kinase pathway (56.28)
Authors: Samten Buka , Peng Hui , Wang Xisheng , Barnes Peter 
Published: January 2023

Abstract
We reported previously that ESAT-6 from Mycobacterium tuberculosis directly inhibits human T cell IFN-γ production and proliferation in response to stimulation with anti-CD3 plus anti-CD28. To determine the mechanism of this effect, we treated T-cells with kinase inhibitors before stimulation in the presence of ESAT-6. Only the p38 MAPK inhibitor, SB203580, abrogated ESAT-6-mediated inhibition of IFN-γ production in a dose-dependent manner. In contrast, SB203580 did not reverse ESAT-6-mediated inhibition of IL-17 and IL-10 production, suggesting a specific effect of SB203580 on IFN-γ production. SB203580 did not act through inhibition of AKT, as an AKT inhibitor did not affect ESAT-6 inhibition of T cell IFN-γ production and proliferation, ruling out the possible off target effect of SB203580 through AKT. ESAT-6 did not expand FoxP3+ T regulatory cells, suggesting that Tregs do not play a role in ESAT-6 inhibition of T cell IFN-γ production. Incubation of T cells with ESAT-6 induced phosphorylation and increased functional p38 MAPK activity, but not activation of ERK or JNK. Silencing of p38α MAPK with siRNA rendered T-cells resistant to ESAT-6 inhibition of IFN-γ production. Taken together, our results demonstrated that ESAT-6 inhibits T cell IFN-γ production in a p38 MAPK-dependent manner.
ESAT-6 inhibits IL-12, but promotes IL-23 production of human dendritic cells (56.9)
Authors: Wang Xisheng , Barnes Peter , Samten Buka 
Published: January 2023

Abstract
Early secreted antigenic target of 6 kD (ESAT-6) is a M. tuberculosis protein that induces protective immunity against tuberculosis in animal models and is a putative vaccine candidate. However, this protein also contributes to virulence and inhibits immune cells activation. In this study, we evaluated the effects of ESAT-6 on the function of human dendritic cells. Immature dendritic cells (DC) were induced from monocytes cultured with GM-CSF plus IL-4. ESAT-6 inhibited IL-12, but promotes IL-23 production of DC during maturation stimulated by LPS plus CD40L. This is correlated with downregulated IL-12p35 and upregulated IL-23p19 transcripts, respectively. ESAT-6 did not affect the induction of TNF-α, IL-6 and IL-8 from DC during maturation. ESAT-6 also inhibited upregulation of co-stimulatory molecules, CD80, CD86, HLA-DR, in both monocyte derived DC and myeloid DC freshly purified from human blood, in response to stimulation of LPS plus CD40L. DC pretreated with ESAT-6 induced less IL-2 and IFN-γ production in mixed lymphocyte reactions, and stimulated less IFN-γ, but more IL-17 production from M.tuberculosis responsive T cells compared to nontreated DC. Blocking TLR1/2 on DC or removing 20 amino acids in C-terminus did not ablate the inhibition of ESAT-6 on IL-12 production. We conclude that ESAT-6 enhances IL-23 production at the expense of IL-12 in a TLR2 independent mechanism, which favors Th17 over Th1 activation. (Supported by the NIH grants AI082335 and AI063514)
Bim is a component of the endosomal-lysosomal interface in Interleukin-7 dependent T cells (57.10)
Authors: Khaled Annette , Ruppert Shannon , Carlson Adina 
Published: January 2023

Abstract
Bim is a key protein in T cell homeostasis. Bim deficiency prevents activated T cell death, and protects splenic T cells in IL-7R/Bim double knockout mice through an undetermined mechanism. We propose a novel function for Bim in T cells involving lysosomal development in both apoptotic and non-apoptotic cells. Using IL-7 dependent T cell lines, Bim-containing and Bim-deficient (Bim-/-), we determined that the transcription of bim increased in the absence of IL-7 and the loss of Bim protected cells from apoptosis induced by IL-7 withdrawal. Treatment of Bim-containing cells with Bim siRNA confirmed these results. Bim-/- cells had increased endosomal and decreased lysosomal proteins, suggesting that Bim plays a role in endosomal to lysosomal trafficking and maturation. Subcellular organelle fractionation revealed that the BimL isoform associated with both endosomal and lysosomal fractions in non-apoptotic cells. However, during IL-7 withdrawal, the BimEL isoform associated with lysosomal fractions and less so with endosomal fractions. In fact, reduced co-localization of endosomes and lysosomes in the absence of Bim was observed by confocal microscopy, suggesting a defect in an endocytic compartment. Overexpression of the individual Bim isoforms restored acidic organelle distribution with BimL contributing the most in non-apoptotic cells. These results demonstrate that Bim has both apoptotic and non-apoptotic activities in T cells that affects lysosomal equilibrium.
Regulation of STAT-6 activation in ovalbumin stimulated murine splenocytes: mechanisms regulating biphasic induction (57.13)
Authors: Lee Soojin , Shan Jichuan , Fixman Elizabeth 
Published: January 2023

Abstract
T cell receptor (TCR) stimulation and IL-4 receptor signaling mediate STAT-6 activation and differentiation of naïve T cells into T helper type 2 (Th2) cells. However, the relationship between TCR stimulation and IL-4-induced STAT-6 activation is poorly understood. STAT-6 is tyrosine phosphorylated (pSTAT-6) in response to IL-4 as well as IL-13, and it also regulates gene expression of these Th2 cytokines. Our data demonstrate that pSTAT-6 is induced in a biphasic manner in splenocytes harvested from OVA-sensitized BALB/c mice and restimulated in vitro with OVA. pSTAT-6 was induced within 2-4h, lost at 12-24h and re-induced at 48-96h. IL-4, but not IL-13, followed similar biphasic kinetics. Inhibition of either IL-4 or the IL-4 receptor selectively during the first phase had no effect on secondary pSTAT-6 and production of IL-4 and IL-13. In addition, while biphasic pSTAT-6 was induced in splenocytes treated simultaneously with OVA and exogenous IL-4, stimulation of splenocytes with IL-4 alone did not induce secondary IL-4 production and pSTAT-6. These data demonstrate that the presence of IL-4 at early time points is neither required nor sufficient for IL-4 production and pSTAT-6 during the second phase. IL-4 production and pSTAT-6 during the second induction phase, on the other hand, are dependent upon OVA-induced TCR signaling. Studies are underway to define the cellular sources of IL-4 and pSTAT-6 as well as the cells required for each phase of the induction.
Targeted-glycosylation of "non-core region" of interleukin-11 modulates its biological function. (57.15)
Authors: Yanaka-Okada Saeko , Sano Emiko , Naruse Norio , Miura Kin-ichiro , Futatsumori-Sugai Mutsumi , Caaveiro Jose , Tsumoto Kouhei 
Published: January 2023

Abstract
Human interleukin-11 (hIL-11) is a pleiotropic cytokine administered to patients for recovering low platelet counts. From a structural point of view hIL-11 belongs to the long-helix cytokine superfamily, which is characterized by a conserved core motif consisting of four alpha-helices. We have investigated the region of hIL-11 that does not belong to the alpha-helical bundle motif, which we have termed “non-core region”. The interleukin was N- or O-glycosylated at specific positions within the non-core region, and the functional consequences of these modifications were examined in cell-based as well as biophysical assays. The data indicated that the non-core region modulates the function of hIL-11 in two ways. First, most of the muteins displayed enhanced cell-stimulatory properties (super-agonist behavior) in a glycosylation-dependent manner, suggesting that the non-core region is biologically designed to limit the cell-proliferative potential of hIL-11. Second, glycosylation of a predicted mini alpha-helix led to cytokine inactivation, demonstrating that this structural element interacts with a second gp130 receptor. These findings have unveiled new and unexpected elements modulating the biological activity of hIL-11, which may be exploited to develop more versatile medications based on this important cytokine. Yanaka S et al. J. Biol. Chem. in press. (2011)
Dose-response immunomodulatory effects of glucocorticoid on gene expression of cytokine and stress hormone receptors in human PBMC (57.18)
Authors: Xiang Lianbin , Marshall, Jr. Gailen 
Published: January 2023

Abstract
Previous studies demonstrate Th1/Th2 cytokine balance is altered with stress hormone equivalent dexamethasone (Dex) levels in human PBMC cultures. The modulatory effects of Dex on gene expressions of FoxP3, IFN-γ receptors (IFN-γR), IL-4 receptors (IL-4R), glucocorticoid receptors (GR), and beta 2 adrenergic receptors (β2AR) were investigated. PBMC from 17 normal humans were cultured with 10-7, 10-8, or 10-9M Dex (mimics high, low, and non stressed states) for 24 hrs (short term) and 11 days (long term). Gene expression changes were assessed by real-time PCR. Results showed mRNA expressions of FoxP3, GR and IL-4R were decreased, whereas β2AR and IFN-γ R were upregulated with various concentrations of Dex (24 hrs). After 11 days, FoxP3 level remained down-regulation, whereas GR and β2AR levels returned to control levels in all cultures. In contrast, IL-4R expression increased (11 days) in all Dex concentrations. This resulted in decreased IFN-γR/IL-4R from 24 hrs (favoring Th1) to 11 days (favoring Th2) with Dex. This suggests that short term Dex exposure (acute stress) can initiate immunoregulatory reactions (i.e. Th1 based) that may be protective against many infectious challenges, possibly through a down-regulation of GR resulting in less suppressive effects of steroids and increased sensitivity to catecholamines. Longer term Dex exposure (chronic stress) may ultimately alter host response resulting in increased susceptibility to infections and/or hypersensitivity states.
Immune mechanisms associated with altered infant CD4+ T cell function (57.20)
Authors: dela Pena Myra Grace , Wicks Megan , Rao Kalyan , Abel Kristina 
Published: January 2023

Abstract
Infant, when compared to adult, CD4+ T cell responses are characterized by a T helper 2 bias and reduced IFN-γ production. We hypothesized that the (1) expression of genes important in TCR signaling is age-dependent and (2) transcription factors involved in cytokine signaling (e.g. signal transducer and activator of transcription (STATs), are differentially activated in infant and adult CD4+ T cells. Naïve and differentiated CD4+ T cells from 2 to 6 months old infant rhesus macaques were FACS-purified, stimulated with anti-CD3 and anti-CD28 antibodies, and analyzed by a Rhesus Th1/2/3 PCR array. The results showed an age-dependent increase in genes associated with Th1 development (e.g. T-bet). Next, human and/or rhesus cord and adult blood samples were stimulated with IL-2, IFN-γ or IL-4 and analyzed by Phosflow for the phosphorylation of STAT5, 1, or 6, respectively. While both infant and adult CD4+ T cells expressed a high percentage of phosphorylated STAT6 positive cells, adult CD4+ T cells had significantly higher frequencies of phosphorylated STAT5 and STAT1 positive CD4+ T cells. Thus, our data indicate that mechanisms of T cell activation differ between infant and adult CD4+ T cells. Defining these differences in distinct signaling pathways may provide novel and critical insights into pediatric HIV vaccine and therapeutics design.
Nogo B Receptor is expressed in a subset of T cells; is AmNogoB a cytokine? (57.21)
Authors: Valle-Rios Ricardo , Burkhardt Amanda , Hevezi Peter , Zlotnik Albert 
Published: January 2023

Abstract
The Reticulon/Nogo is a large family of proteins, which share the C-terminal region of approximately 200 aa, called the Reticulon homology domain (RHD). Many of these molecules have been identified in the Central Nervous System and that is where most studies have focused so far. The best characterized gene of the Reticulon family is RTN4. It is composed of three isoforms: RTN4/Nogo A, RTN4/Nogo B and RTN/Nogo C. Nogo B plays an essential role in vascular remodeling and appears to be important in angiogenesis and metabolic processes. Interestingly, the amino terminal region of Nogo B (amNogo B), can be a soluble peptide that promotes vascular adhesion and migration of endothelial cells by binding the recently reported Nogo B receptor (NgBR). Using a comprehensive database of gene expression in the human body, we made the unexpected observation that the cells exhibiting the strongest expression of NgBR include activated CD4+ and CD8+ T cells. We have confirmed that NgBR is expressed in a subpopulation of activated T cells expressing the activation marker CD69 in mouse, indicating the existence of a new subpopulation of activated T cells that are NgBR+CD69+. Since amNogoB is present in plasma, it should be able to bind this new subpopulation of activated T cells via NgBR and therefore it may play a role in modulating T cell activation. We are currently studying the functional consequences of the amNogoB:NgBR interaction in activated T cells.
MicroRNA-29 stabilizes interferon-gamma mRNA by antagonizing AU-rich element-mediated decay (57.3)
Authors: Savan Ram , Legiewicz Michal , McFarland Adelle , Schwerk Johannes , Bindewald Eckart , Orr Selinda , Ramakrishnan Karthika , Yalamanchili Rajesh , Kronfli Anthony , McVicar Daniel , Carrington Mary , Anderson Stephen , Shapiro Bruce , LeGrice Stuart , Young Howard 
Published: January 2023

Abstract
Tight regulation of interferon-gamma (IFN-g) expression is critical for an optimal immune response. IFN-g mRNA levels are attenuated by AU-rich element (ARE)-mediated decay (AMD) via the tristetraprolin (TTP) complex. Here we show that miR-29 targets the 3'untranslated region of IFN-g mRNA and unlike the conventional inhibitory function of miRNAs, increases IFN-g protein expression by stabilizing the mRNA. Through analysis of RNA structure derived by chemoenzymatic probing, we demonstrate that the AMD function is blocked by a miR-29 induced RNA conformational switch that makes the TTP binding site inaccessible. This effectively results in competition between the miRNA-induced silencing complex and TTP for post-transcriptional control of IFN-g gene expression. Our proposed role of miR-29 in stabilizing IFN-g provides a novel molecular mechanism of miRNA regulation and presents new targets for the manipulation of the immune system in the treatment of human diseases.