bluuebunny/crossref_metadata_2025_split huggingface dataset:
IRF4 Expression Defines Th2 Populations Secreting High Levels of IL-10 (B102)
Authors: Ahyi Ayele-Nati Nathalie , Chang Hua-Chen , Kaplan Mark H 
Published: January 2023

Abstract
We have recently identified the ETS family transcription factor PU.1 as regulating heterogeneity in Th2 populations. To define additional factors that might contribute to Th2 heterogeneity, we examined the PU.1 interacting protein IFN-regulatory factor (IRF)-4, a transcription factor expressed in lymphocytes and macrophages. When Th2 cells are separated based on levels of IL-10 secretion, IRF4 expression segregates into the subset of Th2 cells expressing high levels of IL-10. To investigate the role of IRF4 in cytokine heterogeneity, Th2 cells were infected with retrovirus expressing IRF4. The cells overexpressing IRF4 secreted significantly higher levels of IL-10 compared to cells infected with a control vector while other Th2 cytokines were not affected. To understand the mechanism by which IRF4 regulates IL-10 expression in various Th2 cell subpopulations we used DNA pull down assays as well as co-immunoprecipitation assays to determine transcription factors that interact with IRF4. Our data shows that PU.1, IRF4 and NFATc2 form a complex in Th2 nuclear extract. The role of these complexes and their contribution towards Th2 heterogeineity will be further defined.
Toll-like receptor 4 signaling in lung dendritic cells is required for the induction of T helper cell type 1 responses but dispensable for type 2 (B105)
Authors: Tan Anna Marie , Bottomly Kim 
Published: January 2023

Abstract
We have previously reported that in a mouse model of allergic sensitization, low level inhaled LPS (LPSlow) signaling through TLR4 was necessary to induce Th2 responses while high level LPS (LPShigh) induced Th1 responses to inhaled antigen. The mechanism by which LPS signaling resulted in Th2 sensitization involved the activation of antigen-containing dendritic cells (DC). It remains unclear whether induction of these responses is dependent on TLR signaling in DCs, other lung cells, or in both. Here we report that antigen/LPShigh sensitized chimeric mice specifically lacking TLR4 signaling in the hematopoietic compartment (HPC) but sufficient for TLR4 in the stromal compartment (SC+HPC-) do not mount Th1 responses following antigen challenge while SC-HPC+ mice do. Strikingly, however, SC+HPC- mice mount exaggerated Th2 responses. Stromal TLR4 signaling in SC+HPC- mice leads to upregulation of the Th2-inducing Notch ligand Jagged-1 in DCs but not the Th1-inducing ligand Delta-4. In coculture, DCs activated by the stromal response to LPS polarize naïve antigen specific CD4 T cells to produce Th2 cytokines. These studies demonstrate that the TLR4-mediated response of stromal cells, through conditioning of DCs, is sufficient to induce robust allergic inflammatory responses to inhaled antigen containing LPS and define a novel role for lung stromal cells in the TLR4-dependent induction of allergic Th2 responses.
Priming with Inhaled Antigen: the Role of CCR2 (B106)
Authors: Wilkinson Kathryn Nancy , Bottomly Kim 
Published: January 2023

Abstract
We have developed a murine asthma model in which inhalation of OVA and low levels of LPS results in a Th2 response via a TLR4 dependent mechanism. Unlike asthma models that initiate a response via an intra-peritoneal injection of OVA and alum, our model uses a natural route of exposure and therefore provides insight into how pulmonary Th2 responses are initiated. Asthmatic responses that involve priming via an intra-peritoneal injection of OVA and alum are reported to be CCR2 independent. In contrast, in our model CCR2−/− mice show reduced airway inflammation and antigen specific antibody production. It is known that CCR2−/− mice have decreased recruitment of monocytes to sites of inflammation. In addition, it is known that under inflammatory circumstances CCR2+ monocytes can mature into tissue dendritic cells. In our asthma model, we find that inhalation of OVA and LPS induces recruitment of dendritic cells into the lung. We are currently determining if these recruited dendritic cells contribute to initiation of an asthmatic response and if their absence is responsible for the decreased responses observed in CCR2 knockout mice.
Cathepsin S in a Murine Model of Allergic Asthma (B108)
Authors: Weicker Sean , Cromlish Wanda , Lamontagne Sonia , Gauthier Jacques-Yves , Desmarais Sylvie , Oballa Renata , Ouellet Marc , Percival M. David , Black Cameron , Guimond Alain , Frossard Nelly , O’Neil Gary , Slipetz Deborah , Tan Christopher 
Published: January 2023

Abstract
Cathepsin S (Cat S), expressed predominately on antigen presenting cells, has been proposed as a therapeutic target for asthma. We used genetic and pharmacological tools to investigate the role of Cat S in murine models of allergic asthma. Mice null for Cat S were protected from OVA-induced pulmonary inflammation, but exhibited no protection from OVA-induced airway hyper-reactivity. To determine the role of Cat S during the challenge phase, we identified a potent and selective Cat S inhibitor, Compound A (Cpd A, IC50 mCat S = 0.6 nM, ≥470 fold selective vs mCat B, K, L), which inhibited antigen presentation in a mouse cell-based assay (IC50 = 44 nM). The prodrug of Cpd A, Cpd B, gave excellent plasma levels of Cpd A when dosed in mice by gavage, or in food. In vivo competition in mice with an irreversible pan-selective cysteine cathepsin probe showed that Cpd B gave selective inhibition of lung and spleen Cat S at 1 mpk, but lost selectivity at 50 mpk. Cpd B was dosed in mice (10, 100 mpk in food) over 4 days of the challenge period in the murine ovalbumin model. Both doses had no effect on bronchoalveolar lavage infiltrating cells, despite showing high levels of Cat S inhibition. Thus, Cat S inhibition in a therapeutic mode does not attenuate airway inflammation in antigen sensitised mice suggesting that anti-Cat S therapy would not be an effective asthma treatment.
Role of CCR2+ Monocyte-derived Cells in LPS-induced Acute Lung Injury (B113)
Authors: Chen Yu-Hsun , Lin Kaifeng Lisa , Gunn Michael Dee 
Published: January 2023

Abstract
Leukocytes are believed to cause the lung damage associated with acute lung injury (ALI) but the specific cell types involved have not been clearly demonstrated. Using flow cytometry, we examined the inflammatory cell types that arise in lung after intranasal administration of LPS. We find that LPS results in the accumulation of neutrophils, inflammatory monocytes, exudative macrophages (exMACs), monocyte-derived DC (moDC), and lymphocytes during the acute phase (days 2–3) of ALI. In comparison to WT mice, CCR2-deficient mice given LPS display significantly reduced numbers of lung monocytes, exMACs, and moDC. CCR2-deficient mice also display reduced accumulation of neutrophils and lymphocytes, suggesting that inflammatory monocyte-derived cells promote the accumulation of other cell types. Relative to WT mice, CCR2-deficient mice display decreased weight loss and recover more quickly after LPS challenge. These findings suggest that CCR2+ monocyte-derived inflammatory DC and macrophages play a central role in mediating the lung injury and morbidity associated with LPS-induced acute lung injury.
Intestinal double positive CD4+CD8+ T cells of neonates are highly activated memory cells with higher proliferative capacity compared to single positive CD4+/CD8+ T cells (B115)
Authors: Pahar Bapi , Wang Xiaolei , Lackner Andrew A , Veazey Ronald S 
Published: January 2023

Abstract
Peripheral blood and thymic double positive CD4+CD8+ (DP) T cells from neonates have been described in humans and a number of animals, but the function and immunophenotypic characteristics of other tissue-derived DP T cells are not clearly understood. Here we demonstrate the phenotypic characteristics of DP cells in 6 different tissues including thymus from normal neonatal rhesus macaques (Macaca mulatta) between 0–21 days of age. In general, DP T cells of neonates have higher percentages of memory markers (CD28+CD95+, CD45RA−) compared to single positive (SP) CD4+ and CD8+ T cells. In addition, intestinal DP T cells increase as the animals’ age and levels of CD62L decrease with age suggesting that DP cells proliferate and are activated with maturity and/or antigen exposure. Consistent with this, intestinal DP T cells in neonates express higher levels of activation markers and CCR5 expression. Furthermore, DP T cells have higher rates of proliferation compared to SP CD4+ and SP CD8+ T cells as determined by BrdU labelling techniques. Finally, DP T cells produce higher levels of cytokine production in response to mitogen stimulation compared to SP CD4+ or SP CD8+ T cells. Collectively, these findings demonstrate that intestinal DP T cells of neonates are proliferating, effector cells and are likely involved in regulating immune as compared to the immature DP T cells in the thymus. As in adults, these intestinal DP T cells may be important target cells for early HIV infection in neonates due to their activation, high expression of CCR5, and memory phenotype.
CD137 crosslinking mediates effector T cell death and immune suppression during LCMV infection (B126)
Authors: Zhang Benyue , Mittler Robert S. 
Published: January 2023

Abstract
CD137 (4-1BB) is a member of TNFR superfamily that acts as a costimulatory receptor and plays a role in inducing T cell proliferation, effector function and apoptosis. CD137 is expressed on activated T cells and several other cell lineages e.g. dendritic cells, granulocytes, NK cells and macrophages. Agonist α-CD137 mAbs enhance T cell proliferation, eradicate tumors, suppress humoral immunity and reverse autoimmune disease. Here, we show that α-CD137 can suppress both CD4 and CD8 T cells in an LCMV Armstrong infection model. Suppression only occurs when α-CD137 is injected within 48 hrs of infection. Anti-CD137 injected, LCMV Armstrong infected mice developed elevated levels of IL-10 and prolonged TNF-α production, resulting in decreased virus-specific CD8 T cells and chronic infection like the LCMV Clone 13. By day 8 P.I., both CD4 and CD8 T cells in the treated mice underwent extensive cell death and this correlated with increased levels of TNF-α-dependent Fas and FasL expression on T cells. Anti-CD137-mediated suppression of anti-vial immunity was blocked by injection of a neutralizing anti-TNF-α into IL-10 deficient mice. T cells in LCMV infected, α-CD137 treated Fas KO mice did not undergo apoptosis and CD8 T cell responses were normal, suggesting that suppression is enforced through TNF-Fas-dependent apoptosis. The cell target of α-CD137 responsible for initiating suppression is still under investigation. Our data suggest CD137 signaling at the early stage of virus infection can negatively regulate host anti-viral immunity by inducing T cell deletion through apoptosis.
Respiratory syncytial virus blocks MHC Class-II surface translocation in human myeloid dendritic cell (B127)
Authors: Xu Chuang , Gill Michelle Ann , Bajwa Gagan , Xue Yaming , Pallazo Adam , Banchereau Jacques , Connolly John E. 
Published: January 2023

Abstract
Respiratory syncytial virus (RSV) is the leading cause of lower respiratory tract infection in infants and young children. Antigen presentation by dendritic cells (DCs) is critical for the establishment of antiviral immunity and DCs are frequent target of viral immune evasion. Here we show that primary blood mDCs exposed in vitro to RSV failed to upregulate MHC Class-II. Similar results were observed in mDCs isolated from the nasal mucosa of RSV infected infants. MHC Class-II levels remained low despite the apparent upregulation of other markers of DC maturation such as MHC Class-I, CD83, CD86 and CD40. This inhibition could not be explained by the reduced bio-synthesis of MHC Class-II as class II transactivator (CIITA) level remained unchanged and the total cellular HLA-DR was comparable to flu exposed mDC. Furthermore, SDS stability assay showed similar level of MHC Class-II peptide complex between the two viral treatments, indicating RSV exposure did not block Class-II loading. Consistent with the reduced surface expression, confocal microscopy demonstrated a selective blockade of MHC Class-II surface translocation by RSV. These results demonstrate that RSV blocks DC antigen presentation by inhibiting Class-II peptide complex transport to the surface and suggest a mechanism of viral immune evasion.
This work is supported by grants from Baylor Health Care Systems Foundation, the Children’s Medical Center of Dallas Foundation to MG, and the National Institutes of Health (K08 AI059379-02 to MG, U19 AIO57234 to JB).
Exaggerated sickness behavior and brain proinflammatory cytokine expression in aged mice in response to intracerebroventricular lipopolysaccharide (B13)
Authors: Henry Christopher J. , Huang Yan , Dantzer Robert , Johnson Rodney W. , Godbout Jonathan P. 
Published: January 2023

Abstract
Age-associated changes in glial reactivity may predispose individuals to exacerbated neuroinflammatory cytokine responses that are permissive to cognitive and behavioral complications. The purpose of this study was to determine if aging is associated with an exaggerated sickness response to central innate immune activation. Our results show that intracerebroventricular (i.c.v) administration of lipopolysaccharide (LPS) caused a heightened proinflammatory cytokine response (IL-1β, IL-6, and TNFα) in the cerebellum 2 h post i.c.v. injection in aged mice compared to adults. This amplified inflammatory profile was consistent with a brain region-dependent increase in reactive glial markers (MHC class II, TLR2 and TLR4). Moreover, LPS caused a prolonged sickness behavior response in aged mice that was paralleled by a protracted expression of brain cytokines in the cerebellum and hippocampus. Finally, central LPS injection caused amplified and prolonged IL-6 levels in the periphery of aged mice. Collectively, these data establish that activation of the central innate immune system leads to exacerbated neuroinflammation and prolonged sickness behavior in aged as compared to adult mice.
Hyper-induction of cytokines by avian influenza A (H5N1): The role of signaling pathways and Toll-like receptors (B131)
Authors: Hui Kenrie Pui Yan , Cheung CY , Ng HY , Wu HS , Peiris JSM 
Published: January 2023

Abstract
Avian influenza virus A/HK/483/97 (H5N1) is associated with unusually severe human disease. H5N1 viruses hyper-induce pro-inflammatory cytokines (tumor necrosis factor alpha [TNF-α] and interferon beta [IFN-β]) and macrophage-tropic chemokines from primary human macrophages in vitro and this is paralleled by elevated levels of these cytokines in patients sera. It is therefore important to understand the mechanisms underlying this H5N1 induced differential hyper-induction of cytokines. Unlike H1N1, H5N1 virus strongly activated interferon regulatory factor 3 (IRF3). siRNA mediated gene silencing of IRF3 led to a dramatic reduction of the gene expression of IFN-β in H5N1-infected cells but only a partial decrease in TNF-α gene expression. Thus the differential activation of IRF3 may explain the hyper-induction of IFN-β, but does not fully explain the hyper-induction of TNF-α. Similarly, gene silencing of toll-like receptor 3 (TLR3) did not completely abrogate the TNF-α response. The significance of these findings in the pathogenesis of human H5N1 disease will be discussed.
A novel gammaherpesvirus secreted protein induces Vβ4+ CD8+ T cell lymphocytosis during latency (B132)
Authors: Evans Andrew George , Moser Janice M. , Krug Laurie T. , Speck Samuel H. 
Published: January 2023

Abstract
Despite the important contribution of T cells to the control of lytic viral infection, relatively little is known about their role during latent herpesvirus infection. Murine gammaherpesvirus 68 (γHV68) induces a CD8+ T cell response that persists throughout latency, is characterized by cells bearing a Vβ4+ T cell receptor, and is independent of MHC Class Ia and β2-microglobin expression in vivo. It has been proposed that an unknown viral superantigen or T cell stimulatory ligand could be responsible for their activation. We have demonstrated that the novel γHV68 gene, M1, is required for stimulation of Vβ4+ CD8+ T cells and their interferon-γ (IFN-γ) production. Examination of M1-deficient viral mutants has revealed a role for these T cells in the IFN-γ-dependent control of viral reactivation from latency in C57Bl/6 mice and the development of CD8+ T cell-mediated fibrosis during persistent γHV68 infection of IFN-γ receptor-deficient (IFN-γR−/−) mice. Analysis of recombinant M1 expression reveals that the mature protein is fully secreted, and is capable of stimulating IFN-γ production from Vβ4+ CD8+ T cells ex vivo. Studies are underway to explore the mechanism, be it either non-classical (Class Ib) MHC:peptide presentation or superantigen-like CD8+ T cell activation, by which M1 is capable of eliciting such an enigmatic T cell response.
This work was supported by NIH grants R01 CA95318, CA52004, CA58524, and AI58057.
Expression of Cytokine Genes and Signal Transduction during Orientia tsutsugamushi Infection (B134)
Authors: Yun Ji-Hyun , Goo Jeong-Eun , Koh Young-Sang 
Published: January 2023

Abstract
Orientia tsutsugamushi, an obligate intracellular bacterium, is the causative agent of scrub typhus. TNF-α and IFN-β mRNAs were induced after infection with O. tsutsugamushi. Western blot analysis shows that O. tsutsugamushi-stimulation leads to phosphorylation of ERK1/2, JNK1/2, and p38 MAPKs. Selective inhibitors of ERK1/2, JNK1/2, p38 MAPKs could all completely prevent TNF-α secretion. Host TNF-α production via p38 & JNK pathways by this bacterium was found to be regulated by post-transcriptional mechanism. In contrast, ERK pathway mainly control the transcription step of TNF-α gene regulation. Orientia inactivation by heat did not abolish induction of TNF-α production. However, heat inactivation of bacterium or treatment of host cell with cytochalasin D led to a complete loss of IFN-β induction, suggesting requirement of internalization and escape into cytoplasm by bacteria for host IFN-β response. Selective inhibitors of ERK1/2, p38 MAPKs, or NF-κB could all completely prevent IFN-β induction. In conclusion, our data suggest that distinct mechanism of pathogen detection is involved in activation of TNF-α and IFN-β genes in response to Orientia tsutsugamushi infection.
This study was supported by Brain Korea 21 (BK21) program in 2007.
Age-related Differences in Pulmonary Cytokine Response to Respiratory Syncytial Virus Infection: Modulation by Anti-inflammatory and Antiviral Treatment (B135)
Authors: Boukhvalova Marina S. , Yim Kevin C. , Kuhn Katie H. , Hemming John P. , Prince Gregory A. , Porter David D. , Blanco Jorge C.G. 
Published: January 2023

Abstract
BACKGROUND: Respiratory syncytial virus (RSV) is the major cause of severe lower respiratory tract infection in infants and young children. Recently RSV has also been recognized as a serious health risk in the elderly, but the pathogenesis of RSV infection in the elderly remains unknown.
METHODS: Dynamics of pulmonary cytokine response (including IFN-gamma, IL-4, IL-10, IL-6, MCP-1, and GRO mRNA) during acute RSV infection were investigated in young (&lt;2 months old) and aged (&gt;9 months old) cotton rats S.hispidus. Therapeutic treatments that diminish viral replication (antiviral antibody) and pulmonary pathology (anti-inflammatory corticosteroid) in RSV-infected animals were used to evaluate contribution of virus replication and inflammation to the development of RSV disease with respect to age.
RESULTS: The time of the peak expression of majority of cytokines was shifted with respect to age. Antiviral and anti-inflammatory treatments had similar effect on cytokine expression in aged and young animals. GRO mRNA transcripts were more abundant in the lungs of aged animals.
CONCLUSIONS: The present work reports the age-related delay in the pulmonary cytokine response to RSV, imbalance in chemokine production with respect to age and underscores different components of RSV pathogenesis with respect to their molecular signature.
In situ location of effector and memory CD8 T cells (B137)
Authors: Dauner Joseph G. , Williams Ifor R. , Jacob Joshy 
Published: January 2023

Abstract
CD8 T cells are critical for the clearance of intracellular pathogens. Following viral infection, naïve CD8 T cells differentiate into effector cells that target and eliminate infected cells. Upon viral clearance, a majority of effector cells die, while a small fraction survives to establish a memory population. Upon future exposures to the same pathogen, these memory T cells are able to rapidly respond and efficiently eliminate the infection. Although much is known about the activation and differentiation of CD8 T cells, the precise in situ location of effector and memory CD8 T cells is not well characterized. Here we present an in situ analysis of the localization of effector and memory CD8 T cells during the murine immune response to acute infection with LCMV. We utilized a transgenic mouse model system in which effector and memory CD8 T cells are irreversibly tagged with yellow fluorescent protein (YFP). We tracked YFP-positive effector and memory CD8 T cells in relation to LCMV-infected cells. Following LCMV infection, activated CD8 T cells were first observed within the T cell zones. As the immune response progressed, effector CD8 T cells migrated to the red pulp regions. Upon viral clearance, memory CD8 T cells localized to the T cells zones. Interestingly, CD44hi memory-phenotype CD8 T cells in naïve mice exhibited identical in situ localization as the memory CD8 T cells observed following LCMV infection.
Direct inhibition of CD4+ T cells by Mycobacterium tuberculosis (B139)
Authors: Mahon Robert Norman , Rojas Roxana E. , Drage Michael G. , Fulton Scott A. , Harding Clifford V. , Boom W. Henry 
Published: January 2023

Abstract
For MTB to survive in the face of robust innate and adaptive immune responses multiple immune evasion mechanisms are required. These mechanisms and the MTB molecules responsible for them are beginning to be elucidated. Apart from interfering with the innate and adaptive immune functions of macrophages, recent studies suggest that MTB also can directly modulate CD4+ T cell function. The current study was undertaken to identify MTB molecules and mechanisms for direct inhibition of CD4+ T cell activation. Murine CD4+ T cells were purified from spleens by a combination of negative selection with mAb-coated beads and flow sorting. Purified T cells were activated for 24–48 hrs. with plate-bound anti-CD3 and soluble anti-CD28 mAbs with whole bacilli or subcellular fractions of MTB. Multiple measures of activation were used including IL-2 production by ELISA, proliferation by thymidine incorporation, and cell surface receptor expression by flow cytometry. MTB bacilli decreased T cell activation by all three measures. Fractionation identified a lipophilic fraction of the MTB cell wall as a major inhibitor of anti-CD3/CD28 mediated activation. T cell metabolic activity was unchanged in the presence of the lipophilic fraction. Activation of CD4+ T cells by PMA/ionomyocin was not affected by MTB. Thus lipophilic molecules in the MTB cell wall directly inhibit CD3/CD28 mediated CD4+ T cell activation by interfering with proximal T cell signaling events.