bluuebunny/crossref_metadata_2025_split huggingface dataset:
Programmed cell death ligand 2 regulates Th9 differentiation and induction of chronic airway hyperreactivity (P6261)
Authors: Akbari Omid , Maazi Hadi , Kerzerho Jerome , Speak Anneliese , Szely Natacha , Lombardi Vincent , Lam Jonathan , Van Snick Jacques 
Published: January 2023

Abstract
Asthma is defined as a chronic inflammatory disease of the airways; however, the underlying physiologic and immunologic processes are not fully understood. The aim of this study was to determine whether Th9 cells develop in vivo in a model of chronic airway hyperreactivity (AHR) and what factors control this development. We have developed a novel chronic allergen exposure model using the clinically relevant antigen Aspergillus fumigatus to determine the time kinetics of Th9 development in vivo. Th9 cells were detectable in the lungs after chronic allergen exposure. The number of Th9 cells directly correlated with the severity of AHR, and anti-IL-9 treatment decreased airway inflammation. Moreover, we have identified programmed cell death ligand (PD-L) 2 as a negative regulator of Th9 cell differentiation. Lack of PD-L2 was associated with significantly increased TGF-β and IL-1α levels in the lungs, enhanced pulmonary Th9 differentiation, and higher morbidity in the sensitized mice. Our findings suggest that PD-L2 plays a pivotal role in the regulation of Th9 cell development in chronic AHR, providing novel strategies for modulating adaptive immunity during chronic allergic responses.
Dendritic cell expression of interferon regulatory factor 4 drives Th2 responses and regulates IL-10 and IL-33 production (P6239)
Authors: Williams Jesse , Tjota Melissa , Clay Bryan , Fixsen Bethany , Singh Harinder , Sciammas Roger , Sperling Anne 
Published: January 2023

Abstract
Dendritic cells (DCs) are known for promoting adaptive immune responses; however the molecular mechanisms that drive DCs to promote Th2-responses are poorly understood. We now demonstrate that house dust mite (HDM) allergen stimulation induces Interferon Regulatory Factor 4 (IRF4) expression in bone-marrow derived DCs as well as respiratory DCs. Mice deficient for IRF4 specifically in CD11c+ cells (CD11c-IRF4-/-) had dramatic defects in eliciting Th2-mediated HDM allergic inflammation, as measured by lung eosinophilia and Th2 cytokine production. Yet, the ability of CD11c-IRF4-/- mice to mount protective pulmonary Th1 viral responses remained intact. To determine whether defects in Th2 responses in vivo were due to direct effects of DCs on T cells, in vitro co-culture experiments were performed. CD11c-IRF4-/- DCs failed to induce Th2 differentiation compared to T cells stimulated by WT DCs. Further, genetically increasing IRF4 specifically in DCs augmented Th2 differentiation. Interestingly, we found that stimulation with HDM of WT DCs, but not CD11c-IRF4-/- DCs, increased expression of IL-10 and IL-33; both of which have been reported to play central roles in the development of Th2 responses. Together, these findings identify IRF4 expression in DCs and its ability to modulate cytokine production as a novel mechanism by which DCs regulate Th2 inflammatory responses.
Peanut allergic humans display increased Ag-dependent IL-33/IL-33R responses that regulate recall responses (P6241)
Authors: HayGlass Kent , Xie Jungang , Chooniedass Rishma , Becker Allan , Simons F Estelle 
Published: January 2023

Abstract
Peanut allergy is severe and persistent. IL-33 plays key roles in modulating murine Th2-like responses, shaping serum Ig production, and anaphylactic shock. The potential involvement of IL-33 and receptor components ST2 or IL-1RAcP in food allergy is unexplored as is the impact blocking endogenous IL-33 function. We hypothesized that (i) peanut allergic humans exhibit elevated systemic production and responsiveness to IL-33 vs non-allergic controls and (ii) that neutralizing endogenous IL-33 inhibits undesirable Ag-specific recall responses characteristic of food allergy. Acute peanut-driven restimulation revealed elevated IL-33, ST2 and IL-1RAcP production by PBMC of both peanut allergic and clinically tolerant groups (p&lt;0.001). The intensity of peanut-dependent IL-33 mRNA production is linked to clinical phenotype(p&lt;0.0006). Exogenous IL-33 increased Ag-driven CD4 T cell dependent IL-5, IL-9, IL-13 in both groups, with allergic volunteers most responsive (p&lt;0.005). Soluble IL-33 receptors sST2-Fc and sIL-1RAcP-Fc inhibit elevated IL-5,9,13 recall responses in peanut allergic humans by median 80% (p&lt;0.005). Thus, the data reveal a hitherto unrecognized and prominent role for excessive IL-33/IL-33R production and responsiveness in food allergic humans. Unexpectedly potent inhibition of peanut Ag-driven Type 2 recall responses in peanut-allergic individuals by sIL-33R components suggests potential therapeutic utility in food allergy and other human allergic disorders.
IL-1 released by skn dendritic cells activated through Syk and CARD9 pathway is essential for the sensitization of allergic contact dermatitis. (P6245)
Authors: Hara Hiromitsu , Yasukawa Shinsuke , Furue Masutaka , Yoshida Hiroki 
Published: January 2023

Abstract
Allergic contact dermatitis (ACD) is caused by T cells reactive to environmental and industrial allergens. Optimal T cell priming requires co-stimulatory signals from DCs that are activated through innate immune sensors. However, innate immune pathways through which contact allergens activate skin DCs are not clear. Here we show that stimulation of contact sensitizers (haptens) induces activation of the tyrosine kinase Syk in DCs. This not only induces the synthesis of pro-IL-1α/β and but also engages the NLRP3 inflammasome, resulting in DC release of IL-1α/β, which is essential for the sensitization of effector T cells. Both CARD9 and MyD88-deficient mice failed to induce contact hypersensitivity (CHS) to haptens. DAP12, Syk and CARD9 were required for hapten-induced IL-1 secretion from DCs, whereas IL-1R1-MyD88 signaling was required in T cells being primed by hapten-activated DCs. The CHS-sensitizing ability of DCs required inflammasome activation that is dependent on ROS generation. The DAP12-Syk signaling was essential for the ROS-regulated inflammasome activation induced by haptens, whereas CARD9/BCL10 signaling selectively controlled pro-IL-1 synthesis by regulating NF-κB activation. Finally, DC-specific deletion of CARD9, DAP12, Syk or NLRP3, but not MyD88 in mice by our newly-developed MixC-Treck system resulted in impaired CHS sensitization. Thus, our results identified an essential molecular axis of innate immunity required for the sensitization of ACD.
Using the lymphocytic choriomeningitis virus mouse model of infection to link specific immune responses with epidemiological outcomes (P6318)
Authors: Holechek Susan , Nieves Lizbeth , McAfee Megan , Guzman Vanessa , Lussier Danielle , Bruce Courtney , Blattman Joseph 
Published: January 2023

Abstract
The adaptive immune system can act to prevent infection, reduce disease, and/or prevent shedding of viral pathogens. However, little is known about which specific adaptive immune responses affect each of these epidemiologic outcomes. Lymphocytic choriomeningitis virus (LCMV) is a natural pathogen of both mice and humans. We have shown that transmission from congenitally infected carrier mice occurs at high frequency while transmission from adult persistently infected mice is relatively inefficient. The major difference between these two groups is the presence (in adult infected) or absence (in congenitally infected) of an anti-viral adaptive immune response. We have investigated how CD4 T cell and B cell/antibody responses affect virus shedding from adult LCMV persistently infected mice. CD4-/- or immunocompetent C57BL/6 mice were infected with the clone-13 strain of LCMV and shedding of virus from body fluids sampled. Although we detected high titers of virus in the saliva and blood of all infected animals, we observed higher levels of transmission to susceptible mice from CD4-/- hosts compared to wild-type mice. Because we observed no detectable LCMV-specific antibody responses in the CD4-/- infected mice, these results suggest that CD4 T cells and antibodies may play a role in limiting virus transmission. We have used these data to parameterize mathematical models linking immunological responses with epidemiological outcomes of infection to generate new avenues of inquiry.
Lactobacillus rhamnosus GG (LGG) enhances virus-specific effector T cell responses induced by human rotavirus vaccine in neonatal human gut microbiota associated gnotobiotic pigs (P6320)
Authors: Yuan Lijuan , Wen Ke , Wang Haifeng , Shepherd Megan , Li Guohua , Yang Xingdong , Kocher Jacob , Giri-Rachman Ernawati , Karyala Saikumar , Settlage Robert 
Published: January 2023

Abstract
This study aims to enhance rotavirus vaccine efficacy through modulation of gut microbiota by probiotics and identify the underlying mechanism. We generated a human gut microbiota (HGM) associated neonatal pig model using stool samples from a newborn infant. Germ-free pigs were fed the fecal suspension daily starting at 12 hrs after birth for 3 days to establish human microflora in the pigs. The HGM pigs were divided into three groups: AttHRV only and AttHRV plus 9 or 14 doses of LGG. Daily LGG feeding started at 3 days of age. All the HGM pigs received the oral attenuated human rotavirus (AttHRV) vaccine at 5 days of age and then an oral booster dose 10 days later. A subset of the pigs in each group was challenged with a homotypic virulent HRV at post-AttHRV inoculation day 28. Frequencies of virus-specific IFN-γ producing T cells and TGF-β+/IL-10+FoxP3+ Treg cells in ileum, spleen and blood were determined. The 14-dose LGG regimen significantly increased LGG counts in large intestinal contents at 28 days of age and IFN-γ+CD8+ T cells at challenge and postchallenge and IFN-γ+CD4+ T cells postchallenge in ileum. LGG did not significantly alter frequencies of Tregs. The influence of LGG on the HGM is being characterized by 16sRNA gene V4 region Illumina MiSeq® sequencing. Studies using this novel pig model with defined human microbiota will provide clear evidence of LGG’s adjuvant effect and will facilitate establishment of effective dosing regimens of probiotics for humans.
Epstein-Barr virus infection induces aberrant TLR/MyD88 activation pathway and fibroblast-myofibroblast conversion in systemic sclerosis. (P6322)
Authors: Farina Giuseppina Alessandra , Farina Antonella , Cirone Mara , York Michael , Lenna Stefania , Padilla Cristina , Mclaughlin Sarah , Faggioni Alberto , Trojanowska Maria , Lafyatis Robert 
Published: January 2023

Abstract
Activated fibroblasts, mainly myofibroblasts are considered the principal mediators of fibrogenesis in systemic sclerosis (SSc), although the origin of persistent activation of fibroblasts and myofibroblasts is unclear. Activation of Interferon by Toll-like receptors in immune cells may play a role in the pathogenesis of inflammation in many autoimmune diseases, including SSc. We investigated whether fibroblasts persistently activated by innate immune and infectious stimuli might induce IFNs and TGFβ, two major markers of inflammation and fibrosis implicated in SSc pathogenesis. Since Epstein-Barr virus has been a leading candidate in triggering several autoimmune diseases, we developed methodology for infecting SSc fibroblasts with this virus. We found that EBV signals through the TLR/MyD88-pathway in infected-fibroblasts, activating a distinct innate immune response characterized by the expression of selected IFN- and TGFβ-inducible genes. Intriguingly, activation of the TLR/MyD88-pathway by CpGODN2006 or R837 ligand, significantly induced IFN-regulated genes, but no expression of TGFβ-regulated genes was detected in TLR/MyD88-stimulated fibroblasts. EBV-TLR/MyD88 aberrant activation induces the expression of selected IRFs, ISGs, TGFβ1 and several markers of fibroblast activation, such as smooth-muscle-actin and Endothelin-1, and all of these genes play a key role in determining the pro-fibrotic phenotype in SSc-fibroblasts.
Deconvoluting protective immune responses elicited by the live-attenuated 17D yellow fever virus vaccine (P6324)
Authors: Watson Alan , Lam LK Metthew , Klimstra William , Ryman Kate 
Published: January 2023

Abstract
The safe and efficacious live-attenuated 17D yellow fever virus (YFV) vaccines provide a benchmark for immunization. The contribution of 17D elicited humoral and cell-mediated responses to protection from challenge with wtYFV remains unknown due to a lack of tractable animal models of immunization and disease. By artificially reproducing the primate-specific phenotype of wtYFV to circumvent type I IFN control, we developed a murine model in which challenge with an otherwise lethal wtYFV is limited to low-level replication in the draining lymph nodes following 17D immunization. Moreover, the fatal viscerotropic disease and cytokine storm afflicting naive animals is completely abrogated. Similar to humans, 17D immunization in our model elicits neutralizing antibodies as well as robust YFV-specific CD4+ and CD8+ T cell accumulation with polyfunctional cytokine profiles and markers of early memory differentiation. Transfer of immune sera, CD4+/CD8+ T cells and/or B cell populations from 17D-immunized mice into naïve mice prior to challenge with wtYFV indicates that antibodies are not solely responsible for protection. However, YFV-specific T cells elicited in naive mice infected with wtYFV accumulate to higher numbers than in 17D vaccinated mice, yet fail to protect. We are currently comparing 17D and wtYFV infections to deconvolute mechanisms of 17D-induced immunogenicity and wild-type YFV immune evasion.
The significance of tyrosine kinase 2 gene in encephalomyocarditis-D virus-induced diabetes as studied in Tyk2 gene knockout mice (P6334)
Authors: Nagafuchi Seiho , Teshima Miho , Kai Yuji , Kai Katsuya , Izumi Kenichi , Kurisaki Hironori , Katsuta Hitoshi , Nagafuchi Seiho 
Published: January 2023

Abstract
Type 1 diabetes mellitus results form progressive loss of pancreatic β cells. The virus, as one of environmental factors, has been long considered to play a role in the development of type 1 diabetes. The D variant of encephalomyocarditis (EMC-D) virus induced susceptible strain of mice to become type 1 diabetes. We have already reported that innate immunity may play an important role in protection against EMC-D virus-induced diabetes (Arch Virol, 2008). In the present study, we analyzed the role of Tyk2 gene in the pathogenic mechanism of EMC-D virus-induced diabetes by using Tyk2 gene knockout (KO) mice. Tyk2 gene KO C57BL/6J mice, mouse strain resistant to EMC-D virus-induced diabetes, developed diabetes. In order to examine whether Tyk2 gene expression was important in parenchymal or immune cells to protect against EMC-D virus-induced diabetes, we developed splenic chimera mice. Tyk2 gene expression was important in parenchymal cells, but not in spleen cells, to resist against EMC-D virus-induced diabetes. Consistently, mice specifically expressed Tyk2 gene only in pancreatic β cells prevented EMC-D virus-induced diabetes. These observations suggest that Tyk2 gene expressed in pancreatic β cells plays a significant role in preventing EMC-D virus-induced diabetes in mice.
Dengue virus nonstructural protein 1 vaccine protects against lethal challenge in interferon α/β receptor-deficient mice (P6348)
Authors: Beatty P Robert , Orozco Susana , Killingbeck Sarah , Zompi Simona , Harris Eva 
Published: January 2023

Abstract
Dengue virus (DENV) is a flavivirus that infects 100 million people and causes severe disease in ~500,000 people annually. DENV nonstructural protein 1 (NS1) is secreted by infected cells and found at high levels in patient sera during the acute illness. To investigate the potential for NS1 as a vaccine candidate, we examined the protective efficacy of immunization with recombinant NS1 protein against lethal DENV infection in a mouse model. Interferon α/β receptor-deficient mice were injected intraperitoneally 3 times over an 8-week period with 20 ug recombinant NS1 with different adjuvants, including alum, Sigma adjuvant system (SAS), CpG DNA, MF59 and/or monophosphoryl lipid A (MPLA). Two weeks after the third immunization, vaccinated mice were infected with a lethal dose of DENV2. Vaccination with NS1 combined with SAS and CpG DNA provided complete protection against mortality along with reduced morbidity whereas mice immunized with NS1 combined with alum and/or CpG DNA displayed little or no protection against DENV2 challenge. All vaccination groups demonstrated comparable levels of total anti-NS1 IgG; however, mice immunized with SAS+CpG had higher levels of anti-NS1 IgG2b as compared to alum (p=0.057). Data comparing mice immunized with NS1 together with MPLA and MF59 will also be presented. Thus, immune responses to a DENV nonstructural protein can provide protection against severe disease and NS1 may provide an alternative vaccine against dengue.
T cell mediated mortality in neonatal mice upon LCMV infection (P6302)
Authors: Kenney Laurie , Carter Erik , Selin Liisa 
Published: January 2023

Abstract
Newborns are more susceptible to infections due to their lack of immunological memory and under-developed immune systems. Passive maternal immunity protects neonates until their immune systems have matured. We questioned if a noncytolytic virus that produces strong T cell responses in adults would also induce a response in neonates. Neonates were infected with LCMV at 5e4, 500, 50, 5 and 0.5 PFU. Surprisingly, at all doses the majority of pups succumbed to infection during the peak of the T cell response. Death was caused by T cell-dependent pathology and not viral load as 100% of T cell deficient pups survived with minimal lung and liver pathology. However, passive immunity from LCMV-immune mothers protected 100% of pups from death by helping control viral load early in infection. In adult mice high antigenic stimulation can cause over-activation of T cells leading to clonal exhaustion, where cells undergo a stepwise loss of function. Clonal exhaustion allows for survival from some high dose viral infections and results in persistent infection. We found that neonates without passive immunity that survived to day 14 did not show signs of T cell clonal exhaustion. Furthermore, surviving pups were not persistently infected, clearing virus by week 3. Neonates are commonly thought to have less functional immature immune systems, but these results show that neonates are capable of producing strong T cell responses that contribute to increased mortality.
IL-22 driven neutrophils afford critical protection from acute murine cytomegalovirus infection (P6310)
Authors: Stacey Maria , Marsden Morgan , Dolton Garry , Stack Gabrielle , Jones Emma , Taylor Philip , Jones Simon , Snelgrove Robert , Wilkinson Gavin , Humphreys Ian 
Published: January 2023

Abstract
Pathogenic herpesviruses including cytomegalovirus target numerous host organs during infection, but the immunological mechanisms that afford antiviral protection in different tissue microenvironments require a better understanding. Utilizing the murine cytomegalovirus (MCMV) model, we demonstrate that neutrophils are critical antiviral effector cells that counter acute herpesvirus infection. Depletion of Ly6G+ neutrophils exacerbated virus-induced weight loss and elevated virus load in a tissue-restricted manner. Neutrophils profoundly and directly inhibited virus replication in vitro. MCMV-elicited neutrophil responses were orchestrated by interleukin-22 (IL-22), which was expressed by conventional NK cells and induced neutrophil-attractant chemokines in MCMV-infected peripheral organs. These data demonstrate that IL-22 affords anti-herpesvirus infection in peripheral tissue and highlights a previously unappreciated and critical role for neutrophils in countering cytomegalovirus infection.
Memory CD8 T cells that are bystander-activated during an infection control early pathogen replication in an innate-like manner (P4371)
Authors: Prlic Martin , Chu Talyn 
Published: January 2023

Abstract
Recent studies illustrate that during an infection the antigen non-specific memory CD8 T cell compartment is not simply an inert pool of cells, but can participate in the immune response. This bystander activation of memory CD8 T cells occurs in the absence of cognate antigen recognition, but the overall role of T cell receptor (TCR) mediated signals has not been defined. Furthermore, it is unknown if and how these cells contribute to the clearance of an infection. We measured the strength of TCR signals that bystander activated CD8 T cells (BA-CTLs) receive in vivo and found evidence of TCR signaling, albeit limited. Given this marginal contribution of the TCR, we sought to determine how BA-CTLs efficiently kill target cells. We demonstrate that BA-CTLs recognize and directly eliminate target cells in an innate-like, granzyme-dependent manner. We next selectively inhibited BA-CTL mediated killing in vivo during the course of an infection, which led to a significant defect in pathogen clearance. Our data suggest that BA-CTLs play a previously unappreciated, essential role in the early immune response to pathogens before the onset of a de-novo generated, primary CD8 T cell response.
Switching on memory CD8+ T cells for enlarged pathogen-specific protection (P4375)
Authors: M'Homa Soudja Saidi , Chandrabos Ceena , Veenstra Mike , Ruiz Anne L. , Julien Marie , Lauvau Gregoire 
Published: January 2023

Abstract
Memory CD8+ T cells induced upon immunization exhibit improved functional features that contribute to protection of immunized hosts. Although both cognate antigen recognition and inflammation are important for memory CD8+ T cell reactivation, the relative contribution of these factors and the cell types providing these signals in vivo are poorly defined. In recent work, we have shown that Ly6C+CCR2+ inflammatory monocytes, a subset of monocytes, largely orchestrate memory CD8+ T and NK lymphocytes to become potent effector cells by sensing IL-18 and IL-15-derived inflammatory cytokines from monocytes independently of their cognate antigen. Like NK cells, they underwent rapid mobilization, upregulated intense and sustained effector functions during bacterial, viral and parasitic infections, and contributed to innate responses and protection in vivo. In our most recent experiments, we investigate further the molecular mechanisms of cross-talk between activated memory T cells and innate immune effector cells that allow for pathogen-specific protective immunity. Our results unravel a novel and unexpected level of antigen-dependent spatio-temporal tissue organization that is essential to achieve quick and efficient pathogen confinement and killing. This mechanism depends on memory T cell-derived IFN-γ and chemotactic cues, and on effector monocytes. We will present and discuss these data.