bluuebunny/crossref_metadata_2025_split huggingface dataset:
Anergy-derived Foxp3+ T regulatory cell differentiation in the neonatal mouse
Authors: Morales Milagros Silva , Mueller Daniel L 
Published: January 2023

Abstract
The neonatal period is a natural scenario to study the effects of peripheral self-antigen (Ag) recognition by autoreactive conventional CD4+ T cells under conditions of low Foxp3+ T regulatory cell (Treg) numbers and function. Moreover, the neonatal environment is an interesting scenario to study the relationship between the induction of CD4+ T cell anergy and the peripheral generation of anergy-derived Tregs, given that anergy induction relies on normal Treg function whereas anergy-derived Treg generation is optimal in the setting of Treg cell deficiency. We have hypothesized that the neonatal period is both necessary and sufficient to allow for the induction of anergy as well as the peripheral differentiation of anergy-derived Foxp3+ Tregs from naive conventional CD4+ T cells during self-Ag recognition.
To test our hypotheses we developed a system of neonatal peripheral tolerance induction. Neonatal pups engineered to express the experimental “self” peptide Ag chicken ovalbumin (OVAp) were given OVAp/I-Ab–specific OT-II CD4+ T cells, and the pups were later examined for anergy induction, Treg differentiation, and development of autoimmunity. Our data demonstrate that in the neonatal period: 1) previously naive CD4+ T cells express markers of anergy following exposure to self-Ag, and a small fraction of these cells can be seen to differentiate to a Foxp3+ Treg phenotype, and 2) previously anergic CD4+ T cells typically retain their anergic phenotype but also give rise to a substantial fraction of Foxp3+ Tregs, and 3) animals remain free of autoimmune disease. These findings suggest that during the neonatal period peripheral Foxp3+ Treg cell differentiation may proceed through a conventional anergic CD4+ T cell intermediate.
TAGLN2 is essential for both dendritic cell migration and dendritic cell-mediated T cell stimulation
Authors: Jun Chang-Duk 
Published: January 2023

Abstract
Actin polymerization and depolymerization are essential for many aspects of cell function including migration, adhesion, and activation. However, the importance of actin stabilization has been relatively underestimated. Here, we show that TAGLN2—a small 22-kDa actin-stabilizing protein—is critical for dendritic cell (DC) functioning in vitro and in vivo. TAGLN2 is minimally expressed in DCs, but highly upregulated in response to lipopolysaccharide (LPS), suggesting that TAGLN2 may play a certain role in DCs under the inflammatory conditions. Knockout of TAGLN2 (TAGLN2−/−) gene revealed normal differentiation and activation in terms of their surface marker expression and cytokine production by LPS. Interestingly, however, TAGLN2−/− DCs showed attenuated ability to prime CD4+ T cells as a result of weak contact between DCs and T cells. In addition to the T cell priming, we further observed drastic reduction of TAGLN2−/− DC homing to draining lymph nodes, suggesting that TAGLN2-mediated stabilization of filamentous actin (F-actin) is also important process for DC migration. Accordingly, knockout of TAGLN2 strongly reduced signals linked to the actin remodeling. Collectively, our findings indicate that TAGLN2 positively regulates DC migration and DC-evoked T cell responses via actin stabilization in processes that heavily require dynamic actin rearrangement.
Distinct roles of programmed cell death ligands 1 and 2, based on the type of immunity
Authors: Tanaka Ryota , Ichimura Yuki , Fujimoto Manabu , Okiyama Naoko 
Published: January 2023

Abstract
Programmed cell death-1 (PD-1) is an immuno-regulatory receptor binding to two ligands, PD-L1 and PD-L2, which are expressed on stimulated antigen presenting cells (APCs). Isolated APCs such as macrophages (Mϕ), dendritic cells (DC), and B cells were cultured with interferon (IFN)-γ, interleukin (IL)-4, and IL-17A, respectively, followed by PD-L1/L2 expression analysis using flow cytometry. Upon stimulation by IFN-γ on all APCs and IL-17A on Mϕ and B cells, respectively, strong and moderate upregulation of PD-L1 expression was observed over unstimulated controls. Only stimulation by IL-4 could upregulate PD-L2 expression on all APCs.
Therefore, experiments were performed on murine models, causing 2,4-dinitrofluorobenzene (DNFB)-induced contact hypersensitivity (CHS), fluorescein isothiocyanate (FITC)-induced CHS, and imiquimod (IMQ)-induced psoriasis-like dermatitis, in order to trigger IFN-γ-mediated T helper (Th)1, IL-4-mediated Th2, and IL-17A-mediated Th17-type responses, respectively. In both Th1 and Th17-type immunity models, ear thickness changes in PD-L1 deficient (PD-L1−/−) mice were more severe than in wild-type (WT) and PD-L2 deficient (PD-L2−/−) mice (PD-L1−/−: 26.6±3.0, WT: 12.0±1.8 and PD-L2−/−: 12.3±1.9 [μm] in DNFB-induced CHS; 9.5±0.7, 6.2±0.4 and 5.7±0.6 [μm] in IMQ-induced psoriasis-like dermatitis [P &lt; 0.01 by the U test], respectively). Thickness changes in PD-L2−/− were more severe than those in the WT and PD-L1−/− mice in the Th2-type immunity model (PD-L2−/−: 10.8±1.0, WT: 3.8±0.6 and PD-L1−/−: 3.6±0.6 [μm], [P &lt; 0.01 by the U test], respectively).
Collectively, PD-L1 has predominant roles in Th1 and Th17-type immunity; similarly, PD-L2 for Th2-type immunity.
RORγt-driven TH17 cell differentiation requires epigenetic control by the Swi/Snf chromatin remodeling complex
Authors: Seong Rho H , Lee Sungkyu , Kim Jieun , Min Hyungyu 
Published: January 2023

Abstract
Epigenetic regulation, including chromatin accessibility and posttranslational modifications of histones, is of importance for T cell lineage decision. TH17 cells play a critical role in protective mucosal immunity and pathogenic multiple autoimmune diseases. The differentiation of TH17 cells is dictated by a master transcription factor, RORγt. However, the epigenetic mechanism that controls TH17 cell differentiation remains poorly understood. Here we show that the Swi/Snf complex is required for TH17-mediated cytokine production both in vitro and in vivo. We demonstrate that RORγt recruits and forms a complex with the Swi/Snf complex to cooperate for the RORγt mediated epigenetic modifications of target genes, including both permissive and repressive ones for TH17 cell differentiation. Our findings thus highlight the Swi/Snf complex as an essential epigenetic regulator of TH17 cell differentiation and provide a basis for the understanding of how a master transcription factor RORγt collaborates with the Swi/Snf complex to govern epigenetic regulation.
IFN-γ-induced nitric oxide leads to inhibition of Th17 differentiation via induction of iNOS and nitration of ROR-γ T
Authors: Robinson-Joern Rachel , Dietz Alina , Garza Celeste , Moy Brian , Crisostomo Neil Elijah S. , Vukmirovic Dora , Forsthuber Thomas 
Published: January 2023

Abstract
Elucidating the molecular mechanisms involved in pleotropic cytokine signaling can lead to novel treatment approaches for autoimmune diseases that target proinflammatory functions while maintaining immune-regulatory functions. To that end, we sought to further investigate the immune-regulatory roles of the pleotropic cytokine IFN-γ. Previous studies demonstrated that IFN-γ prevents the differentiation of pathogenic Th17 cells. In addition, nitric oxide generated via inducible nitric oxide synthase (iNOS) prevents differentiation of Th17 cells by nitration of ROR-γT. However, it remains unresolved whether IFN-γ prevents Th17 differentiation directly via inducing nitric oxide (NO) and nitration of ROR-γT. In line with previous observations, we found an increase in the frequency of autoreactive Th17 cells and a decrease in iNOS expression and NO in the absence of IFN-γ in mice with experimental autoimmune encephalomyelitis (EAE), an animal model of multiple sclerosis. Additionally, the increase in Th17 cells in the absence of IFN-γ was reversible both in vitro and in vivo with treatment with a NO donor. This indicates a role for IFN-γ in inhibiting the differentiation of Th17 cells via iNOS-derived NO. We are currently elucidating the underlying mechanisms of NO mediated suppression and the molecular link between ROR-γt-nitration and decreased Th17 differentiation by flow cytometry, single-cell western blotting of key transcription factors, and in vivo adoptive transfer studies. Our studies may lead to a better understanding of the role of IFN-g and NO/iNOS axis in Th17 cell differentiation and autoimmune diseases.
Evidence for a prescribed NK cell Ly49 developmental pathway in mice
Authors: Millan Alberto Jovani , Sindi Suzanne , Manilay Jennifer O. 
Published: January 2023

Abstract
Previous studies of NK cell Ly49 receptors suggest that the inhibitory receptor expression is stochastic. However, similar studies of activating Ly49 receptors have not been an area of focus. We hypothesize that the expression of activating receptors is not stochastic. We analyzed NK cell “clusters” expressing 16 combinations of Ly49I, Ly49G2, Ly49H and Ly49D in B6 mice. We sorted the 16 clusters, and cultured them with IL-15 for 6 days. In parallel, we also transplanted a select group of clusters in vivo. We discovered a prescribed pathway of cluster transitions in vitro and in vivo, and these data suggest that Ly49 activating receptor acquisition is not stochastic. We found that the majority of clusters that express activating receptors maintain their expression. In addition, Ly49D, which is not reported to have an MHC-I ligand in B6 mice, was upregulated on clusters that transition in the prescribed pathway. Previously, other groups have used the product rule to mathematically predict the independent expression of Ly49 inhibitory receptors. However, the product rule has not been applied to predict activating Ly49 receptor frequencies. Our application of the product rule to our data suggest that Ly49H and Ly49D expression is not independent and cannot be predicted by this mathematical model. This suggests that the biological system that controls the Ly49 activating receptors is distinct from inhibitory receptors. Currently we are investigating whether MHC-I is critical in the prescribed pathway via the transplantation of these clusters in MHC-I-deficient mice. Taken together, these data support the idea that NK cell clusters develop in a sequential, non-random manner that is determined by expression of activating Ly49 receptors.
Bile acid metabolites control Th17 and Treg cell differentiation
Authors: Hang Saiyu , Paik Donggi , Yao Lina , Jamma Trinath , Lu Jingping , Ha Soyoung , Nelson Brandon N , Kelly Samantha P , Wu Lin , Zheng Ye , Longman Randy S , Rastinejad Fraydoon , Devlin A Sloan , Krout Michael R , Fischbach Michael A , Littman Dan R , Huh Jun R 
Published: January 2023

Abstract
Bile acids are abundantly present in the mammalian gut, where they undergo bacteria-mediated transformation, generating a large pool of bioactive molecules. While they have been shown to affect host metabolism, cancer progression and innate immunity, it is unknown whether bile acids affect the function of adaptive immune cells such as T cells expressing IL-17a (Th17 cells) and regulatory T cells (Tregs) that mediate inflammatory and anti-inflammatory responses, respectively. By screening a small-molecule library primarily composed of bile acid metabolites, we identified two distinct derivatives of lithocholic acid (LCA), 3-oxoLCA and isoalloLCA, as specific regulators of Th17 and Treg cells. While 3-oxoLCA inhibited Th17 cell differentiation by directly binding to its key transcription factor RORγt (retinoid-related orphan receptor γt), isoalloLCA enhanced Treg differentiation through the production of mitochondrial reactive oxygen species (mitoROS), leading to increased FoxP3 expression. IsoalloLCA-mediated Treg enhancement required an intronic FoxP3 enhancer the conserved noncoding sequence 3 (CNS3), suggesting a distinct mode of action from other previously identified Treg enhancing metabolites that require CNS1. Lastly, oral administration of 3-oxoLCA and isoalloLCA to mice led to reduced Th17 and increased Treg cell differentiation in the intestinal lamina propria. Altogether, our data suggest novel mechanisms by which bile acid metabolites control host immune responses by directly modulating the Th17 and Treg balance.
Pathogen-elicited memory γδ T cells express a broadly reactive canonical TCR or a pathogen-specific non-canonical TCR
Authors: Khairallah Camille F , Bettke Julie , Imperato Jessica Nancy , Zhang Yue , Qiu Zhijuan , Gorbatsevych Oleksandr , Cho Kyungjin , Kim Kwang Soon , Puddington Lynn , Surh Charles D , Bliska James B , Van der Velden Adrianus WM , Sheridan Brian S 
Published: January 2023

Abstract
γδ T cells are critical sentinels protecting barrier surfaces against pathogens. However, our understanding of γδ T cell specificity remains limited. We previously identified a resident memory Vγ4Vδ1 T cell population elicited by foodborne Listeria monocytogenes (Lm) infection. Analysis of the CDR3δ sequences revealed that a large subset of non-canonical clones expanded during primary Lm infection, contracted during memory homeostasis and recalled after secondary Lm infection suggesting antigenic-specificity may be involved in this response. However, most of the response was elicited by cells bearing a canonical Vδ1 TCR suggesting that many Lm-elicited cells may not be Lm-specific. Indeed, stimulation of mesenteric lymph node cells from Lm-immune mice with diverse pathogens induced a functional response by Lm-elicited memory γδ T cells. Similarly, induction of Salmonella colitis (STm-colitis) in Lm-immune mice resulted in a TCR-dependent γδ T cell recall-like response, demonstrating that the majority of these memory cells respond to heterologous infection. Interestingly, most of the non-canonical γδ T cell clones that responded to Lm infection did not expand in response to STm-colitis suggesting some level of specificity is imparted by the priming pathogen. Importantly, other enteropathogens triggered a recall-like response of Lm-elicited memory γδ T cells. Adaptive γδ T cells were also generated after foodborne infection of germ-free mice and in response to diverse bacterial infections of SPF mice, indicating that this population can be induced by a broad range of disseminating pathogens and may provide a broad target for universal mucosal vaccines of the gut.
Characterization of a potential Escherichia coli virulence factor identified in a screen using the social amoeba phagocyte, Dictyostelium discoideum
Authors: Snyder Michelle , Schmidt Katrina , Lane Jorden , Weichseldforfer Matthew 
Published: January 2023

Abstract
Escherichia coli are a typical component of mammalian gut microbiota; however, a number of pathogenic strains remain a health challenge for developing countries. To identify novel bacterial virulence factors, we used the social amoeba, Dictyostelium discoideum, which preys upon soil bacteria, including E. coli, as a model for mammalian phagocytic cells. Using random mutagenesis, screening for mutant E. coli strains resistant to killing upon phagocytosis, and genomic sequencing of these resistant strains, we identified mutations in several potential genes of interest, including an E. coli gene of unknown function, yfaT. Preliminary results suggest that D. discoideum Erk signaling is reduced in response to yfaT-deficient E. coli. Furthermore, mammalian TLR4 signaling in response to yfaT-deficient E. coli also appears attenuated. Our current studies focus on characterizing differences in growth patterns for wild-type and yfaT-deficient E. coli using Biolog screenings, as well as analyzing potential differences in LPS structure in these strains. These studies are aimed at identification and characterization of novel mechanisms that may be involved in bacterial virulence. In addition, given that the development of mechanisms to resist D. discoideum predation may have contributed to the selection and maintenance of bacterial virulence factors, such as yfaT, against mammalian hosts, these studies may provide insight on the evolution of host-pathogen interactions.
Interferon Receptor 2 (IFNAR2) is involved in regulation of host damage responses and fungal clearance during Aspergillus fumigatus pulmonary infection
Authors: Shepardson Kelly , Johns Laura Logan , Malkoc Zeynep , Hernandez Emiliano , Schulein Clyde , Rynda-Apple Agnieszka 
Published: January 2023

Abstract
Three million people globally suffer from infections caused by Aspergillus fumigatus (Af). Over 300,000 of these cases are due to invasive pulmonary aspergillosis (IPA) in patients with suppressed immune systems. The recent increase of aspergillosis in influenza-infected patients suggests that influenza infection creates transiently suppressed immune environments permissive to fungal infection. Consistent with this, we found that influenza infected WT mice had increased Af lung fungal burden and cellular damage compared to Af-only infected mice. We recently discovered that type I interferon (IFN) signaling, via IFNAR2 of the IFNAR1/2 receptor, regulates susceptibility to and damage from influenza. A main factor contributing to IPA pathology and outcome is the level of damage the host incurs. Importantly, we found that IFNAR2 deficiency (Ifnar2−/− mice) resulted in increased cellular damage and morbidity at 24 hrs post-Af compared to WT and Ifnar1−/− mice. Interestingly, Ifnar2−/− mice cleared spores more efficiently than both WT and Ifnar1−/− mice but were unable to control invasive disease and maintain pulmonary architecture, evidenced by hyphal growth and fibrosis-like tissue at 48 hrs post-Af. Although cellular recruitment was unaltered, the levels of inflammatory cytokines in Ifnar2−/− mice was two-fold higher than WT and Ifnar1−/− mice, and Ifnar2−/− neutrophils produced more external ROS in response to Af suggesting altered effector cell function may be involved in the IFNAR2 regulated damage response. Together, our results begin to establish a role for IFNAR2 in regulation of the host damage response to Af and suggest that aberrant type I IFN signaling creates a permissive environment allowing for Af infection to occur.
Controlled human infection with Neisseria lactamica induces B-cell responses that are cross-reactive with Neisseria meningitidis
Authors: Dale Adam P , Theodosiou Anastasia A , Laver Jay R , Roche Eleanor F , Hill Alison R , Gorringe Andrew , Polak Marta E , Vaughan Andrew T , Read Robert C 
Published: January 2023

Abstract
Neisseria lactamica (Nlac) is a commensal of the human oropharynx. Colonisation with Nlac significantly reduces colonisation by N. meningitidis (Nmen). We hypothesised that cross-reactive adaptive cellular immune responses were responsible for this effect.
31 volunteers were inoculated intra-nasally with 105 colony-forming units of Nlac or vehicle control. Nlac/Nmen colonisation status was assessed at baseline and 7-, 14- and 28-days post-inoculation. Nlac/Nmen-specific plasma cells (PCs)/memory B-cells were quantified in PBMCs at all time points using ELISpot assays.
Amongst Nlac-colonised volunteers (n=17), Nlac-specific PC frequencies/2×105 PBMCs increased significantly. Median baseline vs. post-colonisation peak Nlac-specific PC frequencies were 0 (range 0–0.5) vs. 2 (0–31) for IgM, 0 (0–1) vs. 5 (0–20.5) for IgA, and 0 (0–1) vs. 3 (0–27) for IgG (all p&lt;0.0001). Nlac-specific IgG memory B-cell frequencies also increased significantly from baseline to day 28 (0.000% vs. 0.04%, p&lt;0.0001). Interestingly, there was also a significant increase in IgM, IgA and IgG Nmen-specific PCs amongst Nlac-colonised volunteers. Median baseline vs. post-colonisation peak Nmen-specific PC frequencies were 0 (0–0) vs. 0 (0–30) for IgM, 0 (0–1) vs. 0.5 (0–8.5) for IgA, and 0 (0–0.5) vs. 0.5 (0–10) for IgG (all p≤0.01). There was no induction of Nlac-specific PCs/memory B-cells in the control group (n=10).
These data suggest that the previously observed protective effect of Nlac on Nmen colonisation may have an immunological basis. We plan to assess the frequency/effector phenotype of Nlac-specific CD4+ memory T-cells following Nlac colonisation and hypothesise that cross-reactive CD4+ memory T-cells directed towards Nmen will be Th17.
Immune respones against Trypanosoma cruzi infection by oral route in cynomolgus macaques (Macaca fascicularis)
Authors: Nehete Pramod N , Chitta Sriram , Nehete Bharti P , Abee Christian R , Hamer Sarah A , Hodo Carolyn L , Wilkerson Gregory K 
Published: January 2023

Abstract
American Trypanosomiasis is an important neglected reemerging tropical parasitism, infecting about 8 million people worldwide. Its agent, Trypanosoma cruzi, exhibits multiple mechanisms to evade the host immune response and infect host cells. An important immune evasion strategy of T. cruzi infective stages is its capacity to inhibit the complement system activation on the parasite surface, avoiding opsonizing, immune stimulating and lytic effects. Eight male M. fascicularis between 8 and 10 years of age of Chinese origin were infected through oral administration of T. cruzi-infected triatomine bugs and followed over 6 weeks. The purpose of this study was to define cellular immunological responses in T. Cruzi challenged M. fascicularis. We measured immunofluorescent staining and multifunctional T. cruzi antigen specific T-cell responses in experimental infected M. fascicularis. Significant increases in the CD4+ T-cell population and polyfunctional T cell responses were observed in all experimental-infected animals compared with the uninfected time points. We observed a decrease in absolute number of lymphocytes, T cells and T cell subsets, in early phase of infection but recovered in later period. T. cruzi antigen specific IFN-g and IL-12p40 ELISPOT showed no significant infection specific responses during the study period. Circulating cytokines measurement in plasma revealed a significant increase IFN-g and IL-1ra during infection period. In conclusion, our present findings provide the first evidence demonstrating the Trypanosoma cruzi infection by oral route.
The tropic life forms of Pneumocystis alter alveolar macrophage responses to inflammatory stimuli
Authors: Garvy Beth A , Pickett Carol L , Hollifield Melissa L 
Published: January 2023

Abstract
Pneumocystis is an opportunistic fungal pathogen that causes pneumonia in immunosuppressed individuals including patients with HIV. There are two identifiable life forms of Pneumocystis including a cyst or ascus form that has a β-glucan-rich fungal cell wall and a trophic form that lacks the cell wall. In infected lungs the trophic forms can outnumber the asci by as much as 10 to 1. We have previously published that the trophic forms of Pneumocystis are able to inhibit the production of pro-inflammatory cytokines such as TNF induced by β-glucans or LPS in bone marrow-derived dendritic cells. Recently we found that trophic forms also inhibit TNF production by alveolar macrophages when stimulated in vitro. To understand relevance of this observation during Pneumocystis infection, RAG−/− mice were infected with the trophic forms of Pneumocystis, treated with an echinocandin drug to prevent the formation of ascus forms, and challenged with a low dose of LPS given intratracheally. Twenty-four hours later bronchial alveolar lavage fluids were obtained and TNF quantitated. The trophic forms of Pneumocystis significantly inhibited the production of TNF in mice challenged with LPS compared to those given LPS alone or LPS plus echinocandin. Interestingly, there was no difference in the influx of neutrophils into the lungs in LPS-treated mice compared to trophic form infected and LPS-treated mice. It is well known that TNF is an important factor in host defense against Pneumocystis while neutrophils have not been shown to enhance clearance but coincide with lung pathology. Together our data indicates that trophic forms of Pneumocystis alter selected parts of the inflammatory milieu of the lungs.