bluuebunny/crossref_metadata_2025_split huggingface dataset:
TLR5 expression by CD11b+CD4- splenic dendritic cells enhances T cell responses to low dose flagellin immunization (158.15)
Authors: Atif Shaikh , Letran Shirdi , McSorley Stephen 
Published: January 2023

Abstract
Previous studies have demonstrated that TLR5 functions as an endocytic receptor, enhancing antigen presentation to flagellin-specific CD4 T cells. Here, we show that this enables flagellin-specific CD4 T cell activation to occur with low concentrations of antigen in vitro and in vivo. We used this sensitive functional read-out to examine TLR5 expression by splenic dendritic cells (DCs). While CD11b+CD4- DCs were able to activate flagellin specific T cells in a TLR5-dependent manner, CD11b+CD4+ or CD11b-CD8a+ DCs did not. We also examined the role of NLRC4 in flagellin-specific CD4 responses and have found that NLRC4 plays a modest additonal role in enhancing CD4 responses in vitro. Together, these data indicate that CD11b+CD4- DCs express TLR5 and are ideally poised to initiate adaptive immune responses to bacterial flagellins.
Genetic analysis of the CpG hyporesponsiveness in wild-derived MOLF/Ei mice (158.16)
Authors: Moseman Annie , Poltorak Alexander 
Published: January 2023

Abstract
CpG motif containing oligonucleotides are used to mimic the immunostimulatory properties of bacterial DNA in both innate and adaptive immune cells through the activation of toll-like receptor 9. Macrophages are one of the main cell types activated to elicit a pro-inflammatory response to CpG DNA. Downstream signaling of TLR9 is more well characterized and studied compared to upstreams events which remains largely unknown, such as what receptors and mechanisms are involved in CpG DNA receptor-mediated endocytosis and trafficking into endosomal compartments. While all classical laboratory mouse strains are responsive to CpG DNA activation a wild-derived inbred mouse strain, MOLF/Ei, is non-responsive. In this study we have used a forward genetics approach to analyze the CpG response in peritoneal macrophages from panels of N2 backcross mice [MOLF/Ei x (C57BL/6xMOLF/Ei)]. Our genome-wide linkage studies implicate, for the first time, the role of the mannose receptor, C type 1 (Mrc1) in the CpG hypo-responsiveness in MOLF/Ei mice. Furthermore, additional mapping studies have revealed a second receptor that is also involved in CpG DNA signaling for both classical and wild-derived mouse strains, implicating its role in CpG activation for the first time.
Epigenetic mechanisms underlying the reduced response of dendritic cells from aged humans to influenza infections (158.22)
Authors: Agrawal Anshu , Ulagaoozhian Sangeetha , Nguyen Michelle , Agrawal Sudhanshu , Gupta Sudhir 
Published: January 2023

Abstract
Increased susceptibility to respiratory infections is a major cause of age-related morbidity and mortality. Impaired age-associated T and B cell responses are prime suspect yet the mechanisms responsible for the increased risk are complex and are not well understood. Studies in recent years highlight the importance of innate immune cells such as dendritic cells (DC) in fighting infections and generating protective immunity. Our results indicate that monocyte derived DCs from aged subjects display a higher basal level of activation as evidenced by increased activation of NFkB at the basal level. Moreover, the response of aged DCs to influenza virus is impaired and there is reduced secretion of IFN-I and IFN-III compared to their young counterparts. During viral infections, IFNs are expressed and constitute perhaps the most important line of innate antiviral defense. Type III IFNs act specifically on mucosal epithelia and therefore, play an important role in the defense against infections of the respiratory tract. Our investigations using chromatin immunoprecipitation (CHIP-IP) with histone antibodies suggest that there may be increased association of IFN-I and IFN-III promoters with suppressor histone, H3K9 in aged DCs. Age-associated chromatin remodeling may therefore be responsible for the reduced secretion of IFNs by aged DCs and increased susceptibility to influenza infections.
Respiratory Syncytial Virus infection induces alternatively activated macrophages in the lung (158.3)
Authors: Raundhal Mahesh , Krishnamoorthy Nandini , Khare Anupriya , Yarlagadda Manohar , Ray Anuradha , Ray Prabir 
Published: January 2023

Abstract
Asthma is a chronic inflammatory disease of the airways characterized by a heightened response to normally harmless antigens. Respiratory Syncytial Virus (RSV) infections in children have been associated with predisposition to asthma in later life. However, the underlying molecular mechanisms are not well understood. RSV infection was recently shown to induce Th2 type cytokines such as IL-13 within 6 days after infection. Given this early induction of IL-13, we hypothesized that the source of RSV-induced IL-13 is a cell of the innate immune system. Our ongoing studies show rapid induction of alternatively activated macrophages (AAMs) in the lung following RSV infection. RSV induces expression of Arginase I (Arg I), a characteristic marker of AAMs and stimulates secretion of the Th2 cytokines IL-5 and IL-13 from the alveolar macrophages as early as 48 hours after infection. This was found to continue on day 5 after infection, being detectable in the lung tissue as well. These observations suggest that RSV, directly or indirectly, alters gene expression in alveolar macrophages very early after infection, which we hypothesize plays an important role in promoting an allergic immune response in the infected lungs.
Restoration of anti-Aspergillus defense by NETs in human CGD after gene therapy is calprotectin-dependent (158.5)
Authors: Bianchi Matteo , Niemiec Maria , Siler Ulrich , Urban Constantin , Reichenbach Janine 
Published: January 2023

Abstract
Aspergillus spp infection is a potentially lethal disease in patients with neutropenia or impaired neutrophil function. We have previously shown that Aspergillus hyphae which are too large for neutrophil phagocytosis are inhibited by reactive oxygen species dependent neutrophil extracellular trap (NET) formation. This process is defective in chronic granulomatous disease (CGD) due to impaired phagocyte NADPH oxidase function. Here we determined the antifungal agent and mechanism responsible for reconstitution of Aspergillus growth inhibition within NETs after complementation of NADPH oxidase function by gene therapy (GT) for CGD. We identified the host Zn2+ chelator calprotectin as neutrophil-associated antifungal agent expressed within NETs, reversibly preventing A. nidulans growth at low concentration, and leading to fungal starvation at higher concentration. Specific antibody-blocking and Zn2+ addition abolished calprotectin-mediated inhibition of A. nidulans proliferation in vitro. The role of calprotectin in anti-Aspergillus defence was confirmed in calprotectin knockout mice. Reconstituted NET formation by GT for human CGD was associated with rapid cure of pre-existing therapy refractory invasive pulmonary aspergillosis in vivo, underlining the role of functional NADPH oxidase in NET formation and calprotectin release for antifungal activity. These results demonstrate that calprotectin is a critical factor in the human innate immune defense to Aspergillus infection.
Human TLT2 is expressed on and potentiates chemotaxis of cells of both myeloid and lymphoid lineage (158.6)
Authors: Thomas Kimberly , King R. , Justement Louis 
Published: January 2023

Abstract
The TREM locus encodes a family of innate immune receptors, which play diverse roles in modulating the immune response. Trem-like transcript 2, or TLT2, is the only family member expressed on both myeloid and lymphoid cells, and is conserved among mouse and man, with 60% sequence homology between murine (m) and human (h) TLT2. Previous work by our lab defined the expression pattern for mTLT2 on cells of the immune system: granulocytes, macrophages, and B cells all express mTLT2, whereas monocytes and T cells do not. When mTLT2 is ligated with αTLT2 1C5 mAb, neutrophil chemotaxis is enhanced in a dose dependent manner in response to chemokines. To further understand the biological function of TLT2, our lab has characterized hTLT2 expression on peripheral leukocytes and studied its role in potentiating chemotaxis. Human granulocytes, monocytes, macrophages, NK cells, and B cells all express hTLT2 on their surface. Furthermore, interaction with antigen and differentiation downregulates surface expression of hTLT2 on B cells. In contrast, activation of granulocytes or monocytes with PMA upregulates hTLT2 expression. Lastly, naive, memory, and in vitro activated T cells do not express hTLT2, opposed to results from other groups. Functionally, ligation of hTLT2 augments B cell chemotaxis towards CXCL13, and neutrophil migration towards IL-8. In this regard, we observe hTLT2 and mTLT2 to have conserved phenotypic expression and function throughout the immune compartment.
Effects of novel TOR inhibitors on B cell differentiation (159.5)
Authors: Limon Jose , Lomon So , Ke Qiao , Corado Juana , Fruman David 
Published: January 2023

Abstract
A promising drug target frequently disregulated in many cancers is TOR (target of rapamycin). TOR kinase functions in two complexes, TORC1 and TORC2. TORC1 is sensitive to rapamycin that acts as an allosteric inhibitor. Rapamycin and its analogs (rapalogs) are potent immunosuppressants, but have shown limited efficacy in cancer therapy. We reported in Nature Medicine (PMID:20072130) that PP242, an active-site TOR inhibitor (asTORi), has improved anti-leukemic efficacy compared to rapamycin. Unexpectedly, PP242 at anti-leukemic doses had a lesser effect in vitro on lymphocyte proliferation and in vivo on lymphocyte function. Here we present new data comparing rapamycin with asTORi using in vitro assays of B cell differentiation. asTORi treatment increased the number of IgG switching B cells and decreased the differentiation of early antibody-secreting cells. IgM secretion was also decreased with asTORi treatment. We observed similar effects when B cells were treated with an inhibitor that targets Akt, a known TORC2 substrate. Rapamycin potently inhibited B cell differentiation at an early step before commitment to cell division. Gene expression analysis revealed an increased in FOXO target genes AID and Bcl6, and a decrease in BLIMP-1 expression in asTORi-treated B cells. These data indicate that asTORi alter the balance of B cell differentiation, likely through modulation of the TORC2/Akt/FOXO signaling axis.
Expression of a functional B cell receptor with the specificity of VRC01, a broadly neutralizing antibody against HIV (159.8)
Authors: Guo Xiaoti , Yang Zhiyong , Panet Amos , Liu Wanli , Pierce Susan , Nabel Gary 
Published: January 2023

Abstract
VRC01, a CD4-binding site antibody that neutralizes over 90% of HIV-1 isolates has recently been identified. One of its unusual features is that the variable domain goes through extensive somatic hypermutation (30%) from its germline precursors, which leads to greatly enhanced binding affinity and neutralization capacity. To understand the somatic hypermutation process of VRC01 during B cell development and to identify immunogens that drive the affinity maturation of VRC01, the B cell receptor (BCR) form of VRC01 and its germline precursor 02*02 was expressed and examined for antigen-binding, BCR microclustering and BCR signaling. Co-expression of surface IgM and kappa chain transgenes was detected on 293T and Ramos cells by either transfection or lentivirus-mediated transduction. The transgenic VRC01 BCR bound to different gp120 variants as determined by flow cytometry. The VRC01 BCR also exhibited higher binding affinity to the gp120 Resurfaced Stabilized Cores (RSC3) presented on lipid bilayers than to the mutant form ΔRSC3 as indicated by more BCR microclusters upon binding to RSC3. Stimulation of VRC01-BCR-expressing B cells with RSC3 or anti-IgM induced phosphorylation of the B cell signaling tyrosine kinases Fyn and Syk. In conclusion, a functional VRC01-BCR was successfully expressed on 293T and B cells. This transgenic system allows us to test the feasibility of guiding the maturation of VRC01 with appropriate antigens.
IL-17 expression in γδ T cells is negatively controlled by IL-27 (160.12)
Authors: Visperas Anabelle , Do Jeong-Su , O'Brien Rebecca , Min Booki 
Published: January 2023

Abstract
Interleukin 27 (IL-27) is secreted by activated antigen presenting cells in response to inflammatory signals and plays both pro- and anti-inflammatory roles. Particularly interesting is that IL-27 has been shown to antagonize Th17 differentiation by suppressing the expression of Th17-promoting transcription factor, RORγt. However, immunoregulatory roles of IL-27 on non-CD4 T cells have not been extensively examined. γδ T cells account for a small subset of peripheral T cells and have been recently considered ‘innate’ IL-17 producers because of their spontaneous IL-17 expression. We found that in the absence of IL-27ra (WSX-1) on γδ T cells, IL-17 production was dramatically enhanced compared to WT γδ T cells. These cells possessed a highly activated phenotype where a majority was CD44high, increased expression of CCR6 consistent with increased IL-17 production, and an altered Vγ repertoire. In vitro stimulation of γδ T cells in the presence of exogenous IL-27 failed to suppress IL-17 production, consistent with the notion that fully committed Th17 effector T cells are resistant to IL-27-mediated inhibition. We also found that enhanced IL-17 production by IL-27ra-/- γδ T cells was already pronounced in CD44high post-DN4 thymic γδ T cell stage. Our results propose a previously uncharacterized pathway in which IL-17 expression by γδ Y cells in the thymus is modified via IL-27.
The role of KLF7 in hematopoiesis and lymphopoiesis (160.2)
Authors: Burns Audrea , Park Chun-Shik , Yamada Takeshi , Puppi Monica , Lei Lei , Lacroazza Daniel 
Published: January 2023

Abstract
Krüppel-like factors (KLFs) are transcription factors that possess important roles in cell development and differentiation through the regulation of proliferation. Similar to KLF4, KLF7 regulates genes that control cell cycle arrest, specifically increasing p21 expression and downregulating cyclin D1. Based on our previous findings that KLF4 is important in hematopoiesis and negatively regulates CD8+ T cell proliferation, we hypothesize that KLF7 may also be important in hematopoiesis and T cell function. To test this hypothesis, qRT-PCR analysis of lineage negative, progenitor, and mature T cell subsets was performed. KLF7 mRNA expression increases throughout lineage commitment with the highest expression being in erythrocytes and mature T cells. Clonogenic assays revealed a decreased number of common myeloid progenitors (CMP) induced by ectopic expression of KLF7, which suggests that KLF7 is important for regulating commitment to a CMP fate. Further, to test whether KLF7 is important for effector T cell proliferation, KLF7-/- and KLF7+/+ fetal liver cells were transplanted into lethally irradiated congenic recipients (due to neonatal lethality) respectively. Although CFSE dilution assays demonstrated that CD4+ and CD8+ T cell proliferation was similar, thymic T cells from KLF7-/- recipients showed a developmental block from the DP to CD4SP and CD8SP stages in the thymus. Our findings suggest that KLF7 plays important roles in hematopoiesis and T cell development.
GATA-3 regulates the development, homeostasis, and activation of CD8 T cells (160.20)
Authors: Tai Tzong-Shyuan , Pai Sung-Yun , Ho I-Cheng 
Published: January 2023

Abstract
GATA3 is a master transcription factor for the differentiation of T helper 2 (TH2) cells and also essential for CD4 T cell development. GATA-3 is expressed in CD8+ T cells, but its role in this subset of T cells is largely unknown. We have studied the development and function of CD8+ T cells in mice that are deficient in GATA-3 only in T cells (G3KO mice). Although the total number of TCRhi CD8SP thymocytes was normal, we found that these mice contained significantly fewer TCRhiCD24lo CD8SP thymocytes, indicating that GATA-3 is required for the final maturation step of CD8SP thymocytes. Despite the dramatic reduction in thymic output, G3KO mice developed lymphoadenopathy due to abnormal expansion of CD8+T and B cells. This abnormal expansion of G3KO CD8+T cells is mediated by a CD8+T cell-extrinsic mechanism. Paradoxically, G3KO CD8+T cells displayed a cell-intrinsic defect in homeostatic proliferation and were hyporesponsive to TCR stimulation. There was no apparent impairment in signal transduction downstream of TCR in G3KO CD8+T cells, suggesting that GATA-3 may modulate the activation threshold of CD8+ T cells. Taken together, our data demonstrate that GATA3 also plays a critical role in regulating the development, homeostasis, and activation of CD8+ T cell.
TSE3 is an orphan gene essential for thymocytes development (160.3)
Authors: Lu Linrong , Wang Di , Zheng Mingzhu 
Published: January 2023

Abstract
The development of T cells in the thymus involves several differentiation and proliferation events, during which hematopoietic precursors give rise to single positive mature T cells. T cell antigen receptor (TCR) signaling during CD4+CD8+ double-positive stage determines cell survival (thymocytes selection) and lineage commitment (CD4-versus-CD8 lineage choice). However, this process is also regulated by other signaling pathways, which are not fully characterized. To explore this field, we analyzed several expressed sequence tag (EST) libraries from murine thymus and identified several ESTs specifically expressed in thymus including a previous uncharacterized transcript TSE3 (Thymic specific expression, number 3). TSE3 encodes a protein without any known domains or motifs but is conserved among vertebrates. We found that TSE3 is highly expression in different stages of T cell development especially in double positive thymocytes. In TSE3-deficient mice, thymocytes development was impaired reflected by decreased numbers and percentages of mature single positive CD4 and CD8 T cells in both thymus and peripheral lymphoid organs. We are further characterizing the TSE3 deficient mice to reveal the underlying mechanism used by TSE3 to participate in the thymic T cells development.
Developmental arrest of T cells in RpL22-deficient mice is dependent upon multiple p53 effectors (160.4)
Authors: Stadanlick Jason , Zhang Zhiqiang , Lee Sang-yun , Wiest David 
Published: January 2023

Abstract
αβ and γδ lineage T cells are thought to arise from a common CD4-CD8- progenitor in the thymus. However, the molecular pathways controlling fate selection and maturation of these two lineages remain poorly understood. We have demonstrated recently that a ubiquitously expressed ribosomal protein, RpL22, is selectively required for the development of αβ lineage T cells. Germline ablation of RpL22 impairs development of αβ lineage but not γδ lineage T cells through activation of a p53-dependent checkpoint. In this study, we investigate the downstream effectors employed by p53 to impair T cell development. We found that many p53 targets were induced in Rpl22-/- thymocytes, including miR-34a, Puma, p21waf, Bax, and Noxa. Notably, the BH3-only member Bim, while not a direct p53 target, was also strongly induced in Rpl22-/- T cells. While gain-of-function analysis indicated that overexpression of miR-34a caused a developmental arrest reminiscent of that induced by p53 in RpL22-deficient T cells, only a few p53 targets, when individually ablated by gene targeting or knockdown, alleviated developmental arrest. Surprisingly, co-elimination of the primary p53 regulators of cell cycle arrest (p21waf) and apoptosis (Puma) actually abrogated the partial rescue that ablation of Puma alone engendered, suggesting that the G1 checkpoint protein p21waf might actually facilitate thymocyte development in some contexts.
Regulation of Erk activation in T cells through the tail domain of RasGRP1 (160.5)
Authors: Fuller Deirdre , Zhang Weiguo 
Published: January 2023

Abstract
The Ras-guanyl nucleotide exchange factor RasGRP1 plays a critical role linking T cell receptor engagement to Erk activation. Previous studies have emphasized the importance of RasGRP1 for positive selection of thymocytes, activation of T cells, and control of autoimmunity. Unique from its other family members, RasGRP1 contains an approximately 600 nucleotide-long tail domain, the function of which is unknown. In order to determine the role of the tail domain in RasGRP1 function, we generated a knock-in mouse deleting this domain. Thymocytes containing the truncated form of RasGRP1 underwent aberrant selection processes and, following stimulation, were unable to activate Erk. Furthermore, the deletion of the tail domain negatively affected the ability of mature T cells to become activated and proliferate. Strikingly, these mice developed a severe autoimmune disease, marked by splenomegaly, high serum IgE levels, and the accumulation of T cells with an effector memory phenotype. Additionally, in an attempt to determine how the tail domain can regulate Erk activation, we observed that, in Jurkat T cells, the tail-deleted form of RasGRP1 demonstrated improper cellular localization following stimulation. While the DAG-binding C1 domain has long been viewed as the most important factor mediating RasGRP1 function, we have established an essential role for the tail domain, revealing a novel mechanism for the control of Erk activation through RasGRP1.
Dendritic cells patrol epithelium and the lumen of the crypts associated with the organized lymphoid tissue of the colon. (161.1)
Authors: Dzutsev Amiran , Koo Lily , Sui Yongjun , Gagnon Susan , Schwartz Owen , Belyakov Igor , Berzofsky Jay 
Published: January 2023

Abstract
Antigen capture and presentation by the gut dendritic cells (DCs) is a complicated process that often involves a direct sampling of the antigens from the lumen. Peyer’s patches (PP) and colonic patches (CP) contain two distinct population of DCs that are thought to participate in the antigen uptake and transport of antigens from the lumen. One group of the DCs sample the lumen by extending the transepithelial dendrites from the lamina propria. The other group of DCs is localized in the intraepithelial compartment itself. In our study we have shown, by intravital imaging of the colon, that the previously reported population of intraepithelial DCs belongs to the fraction of highly motile CD11c+ cells that circulate between crypts and the T-cell and B-cell zones of the CP. We observed that these CD11c+ cells come from the T-cell zone and make a brief contact with the lumen before retreating. Upon examination of the expression profiles of different chemokines we found that CCL20 is expressed on the apical portion of the colonic patch-associated epithelial cells. Administration of anti-CCL20 antibodies blocked homing of CD11c+ cells to the intraepithelial compartment. Motile CD11c+ cells were also able to uptake fluorescent particles and Salmonella bacteria from the lumen and rapidly transport them to the T- and B-cell zones. Thus intraepithelial DCs might play an important role in antigen uptake and trafficking in the gut lymphoid compartments.