bluuebunny/crossref_metadata_2025_split huggingface dataset:
Cutaneous delivery of Poly(dG) conjugated protein antigens targets and activates DCs in vivo.(100.32)
Authors: Toussaint Helene , Erdos Geza , Donahue Cara , Falo, Jr. Louis 
Published: January 2023

Abstract
Efficient and specific targeting of exogenous antigen to antigen presenting cells (APCs) in vivo is a critical challenge for vaccine design. APCs acquire antigens from a variety of sources and endocytic mechanisms can predetermine intracellular antigen routing, processing and presentation to CD4+ or CD8+ T cells. We have designed an APC targeting strategy based on simple and direct coupling of Poly(dG) oligodeoxynucleotides to protein antigens. In comparison to soluble OVA, we find that conjugates of Poly(dG) and OVA (OVA-Poly(dG)) are rapidly internalized by dendritic cells (DCs) and follow distinct intracellular processing pathways. Functionally, OVA-Poly(dG) is both presented to OVA-specific CD4+ T cells (OT-II cells) and efficiently cross-presented to OVA-specific CD8+ T cells (OT-I cells) by DCs in vitro. Importantly, immunization of naïve animals by direct injection of OVA-Poly(dG) results in efficient priming of potent antigen specific CTL responses. Further, OVA-Poly(dG) generate a specific memory CD8+ T cells response and promote OVA-specific antibody responses. Extending our findings to human skin, we show that I.D. injection of antigen-Poly(dG) conjugates results in efficient uptake by human skin migratory DCs, preferentially dermal CD14+DCs that also acquire potent T cell allostimulatory function. Our data suggests that Poly(dG) can both target antigens to human skin immune APCs and function as an adjuvant to induce potent CD4 and CD8 mediated T cell immunity.
Regulation of expression of “pancreatic” proteases in dendritic cells: a novel mechanism of peripheral tolerance (100.34)
Authors: Farkas Adam , Finn Olivera 
Published: January 2023

Abstract
MUC1 is a tumor-associated antigen. MUC1-specific TCR transgenic CD4+ T cells transferred into MUC1 Tg mice show less proliferation in response to vaccination with DC loaded with MUC1 peptide (DC/MUC1p) compared to WT. To query the underlying regulatory mechanisms, we vaccinated WT and Tg mice with DC/MUC1p and conducted transciptome analysis of splenic RNA. Proteases previously characterized as pancreas-restricted (Trypsin, Elastase and Carboxypeptidase B1) were significantly down-regulated in splenic DC from Tg mice relative to WT. Vaccination with soluble MUC1p gave the same result. Protease mRNA down-regulation in DC correlated with the reduction at the protein level. In related work we have shown that these enzymes are regulated by DC/T effector versus T reg interactions. Inhibition of Trypsin or CPB1 decreases the ability of DC to elicit MUC1-specific CD4 T cell response in vitro, supporting a correlation between deficient protease expression in DC and reduced T cell response in vivo. DC from MUC1p-vaccinated Tg mice express lower levels of MHC II and costimulatory molecules concurrent with decreased protease levels. These proteases are found in MHC II+ and lysosomal compartments, sites of antigen processing. We suggest that one mechanism of peripheral tolerance that regulates anti-MUC1 immunity is inhibition of antigen processing. We propose that pharmacologic modulation of these enzymes could be one approach to improving the potency of TAA-based cancer vaccines.
A new dynamic model of three cell interactions by CD4+ T-licensed DCs and DC-primed CD4+ T cells (100.38)
Authors: Xiang Jim 
Published: January 2023

Abstract
CD8 cytotoxic T lymphocytes (CTLs) kill pathogen-infected cells. Recent in vivo imaging study suggested that presence of DC-CD4 T clusters during CTL priming are essential for T-cell memory, challenging independent roles for the DCs or the CD4 T-cells that dissociate following DC-CD4 T interactions. We have developed a novel in vivo experimental system based on the rapid inducible ablation of diphtheria toxin receptor (DTR) transgenic-DCs and antibody-mediated depletion of CD4 and CD8+ T cells in mice to create DC-CD4 T interactions in vivo first, followed by killing of either CD4 T-licensed DCs or DC-primed CD4 T cells. Later, adoptively transferring naive polyclonal CD8 T cells facilitated their interactions with either licensed-DCs or primed-CD4 T cells, thereby revealing their respective roles in CTL immunity. Our results provide direct in vivo evidence that CD4 T-cells and DCs, once activated by DC-CD4 T interactions, can stimulate CTL responses and programme memory on CTLs independent of DC-CD4 T clusters, uncovering the co-existence of direct and indirect mechanisms of T-cell help for CTLs by licensed DCs and primed CD4 T cells in non-inflammatory situations. In situations in which CTL immunity is heavily dependent on CD4 T-cell help, our findings suggest a new dynamic model of three cell interactions in CTL responses, that dissociated stage of primed CD4 T-cells and licensed DCs represent crucial “immune-intermediates” for CTL responses and memory development.
MHC class I-related FcRn-mediated presentation of immune complexed antigen is associated with endosomal and phagosomal pH and antigen stability in macrophages and dendritic cells (100.56)
Authors: Zhu Xiaoping , Liu Xindong , Lu Li , Yang Ziyan , Palaniyandi Senthilkumar , Zeng Rongyu , Gao Lian-Yong , Mosser David , Roopenian Derry 
Published: January 2023

Abstract
The Fc receptors for the immunoglobulin (Ig) G antibody (FcgammaRs) found on macrophages and dendritic cells (DCs) efficiently facilitate the presentation or cross-presentation of immune-complexed (IC)-antigens to T cells. We found that the neonatal Fc receptor for IgG (FcRn) in both macrophages and DCs failed to have a strong effect on the cross-presentation of IC ovalbumin (OVA) antigen to CD8+ T cells. Interestingly, endosomal FcRn enhanced the presentation of the monomeric OVA-IC to OT-II CD4+ T cells robustly, whereas FcRn in phagosomes exerted distinctive effects on antigen presentation between macrophages and DCs. The presentation of phagocytosed latex-OVA-ICs to CD4+ T cells was also considerably enhanced on wild-type versus FcRn-deficient macrophages, but was not affected in FcRn-deficient DCs. This functional discrepancy was associated with the dependence of IgG-FcRn binding in an acidic pH. Following phagocytosis, the phagosomal pH dropped rapidly to below 6.5 in macrophages but remained in the neutral range in DCs. This disparity in pH determined the rate of degradation of phagocytosed ICs. Thus, our findings reveal that FcRn expression has a different effect on antigen processing and presentation of ICs to CD4+ T cells in the endosomal versus phagosomal compartments of macrophages versus DCs.
Foxo1 is essential for germinal center B cell functions and the development of collagen-induced arthritis (101.15)
Authors: Chang Shih-En , Zheng Biao 
Published: January 2023

Abstract
Foxo1 has been shown to be critical for B-cell lymphopoiesis by regulating several genes involved in immunoglobulin (Ig) rearrangement. However, the role of Foxo1 in germinal center (GC) B cell functions remains unclear. Unlike being downregulated in activated B cells, Foxo1 expression is elevated in GC B cells, suggesting a distinctive regulatory role. In Foxo1 GC B-cell conditional knockout (CKO) mice, both primary and memory antibody responses are severely impaired after immunization with T-dependent antigen NP-CGG. The numbers of NP-specific IgG1-secreting B-cells, as well as the NP-specific IgG1 antibody titer in the serum, are dramatically reduced in the mutant mice. The results indicate an inability to undergo Ig class-switch recombination (CSR) in Foxo1-deficient GC B cells, possibly due to the abolished expression of activation-induced cytidine deaminase. In addition, analysis of mutation rate of Ig genes in the NP-specific B cells reveals that Ig somatic hypermutation (SHM) is impaired in the Foxo1-deficient GC B cells. The clonotypes of B cells responding to NP are also altered in the mutant mice. Remarkably, using collagen-induced arthritis model, we have found that Foxo1 GC B-cell CKO mice are resistant to arthritis induction. Taken together, our data indicate that Foxo1 is essential for normal antibody responses, CSR and SHM of GC B cells. The absence of Foxo1 in GC B cells prevents the development of autoimmune arthritis.
Extra-telomeric function of telomerase in rheumatoid arthritis (101.2)
Authors: Shao Lan , Fujii Hiroshi , Grisar Johannes , Jörg Goronzy , Weyand Cornelia 
Published: January 2023

Abstract
Telomerase, an enzyme that adds DNA onto telomeric ends is upregulated in T lymphocytes upon antigen recognition. How telomerase affects T-cell function is unknown. In patients with the autoimmune syndrome rheumatoid arthritis (RA) induction of T-cell telomerase is impaired and associated with premature immunosenescence. To suppress telomerase activity healthy naïve CD4 T cells were stimulated through the T-cell receptor and transfected with control or hTERT-specific siRNA. Telomerase inhibition significantly increased p53 mRNA (p=0.05) and p53 protein (p=0.002). Pro-apoptotic BH3-only proteins were selectively upregulated; PUMA was increased (p=0.04), Noxa and Bim remained unaffected. hTERT silencing doubled frequencies of apoptotic cells. In RA T cells hTERT expression was spontaneously reduced (p&lt;0.0001); immunostaining localized most of the protein to the cytoplasm (p=0.002). Upon TCR ligation RA T cells had higher levels of p53, phosp53 and PUMA. p53 or PUMA knockdown effectively rescued RA T cells from apoptosis. hTERT over-expression suppressed p53 and PUMA and normalized cellular yield. p53 and PUMA silencing did not correct hTERT expression, placing telomerase upstream of the p53-pathway. In conclusion, T-cell telomerase has extra-telomeric functions and regulates life-death decisions after antigenic stimulation. In patients with rheumatoid arthritis, the survival-protective function of telomerase is defective, causing T cell loss and proliferative stress.
A unique T cell subset, Th40, are pathogenic and diagnostic in mulitple sclerosis (101.30)
Authors: Waid Dan , Carter Jessica , Vaitaitis Gisela , Wagner Rebecca , Gottlieb Peter , Corboy John , Fitzgerald-Miller Lisa , Wagner David 
Published: January 2023

Abstract
Auto-aggressive T cells have been implicated in the pathogenesis and maintenance of MS, including mouse models and human disease. We described a T cell subset, Th40 cells, which proved highly pathogenic and auto-aggressive in autoimmune diabetes. Using flow cytometry, we compared Th40 levels in 90 MS subjects of all subtypes, 238 T1DM and 208 control patients. A subset of MS patients were followed during and after pregnancy as well. RRMS subjects have significantly increased percentages of Th40 cells in PBL compared to non-autoimmune controls. MS subjects (75) had Th40 cell levels equal to or greater than autoimmune T1D (238) subjects. The majority of Th40 cells from MS subjects' are T helpers producing pro-inflammatory cytokines IFNg, TNFa and IL-17. Th40 cells produce high levels of IL-6, an acute phase response cytokine that shunts regulatory T cells into Th17 pathway. During RRMS Th40 cell expansions occur regardless of age or gender and are responsive to known MS associated self antigens including MOG, MBP and PLP. A clonal expansion of TRAV 8.1.3+ cells within the Th40 population was evident. During pregnancy Th40 cell levels dropped dramatically corresponding with remission returning to pathogenic levels postpartum. In the mouse EAE model of MS Th40 cells are highly expanded. Th40 cells could prove diagnostic in RRMS and prove diagnostic to predict relapse. Th40 cells are pathogenic in MS and identification of a clonal expansion in MS further suggests autoimmunity.
Identification of a second mimicry epitope from Acanthamoeba castellanii that induces CNS autoimmunity through the generation of cross-reactive T cells for myelin basic protein 89-101 (101.35)
Authors: Massilamany Chandirasegaran , Steffen David , Reddy Jay 
Published: January 2023

Abstract
Autoimmune responses to myelin antigens have been implicated in the pathogenesis of multiple sclerosis and this requires the mediation of autoreactive T cells and B cells, but the mechanisms by which the disease is initiated are unknown. Environmental microbes are commonly suspected in the initiation of the disease and emerging evidence suggests that exposure to multiple organisms might be a critical requirement to trigger central nervous system (CNS) autoimmunity. We had previously reported that Acanthamoeba castellanii (ACA) contains a mimicry epitope for proteolipid protein 139-151 capable of inducing autoimmune encephalomyelitis in SJL/J mice. We now present evidence that ACA also contains a mimicry epitope for myelin basic protein (MBP) 89-101 namely, NAD 108-120 and the mimicry sequence is derived from NADH dehydrogenase subunit 2 of Acanthamoeba. NAD 108-120 shares 46% sequence identity with MBP 89-101 and it induces clinical and histological EAE similar to that of cognate peptide through the generation of cross-reactive T cells and proinflammatory cytokines that favor CNS autoimmunity. This is the first report to demonstrate that a solitary microbe can predispose to CNS autoimmunity by generating cross-reactive T cells for multiple myelin antigens.
T cell specific deletion of the phosphatase SHP1 decreases incidence and severity of experimental autoimmune encephalomyelitis (101.41)
Authors: Edwards Lindsay , Mauldin Ileana , Lorenz Ulrike , Evavold Brian 
Published: January 2023

Abstract
T cell activation is regulated by a dynamic balance between kinase and phosphatase activity. The tyrosine phosphatase SHP1 is a critical negative regulator of the immune system, and a proximal regulator of T cell receptor signaling. Here, we have utilized two novel models to study the deletion of SHP1 specifically in mature T cells. We have bred mice bearing a floxed SHP1 allele that deletes the majority of the gene with mice bearing an inducible Cre (Mx1 promoter). We also utilized a dominant negative allele of SHP1 whose expression requires Cre-driven recombination. By transferring mature T cells from these mice into T cell deficient hosts and subsequently inducing Cre expression we have isolated the effect of loss of SHP1 activity to T cells. We have determined that selective loss of this phosphatase in mature T cells dramatically attenuates experimental autoimmune encephalomyelitis (EAE). Both severity and incidence were decreased significantly in the conditional knockout and dominant negative mice relative to controls (mean max score 1.0, 1.7, and 2.7, respectively and mean incidence 29, 37 and 79%). These data differ from results in mice heterozygous for the motheaten allele, a naturally occurring SHP1 mutant, which exhibit EAE severity that is similar to or slightly worse than controls. Collectively, this suggests that lack of SHP1 activity in T cells may protect from disease, while deletion in other cell types may exacerbate susceptibility or symptoms.
Memory phenotype CD8 T cells generated in response to inducible self antigen (101.42)
Authors: Jellison Evan , Turner Michael , Blair David , Lefrançois Leo 
Published: January 2023

Abstract
Chronic antigenic stimulation of CD8 T cells by self antigen or chronic infection results in an altered CD8 T cell response and may lead to antigenic tolerance. To study these processes we generated transgenic mice in which antigen (Ag) expression is tightly controlled in DCs by doxycycline (dox). Our system provides the unique ability to examine endogenous CD8 T cell responses to neo-self Ag in the absence of overt inflammation. Dox can be given both chronically and acutely, and Ag expression ceases upon dox withdrawal. Importantly, the transgenic mice are ignorant of Ag prior to induction. Chronic antigen induction (dox on) in these mice resulted in a massive expansion of endogenous Ag-specific CD8 T cells. They upregulated CD44 and LFA-1, and expressed CD69 and PD1, but predominantly did not express KLRG1 or CD127, nor did they generate effector cytokines. Upon Ag removal (dox on, then dox off), the Ag-specific CD8 T cell population waned but the surviving population was enriched for CD127+ memory phenotype cells. The remaining CD8 T cells recalled to subsequent pathogen challenge but did not recall to self Ag challenge (dox back on). These studies indicate that chronic self Ag exposure generates a CD8 T cell population that is non functional, but persists through an addiction to Ag. However, when self Ag is removed, a functional memory phenotype CD8 T cell population emerges, which is regulated depending on the context of subsequent Ag presentation.
Activation of TLR4 on endothelium alone initiates neutrophil adhesion within the liver microcirulation during endotoxemia (102.22)
Authors: McDonald Braedon , Zhuo Lisheng , Kimata Koji , Kubes Paul 
Published: January 2023

Abstract
During sepsis and endotoxemia, neutrophils are recruited to the liver where they cause tissue damage and vascular dysfunction. We have previously reported that neutrophils adhere within sinusoids of the endotoxemic liver via interactions between neutrophil CD44 and endothelial hyaluronan. In this study, we aimed to characterize the cellular sentinels that detect circulating LPS via TLR4 and the pathways leading to initiation of neutrophil adhesion via CD44-hyaluronan interactions. Intravital microscopy of bone marrow chimeric mice revealed that TLR4 expression by non-bone marrow derived cells was required for neutrophil recruitment into the liver during endotoxemia (1 mg/kg LPS, i.v.). Furthermore, LPS-induced neutrophil adhesion in sinusoids was equivalent between wild-type mice and transgenic mice that express TLR4 only on endothelium (tlr4-/-Tie2tlr4, named endoTLR4), but surprisingly, sinusoidal occlusion (vascular damage) was attenuated in endoTLR4 mice. Intravital immunofluorescence imaging demonstrated that stimulation of endothelial TLR4 induced the deposition of serum-derived hyaluronan associated protein (SHAP) within liver sinsusoids, which was required for activation of endothelial hyaluronan to bind neutrophil CD44. These data reveal that endothelial cells are the key sentinels that recognize circulating LPS and initiate neutrophil adhesion in the liver during endotoxemia, but the development of liver pathology requires TLR4 activation on additional cell types.
TLT2 signaling regulates a positive feedback loop that promotes neutrophil activation and chemotaxis. (102.24)
Authors: Halpert Matthew , King R. Glenn , Justement Louis 
Published: January 2023

Abstract
TLT2 is one of four receptors conserved between mouse and human within the TREM locus, and is expressed on B cells, macrophages, and neutrophils. TLT2 ligation on murine macrophages induces the production of chemokines and growth factors, as evidenced by ex vivo treatment with αTLT2 mAbs. This is recapitulated in vivo following injection of αTLT2 mAbs resulting in the production of chemokines and growth factors, which ultimately lead to enhanced neutrophil recruitment. Ligation of TLT2 on murine neutrophils results in an enhanced respiratory burst, as well as potentiation of degranulation and chemotaxis in response to agonists that bind G protein coupled receptors (GPCR), including FMLP, KC, MIP-2, IL-8, and C5a. However, the neutrophil responses to GM-CSF, LPS, and FcR ligation were unaltered, suggesting that TLT2 specifically potentiates the neutrophil response to signals derived from GPCRs. Administration of αTLT2 mAb results in enhanced neutrophil accumulation in response to nonspecific inflammatory mediators in vivo, and competitive adoptive transfer experiments demonstrate enhanced recruitment of αTLT2 mAb treated neutrophils compared to control neutrophils in response to lung inflammation. These results demonstrate that TLT2 regulates an intricate feed-forward loop wherein it is important for driving the production of factors that recruit neutrophils, as well as enhancing the response of neutrophils towards chemokines and bacterial products that signal via GPCRs.
Langerhans cells are critical in the pathogenesis of atopic dermatitis via TSLP receptor signaling (103.1)
Authors: Nakajima Saeko , Miyachi Yoshiki , Kabashima Kenji 
Published: January 2023

Abstract
In the skin, there exist at least two populations of dendritic cells (DCs), epidermal Langerhans cells (LCs) and dermal DCs. It has been reported that cutaneous DCs mediate the pathogenesis of atopic dermatitis (AD), but it remain unknown which subset is directly involved. Using mice with Langerin-diphtheria toxin receptor, we found that LC depletion showed much milder clinical manifestations together with lower serum IgE levels in a topical OVA application-induced AD-like mouse model. In addition, LC depletion impaired OVA-specific T cell proliferation and IL-4 production in the draining lymph nodes. Recent work has identified TSLP as promoting Th2-dominant inflammations. Since TSLP is expressed in the epidermis, we hypothesize that TSLP secreted by keratinocytes acts on epidermal LCs to prime naïve T cells into Th2 cells. To this end, we used TSLP receptor-deficient mice and newly generated LC-specific TSLP receptor-deficient mice by bone marrow reconstitution of wild-type mice into irradiated TSLP-receptor deficient mice by taking advantage of radio-resistance of LCs. We induced AD-like skin conditions to these mice by sensitization with OVA percutaneously. We found that LC-specific TSLP receptor-deficient mice showed much milder clinical and histological findings together with lower IL-4 and IgE levels. Taken together, these results suggest that epidermal LCs play a critical role in the development of AD via TSLP-TSLP receptor signaling.
Lung surveillance revealed by two-photon live imaging (103.3)
Authors: Thornton Emily , Looney Mark , Sen Debasish , Sheppard Dean , Huang Xiaozhu , Krummel Matthew 
Published: January 2023

Abstract
The lung is a major mucosal site of allergen and pathogen encounter and is also the site of damage resulting in immune-based repair. Despite the interest in how immune cells enter and function in this organ, direct observation of these events has not been possible due to obligate movements made during respiration and blood flow. Real-time imaging of cellular and sub-cellular dynamics in the lung requires image resolution, image-registration, and intact physiology to be simultaneously optimized. We have developed both in vitro slice and intravital stabilized imaging systems. We have applied these methods to visualize how phagocytes function along this mucosal surface. Imaging under basal conditions reveals constitutive surveillance of the alveolar surface by resident dendritic cells (DC). These DCs actively sweep the epithelium, taking up model antigens, whereas alveolar macrophages (AMs) lie immotile within the alveolar space. DC number dramatically increases after allergen challenge; however, sampling behavior is not affected, leading to increased antigen uptake by these proinflammatory cells. These antigen-positive DCs then play a critical role in the activation of T cells visualized in this system. We will discuss the integration of innate and adaptive cells as it occurs in the lung.