bluuebunny/crossref_metadata_2025_split huggingface dataset:
Subcapsular sinus macrophage infection after viral dissemination to distal lymph nodes maximizes germinal center responses
Authors: Kalia Anurag , Aguilar Cynthia C , Hickman Heather D 
Published: August 2023

Abstract
Neutralizing antibodies are a hallmark of protective humoral response against many viral infections. Microanatomical structures called germinal centers (GCs) within the secondary lymphoid organs are the sites where B cells get differentiated into high affinity antibody secreting, class switched and long-lasting plasma and memory B cells. Most studies of antigen movement leading to B cell activation have been performed using subcutaneous injection, mimicking the natural route of infection. Under this condition, virus infects sinusoidal lymph node macrophages which relay the antigen to B cells to drive the GC responses. However, not much is known about antigen movement during the generation of GCs in the non-draining (or distal lymph nodes) after systemic viral dissemination. Using ZIKV infection of mice, we have mapped virus dissemination through two separate lymph node chains. Surprisingly, GCs efficiently formed in distal LNs, although with delayed kinetics compared to those directly draining the infection site. Remarkably, virus in the blood alone was not sufficient to produce GCs. Instead, virus still reached the LNs through the lymphatics and infected LN sinusoidal macrophages. This coincided with virus-induced vascular permeability in the tissue. Thus, GC formation still proceeds through sinusoidal LN macrophages even when virus is spread through the blood. Our findings reveal a conserved mechanism for antiviral B cell development in LNs distal from the site of infection.
Coxsackievirus B3 elicits a protective, sex-specific CD8+ T cell response in female mice
Authors: Robinson Christopher M , Dhalech Adeeba H , Condotta Stephanie A , Corn Caleb , Richer Martin J 
Published: August 2023

Abstract
Sex is a significant contributor to the outcome of human infections. Males are frequently more susceptible to viral, bacterial, and fungal infections, often attributed to weaker immune responses. In contrast, a heightened immune response in females enables better pathogen elimination but leaves females more predisposed to autoimmune diseases. Unfortunately, the underlying basis for sex-specific immune responses remains poorly understood. Here, we show a sex difference in the CD8+ T cell response to an enteric virus, Coxsackievirus B3 (CVB3). We found that CVB3 induced expansion of CD8+ T cells in female Ifnar−/−mice but not in male Ifnar−/−mice. Using a recombinant CVB3 virus expressing a model CD8+ T cell epitope, we found that the expansion of CD8+ T cells is viral-specific and not due to bystander activation. CVB3 also increased the proportion and number of CD11ahiCD62Llo CD8+ T cells in female mice, indicative of T cell activation. However, CD8+ T cell activation is dampened by the primary male sex hormone, testosterone, in male mice. Finally, using antibodies to deplete CD8+ T cells, we found that CD8+ T cells are required to limit CVB3-induced disease in female mice. These data demonstrate that CVB3 induces a sex-dependent CD8+ T cell response that is important for viral clearance in female mice and highlights the importance of sex differences in the immune response to viral pathogens.
This work was funded by a K01 DK110216, R03 DK124749, and a Biomedical Research Grant from the Indiana Clinical and Translational Sciences Institute to CMR.
B cells regulate early lung macrophage activation during influenza virus infection via production of acetylcholine
Authors: Prieto Antonio Cembellin , Murray Kaitlin , Luo Zheng , Reardon Colin , Baumgarth Nicole 
Published: August 2023

Abstract
The neurotransmitter Acetylcholine (ACh) is produced by the enzyme choline acetyltransferase (ChAT). Recently, ChAT expression was found in leukocytes, however, the function of leukocyte-derived ACh is incompletely understood. Flow cytometry showed that most ChAT-expressing cells in the spleen, lymph nodes, lung, and pleural cavity of ChAT-GFP reporter mice are B cells. B-1 cells contain the highest frequencies of ChAT-expressors. B cell-specific Mb1-Cre+ ChATfl/fl knockouts (BChat-KO) showed comparable bone marrow B cell development and steady-state serum IgG and IgM production as wild-type littermate controls. Given earlier studies showing TLR-mediated induction of ChAT in B cells, we studied infection of ChAT-GFP mice with Influenza A/Puerto Rico/8/34. Infection resulted in an accumulation of ChAT-expressing B cells in the lungs by 1- and 3-days post infection (dpi). Moreover, BChat-KO mice showed significant reductions in viral loads at 1 dpi, suggesting that B cell-derived ACh regulates early innate antiviral immunity. Indeed, BChat-KO showed increased TNFa-expressing and CD86hi lung macrophages at 1dpi. Consistent with this, acetylcholine reduced TNFa-expression in LPS-stimulated macrophages in vitro. In contrast, Lck-Cre+ ChATfl/fl that lack ChAT in T cells showed no difference in lung viral loads at 1dpi compared to controls, and the numbers of ChAT-expressing T cells in the lungs and draining lymph nodes did not increase until 7dpi. Together these data suggest a new regulatory function for B cells in early virus-induced lung inflammation via production of ACh.
- Chan Zuckerberg Initiative to Colin Reardon and Nicole Baumgarth - NIH/NIAID R01AI148652 Nicole Baumgarth
TGF-β promotes the resolution of acute hepatitis B virus infection
Authors: Cimino Jesse L , Moshkani Safiehkhatoon , Bailey Jacob T , Rexhouse Catherine , Robek Michael D 
Published: August 2023

Abstract
An estimated 296 million people live with a chronic hepatitis B virus (HBV) infection, resulting in approximately 800,000 annual deaths. Thus, despite the availability of an effective vaccine, HBV remains a global health concern. Most children and a fraction of adults infected with HBV develop a persistent liver infection that yields lifelong complications. It is believed that the immune tolerogenic environment of the liver and the dysfunction of T and B cells contribute to HBV persistence in these individuals. Here, an adeno-associated virus (AAV)-based mouse model of HBV infection was utilized to investigate the underlying mechanisms of immune dysfunction that impede viral clearance. HBV infection was initiated in mice by AAV-HBV transduction, and TGF-β was depleted to determine the role of this cytokine in HBV persistence. As TGF-β is often associated with negative regulation of the immune response, we hypothesized that its inhibition might improve HBV-specific T and B cell responses. However, the lack of TGF-β resulted in impaired HBV surface antigen (HBsAg) clearance and diminished anti-HBsAg antibody levels, revealing a positive role for TGF-β in the antibody response to HBV. This effect of TGF-β on the antibody response to HBsAg was unique to AAV-HBV transduction, as a similar increase in anti-HBsAg was not observed by TGF-β depletion following infection with recombinant vesicular stomatitis virus expressing HBsAg. We also observed differences in B cell activation marker expression during HBsAg clearance in mice transduced with AAV-HBV and depleted of TGF-β. Together, these findings highlight the impact of TGF-β on the B cell response to HBV and have begun to define a unique role for this cytokine in promoting HBV clearance.
Supported by the National Institute of Allergy and Infectious Diseases of the National Institutes of Health under award number R01AI148354. The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health.
Terminally exhausted CD8+ T cells contribute to age-dependent severity of human metapneumovirus
Authors: Parks Olivia Bartlett , Eddens Taylor John , Sojati Jorna , Lan Jie , Zhang Yu , Ramsey Manda , Erickson John , Byersdorfer Craig A , Williams John V 
Published: August 2023

Abstract

Objective
Human metapneumovirus (HMPV) is a leading cause of acute respiratory infection with severe morbidity and mortality among older adults. HMPV seropositivity is universal due to childhood exposure, yet antibodies do not fully protect. We hypothesized that severe HMPV disease in the elderly was due to deficient CD8+T cell responses.

Methods
B6 aged 70–71wk mice and young 6–7wk mice were infected with 2×106 PFU HMPV. Seven days post infection, mice were euthanized and lung, bronchoalveolar lavage (BAL), spleen, and draining lymph nodes were collected for flow cytometry. Lung and BAL supernatant was collected for viral titer, histology, and cytokine measurement.

Results
Aged 70–71wk C57BL/6 mice exhibited worsened weight loss, disease, and lung pathology with delayed viral clearance compared to young adult mice. Aged mice developed fewer HMPV tetramer+ CD8+ T cells, which demonstrated higher expression of PD-1 and other inhibitory receptors and were less polyfunctional with decreased granzyme B. Transplant of aged T cells into young mice and vice versa, as well as adoptive transfer of young or aged CD8+ T cells into Rag1−/− mice, recapitulated the HMPV aged phenotype, suggesting a cell-intrinsic age-associated defect. HMPV-specific aged CD8+ T cells exhibited a terminally exhausted TCF1− TOX+ EOMES+ phenotype. PD-1 blockade or 4-1BB agonist failed to improve the aged CD8+ T cell response.

Conclusion
Aged mice exhibit more severe respiratory disease when infected with HMPV. There is a cell-intrinsic age-associated defect in CD8+ T cells as shown through the transplant models. This study also identifies terminal CD8+ T cell exhaustion as a mechanism of severe HMPV disease in the elderly.

NIH AI085062 (JVW)
1F30HL159915-01A1 (OBP)
T32 GM-008208 (OBP, JS)
Henry L. Hillman Foundation (JVW)
T32 AI089443 (YZ)
K12 HD000850 (TE)
Determination of autoantibody repertoire in the mouse model of viral myocarditis and in patients with non-ischemic cardiomyopathy by PhIP-Seq
Authors: Rasquinha Mahima T , Jayaraman Sahana , Lasrado Ninaad , Duryee Michael J , Qiu Haowen , Riethoven Jean-Jack , Mone Kiruthiga , Sur Meghna , Anderson Daniel , Larman H Benjamin , Reddy Jay 
Published: August 2023

Abstract
Various infectious and non-infectious agents can cause myocarditis that may lead to cardiomyopathy with viruses being the most common suspects. Mechanistically, autoantibodies have been demonstrated for various antigens, in animal models and dilated cardiomyopathy patients, but their role continues to be enigmatic. First, by using the Coxsackievirus B3 (CVB3) infection model in A/J mice, we applied PhIP-Seq, a high-throughput platform to evaluate antibodies for various antigens. The data revealed the identification of antibodies to 32 antigens that were not previously reported. By investigating the biological significance of a few select antigens, we noted that cytochrome c oxidase assembly factor 4 homolog (COA4)-reactive antibodies were generated only in mice infected with CVB3 but not in influenza-infected animals proving virus specificity for antibody reactivity to COA4. Further immunogenicity studies revealed that animals immunized with COA4 did not develop myocarditis, nor was the T cell response generated, implying that COA4 is unlikely to act as a bonafide autoantigen. Alternatively, the COA4-reactive antibodies may represent biomarkers of viral myocarditis. Second, using the PhIP-Seq platform, we investigated the antibody profiles of human sera obtained from 25 age-matched non-ischemic cardiomyopathy patients and healthy controls. The analysis revealed significantly elevated levels of antibodies to 33 antigens, and the detection of the major candidates is being analyzed by ELISA as a secondary assay. Overall, our data suggest that the PhIP-Seq allows us to comprehensively analyze antibody repertoires that may lead to the identification of novel autoantibodies or their use as biomarkers.
This work was supported in part by the institutional funds from the University of Nebraska-Lincoln (J.R.), the Transformational Grant 18TPA34170206 from the American Heart Association (J.R.), and the National Institutes of Health grants R01 HL114669 (J.R), R01 GM136724 (H.B.L.).
Steady-state Langerhans cells induce Tfh and B cell responses through a type I interferon and IL-6 independent mechanism
Authors: Bouteau Aurélie , Zurawski Sandra M , Zurawski Gerard , Igyártó Botond Z 
Published: August 2023

Abstract
Langerhans cells (LCs) can support the induction of antibody responses against foreign antigens without a danger signal. These findings contradict the danger model proposed to define how the adaptive immune responses are mounted. Deciphering how LCs, and some other dendritic cell subsets, support adaptive immune responses in steady-state could lead to a better understanding of how immune responses are induced and regulated and, ultimately, to developing more efficient immunotherapeutics for autoimmune- and infectious diseases. Here we used a well-established steady-state antigen targeting model to dissect the mechanism by which LCs support T follicular helper (Tfh) cells and antibody responses. Using bone marrow chimeras, Cre-lox system, and blocking antibodies, we found that IL-6, which is critical in the induction of Tfh cells and antibody responses in inflammatory conditions, played no role in LC-induced adaptive immune responses at steady-state. Type I interferon signaling was also dispensable in this regard. However, our preliminary data support that induction of humoral immune responses by steady-state LCs depends on membrane-bound co-stimulatory molecules, such as ICOS/ICOS-L. Thus, these data suggest that adaptive immune responses against foreign antigens in the absence of inflammation are generated through a distinct mechanism that likely does not involve inflammatory cytokines.
Supported by grants from NIH R01AI146420 and Thomas Jefferson University startup funds.
Intrinsic B cell TLR-BCR linked coengagement induces class-switched, hypermutated, neutralizing antibody responses in absence of T cells
Authors: Rivera Carlos Eduardo , Zhou Yulai , Chupp Daniel P , Yan Hui , Fisher Amanda D , Simon Raphael , Zan Hong , Xu Zhenming , Casali Paolo 
Published: August 2023

Abstract
Maturation of an antibody response entails somatic hypermutation (SHM), class-switch DNA recombination (CSR), plasma cell differentiation and generation of memory B cells, and is thought to be generally dependent on T cell help. We show here that B cell TLR4-BCR (B cell receptor for antigen) coengagement by NP-LPS (from E. coli) or TLR5-BCR coengagement by Salmonella flagellin induced specific, mature antibody responses in Tcrβ−/− Tcrδ−/− mice and in NSG/B mice (B cells only). Such coengagement requires physical linkage of TLR and BCR ligands, “linked coengagement”, which induced germinal center-like differentiation, clonal expansion, CSR/SHM, intraclonal diversification, plasma cell differentiation, TLR expression, production of specific antibodies and generation of memory B cells supporting anamnestic antibody responses, overall indicating an affinity maturation process. In Tcrβ−/− Tcrδ−/− mice, linked coengagement of TLR4 and cognate BCR by LPS (Lipid A and polysaccharidic O-antigen) or TLR5 and cognate BCR by flagellin induced neutralizing and protective antibodies to E. coli or S. Typhimurium, limiting infection and pathology. Intrinsic B cell TLR-BCR linked coengagement likely plays an important role in inducting mature and neutralizing antibody responses in the absence of T cells. It would also play an important role in early stages of T-dependent anti-microbial responses when T cell help is not yet available, as well as potentiate the late-stage response when T help is available. Finally, it may inform the development of B cell TLR-based vaccines to microbial pathogens, particularly for subjects with an immature T cell compartment, such as the infant, or declining T cell function and clonality, such as the elderly.
Supported by NIH grants AI 079705, AI 105813/105813S1, AI138944, AI 167416 and Lupus Research Alliance grant LRA 641363 to PC and PHS grant K12 GM111726.
Diminished γδ T Cells during allergic skin inflammation is mediated by IL-4 signaling in keratinocytes
Authors: Zhang Wenwu , Pajulas Abigail , Akhtar Nahid , Zhao Jennifer , Kaplan Mark H 
Published: August 2023

Abstract
Atopic dermatitis results in profound changes in the function of the skin that include diminished barrier function and altered production of antimicrobial peptides. Dendritic epidermal γδ T cells (DETC) are a subset of γδ T cells that play an important role in the wound repair and inflammation process. Our previous work identified a loss of DETC in Stat6VT mice and in MC903 induced skin inflammation mouse model that was dependent on IL-4. However, the mechanisms through which IL-4 mediates this loss of DETCs are still not clear. In this study, we show that IL-4Rα germline knockout mice (Il4ra−/−) have an increased DETC population in skin that correlates with a higher rate of wound closure and increased EDC gene and fibronectin 1 expression. In Il4ra−/− mice, MC903 induced loss of DETCs was alleviated. Bone marrow chimeras of Il4ra−/− and WT bone marrow into Il4ra−/− mice retained the increased DETCs in the skin of Il4ra−/− host mice. Importantly, IL-15 secretion from skin keratinocytes was decreased dramatically in the MC903 induced skin inflammation model and injection of IL-15 rescued the loss of DETCs. Furthermore, conditional knock out of IL-4Rα from Keratinocytes of Il4ra fl/fl K14cre mice also showed an increase of this DETC populations in skin, increased IL-15 expression and less skin inflammation. Together, these results identify an IL-4-dependent circuit that regulates DETCs in the skin by repressing IL-15 expression in keratinocytes. This provides further insights into the ability of IL-4 to promote the development of atopic lesions and impair wound healing.
Supported by grants from NIH (R01AI095282)
DJ-X-013 ameliorates inflammation by reducing TNF-α/NF-κB expression and experimental colitis by inducing myeloid-derived suppressor cells
Authors: Mandal Mousumi , Rakib Ahmed , Kiran Sonia , Hwang Dong-Jin , Li Wei , Miller Duane D , Singh Udai P 
Published: August 2023

Abstract
Inflammation is a body’s defense response for a short duration however if persists for long periods, it causes tissue damage and pathological consequences. Moreover, it paves the way for several diseases including inflammatory bowel disease (IBD). Therefore, there is an urgent need for a natural and safe anti-inflammatory therapeutic compound. To address this issue, we aimed to determine the anti-inflammatory effects of DJ-X-013, using lipopolysaccharide (LPS) activated RAW 264.7 macrophage in vitro and dextran sodium sulfate (DSS) induced experimental model of colitis in vivo. DJ-X-013 drastically reduced tumor necrosis factor-alpha and inducible nitric oxide synthase expression in LPS-activated RAW 264.7 macrophages. Further, DJ-X-013 also impeded the expression of NF-κB and other inflammatory markers and pathways like IL-6, IL-1β, STAT3, ERK, and JNK as compared to LPS-activated cells. Additionally, DJ-X-013 also modulates the migratory activity of RAW 264.7 macrophages during wound healing. Next, using DSS induced colitis model, we observed that the reduction of body weight and colon length were slightly improved in the DJ-X-013 group compared to the control. Intriguingly, myeloid-derived suppressor cells, neutrophils, and CD8+ T cells increased, while Th17 cells frequency decreased in the spleen, mesenteric lymph nodes, and colon lamina propria in DJ-X-013 treated group as compared to DSS. However, natural killer and natural killer T cells were marginally enhanced in the DJ-X-013 group as compared to the DSS alone. Hence, the DJ-X-013 exhibits an immunomodulatory effect and might be a promising drug for IBD and other inflammatory diseases, however, further investigation is required for prudent conclusions.
This research is supported by NIH grant R01 AI140405
Host metabolic reprogramming ameliorates disease severity and colitis during Clostridioides difficile infection
Authors: Tubau-Juni Nuria , Bassaganya-Riera Josep , Leber Andrew J , Alva Sameeksha S , Baker Ryan , Hontecillas Raquel 
Published: August 2023

Abstract
Clostridioides difficile is an anaerobic, opportunistic bacterium that can cause severe infections in the gastrointestinal tract upon disruption of gut microbiome. C. difficile infection (CDI) affects 450,000 people yearly only in the U.S. The high recurrence rates associated to antibiotic regimen, the current standard of care, highlight the need to investigate novel antimicrobial free therapeutic approaches for the treatment of CDI. Here, we have conducted a global transcriptomics analysis and metabolic computational modeling, using our developed M2 pipeline, of an in vivo murine 10-day time course study of CDI to identify novel host metabolic mechanisms with therapeutic potential. Our analysis has reported a biphasic modulation of colonic metabolism, characterized by increased glycolysis during the induction of effector responses, while mitochondrial metabolism is favored in the recovery phase of the infection, when regulatory and healing processes are predominant. Inhibition of glycolysis through administration of 2-Deoxy-D-glucose (2-DG) ameliorates diseases severity, protects from mortality, and reduces colitis in a mouse model of CDI. In vitro treatment with 2-DG, an inhibitor of glycolysis, in T-84 cells exposed to C. difficile toxins A and B protects epithelial barrier integrity and decreases secretion of inflammatory mediators. In conclusion, host immunometabolic reprogramming represents a promising novel antimicrobial-free therapeutic approach for CDI.
Supported by a grant from DTRA (HDTRA1-20-1-0021)
Skin immunity during pregnancy
Authors: Sun Lillian , Corral Dan , Chi Liang , Enamorado Michel , Bouladoux Nicolas , Belkaid Yasmine 
Published: August 2023

Abstract
Pregnancy presents a challenging immunological dilemma. The maternal immune system must tolerate fetal antigens, which implies pregnancy may induce specific mechanisms of immunoregulation. Yet within this regulatory milieu, protection against pathogens must be maintained. How does the maternal immune system navigate these opposing demands? Successfully navigating this immunological dilemma is essential for supporting the reproductive fitness of the organism, and generally, the survival of any mammalian species.
Of particular importance in this context are barrier tissues, like the skin, which represent the primary portal of entry for pathogens. These barrier tissues are an especially important first line of defense during pregnancy, since adaptive immunity must be regulated to tolerate the fetal antigens which distribute throughout maternal tissues. However, little is known about how immunity in barrier tissues is altered during pregnancy.
Our preliminary studies have identified an increase in ceramide levels in the skin during pregnancy. Ceramides have been shown to be critical mediators of skin barrier function, and may prevent pathogens from breaching the skin. Additionally, in the setting of S. aureus infection, pregnant skin demonstrated increased infiltration of innate immune cells, as well as an increase in type I immunity among adaptive cells. Together, these data suggest that the protective mechanisms of the skin are altered during pregnancy. Further insights in this area may elucidate an especially critical role for barrier tissue immunity in defending against infection during pregancy, and may eventually help guide improved clinical strategies to prevent and treat infections in pregnant mothers.
Supported by Perelman School of Medicine’s Medical Scientist Training Program and intramural research funding from NIAID.