bluuebunny/crossref_metadata_2025_split huggingface dataset:
Characterization of human soluble Tim-3 and its role in HIV infection (VIR1P.1002)
Authors: Clayton Kiera , Douglas-Vail Matthew , Medcalf Karyn , Chew Glen , Tandon Ravi , Ndhlovu Lishomwa , Ostrowski Mario 
Published: January 2023

Abstract
Chronic Human Immunodeficiency Virus Type-1 (HIV) infection results in a loss of HIV-specific CD8+ T cell effector function, termed “exhaustion”, which is mediated, in-part, by the co-inhibitory receptor T-cell immunoglobulin mucin domain-containing protein 3 (Tim-3). Like many other receptors, a soluble form of this protein has been described in human blood plasma. However, this soluble Tim-3 (sTim-3) is poorly characterized and it’s unclear whether it plays a role in HIV pathogenesis. Using a Tim-3 ELISA, we found that levels of sTim-3 were significantly elevated in HIV+ antiretroviral treatment naïve patient plasma compared to healthy controls or HIV+ antiretroviral treated patients, and significantly correlated positively with viral load but not with CD4+ T cell counts. To characterize this construct, we immunoprecipitated the protein from HIV+ patient plasma; western blotting analysis revealed that plasma sTim-3 is the approximate size of the Tim-3 ectodomain. Following detection of sTim-3 from activated PBMCs in culture, no alternatively spliced Tim-3 constructs were observed, however, levels of sTim-3 were abrogated with the inclusion of a matrix metalloproteinase, ADAM10, inhibitor. Further, we showed that this sTim-3 was produced from activated T cells treated with an ADAM10 agonist and was the approximate size of plasma sTim-3. Our results suggest that increasing levels of viral antigen result in increased Tim-3 shedding from the T cell surface during HIV infection.
Hepatitis B Virus X protein inhibits A20 expression and sensitizes TRAIL-induced apoptosis in hepatocyte cells (VIR1P.1006)
Authors: Shi Liyun , Zhang Hang , Kang Yanhua , Lu Zhe , Wang Huanhuan 
Published: January 2023

Abstract
Hepatitis B virus (HBV) infection is a crucial cause of hepatocyte death, cirrhosis, and hepatocellular carcinoma. However, the molecular mechanism causing the death of hepatocytes during HBV infection was not completed understood. A20, also named tumor necrosis factor alpha-induced protein 3 (TNFAIP3), is a key regulator in inflammation and immunity, and was identified as a target of miR-125a. Here, we report that miR-125a is induced by hepatitis B virus X protein (HBx) and leading to repression of A20. We also found HBx or miR-125a transfection of hepatoma cell line L-O2 significantly increased its sensitivity to TRAIL-induced apoptosis. The increasing of TRAIL sensitivity was associated with repression of A20 protein expression, and HBx activates caspase-8, due to the direct cleavage of RIP1 by A20-inhibition. We also found caspase-8 K63-linked polyubiquitination was repressed by HBx. Thus, our study indicates that HBx sensitizes hepatocytes to TRAIL-induced apoptosis through upregulating miR-125a and targeting A20 through caspase-8 activation and the regulation of RIP1 ubiquitination. So these results suggest that miR-125a and A20 represent key diagnostic markers and potential therapeutic targets for the prevention and treatment of HBV infection.
Natural killer cells suppress humoral immunity and development of neutralizing antibodies (VIR1P.962)
Authors: Rydyznski Carolyn , Daniels Keith , Karmele Erik , Brooks Taylor , Sutiwisesak Rujapak , Welsh Raymond , Waggoner Stephen 
Published: January 2023

Abstract
Pathogen-specific neutralizing antibodies (nAbs) are a key component of protective immunity after infection or vaccination. However, broadly-specific nAbs that can prevent infections with highly mutable viruses like HIV are rarely seen in infected patients and are poorly elicited by current vaccines. Therefore, new vaccine strategies are needed to enhance the induction of nAbs, potentially by augmenting the germinal center (GC) reactions that facilitate somatic hypermutation, affinity maturation and development of high-affinity nAbs. Here, we demonstrate that natural killer (NK) cells impair humoral immunity by contributing to a weak GC response and subdued generation of virus-specific nAbs after acute lymphocytic choriomeningitis virus (LCMV) infection of mice. The magnitude and duration of the LCMV-induced GC response was substantially reduced by NK cells, which constricted the number of both follicular helper T cells (Tfh) and GC B cells present in lymphoid tissues. NK cell-mediated suppression of GC responses was also observed in different stains of mice and after infection with a variety of dissimilar pathogens, suggesting that NK cell suppression of humoral immunity is a universal feature of infection. Notably, NK cell inhibition of the GC response during LCMV infection resulted in a markedly delayed and relatively weak nAb response. Thus, targeting of immunosuppressive NK cells could represent a revolutionary method to enhance the efficacy of future vaccine regimens.
Myeloid cell Arg1 and iNOS inhibit control of arthritogenic alphavirus infection by suppressing anti-viral T cells (VIR1P.965)
Authors: Burrack Kristina , Her Zhisheng , Gill Ron , Ng Lisa , Morrison Thomas 
Published: January 2023

Abstract
Mosquito-borne alphaviruses, including chikungunya virus (CHIKV) and Ross River virus (RRV), cause a debilitating, and often chronic, rheumatologic disease in humans. Utilizing mouse models that recapitulate many aspects of the human disease we found that arginase 1 (Arg1) and nitric oxide synthase 2 (iNOS) are highly induced in inflamed musculoskeletal tissues and infiltrating macrophages in RRV- and CHIKV-infected mice. Similar to myeloid-derived suppressor cells (MDSCs), these Arg1/iNOS-expressing macrophages suppress T cell proliferation ex vivo. Depletion of T cells restored RRV loads in musculoskeletal tissues of Arg1-deficient mice to similar levels as T cell-depleted WT mice, suggesting that Arg1+ suppressor cells inhibit T cell-mediated control of alphavirus infection. Moreover, myeloid cell Arg1 reduced T cell production of anti-viral cytokines and altered the activation phenotype of virus-specific T cells in inflamed muscle tissue, but not lymphoid tissue, of RRV-infected mice. Furthermore, the expression of Arg1 and several other MDSC-associated genes were significantly higher in PBMCs collected from CHIKV-infected patients compared to PBMCs from healthy controls. Expression of Arg1 remained elevated months after illness onset, and increased expression levels of Arg1 correlated with higher viremia. These studies suggest that CHIKV/RRV infection activates immunosuppressive monocytes/macrophages that antagonize virus control and may contribute to chronic disease.
Crossreactive Epstein-Barr virus (EBV)-influenza A virus (IAV) specific CD8 memory T cells during acute symptomatic IAV infection. (VIR2P.1022)
Authors: Mishra Rabinarayan , Gil Anna , Aslan Nuray , Luzuriaga Katherine , Selin Liisa 
Published: January 2023

Abstract
We previously showed that crossreactivity is common between IAV and EBV in HLA-A2+ patients during infectious mononucleosis. IAV-M1 specific CD8 T cells, along with expanded populations of IAV-M1/EBV-BRLF-1 and IAV-M1/EBV-BMLF-1 double-tetramer+ cells were detected directly ex-vivo in 5 HLA-A2+ patients. Altered IAV-M1, EBV-BRLF1 and -BMLF1 TCR repertoires were observed over the course of infection and in comparison to healthy donors. After culture, cells were sorted and analyzed by gene array in order to assess global changes in immune responses following different stimulations, either cognate or crossreactive, in different patient populations. M1- and BRLF1-specific cells had similar immune-response gene signatures, but the BMLF1-specific CD8 cells were more similar to the two-crossreactive populations. Crossreactive M1/BRLF1 cells from the BRLF1 line were different in their activation status than the BRLF1-specific cells, consistent with BRLF1 ligand stimulation of different gene activation profiles in these two populations. These results suggest that during symptomatic IAV infection there is an expansion of EBV/IAV crossreactive memory CD8 T cell responses. Ongoing studies are investigating whether EBV-IAV cross-reactive CD8+ T cells may contribute to immunopathology during acute IAV infection.
Increased PGD2 is associated with delayed dendritic cell maturation in neonates during respiratory viral infection (VIR2P.1031)
Authors: Shornick Laurie , Bhattacharya Somashubhra , Tumala Brunda 
Published: January 2023

Abstract
During respiratory viral infection in adults, inflammatory cytokines stimulate conventional dendritic cells (cDC) to increase expression of MHC class II molecules, co-stimulatory molecules, and chemokine receptors. Activated cDC then migrate from the lung to the draining lymph nodes where they present antigen to T cells. Our previous studies demonstrated that neonatal mice exhibit reduced inflammation and inflammatory cytokine expression during paramyxoviral infection. Thymic stromal lymphopoietin (TSLP), a cytokine known to participate in cDC activation, is expressed at significantly lower levels in neonatal mice during respiratory viral infection compared to adults. Thus, we hypothesized that cDC maturation and migration to lymph nodes may be delayed or impaired in neonates. Adult and two-day old neonatal C57BL/6 mice were inoculated intranasally with Sendai virus (500 pfu/g body weight). Adult cDC had increased expression of MHC Class II and CCR7 and had migrated to the lymph nodes on post-infection days 1 and 3. However, these events were delayed in neonates and did not reach adult levels until post-infection day 7. Interestingly, studies in geriatric mice suggest that high levels of Prostaglandin D2 (PGD2) may inhibit cDC maturation and migration to lymph nodes. We also observed higher PGD2 expression in neonatal bronchoalveolar lavage fluid compared to adults during paramyxoviral infection, and this may contribute to the impairment of DC maturation in neonates.
The role of miR-328 in respiratory diseases (INM3P.410)
Authors: Tay Hock , Kaiko Gerard , Mattes Joerg , Hansbro Philip , Foster Paul 
Published: January 2023

Abstract
Introduction: MicroRNAs (miRNAs) are small non-coding RNA that can bind to multiple target mRNA to repress protein production. Deregulation of miRNAs have been linked with pathogenesis of multiple human diseases. In immune cells, miRNAs regulate cell development, differentiation and production of inflammatory mediators. Aim: To investigate the roles of miRNAs in regulating immune cell function and its role in respiratory diseases. Methods: Lung miRNAs that were differentially expressed following non-typeable Haemophilus Influenzae (NTHi) challenge were identified by microarray. miRNA inhibitors (antagomirs) were used to investigate the role of miRNA in regulating bacterial clearance in in mouse models of immunosuppresion and emphysema. Results: Upon NTHi infection, 15 miRNAs were up-regulated while 49 were down-regulated by &gt; 2.5 fold in lungs. In vitro, miR-328 knockdown reduced bacterial load and increased phagocytosis by macrophages and neutrophils. Transferred of macrophages or neutrophils (deficient in miR-328) to naïve recipient mice enhanced clearance of the bacteria in vivo. Similarly, inhibition of miR-328 by antagomirs promote NTHi clearance in mouse models of immunosuppresion and emphysema. Conclusion: : Our study identify a novel role for miR-328 in the regulation of phagocytosis and provide proof of principle that miRNA pathways can be targeted in the lung and offer a potential new anti-microbial approach for the treatment of respiratory infection.
Physiologic stress molecules activate an acute phase response and enhance macrophage antimicrobial activity to Mycobacterium leprae (INM3P.411)
Authors: Scumpia Philip , Botten Giovanni , Kelly-Scumpia Kindra , Modlin Robert , Smale Stephen 
Published: January 2023

Abstract
Leprosy is a disease caused by the pathogen Mycobacterium leprae (mLEP). Patients can present with the progressive, lepromatous form of the disease or the self-limited, tuberculoid form of the disease. Physiologic stress is thought to inhibit host defense mediated by adrenergic catecholamines and neuroendocrine glucocorticoids. We hypothesize that acute treatment with adrenergic agents or glucocorticoids would inhibit in vitro macrophage mediated antimicrobial activity. Human monocyte-derived macrophages or mouse bone marrow-derived macrophages were treated with the adrenergic agonist metaproterenol hemisulfate (MPH, 1μM) or the glucocorticoid dexamethasone (Dex, 100nM) for two hours followed by LPS (100ng/ml) or mLEP (MOI 5). RNASeq was performed at various time points or an mLEP viability measurement was performed at 24 hours following infection. Unexpectedly, when compared to vehicle (DMSO), pretreatment with MPH resulted in greatly enhanced antimicrobial activity against mLEP, similar to interferon-γ pretreatment, whereas Dex resulted in a more modest induction of antimicrobial activity. Both Dex and MPH did not reduce the expression of the antimicrobial peptide cathelicidin, but did induce a dramatic increase in expression of genes involved in the acute phase response. Our findings suggest that molecules involved in the physiological stress response may be acutely beneficial during initial encounter with mLEP.
Dendritic cell homologous antigenic loading initiates AIMp1-mediated TH1 immunity (IRC7P.432)
Authors: Halpert Matthew , Liang Dan , Konduri Vanaja , Pautler Robia , Klumpp Sherry , Bhardwaj Ratan , Levitt Jonathan , Decker William 
Published: January 2023

Abstract
Attempts to treat cancer by vaccine immunotherapy have produced unsatisfactory results in part due to an inability to generate effective TH1 immunity. Here we demonstrate the existence of an elegant TH1 regulatory mechanism based upon release of the AIMp1 proinflammatory cytokine and elicited by the loading of dendritic cells (DC) with MHC class I and II antigenic epitopes of overlapping (homologous) amino acid sequence. Using a variety of distinct model systems, we demonstrate that DC possess a physical mechanism by which to compare amino acid sequence homology of bound class I and II epitopes, releasing AIMp1 when significant homology among such epitopes exists. AIMp1 release was shown to be upstream of microsomal CTLA-4 secretion, events that were inversely correlated and directly dependent upon the presence of homologous class I and II antigenic epitopes. Antigenic homology could mediate DC TH1 polarization and subsequent enhancement of CD8+ responses only when MHC molecules were present and able to be loaded, in an AIMp1-dependent manner, and when bound class I and II peptides shared uninterrupted sequence homology of at least five amino acid residues. Physiologic relevance and translational applicability to cancer were also demonstrated. The existence of this surprising and novel regulatory mechanism alters the paradigm by which regulation of cellular immunity is generally understood.
The tetraspanin CD151 is a T cell activation marker demarcating hyper-responsive CD8+ CD28- T cells in HIV patients (IRC7P.433)
Authors: Seu Lillian , Sabbaj Steffanie , Duverger Alexandra , Wagner Frederic , Goepfert Paul , kutsch olaf 
Published: January 2023

Abstract
HIV-infected patients, despite suppressive ART, exhibit signs of immune hyperactivation and premature senescence, compromising the success of long-term ART. Elucidation of the molecular mechanisms underlying immune dysfunction will be critical to develop future immuno-modulatory therapies to improve the long-term health status of HIV patients. To achieve this goal, biomarkers that resolve dysfunctional T cell populations are needed. To this end, we here demonstrate that the tetraspanin CD151 in HIV patients on ART is highly expressed on CD28- T cells (p&lt;0.05 compared to healthy donors), a population that is massively increased in HIV patients and considered immunologically senescent. Functionally, we define CD151 as a T cell activation marker that is not affected by the presence of cytokines (e.g. TNF-a, IL-2), but is upregulated following TCR engagement. Surprisingly, the majority of CD8+ CD28- T cells responsive to CMV pp65 peptides were CD151+ as measured by Granzyme B+ and IFN-γ+. Blocking experiments with CD151 mAb led to a dose-dependent reduction of IFN-γ secretion from CMV pp65- stimulated PBMCs. In summary, CD151 is elevated on senescent CD8+ CD28- T cells that demonstrate enhanced antigen-responsiveness. As prior data shows that CD151 on T cells stabilizes the immune synapse and primes T cell activation, CD151 expression may confer responsiveness of otherwise senescent T cells and present one underlying cause of immunological hyperresponsiveness in HIV patients.
Rho kinase activity dampens the activation of CD4+ T cells (IRC7P.435)
Authors: Thauland Tim , Butte Manish 
Published: January 2023

Abstract
T cells respond to increasing doses of antigen with enhanced proliferation and cytokine production, both in vitro and in vivo. Furthermore, effector T cells respond more robustly to limiting amounts of peptide than naïve cells. Although much is known about the signaling pathways downstream of the T cell receptor, the molecular mechanism responsible for maintaining the threshold for activation in T cells remains obscure. We have previously shown that the T cell cytoskeleton softens upon T cell activation. Here, we show that effector T cells form larger interfaces with antigen presenting cells (APCs) than naïve cells after correcting for cell volume. We also demonstrate that the RhoA effector Rho-associated protein kinase (ROCK) is more active in naïve than activated T cells. Inhibition of ROCK activity with a small molecule inhibitor, glycyl-H-1152, softened the actin cytoskeleton, independent of stimulation through the T cell receptor. The size of T-APC contacts were increased upon ROCK inhibition, and calcium flux was enhanced. These data demonstrate that ROCK has a central part in tuning the response of T cells to antigen. In the future, we will identify and examine the downstream targets of ROCK that are involved in modulating T cell activation.
Genome-wide profiling of H3K4me3 and H3K27me3 dynamics reveals fundamental epigenetic influences upon CD4 T cell activation (IRC7P.423)
Authors: LaMere Sarah 
Published: January 2023

Abstract
H3K4me3 and H3K27me3 are frequently studied in the context of their association with gene expression, but their cause and effect relationship during CD4 T cell activation has not been determined. Using ChIPseq for H3K4me3 and H3K27me3 alongside RNAseq in naïve and memory human CD4 T cells at rest and after activation at 24 hours, 5 days, and 2 weeks, we have defined the roles these modifications are playing throughout the process of activation. Our results demonstrate that promoter H3K4me3 is acting in a feed-forward fashion, where lower expression genes containing H3K4me3 at rest increase expression more rapidly than genes without H3K4me3, and H3K4me3 deposition acts to reinforce increased expression. Conversely, promoters containing H3K27me3 at rest generally show a decrease in expression after activation, particularly in higher expressing genes. However, changes to promoter H3K27me3 after activation act to reinforce basal expression. H3K27me3 demethylation is a prominent finding in both naïve and memory cells during activation, and inhibiting this demethylation leads to decreased proliferation, blunted upregulation of IL2RA, and changes to the cell cycle, suggesting H3K27me3 demethylation is integral to achieving full T cell activation. Our results enhance our understanding of the role these histone modifications play during CD4 T cell activation and underscore key differences between naïve and memory cells in their activation dynamics.
CTLA4-Ig treatment improves RBP4-induced adipose tissue inflammation and insulin resistance triggered by MyD88, JNK, ERK and p38 pathways (IRC8P.443)
Authors: Vieira Pedro , Castoldi Angela , Aryal Pratik , Wellenstein Kerry , Yore Mark , Peroni Odile , Kahn Barbara 
Published: January 2023

Abstract
Adipose tissue (AT) inflammation and impaired insulin action is a major cause of type 2 diabetes. RBP4 is an adipocyte- and liver-derived protein that has an important role in insulin resistance, metabolic syndrome and AT inflammation. RBP4 elevation causes AT inflammation by activating innate immunity that elicits an adaptive immune response. Our aims are to determine the signaling pathways involved in RBP4-induced macrophage activation and the resulting antigen presentation and Th1 polarization and whether the blockade of antigen presentation improves AT inflammation and insulin resistance. RBP4-overexpressing mice (RBP4-Ox) are insulin resistant and glucose intolerant and have increased AT macrophage and Th1 cell infiltration. In RBP4-Ox, AT macrophages display enhanced JNK, ERK and p38 phosphorylation, and in vitro inhibition of these pathways reduces macrophage activation and macrophage-induced CD4 T cell proliferation and Th1 polarization. Moreover, macrophages obtained from MyD88 knockout mice and activated with RBP4 do not secrete TNF, IL12 and IL-1b and fail to induce CD4 T cell proliferation and Th1 polarization. Treatment of RBP4-Ox mice with CLTA4-Ig reduces AT inflammation and improves insulin resistance. Thus, RBP4 causes insulin resistance, at least partly, through MyD88 pathway and downstream by activating JNK, ERK and p38 pathways. These pathways induce macrophage activation and Th1 polarization, which can be blocked by inhibiting antigen presentation.
miR-146a as a negative regulator in controlling humoral immunity (IRM10P.612)
Authors: Lee Hyang-Mi , Choi Youn , Cho Sunglim , Lin Ling-Li , Kang Seung , Aly Khan , Xiao Changchun , Crotty Shane , Lu Li-Fan 
Published: January 2023

Abstract
The germinal center (GC) reaction is the hallmark of B cell-mediated immune responses to T cell-dependent antigens Recently, a specialized immune population of follicular helper T (Tfh) cells has emerged as a central player in driving GC B cell response and promoting humoral immunity. It has been shown that many genes that are critically involved in the generation of GC B cells also play an indispensable role in the differentiation of Tfh cell population from naive T cells. Here, we show miR-146a is highly upregulated in both Tfh and GC B cells. Our analysis of mixed bone marrow chimeras as well as mice with cell-type-specific deletion of miR-146a demonstrated that elevated levels of miR-146a in both Tfh and B cells are pivotal to control corresponding responses during GC reactions in a cell intrinsic manner. Moreover, deletion of both miR-146a and its paralog, miR-146b resulted in further enhance phenotypes, suggesting that both miR-146 family members contribute to the negative regulation of humoral immunity. Finally, combining transcriptional profiling and biochemical approaches including HITS-CLIP (high-throughput sequencing of RNAs isolated by crosslinking immunoprecipitation), several miR-146a targets with potential roles in controlling Tfh and GC B cell responses have been identified. In sum, our study identifies a miRNA family highly enriched in GC cell subsets with the capacity to control GC reaction by limiting differentiation of Tfh and GC B cells.