bluuebunny/crossref_metadata_2025_split huggingface dataset:
Direct ODN ligation on CD4+ T cells results in the activation of TLR9 signaling
Authors: Sharma Ravi Kumar , Sharma Jyoti , Pattekar Ajinkya , Jain Pooja , Sachdeva Naresh 
Published: January 2023

Abstract
Oligodeoxynucleotides (ODNs) are established ligands for TLR9, however functional response via ODN in CD4+ T cells has been believed to be independent of TLR9 and MyD88. Here, we studied the uptake of ODN2216 in human peripheral CD4+ T cells and assessed its effect on TLR9 signaling. We observed that ODN2216 was taken up intracellularly by endocytosis in CD4+ T cells, leading to increase in gene expression of TLR9 in a time dependent manner (p=0.029). The inhibition of endocytosis by dynasore and promethazine resulted in lower uptake of ODN2216 by CD4+ T cells. Inhibition of MyD88 resulted in decreased uptake of ODN2216 (p=0.0009) by CD4+ T cells, while there was no significant effect of inhibiting IRAK1 or IRAK4. Post uptake, we observed a significant increase in gene expression of TLR9, MyD88, IRAK1, IRF-7, and TRAF3 but unlike canonical TLR9 signaling, there was no significant increase in expression of IRAK4, IRF-3, and TRAF6 (p&lt;0.0001). Moreover, TLR9 expression on CD4+T cells also decreased significantly upon treatment with endocytosis inhibitor (p=0.0001), MyD88 inhibitor (p=0.016), IRAK1 inhibitor (p=0.0001) but not IRAK4 inhibitor as compared with untreated CD4+ T cells. Further the uptake of ODN2216 led to an increase in TGF-β synthesis in TLR9 signaling dependent fashion by CD4+ T cells (p&lt;0.0001). Collectively, our results demonstrate a direct but distinct TLR9 agonist ligation induced signaling pathway in CD4+ T cells which is independent of antigen presenting cells. This TLR9 signaling pathway may have a significant role in modulation of T-cell responses in exaggerated inflammatory responses.
Delayed neutrophil apoptosis is regulated by cancer associated a2 isoform vacuolar ATPase
Authors: Ibrahim Safaa A. , Kulshrestha Arpita , Katara Gajendra K , Beaman Kenneth D 
Published: January 2023

Abstract
Neutrophils are short life span cells but they can live for weeks in cancer tissues and promote tumor progression. Identifying cancer derived factors that enhance neutrophil survival will provide new targets for cancer therapy. A peptide from the N-terminal domain of a2- isoform vacuolar ATPase (a2NTD) is specifically secreted from cancer cells and promotes the neutrophil protumorigenic properties which in turn, enhance tumor progression. This gives a2NTD the propensity to regulate neutrophil survival. In fact the treatment of human neutrophils with recombinant a2NTD led to 2.1 fold increase in the percentage survival of neutrophils (P &lt; 0.001). a2NTD treatment modulates different apoptosis pathways. Executive pathway; a2NTD treated neutrophils (a2Neuφ) showed a significantly decreased gene expression of caspase-3, -6, -7, that corresponded with decreased activity of these caspases. Intrinsic pathway; a2NTD treatment upregulates the gene expression of anti-apoptotic factors; Bcl2-A1, Bcl-xL and downregulates the pro-apoptotic factors; BAX and Apaf-1. Extrinsic pathway; a2NTD treatment dowenregulats the gene expression and the activity of caspase-8 and upregulates the gene expression of c-Flip. a2NTD treatment also stimulates reactive oxygen species generation that activate NF-kB p65 in neutrophils. Moreover, NF-kB inhibition negated that promoted neutrophil survival that was associated with downregulation of the gene expression of Bcl2-A1, Bcl-xL, G-CSF and upregulation of BAX. Thus, a2NTD enhances neutrophil survival by activating the NF-kB pathway in neutrophils. Together, these data demonstrate a novel role of the cancer associated a2-vacuolar ATPase on regulating neutrophil survival by the action of a2NTD.
Versican proteolysis is associated with robust CD8+ T-cell infiltration in human mismatch repair-proficient and -deficient colorectal cancers
Authors: Asimakopoulos Fotis , Hope Chelsea , Emmerich Philip , Pagenkopf Adam , Matkowskyj Kristina , Van De Hey Dana , Payne Susan , Clipson Linda , Papadas Athanasios , Johnson Michael G , Deming Dustin 
Published: January 2023

Abstract
Colorectal cancer (CRC) originates within immunologically complex microenvironments. To date the benefits of immunotherapy have been modest except in neoantigen-laden mismatch repair (MMR)-deficient tumors. Approaches to enhance tumor-infiltrating lymphocytes in the tumor bed may substantially augment clinical immunotherapy responses. We recently reported that proteolysis of the tolerogenic matrix proteoglycan versican (VCAN), in myeloma tumors, generates a bioactive fragment, versikine, with putative immunostimulatory activities. We show that VCAN proteolysis strongly correlated with CD8+ T-cell infiltration in CRC. Tumors displaying active VCAN proteolysis and low total VCAN were associated with robust (10-fold) CD8+ T-cell infiltration. The correlation between VCAN proteolysis and CD8+ T-cell infiltration was maintained in MMR-proficient and -deficient CRCs. Tumor-intrinsic WNT pathway activation was associated with CD8+ T-cell exclusion and correlated with VCAN accumulation. Our findings indicate VCAN proteolysis may shape CRC immune contexture and provide a rationale for testing VCAN proteolysis as a predictive and/or prognostic immune biomarker. Therapeutic manipulation of the VCAN-versikine axis may augment immunotherapy efficacy against CRC.
Ectopic B cell response to Ehrlichia muris in the liver
Authors: Trivedi Nikita H , Kader Muhamuda , Diniro Roberto , Ismail Nahed , Shlomchik Mark J 
Published: January 2023

Abstract
The development of high-affinity, isotype-switched Abs and memory cells is generally facilitated by Germinal Center reactions (GCs) that form in the secondary lymphoid organs within 4–5 days of antigen encounter. However, in the case of Ehrlichia muris (E. Muris), an obligate intracellular tick borne pathogen, GCs are not detectable up to day 35. Instead a robust B cell response dominated by IgM antibody forming cells (AFCs) originates from extrafollicular (EF) sites in the spleen, with somewhat lower, but still large frequencies of IgG AFCs. Interestingly, E. Muris is known to infect the liver, and we found both AFCs as well as histologic collections of plasmablasts in the liver parenchyma. In both cases the number of total AFCs was far larger than that which bound to lysates that contain E. Muris antigens, suggesting either a non-specific or very low affinity response. We hypothesize that these EF sites to be locations where B cells undergo somatic hypermutation (SHM) and acquire mutations that increase affinity to E. muris. Such mutations would allow what appear to be low affinity non-specific responses to gain detectable affinity for E. Muris. To test this, we performed laser microdissection of these plasmablast patches followed by sequencing of BCR variable regions. These studies revealed that somatic hypermutation occurred in the spleen as well as liver and thus demonstrated that liver is a novel locus for generating B cell immune responses that include V region mutation and affinity-based selection.
HVEM-BTLA interactions stimulate lung innate immunity following S. pneumoniae infection.
Authors: Hitomi Kaori , Shui Jr-Wen , Del Rio Maria Luisa , Rodriguez-Barbosa Jose-Ignacio , Kronenberg Mitchell 
Published: January 2023

Abstract
Streptococcus pneumoniae (S. pneumoniae) is the leading cause of bacterial pneumonia in children and the elderly and it kills close to half a million children under 5 years old worldwide every year. Recent reports indicate that epithelial cells act not only as a physical barrier to pathogen invasion, but also as an extension of the immune system to prevent infection or eliminate pathogen. The herpes virus entry mediator (HVEM) is a member of the tumor necrosis factor (TNF) receptor super family. HVEM polymorphisms are a risk factor for several inflammatory and infectious diseases. Although lymphocytes and myeloid cells express HVEM, our previous data suggested that HVEM expression by epithelial cells was critical for innate immunity in the lung. However, the mechanism of HVEM-mediated host defense against S. pneumoniae is still unknown. To address the issue, we have analyzed mice with a lung epithelial cell-specific deletion of HVEM (Cc10-cre x Hvemfl/fl). We found that Cc10-cre x Hvemfl/fl mice were highly susceptible to S. pneumoniae, with an increased bacterial load by 24h and reduced survival. Mice treated with an antibody that blocks HVEM had a similar outcome, confirming that HVEM expression is required during the infection. HVEM has three ligands: the TNF super family member LIGHT and the Ig super family members BTLA and CD160. We determined that BTLA-deficient mice showed increased bacterial load in the lung and reduced survival, similar to HVEM deficiency. Moreover, CD11c-cre x BTLA fl/fl mice were highly susceptible to S. pneumoniae. Our data show that interaction between BTLA expressed by a CD11c positive myeloid cell type and HVEM expressed by lung epithelial cells leads to a protective innate response in the lung after infection.
Atypical activation of human primary dendritic cells by Plasmodium falciparum
Authors: Goetz Anton , Tang Mei San , Ty Maureen , Rodriguez Ana 
Published: January 2023

Abstract
Malaria is characterized by high levels of inflammation and while an early inflammatory response is important for parasite clearance, excessive and persistent inflammation can contribute to severe forms of the disease. At the same time, P. falciparum infections fail to induce sterile immunity. Reports about the role of dendritic cells (DCs) in the immune response to P. falciparum and how they contribute to the activation of CD4+ T cells have been contradictory. To analyze this critical part of the malaria immune response we enriched primary human DCs from peripheral blood of naïve donors and co-incubated them with P. falciparum-infected red blood cells. Although DCs up-regulated surface expression of HLA-DR, co-stimulatory markers, and secretion of chemokines, they did not secrete significant amounts of inflammatory cytokines. Surprisingly, these parasite-activated DCs were able to activate and polarize naïve autologous CD4+ T cells into Th1-like cells secreting high levels of IFNγ and TNF. A re-stimulation with autologous P. falciparum-activated DCs increased proliferation and cytokine secretion of primed CD4+ T cells, indicating these DCs are able to induce an antigen-specific response. We further analyzed the activation phenotype of the two major DC subsets, myeloid and plasmacytoid DCs. Contact-dependent co-culture of both subsets was essential to up-regulate parasite-induced chemokine secretion while plasmacytoid DCs were dispensable for CD4+ T cell activation. RNA-seq of myeloid DCs revealed a distinct transcriptional profile induced by the parasite. Our findings might contribute to a better understanding of the mechanisms involved in the initiation of the adaptive immune response against P. falciparum.
The Kallikrein-kinin system: a novel player of IL-17-driven anti-Candida immune response in the Kidney
Authors: Biswas Partha Sarathi , Ramani Kritika , Garg Abhisek V , Jawale Chetan V , Conti Heather R , Whibley Natasha , Kolls Jay , Gaffen Sarah L 
Published: January 2023

Abstract
Disseminated candidiasis is the fourth most common hospital acquired infection and is associated with a 40–60% mortality rate. During disseminated candidiasis, Candida albicans form invasive hyphae that damage kidney, leading to renal failure. Treatment of candidiasis is hindered by drug toxicity, the development of antifungal drug resistance and lack of vaccines against fungal pathogens. Previous studies have identified a key role of interleukin-17 (IL-17) in controlling systemic infection. The mechanisms of IL-17-mediated renal immunity have so far been assumed to occur solely through the regulation of antimicrobial mechanisms. Here, we discovered an unanticipated role for IL-17 in inducing the Kallikrein (Klk)-Kinin System (KKS) in the infected kidney, and we show that the KKS provides significant renal protection in candidiasis. Consequently, overexpression of Klk1 or treatment with bradykinin rescued IL-17RA−/− mice from candidiasis. Therapeutic manipulation of IL-17-KKS pathways restored renal function and prolonged survival by preventing apoptosis of renal cells following disseminated infection. Moreover, combining a minimally effective dose of fluconazole with bradykinin strikingly improved survival compared to either drug alone. These findings have potential translational significance, as agonists of the KKS are in routine clinical use. Therefore, these results not only identify downstream mediators that could serve as novel drug targets, but could possibly be used to guide decisions on whether targeting these mediators could be a useful therapeutic option in conjunction with current antifungal drugs.
A single nucleotide polymorphism in an AP2 transcription factor encoded in the malaria-causing Plasmodium berghei alters the development of host immunity
Authors: Sheehan Patrick William , Akkaya Munir , Bansal Abhisheka , Arora Gunjan , Otto Thomas Dan , Qi Cheng-Feng , Pena Mirna , Yazew Takele , Billker Oliver , Miller Louis , Pierce Susan K 
Published: January 2023

Abstract
The Apetela2 (AP2) family of transcription factors is a major regulator of Plasmodium parasite gene expression. Twenty seven members of this family have been identified since their discovery in 2005. However, our understanding which AP2 members regulate key features of Plasmodium biology is incomplete. Here we describe the impact of a single nucleotide polymorphism (SNP) in the active site of the AP2 protein, PBANKA_011210, on the outcome of infection in mice. Plasmodium berghei Anka (PbA), the only rodent parasite that causes experimental cerebral malaria (ECM), codes for a phenylalanine at position 1823 whereas all other Plasmodium parasite strains, none of which cause ECM in mice, including PbNK65, have a serine in this position. Using CRISPR, we modified the PbNK65 parasite (PbNK65-WT) to encode the PbA SNP (PbNK65-PbA). The course of infection with PbNK65-WT or PbNK65-PbA were similar and showed no ECM pathology indicating that the PbA AP2 SNP is not sufficient to cause ECM. However, mice infected with PbNK65-PbA generated dramatically higher germinal center responses and produced higher titers of parasite-specific antibodies. When infected mice were treated with sub-therapeutic doses of the anti-malarial, chloroquine, to lower the parasitemias PbNK65-PbA-infected mice cleared the infection whereas mice infected with PbNK65-WT were unable to control the infection resulting severe anemia and death. These results reveal a novel role of AP2 proteins in controlling host immunity to Plasmodium infections.
Neuraminidase-mediated TGF-β activation facilitates evolution of protective Th17 immunity
Authors: Dutta Avijit , Huang Ching-Tai , Chen Tse-Ching , Lin Chun-Yen , Lin Yung-Chang , Chang Chia-Shiang , He Yueh-Chia , Huang Yu-Lin 
Published: January 2023

Abstract
The immune system responds to influenza virus infection for eradication of the virus but the associated inflammation may cause tissue damage to the host. In our antigen-specific mouse system, naïve influenza hemagglutinin (HA)-specific CD4+ T cells adoptively transferred with infection respond with Th1 phenotype and produce IFN-γ. Some of them secrete IL-17 as well. Second batch HA specific CD4+ T cells, adoptively transferred on day 4 after infection and the first transfer, respond to the infection with Th17 phenotype. They produce IL-17 but not IFN-γ. Both the Th1 and Th17 cells are activated with similar levels of ZAP-70 phosphorylation and T-bet induction. For the Th17 cells, IFN-γ deficiency is associated with excessive ROR-γt induction and altered T-bet dominance. Th17 cells display surface LAG-3 expression, suppress T cell activation in vitro and decrease lung inflammation in vivo. The evolution of Th17 cells is augmented in IL-10 deficiency, with IL-10 knockout mice as the recipients transferred with IL-10 knockout HA specific CD4+ T cells. There is increased neuraminidase-mediated TGF-β activation in this IL-10 deficient environment. Viral neuraminidase mediated TGF-β activation in the first batch of HA specific CD4+ T cells facilitates the Th17 evolution of the 2nd batch of cells. The 6.5 T cell receptor (TCR) transgenic mice of monotonous HA specific TCR repertoire respond to influenza virus infection with Th17 deviation and demonstrate survival benefit. Consecutive waves of naïve HA specific T cells from the thymus in 6.5 mice may evolve with mechanisms similar to consecutive adoptive transfers. Evolution of protective Th17 immunity is facilitated by neuraminidase-mediated TGF-β activation.
Effects of the PKC agonist Ingenol-B on HIV suppression by CD8+ T cells
Authors: Kwaa Rebecca Abena K. , Goldsborough Kennedy , Walker-Sperling Victoria , Gama Lucio , Blankson Joel 
Published: January 2023

Abstract
Shock and kill strategies have been proposed as a possible mechanism for HIV-1 eradication. These strategies involve the use of latency-reversing agents (LRAs) such as PKC-agonists, to “shock” latently infected CD4+ T cells and myeloid cells into producing viral proteins that could then be recognized by effector cells leading to the “kill” component of the strategy. In its wake, recent studies have shown that some LRAs inhibit HIV-specific CD8+ T cell responses, suggesting that LRAs should be screened for immunosuppressive properties before use in clinical trials. In a prior study to determine whether PKC agonists could inhibit the potent HIV-specific CD8+ T cell responses seen in patients who control HIV replication naturally (elite suppressors, ES), we found that Bryostatin-1, but not Prostratin, inhibited ES CD8+ T cell responses. Ingenol-B is another PKC agonist with potent LRA activity both by itself and in combination with the bromodomain inhibitor JQ1. In this study, we determined the effect of this drug on CD8+ T cells from 6 ES.
We show here that while Ingenol-B had no effect on the ability of CD8+ T cells to suppress viral replication (65.3% suppression versus 59.3% with DMSO, p &gt; 0.05), its combination with JQ1 caused a modest, but significant, decrease in this suppressive capacity (39.9%, p= 0.033). The mechanism of this inhibitory effect could not be readily explained by differences in PD-1, TIM-3 or CD3 expression on CD8+ T cells. We conclude that since robust CD8+ T cell activity is essential for the eradication of reactivated latently infected cells, the potency of LRA combinations must be balanced against their effect on HIV-specific CD8+ T cell responses.
Natural killer cells support myeloid suppressor cell expansion during persistent viral infection
Authors: Ohayon David E , Brooks Taylor R , Mahl Sarah E , Cranert Stacey A , Waggoner Stephen N 
Published: January 2023

Abstract
Persistent viral infections in mice (e.g. lymphocytic choriomeningitis virus, LCMV) and humans (e.g. HIV, hepatitis C virus) are characterized by chronic inflammation. This sustained inflammatory milieu promotes T cell exhaustion, which limits harmful tissue damage but prevents effective viral control. We found that natural killer (NK) cells aid in the establishment of this tolerogenic state through cytolytic elimination of antiviral T cells. In parallel, others shown that chronic infection encourages expansion of immunoregulatory IL-10-expressing myeloid cells and bona fide myeloid-derived suppressor cells (MDSCs) that contribute to T cell inhibition immune exhaustion and cell injury. We now report that depletion of NK cells prior to persistent infection with the clone 13 strain of LCMV abrogates the expansion of immunosuppressive myeloid cells. In the absence of NK cells, the levels of myelo-stimulatory cytokines, including TNF-a, MCP-1, and IL-6 were also reduced. Furthermore, frequencies of myeloid precursor cells were reduced in the bone marrow during infection in the absence of NK cells. Our results suggest that NK cells support an inflammatory milieu promoting expansion of the myeloid niche and specifically suppressive myeloid cells during chronic infection. This cross-talk between NK cells and myeloid cells during inflammation has the potential to contribute to immune dysfunction during both chronic infection and in cancer.
Neonatal dendritic cells alter the immunodominance hierarchy of the CD8 T cell response during influenza infection
Authors: Heil Luke , Oliphant Samantha , Lines Louise , Hollifield Melissa , Garvy Beth A 
Published: January 2023

Abstract
Neonates are more susceptible to influenza virus infection than adults, resulting in increased morbidity and mortality as well as delayed clearance of the virus. Multiple differences between the adult and neonatal immune response to influenza help explain this vulnerability. Dendritic cells are of particular interest in this process as their decreased function in neonates results in the poor T cell activation observed during neonatal influenza infections. We sought to understand how differences in neonatal dendritic cells shape CD8 T cell specificity and immunodominance during influenza infection as well as how this may affect memory formation and viral clearance. We found that neonatal C57BL/6 mice display an altered CD8 T cell immunodominance hierarchy, preferentially responding to the influenza protein PA rather than the dominant adult epitope in the NP protein. Additionally, upon secondary infection, mice first infected as pups suffered increased morbidity compared to mice infected previously as adults. Finally, transfer of influenza infected adult dendritic cells to pups resulted in increased T cell activation and enhanced viral clearance. Taken together, these data suggest that neonatal dendritic cells alter CD8 immunodominance, and this may compromise viral clearance and memory formation.
Investigation of CD8+ T Cell Immunity in Zika Virus Infection Using Mouse Models
Authors: Ngono Annie Elong , Vizcarra Edward A , Tang William W , Sheets Nicholas , Joo Yunichel , Kim Kenneth , Gorman Matthew J , Diamond Michael S , Shresta Sujan 
Published: January 2023

Abstract
CD8+ T cells may play a dual role in both protection against and pathogenesis of Flaviviruses, including Zika virus (ZIKV). However, virtually nothing is currently known about the role CD8+ T cells play during ZIKV infection in humans and animal models. The goal of our study is to investigate the role of CD8+ T cells during primary ZIKV infection in mice. Using LysMCre+IFNARfl/fl C57BL/6 (H-2b) mice that lack type I IFN receptor in a subset of myeloid cells, we characterized a new mouse model susceptible to infection with both East African lineage (MR766) and Asian lineage (FSS13025) ZIKV strains. A screening of 244 ZIKV epitopes predicted to bind H-2b class I molecules, defined a specific map of 26 and 15 peptides for MR766 and FSS13025 ZIKV strains, respectively. Intracellular cytokine staining confirmed the identity of these epitopes and demonstrated induction of polyfunctional ZIKV-specific CD8+ T cells. Furthermore, adoptive transfer of ZIKV-immune CD8+ T cells reduced viral burdens, whereas depletion of CD8+ T cells led to higher tissue burdens and mortality was increased in ZIKV-infected CD8−/− mice compared to Wild-type. These results demonstrate that CD8+ T cells are important mediators of protection during primary ZIKV infection and provide a H-2b mouse model for investigating ZIKV-specific CD8+ T cell responses. Based on these findings, studies are in progress towards defining the role of resident memory CD8+ T cells in protection against ZIKV infection using our recently developed mouse models of ZIKV systemic infection and sexual transmission.