bluuebunny/crossref_metadata_2025_split huggingface dataset:
Dynamics of antigen re-exposure to CD8+ T cells during Toxoplasma gondii infection
Authors: Shallberg Lindsey , Phan Anthony T , Christian David A , Hunter Christopher A 
Published: January 2023

Abstract
The role of T cell Receptor (TCR) stimulation in activation, expansion, and eventual exhaustion of CD8+ T cells has been well characterized in multiple mouse models of disease. What has not been well characterized is the dynamics of antigen re-exposure to CD8+ T cells in non-lymphoid tissues throughout disease progression, and what proportion of CD8+ T cells have been re-stimulated by antigen at any given time. To answer this question, Nur77-GFP reporter OT-I mice were utilized, which provides a sensitive fluorescent reporter for recent TCR stimulation. In mice infected with a transgenic version of the parasite Toxoplasma gondii expressing OVA, the response of Nur77-GFP OT-I to this stimulus was assessed during the acute and chronic phases of infection. Data from these experiments showed that TCR stimulation varies between infected tissues, but largely correlated with infectious burden. For example, during acute infection, up to 50% of the OT-I in the brain had recently re-encountered antigen whereas during the chronic phase approximately 15% of the OT-I expressed Nur77-GFP. Furthermore, characterization of Nur77GFP+ versus Nur77-GFP− OT-I revealed a role of TCR stimulation in co-expression of the inhibitory receptors Tim3 and PD-1. This model system provides a better understanding of how frequently pathogen specific T cells re-encounter cognate antigen and future studies will focus on the role antigen re-exposure plays in CD8+ T cell effector function and memory formation.
CBLB Constrains Inactivated Vaccine-Induced CD8+ T Cell Responses and Immunity against Lethal Fungal Pneumonia
Authors: Nanjappa Somashekarappa Gowda , Mudalagiriyappa Srinivasu , Fites J. Scott , Suresh M. , Klein Bruce S 
Published: January 2023

Abstract
Fungal infections in CD4+ T cell immunocompromised patients have risen sharply in recent years. Although vaccines offer a rational avenue to prevent infections, there are no licensed fungal vaccines available. Inactivated vaccines are safer but less efficacious and require adjuvants that may undesirably bias toward poor protective immune responses. We hypothesized that reducing the TCR signaling threshold could potentiate antifungal CD8+ T cell responses and immunity to inactivated vaccine in the absence of CD4+ T cells. In this study, we show that CBLB, a negative regulator of TCR signaling, suppresses CD8+ T cells in response to inactivated fungal vaccination in a mouse model of CD4+ T cell lymphopenia. Conversely, Cblb deficiency enhanced both the type 1 (e.g., IFN-γ) and type 17 (IL-17A) CD8+ T cell responses to inactivated fungal vaccines and augmented vaccine immunity to lethal fungal pneumonia. Furthermore, we show that immunization with live or inactivated vaccine yeast did not cause detectable pathologic condition in Cblb−/− mice. Augmented CD8+ T cell responses in the absence of CBLB also did not lead to terminal differentiation or adversely affect the expression of transcription factors T-bet, Eomes, and RORγt. Additionally, our adoptive transfer experiments showed that CBLB impedes the effector CD8+ T cell responses in a cell-intrinsic manner. Finally, we showed that ablation of Cblb overcomes the requirement of HIF-1α for expansion of CD8+ T cells upon vaccination. Thus, adjuvants that target CBLB may augment inactivated vaccines and immunity against systemic fungal infections in vulnerable patients.
Upregulation of Neuronal VEGF in Experimental Cerebral Malaria Coincides with Disease Severity Biomarkers in Humans: A Novel Mechanism of Pathophysiology
Authors: Fain Cori E. , Rana Sabhya , Huggins Matthew A. , Sieck Gary C. , Johnson Aaron J. 
Published: January 2023

Abstract
Cerebral malaria (CM) is a deadly neurological complication of Plasmodium falciparum infection resulting in high mortality or severe cognitive deficit. Current therapeutics are highly ineffective, namely due to drug resistance and lack of mechanistic insight into pathophysiology. CM is characterized by VEGF upregulation, disruption of blood-brain barrier (BBB), vascular permeability, and severe edema detectable by MRI. Using small animal MRI and the established animal model of CM Plasmodium berghei ANKA, we recapitulate these features of human disease. Here we show that regions of brain permeability during CM as identified by T1-weighted gadolinium-enhanced and T2-weighted MRI coincide with VEGF mRNA upregulation. Regions of analysis include granular and glomerular cell layers of main olfactory bulb and superior medullary brainstem. We determined through RNA in situ hybridization that neurons are the major cell type responsible for the increased VEGF production during CM. Interestingly, we identified another cell type found to minimally upregulate VEGF in close proximity to these neurons. These VEGF expressing cells may play a role in support or induction of the neuronal response. Intriguingly, astrocytes show no VEGF upregulation during this pathology. Overall, these findings suggest a novel role for neuronal-VEGF in promoting CNS pathology, and a putative mechanism of BBB disruption and vascular permeability during CM.
Enterohepatic Helicobacter (EHH) species differ in their effects on colonic inflammation and colitis-associated colon tumorigenesis in mice
Authors: Alkarkoushi Rasha Raheem , Chatzistamou Ioulia , Hui Yvonne , Nagarkatti Mitzi , Nagarkatti Prakash , Testerman Traci L. 
Published: January 2023

Abstract
Enterohepatic Helicobacter (EHH) species are gram-negative bacteria that colonize the colons and sometimes the biliary tracts of humans, primates, rodents, and other mammals. Though ~20% of the human population may be infected, EHH species are poorly studied in humans. H. hepaticus is known for causing colitis in mice with severe immunologic abnormalities; however, virtually nothing is known about the influence of EHH species on colitis in wild-type mice, which are more relevant to humans. Dextran sulfate sodium (DSS) treatment and DSS plus azoxymethane (AOM ) are widely used as mouse models of ulcerative colitis and colitis-associated colon cancer. We hypothesized that specific EHH species would alter the course of DSS-induced colitis and colitis-associated colon tumorigenesis in mice. We infected C57BL/6 mice with human- and rodent-associated EHH species +/− DSS, or +/− DSS/AOM and measured the effects on pathology and inflammation markers. We found that H. cinaedi, H. pullorum, H. fennelliae exacerbate DSS-induced colitis and delay recovery, whereas H. hepaticus reduced the effect of DSS-induced colitis severity. H. hepaticus also prevented tumor development in the AOM/DSS colon cancer model. We measured the proinflammatory and the anti-inflammatory cytokines in serum and colon homogenates and found that cytokine induction varied among the EHH species. Therefore, EHH species alter susceptibility to DSS-induced colitis and DSS-AOM colon cancer. These results suggest that EHH species could increase or decrease the risk of inflammatory bowel disease or colorectal cancer in humans, making it important to identify the infecting species.
Protective role of secreted aspartyl proteinase in murine systemic candidiasis caused by non-albicans Candida species
Authors: Shukla Manisha , Alam Shahid , Rohatgi Soma 
Published: January 2023

Abstract
Non-albicans Candida species are increasingly becoming more prevalent globally and emergence of drug resistance is another cause of concern. We investigated the protective potential of secreted aspartyl proteinase (Sap2), a leading candidate vaccine antigen identified from research based on C. albicans, in murine systemic candidiasis caused by non-albicans Candida species. The Sap2 genes were successfully cloned and expressed as recombinant proteins from C. albicans, C. tropicalis and C. parapsilosis. Groups of Balb/c mice were immunized with individual rSap2 protein along with alum as adjuvant, followed by systemic infection with lethal dose of C. tropicalis. The protective potential of each rSap2 protein was evaluated using survival analysis and estimation of organ fungal burden. Mice immunized with rSap2 cloned from C. parapsilosis showed highest increase in survival time (p=0.02) and maximum reduction in organ fungal burden (spleen, kidneys, lungs, brain) (p&lt;0.05); compared to sham immunized controls. Immunization with rSap2 cloned from C. albicans did not improve survival in non-albicans C. tropicalis infection, despite the protein having ~60% homology across species. Mice immunized with rSap2 cloned from C. parapsilosis also exhibited significantly higher levels of IFN gamma and IL-4 cytokine levels just before infection, which correlated with protection. The anti-Sap2 specific antibody titres were measured. No correlation was observed between level of Sap2-specific IgG titres and survival outcome. The IgG response was primarily Th2, belonging to IgG1 subtype. Further cellular and histological studies are in progress to characterize the murine rSap2-parapsilosis specific protective immune response in detail.
Deciphering multicellular microenvironment of tuberculosis lung granulomas associated with bacterial control using high-throughput single-cell mRNA sequencing
Authors: Gideon Hannah Priyadarshini , Hughes Travis K , Wadesworth Marc H , Fortune Sarah M , Shalek Alex K , Flynn JoAnne L 
Published: January 2023

Abstract
Infection with Mycobacterium tuberculosis results in the formation of tuberculosis (TB) lung granulomas, which are complex structures with a network of multiple immune cells closely intertwined and function together. Within a given host, granulomas have unique trajectories and outcomes. Some granulomas are able to control bacterial replication, while others fail resulting in persistent bacterial replication. The molecular features associated with these outcomes are not well understood. Using high-throughput single-cell mRNA sequencing on individual TB lung granulomas and computational algorithms, we are generating models to understand infection dynamics that incorporate immune cell composition, its function and interaction; bacterial burden and trajectories of the granulomas to identify robust drivers of bacterial control. We evaluated 28 granulomas from 4 cynomolgus macaques, that were infected for 10 weeks with the Erdman strain of M. tuberculosis. We identified over 30 functional clusters of cells spanning multiple immune and non-immune cells types including T cells, B cells, plasma cells, dendritic cells, mast cells, macrophages, neutrophils, type 2 pneumocytes, fibroblasts and endothelial cells. We observe differential cellular composition and host-cell intercellular communication constituting granulomas that are associated with bacterial burden, that may inform systems level properties across granulomas and animals. By understanding features of the cellular microenvironment that limit bacterial replication, we hope to identify novel targets for host-directed immune therapies and prophylactics in M. tuberculosis infection and other granulomatous disease.
Production of IL-17A by different subsets of γδ T cells in response to the commensal Corynebacterium mastitidis has distinct requirements for IL-1R and TCR recognition
Authors: xu xiaoyan , St. Leger Anthony , Zhu Wenjie , Bing So Jin , Horai Reiko , Mattapallil Mary , Caspi Rachel R 
Published: January 2023

Abstract
The ocular surface is a mucosal site that interacts with the environment and protects the eye. We previously identified an ocular surface commensal, Corynebacterium mastitidis (C. mast.), which induced IL-17A production from γδ T cells in the conjunctiva, affording protection from infection. In the current study we dissect the requirement for IL-17A production in response to C. mast by Vγ4+and Vγ4−γδ T cell subsets. We found that colonization of C. mast-negative mice with C. mast. increased the frequency of IL-17A+ cells in eye-draining lymph nodes by several fold in both subsets. However, whereas Vγ4−γδ T cells upregulated their expression of IL-1R, Vγ4+γδ cells downregulated their CD3 expression, possibly secondary to TCR engagement. To examine this further, we performed in vitro co-cultures of dendritic cells and γδ T cells. With C. mast as the sole stimulant, only Vγ4+ cells, but not Vγ4− cells, produced IL-17A. Addition of exogenous IL1 to the co-cultures elicited production of IL-17A also from the Vγ4− subset, whereas inhibition of downstream TCR signaling events by FK-506 or CsA abrogated IL-17A production in the Vγ4+ subset. Furthermore, C. mast produced a positive Nur77-GFP signal only in the Vγ4+ subset. IL-1R blocking antibody abrogated IL-17A production in both subsets.
We propose that Vγ4+and Vγ4− subsets may sense and respond to C. mast by IL-17A production using distinct pathways. Although an IL-1R signal is needed by both subsets, their level of dependence on this signal differs. IL-1R signaling is dominant in Vγ4−γδ T cells, whose TCR does not appear to respond to C. mast. In contrast, a much lower level of IL-1 appears to be sufficient for triggering IL-17A production from Vγ4+ γδ T cells, which recognize C. mast via their TCR.
Mycobacterium tuberculosis enhances macrophage P-glycoprotein (MDR-1) expression and activity to promote intracellular survival
Authors: Rajaram Murugesan , Wu Qian , Hossfeld Austin , Gerberick Abigail , Saljoughian Noushin , Tiwari Charu , Ganesan Latha Prabha , Wozniak Daniel 
Published: January 2023

Abstract
Tuberculosis (TB) is a communicable disease caused by Mycobacterium tuberculosis (M.tb), a serious problem worldwide with over one third of the global population being infected; resulting in 1.3 million deaths. TB treatment includes a combination of 3 or more anti-TB drugs over a prolonged period of time. In the last few decades, multi drug resistant (MDR-TB) and extensively drug resistant TB (XDR-TB) strains have emerged due to the mismanaged use of anti-TB drugs. In this study, we discovered that M.tb infection increases the expression of macrophage drug efflux pump P-Glycoprotein (MDR-1) to extrude various chemical substances including the anti-TB drugs to benefit the M.tb survival. M.tb infection in macrophages suppresses the heat shock factor-1 (HSF1), a transcriptional regulator of MDR-1 through the up regulation of miR-431. Notably, the non pathogenic mycobacterium M. smegmatis or BCG did not increase the MDR-1 expression in human macrophages. Additionally, the inhibition of M.tb phoPR secretion system by pharmacological inhibitor reverses the M.tb mediated up regulation of MDR-1 in macrophages. Finally, inhibition of MDR-1 in macrophages enhances the anti TB drug mediated killing of M.tb. In conclusion, we report a novel finding that M.tb up regulates the MDR-1 in macrophages which limits the exposure of M.tb to sub-lethal concentrations of drugs that promotes M.tb survival and emergence of resistant variants.
Characterization of a novel Plasmodium Virulence Factor
Authors: Akkaya Munir , Bansal Abhisheka , Sheehan Patrick , Miller Louis , Pierce Susan K 
Published: January 2023

Abstract
Plasmodium is a deadly parasite that claims lives of nearly half a million individuals each year. Identification of the mechanisms the parasite uses to evade the immune response is a critical goal to develop the much needed vaccine against this pathogen. However, we know very little about how individual parasite genes function. Here, by using CRISPR/Cas9 strategy, we altered the DNA binding domain of a Transcription Factor (TF) (PBANKA_011210) that is essential for the completion of Plasmodium Berghei life cycle. In mice, compared to the WT parasite, the mutant one showed differential expression of 46 genes, most of which are thought to be involved in generating parasite surface antigen diversity. Furthermore, unlike WT parasite which successfully hides from immune system, mutant parasite triggered high levels of IFN-g which translated into formation of prolonged germinal centers and development of higher titers of parasite specific IgG2b and IgG2c type antibodies. At low inoculum levels this resulted in successful clearance of infection and development of protective immunological memory in mutant parasite infected animals in contrast to a deadly outcome in WT parasite infected group. The differential development of the immune response was dependent on the host’s ability to produce IFNg as the phenotype was lost in IFNg KO mice. We therefore conclude that (PBANKA_011210) TF is a novel virulence factor acts as an immune modulator and dampens IFNg mediated immune response against parasite
Mosaic response of T cells to commensal bacteria derived polysaccharide
Authors: Alvarez Carlos A , Jones Mark B , Cobb Brian A 
Published: January 2023

Abstract
Polysaccharide A (PSA) is a component the commensal gut bacteria Bacteroides fragilis capsule. Over the last 40 years, PSA has been shown to possess potent inflammatory traits while also serving as a robust stimulator of immune suppression. This duality was shown in rodents in which PSA induces abscess and adhesion formation in sepsis models, but can also inhibit asthma, IBD, and EAE through the induction of regulatory T cells. However, despite decades of study, there remains an inability to explain how PSA is able to balance both potent pro- and anti-inflammatory responses. Here, we utilized a systems immunology approach, consisting of RNAseq transcriptomics, high-throughput flow cytometry and Luminex analyses, to characterize the full impact of PSA-mediated stimulation of both MHCII+ antigen presenting cells and CD4+ T cells. The goal was to better understand the molecular foundations of microbiota-mediated immune homeostasis. We found upregulation of TNF superfamily genes and cell surface markers associated with activated T cells and maintenance of the immune response such as OX40, OX40L and GITR. Immune checkpoints such as CTLA4 and BTLA are downregulated while important cell motility and chemotactic markers such as CD11c and ICAM1 are upregulated in response to PSA. Thus, PSA led to the production of activated and experienced T cells that should be able to navigate towards sources of inflammation, but these cells also showed increases in immune checkpoint markers such as Ly-6A/E, CD73 and PDL1. Taken together, PSA responding cells display a curious mixture of pro and anti-inflammatory markers, consistent with known in vivo function, potentially revealing novel pathways to restore homeostasis in patients with inflammatory disease.
Infection of the spleen by Chlamydia muridarum following per-vaginal inoculation causes splenomegaly and is essential for its dissemination into the gastro-intestinal tract
Authors: Shillova Nita , Howe Savannah E , Konjufca Vjollca H 
Published: January 2023

Abstract
Chlamydia trachomatis is a leading cause of preventable blindness and bacterial sexually transmitted disease (STD) worldwide. C. trachomatis infections in women can result in pelvic inflammatory disease, ectopic pregnancy, chronic pelvic pain, and infertility. In addition to infecting the female reproductive tract (FRT), Chlamydia spp. colonize the gastro-intestinal (GI) tracts of animals and humans and can be a reservoir for reinfection of the FRT. In mice, C. muridarum disseminates from the FRT to the GI tract via an internal, non-oral, non-rectal route. Here we show that C. muridarum disseminates from the FRT to the GI tract in a step-wise manner, by first infecting the FRT-draining iliac lymph nodes (ILNs), then the spleen, inducing extramedullary erythropoiesis and splenomegaly, which peaks at 7 days post per-vaginal (PV) infection, thus splenomegaly is transient. Infection of and proliferation of C. muridarum in the spleen is essential for its dissemination to the GI tract, as colonization of the GI tract by C. muridarum is significantly reduced or completely inhibited in splenectomized mice following per-vaginal inoculation. While intra-venously infected mice clear C. muridarum from ILNs by day 9 of infection, PV-infected mice do not, indicating that infection of ILNs from FRT is the first step of C. muridarum systemic dissemination. Furthermore, inhibition of cell egress with FTY720 significantly inhibits Chlamydia dissemination from ILNs to the spleen and GI tract, indicating a cell-mediated transport of this pathogen. Further elucidation of the mechanisms of C. muridarum systemic dissemination and ensuing immune responses will be essential for developing therapies and vaccination approaches to target this pathogen.
Moringa oleifera Treatment Induces T Cell Activation in Plasmodium chabaudi Infection
Authors: Pilotos Jennifer , Mowa Nathan C , Opata Michael M 
Published: January 2023

Abstract
Malaria is a chronic infection that induces the generation of effector T cells and pro-inflammatory cytokines but never results in sterile immunity. Anti-malaria drugs can alleviate the life-threatening symptoms associated with primary infection, but many of these life-saving drugs are becoming obsolete due to growing resistance. This calls for the development of new strategies to control the disease, and the herbal plant Moringa oleifera is a promising candidate. Studies have shown that Moringa oleifera possesses potent suppressive and curative antimalarial properties, but these studies have mostly been restricted to assessment of parasitemia. Therefore, we sought to investigate the effect of Moringa on malaria immunity in vivo using the rodent parasite strain P. chabaudi. We observed that Moringa treatment slightly reduced parasite burden compared to the untreated controls. Looking at the immune response, mice treated with high dose Moringa (60 mg/mouse) for a short time (7 days) or low dose Moringa (30 mg/mouse) for a longer time (3 weeks), exhibited increased numbers of Teff cells accompanied by an increase in Tbet expression. To further investigate this, we treated mice with Moringa after infection (curatively) or before infection (prophylactically), and observed that mice that were treated with Moringa after infection exhibited increased Teff numbers, IFNγ and TNFα secretion. Interestingly, the mice that were treated before infection had significantly higher Tbet expression. These data suggest that Moringa treatment leads to CD4 T cell activation and production of pro-inflammatory cytokines after malaria infection. Future studies will investigate the mechanism by which Moringa treatment modulates CD4 T cell functions.