bluuebunny/crossref_metadata_2025_split huggingface dataset:
Recruitment of myeloid cells into mycobacterial granulomas.
Authors: Herbath Melinda , Harding Jeffrey S. , Haskó György , Nagy András , Fábry Zsuzsanna , Sándor Mátyás 
Published: January 2023

Abstract
Granuloma formation is a hallmark of mycobacterial infection. The dominant cell types in granuloma are the blood monocyte derived macrophages and inflammatory dendritic cells that represent up to 80% of cells in these lesions. Using granuloma transplantation we demonstrated that in a week more than the third of these cells are replaced. Innate and cognate immunity against the bacteria induces a battery of chemokines that are important in this recruitment and MCP1-CCR2 is one of the main representatives of these pathways. We have also shown that cell death and death-induced extracellular ATP through P2X7R promote VEGF production in a subpopulation of granuloma macrophages and that is also important for myeloid cell recruitment through VEGFR1 displayed by blood monocytes. These factors affect granuloma size, numbers and the number of extravasated monocytes in the tissue around granulomas.
We further compare BCG-induced liver and Mtb-induced lung granulomas in wild type, hypoVEGF, macrophage VEGF production ablated, selective macrophage P2X7R deficient, and CCR2 deficient mice. Additionally to the size and frequency of granulomas we compare cell composition, the cytokines present and bacterial load in the lesions. These data clarify the role of immune response and cell death driven cell recruitment pathways in the granuloma maintenance.
NLRP3 inflammasome plays an important role in the innate immune response to Acinetobacter baumannii infection
Authors: Sukumaran Bindu , Dikshit Neha 
Published: January 2023

Abstract
Acinetobacter baumannii is an emerging multi- or pan-drug resistant nosocomial and community associated bacterium that is increasingly becoming a serious health threat world-wide. Pneumonia, bacteremia, urinary tract infections, and wound infections are some of the important clinical manifestations of A.baumannii infection. However, the innate immune pathways leading to various clinical outcomes associated with A. baumannii infections are not fully characterized yet. We identified that A. baumannii invades and survives within host cells and hypothesized that intracellular innate immune receptors might play a role in the host defense to A. baumannii infection. Inflammasomes are intracellular multiprotein complexes that play critical roles in innate immunity. But whether inflammasome pathway plays any role in the pathogenesis of A. baumannii infection is not studied yet. Through in vitro and in vivo murine pneumonia infection models, we demonstrate that the most extensively studied inflammasome, NLRP3, is an important player in the host defense and inflammatory response associated with A. baumannii infection. We show that A.baumannii infection primes as well as activates the NLRP3 inflammasome assembly in mouse bone marrow-derived macrophages. A.baumannii infection induced IL-1β/IL-18 production is entirely dependent upon ASC/NLRP3/Caspase-1 axis. A.baumannii activates NLRP3 inflammasome by various overlapping mechanisms such as ROS generation/Potassium ion imbalance. Thus we identified a previously unrecognized role for inflammasome components in the host innate immune response to A. baumannii infection and this information may provide alternative therapeutic approaches to tackle A. baumannii infections.
A TLR4-interacting surfactant protein-A-derived peptide improves host defense against Pseudomonas aeruginosa.
Authors: Awasthi Shanjana , Singh Bhupinder , Ramani Vijay , Awasthi Vibhudutta , Xie Jun , Kosanke Stanley 
Published: January 2023

Abstract
Interaction between surfactant protein-A (SP-A) and toll-like receptor (TLR4) plays a critical role in host defense. We have identified SPA4 peptide (amino acids: GDFRYSDGTPVNYTNWYRGE) from a TLR4-interacting region of SP-A. The SPA4 peptide binds to TLR4 and suppresses the secreted levels of inflammatory cytokines against Gram-negative bacterial lipopolysaccharide. In this work, we studied the host defense function of SPA4 peptide against Pseudomonas aeruginosa. We examined the binding of SPA4 peptide to cellular TLR4 and bacteria, and direct antibacterial activity against P. aeruginosa. Pro-phagocytic and anti-inflammatory activities of SPA4 peptide were investigated in nontransfected and TLR4-transfected dendritic cells and primary mouse alveolar macrophages. The biological activity of SPA4 peptide was then studied in a mouse model of P. aeruginosa lung infection. Our results demonstrate that the SPA4 peptide binds to TLR4, but does not interact with live bacteria. Correspondingly, the SPA4 peptide does not directly affect bacterial growth. The SPA4 peptide treatment induces the uptake and localization of bacteria in the phagolysosomes of immune cells. At the same time, the secreted levels of inflammatory cytokines are significantly suppressed. Over-expression of TLR4 augments the pro-phagocytic and anti-inflammatory activity of SPA4 peptide. Furthermore, treatment with SPA4 peptide reduces the bacterial burden, inflammatory cytokines, phosphorylation of p38 MAPK, p54 SAPK/JNK and NF-κB-p65, and alleviates lung edema and pathology in a mouse model of P. aeruginosa infection. Together, our results suggest that the immunomodulatory activity of SPA4 peptide can potentially help control infection.
Control of lupus nephritis by the gut microbiota
Authors: Luo Xin M , Mu Qinghui 
Published: January 2023

Abstract
Dysbiosis of gut microbiota promotes autoimmune disorders that damage organs outside the intestine. Here we report the role of gut microbiota in the pathogenesis of renal dysfunction in systemic lupus erythematosus. In a classical mouse model of lupus nephritis, MRL/lpr, we found marked depletion of Lactobacillus spp. in the gut microbiota. Increasing Lactobacilli in the gut improved renal function of these mice. Further studies revealed that MRL/lpr mice possessed a “leaky” gut, which was reversed by Lactobacilli. Lactobacillus treatment also decreased mucosal IL-6 and increased mucosal IL-10, thereby providing an anti-inflammatory environment in the gut. In addition, it increased IL-10 and decreased IgG2a in the circulation, the latter a major immune deposit in the kidney of MRL/lpr mice. Inside the kidney, Treg-Th17 balance was skewed towards Treg with Lactobacillus treatment. These effects of Lactobacilli were present in female and castrated male mice, but not in unaltered males, suggesting that beneficial bacteria in the gut attenuate lupus nephritis in a sex hormone-dependent manner.
Role of the innate immune system in systemic enterococcus dissemination and clearance
Authors: Chakraborty Rajrupa , Kommineni Sushma , Hayward Michael , Nelson Tamara , Kristich Christopher J , Salzman Nita H 
Published: January 2023

Abstract
Enterococci are gram-positive commensals of the mammalian intestinal tract and intrinsically resistant to broad-spectrum cephalosporin antibiotics. They proliferate in the gut and disseminate systemically causing infections in immunocompromised individuals and hospitalized patients undergoing cephalosporin therapy. Using a unique mouse model with stable intestinal colonization with a lab strain of Enterococcus faecalis (EF), we investigated the role of the immune system in EF dissemination and clearance from mice treated with cephalosporins. Ceftriaxone mediated depletion of indigenous microbiota was associated with expansion of EF throughout the gut, reduced levels of gut mucosal barrier components and eventually EF dissemination to peripheral organs. We observed that EF was not associated with the FACS sorted populations of lamina propria mononuclear phagocytes suggesting that these immune cells did not actively translocate EF across the intestinal mucosa. Mice cleared EF systemically by 2 weeks post-antibiotic treatment without evidence of adaptive immune response. Studies in Rag1−/− mice suggested that adaptive immune system was not essential in EF clearance or containment. Our observations support that intestinal containment and systemic clearance of EF are mediated by innate immune mechanisms. We predict that this reflects general mechanisms for host containment and management of the intestinal commensal microbiota.
Identification of ribosomal targets for protective CD4+ T cell responses against mycobacteria
Authors: Johnson Alison Joy , Kennedy Steven C , Lindestam Arlehamn Cecilia S , Hegde Subray S. , Blanchard John S. , Sette Alessandro , Chan John , Jacobs William R. , Porcelli Steven A. 
Published: January 2023

Abstract
Mycobacterium tuberculosis (Mtb) is a significant health burden, infecting one-third of the global population. A more efficacious vaccine is urgently needed for control and prevention of disease caused by Mtb. We previously reported a genetically modified strain of Mycobacterium smegmatis called IKEPLUS, which is a promising vaccine candidate due to its ability to generate an unprecedented level of bactericidal immunity against Mtb in mice. Protective immunity induced by IKEPLUS is dependent on antigen-specific CD4+ T cell memory, and we hypothesized that specificity of the CD4+ T cell response was a critical feature of this protection. Using in vitro assays of IFNγ production by splenocytes from immunized mice, we identified an immunogenic peptide within the mycobacterial RplJ protein encoded by the Rv0651 gene in mice immunized with IKEPLUS, but not in mice immunized with the currently available M. bovis BCG vaccine. This difference in the immune response generated by the two vaccine strategies led us to further investigate the immunogenicity of the mycobacterial ribosome for additional immunogenic targets. Screening a synthetic peptide library based on the sequences of the 57 mycobacterial ribosomal proteins with CD4+T cells from IKEPLUS-immunized mice, we identified six additional immunogenic peptides, derived from six different mycobacterial ribosomal proteins. Our results demonstrate that the CD4+ T cell response in IKEPLUS-immunized mice has multiple targets including components of the mycobacterial ribosome. Further studies to more fully define the CD4+ T cell responses to ribosomal targets should help to inform the design of effective vaccines against Mtb.
TGF-β-mediated inhibition of IFN-γ production by Mycobacterium tuberculosis-specific T cells in the infected lung
Authors: Adams Kristin N , Moguche Albanus O , Plumlee Courtney R , Urdahl Kevin B 
Published: January 2023

Abstract
Tuberculosis (TB) is a major global health problem killing over one million people every year. The emergence of multi and extremely-drug resistant (MDR and XDR) strains of Mycobacterium tuberculosis (Mtb) has made treatment difficult and has spurred interest in developing host-directed immunotherapeutics. A critical roadblock is our failure to understand how Mtb escapes eradication despite an apparently robust adaptive immune response. Interferon-γ (IFN-γ) producing CD4 T cells are critical for immunity, yet their abundance in the blood does not correlate with protection to TB, suggesting that their activity may be blocked locally at the primary site of infection in the lung. A leading candidate for IFN-γ suppression in the lung is transforming growth factor-β (TGF-β), a multifunctional cytokine that is capable of inhibiting IFN-γ. TGF-β is produced in excess at sites of active Mtb infection in both murine and human TB. Neutralization of TGF-β improves T-cell responses of active TB patients in vitro, but the extent of its role during in vivo TB is unknown. Here, we generated mixed bone marrow chimeras using WT mice and mice with a T cell-specific conditional deletion of TGF-β receptor II (dLck-Cre:TGFbRIIfl/fl). Mtb-specific TGF-βRII knockout cells outcompeted their WT counterparts and exhibited increased IFN-γ production during Mtb infection. Furthermore, Mtb-infected dLck-Cre:TGFbRIIfl/fl mice had decreased bacterial loads early during infection. Finally, two pharmacological inhibitors of TGF-β signaling lowered the bacterial loads of lungs from Mtb-infected mice both early and late during infection. Targeting TGF-β may pave the way for new host-directed immunotherapeutics for TB.
The tetraspanin CD151 is an activation molecule that characterizes M. tuberculosis- specific effector CD4+ T cells
Authors: Seu Lillian , Sun Jim Jian , Schaaf Kaitlyn Ruth , Duverger Alexandra Emilie , Kutsch Olaf , Goepfert Paul Andres 
Published: January 2023

Abstract
Tetraspanins are a family of membrane proteins regulating cell morphology, motility, fusion, and signaling. CD151 is expressed on T cells that stabilizes the immune synapse during antigen recognition, engages in integrin signaling, and primes T cell activation. We have recently demonstrated that CD151 expression leads to increased proliferation and activation in human CD4+ T cells. Given its important functional role, we hypothesized that CD151 may be elevated on M. tb-specific effector CD4+ T cells. We assessed CD151 on ex vivo PBMCs from PPD+ donors (Purified Protein Derivative from M. tb) stimulated with M. tb H37Rv whole cell lysate. CD151+ frequencies were elevated on IFN-γ+ (52 ± 6% vs. 17 ± 2%, P&lt;0.001) and TNF-α+ (74 ± 6% vs. 17 ± 2%, P&lt;0.0001) CD4+ T cells compared to overall baseline levels. To assess the functionality of CD151 on M. tb-specific CD4+ T cells, we established an ex vivo culture model with M. tb-infected monocyte-derived macrophages (MDMs) in the presence of autologous PPD+ or PPD− donor CD4+ T cells. Upon day 6 of culture, PPD+ donor cultures, proliferating Ki67+ CD4+T cells were elevated in CD151 and CD25, but diminished in CD57, cell surface expression. Additionally, enhanced frequencies of CD151+ Ki67+CD4+T cells were associated with reduced M. tb growth within autologous MDMs during ex vivo culture. In summary, CD151 is a novel T cell activation marker that is elevated on M. tb- specific CD4+ T cells, and is associated with diminished M. tb growth in culture. CD151 could thus be an interesting candidate to supplement the existing TB-TAM diagnostic (T cell activation marker of tuberculosis) – the first to assess the quality of the CD4+ effector T-cell response to M. tb – and may guide future CD4+ T-cell based vaccine strategies.
Kinome analysis of chicken macrophages infected with Salmonella Enteritidis or S. Heidelberg
Authors: He Haiqi , Arsenault Ryan J , Genovese Kenneth J , Kogut Michael H 
Published: January 2023

Abstract
Macrophages are important innate immune cells that play a central role in the first line defense against microbial infection. Although, chicken macrophages are equipped with effective antimicrobial mechanisms that can be readily activated in response to microbial infection, many Salmonella strains are able to survival inside the macrophage. A previous study has shown that S. Enteritidis was better equipped to survive in the chicken macrophages than S. Heidelberg, in which S. Enteritidis, but not S. Heidelberg, was able to suppress the host’s nitric oxide response. The interaction between chicken macrophages and Salmonella as well as intracellular survival of Salmonella in chicken macrophages remains poorly understood. Here, we used a species-specific immunometabolism kinome peptide array to identify pathways that are involved in chicken macrophages’ response to Salmonella infection. The kinome assay was performed on chicken HD-11 macrophages collected at 0.5, 2, and 6 hr post-infection with either S. Heidelberg or S. Enteritidis. We observed significant changes of phosphorylation (p ≤ 0.05) in a large number of peptides during the infection: 390, 449, and 575 peptides for S. Enteritidis and 185, 470, and 442 for S. Heidelberg at 0.5, 2, and 6 hr, respectively. Additionally, a relatively small number of peptides that showed infection-induced phosphorylation changes in opposite directions when comparing the two serovars: 142 peptides at 0.5 hr, 141 at 2 hr, and 82 at 6 hr. Analyzing phosphopeptides, we found that a number of pathways involved in immunity, signal transduction, cellular process, and metabolism were significantly altered, in some case differentially, during the infection with the two serovars.
Inclusion of non-Francisella epitopes promotes expansion of high avidity, antigen-specific CD4+ T cells for improvement of existing Francisella vaccines
Authors: Roberts Lydia M , Crane Deborah D , Wehrly Tara D , Fletcher Joshua R , Jones Bradley D , Bosio Catharine M 
Published: January 2023

Abstract
Francisella tularensis subsp. tularensis strain SchuS4 (Ftt) is a highly virulent bacterial pathogen and the causative agent of tularemia. There are no licensed tularemia vaccines and experimental live vaccine strains (LVS) vary in their protective efficacy and are poorly defined. Development of novel vaccines will require improvement of protection over the existing LVS and preferably incorporation of well-defined epitopes. However, protective epitopes for tularemia have not been identified. Surviving tularemia requires a strong polyfunctional CD4+ T cell response. Due to the importance of the CD4+ T cell response, we hypothesized ectopic expression of an epitope recognized by high avidity CD4+ T cells would enhance existing vaccine efficacy, regardless of the epitope’s origin. gp61 and LLO are well characterized CD4+ T cell epitopes derived from LCMV and Listeria, respectively, and are recognized by C57Bl/6, but not Balb/c mice. Expression of gp61 or LLO during primary infection with LVS or Ftt improved survival of C57Bl/6, but not Balb/c mice, indicating the presence of low numbers of high avidity CD4+ precursor T cells alters survival during Francisella infection. Furthermore, mice vaccinated with LVS gp61 had significantly improved survival during low and high dose secondary Ftt infection and decreased bacterial burdens compared to controls. Together, this demonstrates that improved efficacy of current tularemia vaccine platforms is achieved by properly targeting appropriate antigen-specific cellular responses. Moreover, the elucidation of Francisella epitopes that elicit high-avidity CD4+ T cell responses, specifically in humans, will be required for successful vaccine development.
IFN-γ production by CD4 CD8 double positive cells is essential for expansion of Proteobacteria in the neonatal murine intestine.
Authors: Mirpuri Julie , Thomas Sarah , Yarovinsky Felix 
Published: January 2023

Abstract

Background
Expansion of Proteobacteria is seen in the neonatal intestine in both humans and mice. Proteobacteria are also significantly over-represented in preterm infants that develop Necrotizing Enterocolitis (NEC). Neonatal mice are more susceptible to models of NEC. The mechanism of expansion of Proteobacteria in neonatal mice and susceptibility to NEC remain undefined.

Objective
To identify immune modulators that favor expansion of Proteobacteria in the neonatal murine intestine.

Methods
qRT-PCR of bacterial 16S rRNA gene sequence tags of colonic fecal contents from 1–3 week (wk) old wild type (WT), IFN-γ knock out and Rag deficient mice was performed to identify major bacterial groups. qRT-PCR and ELISA of whole colon were used to profile cytokine expression. Flow-cytometry of lamina propria cells was used to characterize cells in 1-,2- and 3-wk old mice. IFN-γ neutralizing Ab was given IP to 3 day old mice and then similarly examined at 2 wks.

Results
2-wk-old WT mice showed increased expansion of Proteobacteria and increased production of IFN-γ. IFN-γ KO mice had minimal expansion of Proteobacteria in the colon, this was also seen in WT mice blocked with IFN-γ Ab. Flow-cytometry revealed a unique subset of CD4 CD8 double positive cells, only present in neonatal mice, that produce IFN-γ in WT mice. Rag deficient mice did not have this subset of cells and also had minimal colonization by Proteobacteria at 2-wks.

Conclusions
IFN-γ promotes the expansion of Proteobacteria in the neonatal intestine. A unique and transient subset of CD4 CD8 cells, that are absent in Rag deficient mice, appear to be responsible for the increased IFN-γ in neonatal mice. This is a potential target for intervention in the prevention of NEC in preterm infants.
Dysbiosis-induced IL-33 contributes to impaired antiviral immunity in the genital mucosa
Authors: Lee Heung Kyu , Oh Ji Eun 
Published: January 2023

Abstract
Commensal microbiota are considered to play an important role in antiviral immunity. However, the consequence of dysbiosis on antiviral immunity remains unclear. We demonstrate that dysbiosis caused by oral antibiotics directly impairs antiviral immunity following viral infection of the vaginal mucosa. Antibiotic-treated mice succumbed to mucosal herpes simplex virus type 2 infection more rapidly than water-fed mice. The susceptibility of antibiotic-treated mice was attributed to compromised effector T cell responses rather than defects in innate immunity. By screening the factors controlling antiviral immunity, we found that interleukin-33 was secreted from vaginal epithelium after the depletion of commensal microbiota. This cytokine suppresses local antiviral immunity by blocking the migration of effector T cells to the vaginal tissue, thereby inhibiting the production of interferon-γ at local infection sites. These findings provide insight into the mechanisms of homeostasis maintained by commensal bacteria, and reveal a deleterious consequence of dysbiosis in antiviral immune defense.
Microbiota-inducible Innate Immune, Siderophore Binding Protein Lipocalin 2 is Critical for Intestinal Homeostasis
Authors: Singh Vishal , Yeoh Beng San , Chassaing Benoit , Zhang Benyue , Saha Piu , Xiao Xia , Awasthi Deepika , Shashidharamurthy Rangaiah , Dikshit Madhu , Gewirtz Andrew T , Vijay-Kumar Matam 
Published: January 2023

Abstract
Lipocalin 2 (Lcn2) is a multifunctional innate immune protein whose expression closely correlates with extent of intestinal inflammation. However, whether Lcn2 plays a role in the pathogenesis of gut inflammation is unknown. Herein, we investigated the extent to which Lcn2 regulates inflammation and gut bacterial dysbiosis in mouse models of IBD. Lcn2 expression was monitored in murine colitis models and upon microbiota ablation/restoration. WT and Lcn2 knockout (Lcn2KO) mice were analyzed for gut bacterial load, composition by 16S rRNA gene pyrosequencing and, their colitogenic potential by co-housing with Il-10KO mice. Acute (dextran sodium sulfate) and chronic (IL-10R neutralization) colitis was induced in WT and Lcn2KO mice with or without antibiotics. Lcn2 expression was dramatically induced upon inflammation and was dependent upon presence of a gut microbiota and MyD88 signaling. Use of bone-marrow chimeric mice revealed non-immune cells are the major source of circulating Lcn2. Lcn2KO mice exhibited elevated levels of entA-expressing gut bacteria burden and, moreover, a broadly distinct bacterial community relative to WT littermates. Lcn2KO mice developed highly colitogenic T-cells and exhibited exacerbated colitis upon exposure to DSS or neutralization of IL-10. Such exacerbated colitis could be prevented by antibiotic treatment. Moreover, exposure to the microbiota of Lcn2KO mice, via cohousing, resulted in severe colitis in Il-10KO mice. Lcn2 is a bacterially-induced, MyD88-dependent, protein that play an important role in gut homeostasis and a pivotal role upon challenge. Hence, therapeutic manipulation of Lcn2 levels may provide a strategy to help manage diseases driven by alteration of the gut microbiota.