bluuebunny/crossref_metadata_2025_split huggingface dataset:
Activated human neutrophil control macrophage infection by L. amazonensis (37.14)
Authors: Brodskyn Claudia , Afonso Lilian , Khoury Ricardo , Santos Theo , Clarencio Jorge , de Oliveira Camila , Barral Aldina , Barral-Netto Manoel , Borges Valeria 
Published: January 2023

Abstract
Neutrophil granulocytes are rapidly recruited from the bloodstream to the site of infection via transmigration through the vascular endothelium and they can be activated in this process. Recently, our group showed that phagocytosis of resting apoptotic human neutrophils by L. amazonensis-macrophages induced an increase in the number of intracellular parasites, whereas phagocytosis of necrotic neutrophils by infected macrophages induced killing of parasites in a mechanism dependent on TNF-α and NE. In the present study, we activated the human neutrophils using extracellular matrix proteins and evaluated the effect of viable and apoptotic activated human neutrophils on macrophage infection by Leishmania amazonensis. Fibronectin interaction with neutrophils induced a higher level of cell activation as evidenced by an increased expression of surface markers, such as CD11b as well as a decrease in CD62L and Annexin V. We also detected an increased production of MMP-9 and NE. Phagocytosis of viable and apoptotic fibronectin-activated neutrophils by Leishmania-infected macrophages led to a decrease in parasite burden in a mechanism dependent of NE, MPO and MMP-9. We also observed increase levels of TNF- α , LTB4 and superoxide production in the co-cultures. Given that the events following Leishmania infection involve interactions with neutrophils, our study describes novel mechanisms associated with parasite elimination, based on neutrophil and the infected macrophage collaboration.
Src-family tyrosine kinases regulate alveolar macrophage alternative activation during Pneumocystis murina lung infection (37.28)
Authors: Christmann Benjamin , Nelson Michael , Metz Allison , Steele Chad 
Published: January 2023

Abstract
We have previously shown that mice triple-deficient in the Src-family tyrosine kinases (SFKs) Hck, Fgr and Lyn (SrcTKO mice) have augmented innate lung clearance of P.murina as a result of elevated proinflammatory cytokine (e.g. IL-1β) and chemokine (e.g. CCL2/MCP-1) levels and increased inflammatory cell recruitment. Augmented clearance in SrcTKO mice correlates with a higher ability of alveolar macrophages (AMs) from these mice to kill P.murina in vitro, though this enhancement is not associated with elevated AM inflammatory responses. Since SrcTKO AMs are not hyper-inflammatory yet kill more efficiently, we hypothesized that they have a different activation pattern compared to WT. We show that AMs and whole lungs from P.murina-infected SrcTKO mice express higher mRNA and protein levels of the alternative macrophage activation markers RELM-α and Arg-1 compared to WT. There is surprisingly no difference in the levels of the pro-alternative activation cytokines IL-4 and IL-13 or other cytokines known to modulate AM activation, e.g. IFN-γ or GM-CSF. However, infected SrcTKO mice have higher lung levels of M-CSF, CCL17/TARC and the IL-4/IL-13 receptor, IL4ra. Treatment of WT AMs with IL-4 or IL-13 enhances their ability to kill P.murina, while a blockade of IL4ra or inhibition of phagolysosome maturation inhibits killing. These results indicate that SFKs regulate AM activation during P.murina infection, and that alternatively activated AMs are better equipped to kill P.murina.
Macrophage responses to interleukin-17 are regulated by location and inflammation (37.35)
Authors: Barin Jobert , Baldeviano G. , Talor Monica , Quader Farhan , Wu Lei , Chen Ping , Zheng Dongfeng , Čiháková Daniela , Rose Noel 
Published: January 2023

Abstract
The purpose of this study was to examine how macrophage-lineage cells participate in T helper 17 (Th17)-mediated inflammatory responses. We were interested in how this response may be affected by compartmentalization, and the presence of an inflammatory microenvirionment. We isolated primary murine F4/80+ macrophages (Mϕ) from a broad variety of compartments including spleen, peripheral blood, peritoneum, gut, lung, liver, and CNS. We assayed the expression of the receptors IL17RA and IL17RC on these cells by flow cytometric methods, and observed the highest levels of IL17RA and IL17RC expression on Mϕ associated with mucosal surfaces, particularly gut and lung. In order to examine the influence of inflammatory stimuli on the expression of IL17RA and IL17RC in vitro, bone marrow-derived macrophages, which express low levels of IL17RA and IL17RC were stimulated with combinations of TLR ligands, and proinflammatory cytokines. We observed coordinate expression of both IL17 receptor subunits controlled by TNFα and peptidoglycan signaling. Following encounter with CFA adjuvant in vivo, the expression of both IL17RA and IL17RC was most dramatically increased on Mϕ in the liver. We further wished to determine biological consequences of IL17 signaling, and have begun to identify genes regulated by IL17 in macrophage-lineage cells. Together, these data indicate that macrophages participate in Th17-mediated immunity in a manner regulated by localization and inflammation.
Proinflammatory cytokines and type I interferon are differentially induced by virulent and avirulent mycobacteria in human macrophages (37.36)
Authors: Novikov Aleksey , Thompson Robert , Sher Alan , Feng Carl 
Published: January 2023

Abstract
One third of the world's population is latently infected with Mycobacterium tuberculosis (MTB), a virulent intracellular pathogen that can survive in macrophages even in the presence of a strong adaptive immune response. The molecular mechanisms underlying MTB persistence are not fully understood. Production of type I interferon (IFN) has been linked to the exacerbation of pulmonary tuberculosis (TB) in mice. However, the role of type I IFN in human TB is as yet undefined. In this study, primary macrophages derived from elutriated monocytes of healthy individuals were infected with MTB or M. bovis Bacillus Calmette-Guérin (BCG), an attenuated vaccine strain, and their responses analyzed by qPCR. We observed that compared to BCG, MTB infection induced markedly lower expression of the NF-kB-dependent pro-inflammatory cytokine genes IL-1 and IL-8 at all time-points examined. On the other hand, transcript levels of the type I IFN associated genes CXCL10 and IFIT1 were significantly higher in MTB infected compared to BCG-infected macrophages. These findings suggest that the differential regulation of type I IFN is a determinant of mycobacterial virulence in human macrophages and that MTB may exploit the host type I IFN pathway to subvert anti-microbial programs in these host cells. This work was supported by the Intramural Research Program of the NIAID and by the Howard Hughes Medical Institute-National Institutes of Health Research Scholars Program.
Intracellular colocalization of galectin-3 with Listeria monocytogenes in macrophages and its implications (37.45)
Authors: Weng I-Chun , Chen Huan-Yuan , Hsu Daniel , Liu Fu-Tong 
Published: January 2023

Abstract
Galectin-3 is a β-galactoside-binding animal lectin expressed in epithelial cells and various immune cell types. In macrophages, It has been shown to be a positive regulator for FcγR-mediated phagocytosis and a negative regulator for LPS-mediated inflammation. However, its role in macrophages during infection process remains unclear. Here we investigated the role of galectin-3 in macrophages during the infection of a Gram-positive bacterium, Listeria monocytogenes (LM). Survival of LM in galectin-3-deficient (gal3-/-) bone marrow-derived macrophages (BMM) was impaired compared to that in galectin-3 wild-type (gal3+/+) BMM. This was not due to a difference in the production of bactericidal mediators nitric oxide and superoxide anion, nor a difference in the efficiency of LM escape from phagosomes between gal3+/+ or gal3-/- BMM. Interestingly, by immunofluorescence staining we detected colocalization of intracellular galectin-3 with LM at as early as 15 min after infection. The colocalization proportion peaked at 30 min post-infection, coinciding with the timing of LM escape. In vitro incubation of LM with recombinant galectin-3 was shown to promote LM growth. Based on these findings, we hypothesize that LM utilizes intracellular galectin-3 to improve its own survival and growth after escape into the host cytosol.
LPS stimulates bactericidal activity in the social amoeba Dictyostelium discoideum (37.47)
Authors: Snyder Michelle , Walk Alexander , Callahan Jennifer , Srisawangvong Pat , Leuschner Jessica , Samaroo Dave , Cassilly Daniel 
Published: January 2023

Abstract
Innate immune cells use evolutionarily-conserved pattern-recognition machinery to detect pathogen-associated molecular patterns (PAMPs). The conservation of pattern-recognition machinery allows for its characterization in various model organisms. The social amoeba Dictyostelium discoideum is a unique model system that can exist as single-celled amoebae that phagocytize bacteria for nutritional uptake. Although D. discoideum has been used to study bacterial phagocytosis, it has not been determined whether D. discoideum uses pattern-recognition machinery to detect bacterial PAMPs. Here we show that D. discoideum mounts responses against the bacterial cell wall PAMP, lipopolysaccharide (LPS). LPS treatment of D. discoideum results in more efficient uptake of bacteria and more efficient clearance of phagocytized bacteria. In addition, as shown by qRT-PCR, D. discoideum treated with LPS upregulate expression of putative pattern-recognition and phago-lysosomal genes. Both LPS-enhanced bactericidal activity and gene expression are dependent on MAPK signaling. We currently are determining the mechanisms by which LPS stimulates D. discoideum by studying intracellular trafficking of phagocytized bacteria and by creating D. discoideum cells that overexpress or are deficient for pattern-recognition and phago-lysosomal genes. The characterization of pattern recognition in D. discoideum should provide insight into conserved molecular mechanisms underlying microbial detection.
IL-17 is essential for host defense against cutaneous Staphylococcus aureus infection (37.50)
Authors: Cho John , Pietras Eric , Garcia Nairy , Ramos Romela Irene , Farzam David , Monroe Holly , Magorien Julie , Blauvelt Andrew , Kolls Jay , Cheung Ambrose , Cheng Genhong , Modlin Robert , Miller Lloyd 
Published: January 2023

Abstract
Although neutrophil recruitment is required for immunity against Staphylococcus aureus, a role for T cells has been suggested based on the increased susceptibility of humans who have altered T cell immune responses to S. aureus cutaneous infections. Here, the contribution of T cells to host defense was investigated in a mouse model of S. aureus cutaneous infection. Mice deficient in γδ but not αβ T cells had substantially larger skin lesions with higher bacterial counts and impaired neutrophil recruitment compared with wild-type mice. This neutrophil recruitment was dependent upon epidermal Vγ5+ γδ T cell production of IL-17 but not IL-21 and IL-22. Further, IL-17 induction required IL-1, TLR2 and IL-23 and was critical for host defense, since IL-17R-deficient mice had a similar phenotype as γδ T cell-deficient mice. Importantly, γδ T cell deficient mice treated with a single dose of recombinant IL-17 had lesion sizes and bacterial counts that resembled wild-type mice, demonstrating that IL-17 can restore the impaired immunity in γδ T cell deficient mice. This study defines a novel role for IL-17-producing epidermal γδ T cells in innate immunity against S. aureus.
Suppressive Th17 responses in patients with active tuberculosis is associated with reduced IL-6R expression on CD4+ T cells (37.51)
Authors: Chen Xinchun , Zhang Mingxia , Liao Mingfeng , Zhou Boping 
Published: January 2023

Abstract
The frequencies of IFN-γ-, IL-4-, IL-17-, FoxP3- and IL-6R- expressing CD4+ T cells in blood and/or pleural effusion sample of healthy donors, subjects with latent tuberculosis infection and patients with active tuberculosis, were analyzed by flow cytometry. The frequency of Th17 cells in patients with active tuberculosis is significantly lower than those in healthy donors and individuals with latent tuberculosis infection. The reduction of Th17 response was significantly more profound in patients with severe tuberculosis disease compared to those with pulmonary tuberculosis only. The frequency of Th17 cells was significantly lower in pleural effusion samples than in cohort peripheral blood from patients with tuberculous pleurisy. Correlation analysis showed that suppressive Th17 response observed in patients with active tuberculosis was significantly correlated with the reduced expression of interleukin-6 receptor on CD4+ T cells, but not the concentration of cytokine TGF-βand IL-6. consistently, in vitro study showed that Mycobacterium tuberculosis products inhibit the expression of interleukin-6 receptor on CD4+ T cells. Our results demonstrated that decreased Th17 responses were associated with the clinical outcome of Mycobacterium tuberculosis infection. Suppression of Th17 response through down-regulation of interleukin-6 receptor expression may be an important mechanism in the development of active tuberculosis.
IL-18, TNF-α, and IFN-γ are involved in a network of cytokine interactions that promote control of Mycobacterium tuberculosis by human macrophages (37.52)
Authors: Robinson Cory , Nau Gerard 
Published: January 2023

Abstract
Mycobacterium tuberculosis (MTB) is one of the most successful human pathogens and has infected approximately one-third of the global population. Understanding fundamental aspects of positive immune responses is pivotal to developing new strategies to combat infections. We previously published that treatment of primary human macrophages with interleukin (IL)-12 and a soluble reagent to neutralize IL-27 restricts MTB growth during infection. To understand this at the mechanistic level, we have investigated the immunological parameters that are essential in the control of MTB growth. IL-18, tumor necrosis (TNF)-α, and interferon (IFN)-γ are among the cytokines produced by human macrophages during infection when IL-12 is supplied and IL-27 is neutralized. We have explored the contribution of each of these cytokines and found them all to play a significant role in controlling MTB growth in human macrophages. IL-18 is important for achieving optimal levels of IFN-γ production in response to IL-12 and MTB. Similarly, IFN-γ enhances TNF-α expression and secretion. Furthermore, quantitative assays have shown that IFN-γ increases expression of the TNF receptor. In turn, TNF-α augments expression of the receptor for IFN-γ resulting in more receptor chains at the cell surface that are available for cytokine-induced signaling. These results suggest that IL-18, TNF-α, and IFN-γ interact in cooperative fashion to restrict growth of MTB in primary human macrophages.
Enhancing innate immune defense against Staphylococcus aureus infection by therapeutic targeting of virulence regulation (37.55)
Authors: Sully Erin , Alexander Susan , Hall Pamela , Gresham Hattie 
Published: January 2023

Abstract
Staphylococcus aureus is a medically significant pathogen that uses both cell-associated and secreted virulence factors to evade innate immune host defense. Because antibiotic resistance is an emerging and increasing problem with this pathogen, an alternative strategy for ameliorating the infection is to enhance host defense by inhibiting production of these virulence factors. We screened libraries of small molecules for inhibition of a pheromone-dependent quorum sensing operon, agr, which regulates expression of over 80 different genes including toxins and capsule that directly antagonize phagocyte-dependent host defense. A uricosuric drug used to treat gout, benzbromarone, inhibited pheromone dependent virulence without affecting bacterial viability in multiple S. aureus strains. When complexed with cyclodextrin as a vehicle, it inhibited S. aureus infection in a mouse model of dermonecrosis. More detailed in vitro studies revealed that the drug/cyclodextrin complex affected expression of both cell-associated and secreted virulence factors making the bacteria more susceptible to killing by oxidants and acid. Even after 50 generations of bacterial growth in the presence of benzbromarone, pheromone dependent virulence was still inhibited in the presence of the drug. These data indicate that signaling in bacterial pathogens can be targeted to enable killing and clearance by the innate immune system while limiting the development of induced resistance.
Immunoglobulin Class Switching During RSV Infection Is PKR-Dependent (38.1)
Authors: Thakur Sheetal , Zallinger Zachary , Corn-Minor Radiah , Johnson Teresa , Graham Barney 
Published: January 2023

Abstract
Adaptive immune responses play a critical role in protection against many pathogenic viruses including respiratory synctial virus (RSV). Previous studies from our laboratory have established protein kinase R (PKR) as an important mediator of RSV-induced innate immunity and immunopathology. Thus far, very little is known about the role of PKR in adaptive immune mechanisms involving B cells following RSV infection. Therefore, in this report the role of PKR in regulation of RSV-induced immunoglobulin (Ig) class switching in a mouse model was investigated. Wild type (WT) and PKR-deficient (PKR-/-) mice were infected with RSV intratracheally (1x 107 pfu/mouse) and serum Ig levels were determined at 3, 7 and 14 days postinfection. Increased serum levels of IgA, IgG and IgE were observed in WT mice compared to the PKR-/- mice. Furthermore, western blot analysis on extracts from RSV infected cells, showed that serum from infected WT mice contained significantly greater levels of RSV-specific IgG and IgA than serum from PKR-/-mice. Several immunoregulatory cytokines including TGF-β, IL-12 and IFN-γ significantly lower in PKR-/- mice compared to the WT mice. These cytokines are known to be critical factors in determining the modulation of B cell activation, differentiation which includes class switch recombination. Taken together, these results demonstrate that PKR plays an important role in virus specific Ig responses.
Protective human MAbs to a highly conserved conformational determinant on influenza M2e (38.14)
Authors: Grandea Andres , Olsen Ole , Cox Tom , Renshaw Mark , Hammond Philip , Chan-Hui Po-Ying , Mitcham Jennifer , Cieplak Witold , Stewart Shaun , Grantham Michael , Pekosz Andrew , Hatta Masato , Kawaoka Yoshihiro , Moyle Matthew 
Published: January 2023

Abstract
Specific antibody responses to the annual influenza vaccine can protect against infection if the vaccine and the infective strain are antigenically well-matched. However, due to the variability of the influenza genome, emergent strains arise for which the vaccine proves to be ineffective, and moreover, necessitate its yearly reformulation. Efforts have been made into identifying epitopes within more conserved elements of the influenza virus as an alternative attack on a wider range of strains. Through our platform of examining monoclonal antibodies (MAbs) expressed from plasmacytes derived from memory B cells from normal healthy human donors, we have found a previously unknown conformational antigenic determinant within the relatively invariable ectodomain of M2 (M2e) of influenza A. The MAbs bind to virus and cell-surface expressed M2, but not to the corresponding M2e peptide. The M2e region recognized is in almost all strains isolated to date. Furthermore, in a mouse model of infection, the MAbs can protect against lethal challenge. These results suggest that naturally expressed M2 can elicit a broadly cross-reactive and protective antibody response. And, the human recombinant anti-M2e MAbs might serve as therapeutic agents against infection.
ATAK Cells Require Intact Cytochrome Oxidase Activity to Kill Fungi (38.18)
Authors: Lin Lin , Luo Guanpingsheng , Baquir Beverlie , Ibrahim Ashraf S. , Fu Yue , Spellberg Brad 
Published: January 2023

Abstract
Invasive fungal infections cause high mortality rates in neutropenic patients. We developing an immunotherapy based on activation of HL-60 cells into Activated Targeted Killer (ATAK) cells. We have shown that ATAK cells phagocytize and kill C. albicans in vitro, and protect neutropenic mice from invasive candidiasis and aspergillosis. However, the mechanism by which ATAK cells kill fungi were unclear. Because we have recently found that gp91phox deficient mice were hypersusceptible to invasive candidiasis, we used siRNA to suppress gp91-phox expression in ATAK cells to define impact of suppression of NADPH-superoxide formation on fungal killing. We use a lentivirus to stably transfect a gp91-phox-targeting siRNA construct into HL-60 cells. Stable transfectants had significantly suppressed mRNA level (by RT-PCR) and protein expression (by western blot) of gp91-phox. To confirm functional suppression, we compared the superoxide production in wild-type ATAK cells and gp91-phox-/- cells by DHR123 staining and flow cytometry. We found the gp91-phox -/-cells had markedly reduced superoxide generation. In in vitro killing assays, gp91-phox-/- ATAK cells had marked reductions in their killing of C. albicans relative to wild type cells. Finally, gp91-phox deficient ATAK cells were unable to protect neutropenic mice from invasive candidiasis or invasive aspergillosis. Thus, ATAK cell fungal killing and in vivo efficacy requires intact superoxide production by the NADPH-oxidase system.
Enhancement of virus-specific expansion of transgenic CD8 T cells in aged mice by dendritic cells (38.3)
Authors: Jiang Jiu , Fisher Erin , Bennett Andrew , Murasko Donna 
Published: January 2023

Abstract
Aging is associated with a decreased CD8 T cell response to virus infection. Although both intrinsic and extrinsic factors have been shown to contribute to the decrease, the mechanisms are still largely unknown. In this study, the role of dendritic cells (DCs) in the age-associated decrease was examined. Influenza-specific TCR transgenic CD8 T cells of young mice demonstrated limited expansion in response to influenza infection when adoptively transferred to aged compared to young mice. This decreased response in aged mice could be significantly enhanced when DCs of young mice were co-transferred. Co-transfer of DCs had no impact in young recipient mice. Adoptive transfer of the DCs also increased the endogenous CD8 T cell response of intact aged mice, although to a lesser degree. These results suggest that the diminished CD8 T cell response to virus infection in aged mice is partially attributable to age-associated changes in DCs.