bluuebunny/crossref_metadata_2025_split huggingface dataset:
Protection from acute viral disease by memory CD8+ T cells of a single specificity (132.23)
Authors: Chhann Sanda S , Sigal Luis J 
Published: January 2023

Abstract
Ectromelia virus (ECTV), the causative agent of mousepox, is a highly lethal mouse pathogen of the Orthopoxvirus (OPV) genus which also includes vaccinia virus (VACV) and variola virus. Mouse strains such as C57Bl/6 (B6) are naturally resistant to ECTV infection while others such as BALB/c and DBA2/J are highly susceptible. We have previously shown that resting memory CD8+ T cells can protect BALB/c mice from mousepox. To establish a model in the B6 background, we tested B6.D2(D6Mit149-D6Mit15)Lus/J (B6D2-D6) mice, a B6 congenic strain with the NK complex from DBA2/J (where a susceptibility gene to ECTV maps). We found that B6D2-D6 mice are sensitive to ECTV and can be protected by adoptive transfer of multivalent memory CD8+ T cells obtained from convalescent mice. To test whether memory CD8+ T cells of a single specificity can protect, we immunized B6D2-D6 mice with dendritic cells pulsed with B8R20-27, the dominant VACV/ECTV determinant in the B6 background. Strikingly, all the mice immunized with DC-B8R20-27 but not control peptide resisted the disease. Thus, memory CD8+ T cells of a single specificity are sufficient for protection. Because it would be of interest to know whether subdominant determinants can also be targets of protective memory cells, we used intracellular cytokine staining and in vivo cytotoxicity assays to identify additional VACV determinants conserved in ECTV. Interestingly, several determinants classified as subdominant based on their low IFN-γ production were found to be good targets of killing by effector CD8+ T cells. Future work will determine whether memory cells of these subdominant specificities also protect.
This work was supported by NIH grant R01AI065544 to LJS.
NK cells inability to produce IFN gamma in MyD88-/- mice contributes to the delayed clearance of Chlamydia muridarum primary genital infection (133.2)
Authors: Nagarajan Uma M , Sikes James D , Prantner Daniel , Goodwin Anna , Darville Toni 
Published: January 2023

Abstract
We have previously shown that MyD88-/- mice have delayed clearance of C. muridarum genital infection in comparison to wild type (WT) mice. The goal of the present study was to investigate the specific mechanisms by which MyD88 protects against C.muridarum infection. A 10-fold higher bacterial load was observed in cervical tissues of MyD88-/- mice at day (d) 4-post infection, suggesting impairment in the early innate response. Further, IFNγ levels were undetectable in the genital secretions of MyD88-/- mice until d4-d5 post infection, though they were restored to normal levels by d7 post infection. Interestingly, recruitment of inflammatory cells such as PMNs, macrophages and NK cells to mouse cervix remains mostly unchanged between WT and MyD88-/- mice at d4 post infection. To address this conundrum, NK cells from the cervix of infected mice at d4 post infection were FACS sorted and the levels of IFNγ mRNA assessed. Overall, MyD88-/- NK cells induced 16 fold less IFNγ than WT NK cells. Surprisingly, this defect in IFN gamma production did not translate to T cells isolated at d7 post-infection from iliac nodes of MyD88-/- mice, suggesting cell type specific regulation. The NK cells dysfunction in MyD88-/- mice also led to ineffective suppression of Th2 response, a plausible explanation for the delayed clearance of infection in MyD88-/- mice. Interestingly, MyD88-/- mice resolve a challenge infection of C. muridarum as effectively as WT mice, suggesting that an adaptive memory response is not impaired in the absence of MyD88 signaling.
Effect of caspase inhibitors on Salmonella typhimurium induced apoptosis of chicken macrophages (133.27)
Authors: Babu Uma S , Gaines Dennis , Raybourne Richard B , Fonseca Maira , Williams Kristina , Bigley Elmer , Pereira Marion 
Published: January 2023

Abstract
Salmonella typhimurium SR11 (ST) induced apoptosis of chicken macrophage cell line (HD11 cells) was assessed with or without caspase inhibitors. Apoptosis was measured upon the uptake of green fluorescent protein-labeled bacteria using flow cytometry. Dual staining of HD11 cells with annexin V PE and 7-amino-actinomycin-D (7-AAD) allowed differentiation of dead and damaged cells from those undergoing apoptosis. Our results reflect the late apoptotic cells that were positive for annexin V PE and 7-AAD staining. HD11 cells were infected for up to 48 hours and apoptosis was determined at baseline, 24 and 48 hours post-infection. We tested the effect of caspase inhibitors including, general, 1, 2, 3, 4, 6, 8, 9, 10 and 13 at100 and 200 μM concentrations on ST mediated apoptosis. Our data showed that ST induced significant apoptosis at 24 and 48 hours post-infection compared to uninfected cells. In addition, most of the caspase inhibitors inhibited apoptosis at very similar levels however 10 and 13 were the most effective at 24 and 48 hours. At 48 hours, most of the cells were in the necrotic state but incubation with caspase inhibitors 10 and 13 resulted in higher number of viable cells.
Feedback inhibition of macrophage responses to IFNγ during bacterial infection is mediated by IFNαβ (133.32)
Authors: Lenz Laurel L , Rayamajhi Manira , Andreasen Karl , Humann Jessica 
Published: January 2023

Abstract
We previously showed that increased IFNγ production by natural killer (NK) cells correlates with increased susceptibility to infection with Listeria monocytogenes. Here, we report that L. monocyogenes suppresses macrophage responsiveness to IFNγ and describe a mechanism contributing to this suppression. Macrophages infected with L. monocytogenes produced a soluble factor that reduced IFNGR1 transcripts and cell surface expression of both IFNGR1 and IFNGR2 proteins on infected and bystander macrophages and on certain other immune cells. We identify this factor as IFNβ or a substance induced by type I IFN, since (1) only L. monocytogenes strains that induce IFNβ caused IFNGR downregulation, (2) IFNGR downregulation was not seen in macrophages lacking a functional type I IFN receptor (IFNAR1-deficient mice), (3) IFNGR-downregulation was partially dependent on STAT1 and was induced by treatment of cells with recombinant IFNβ or IFNαβ -inducing toll like receptor (TLR) agonists. Our findings demonstrate that IFNβ induced during intracellular bacterial infection feeds back through IFNAR to inhibit IFNGR expression and IFNγ-dependent gene expression. These findings offer a common mechanistic explanation for the ability of IFNβ to enhance host susceptibility to intracellular bacterial infection and to suppress inflammation in the context of diseases such as multiple sclerosis.
Multiplex paracrine signaling leads to antiviral activated DC State (133.40)
Authors: Hartmann Boris M , Borderia-Giner Antonio V , Moran Thomas M , Sealfon Stuart C 
Published: January 2023

Abstract
Infection of immature dendritic cells (DCs) by virus stimulates their maturation into antigen presenting cells (APC). Infected DCs secrete TNFα, IFNα, IFNβ, MIP1α, RANTES, IL-6 and IL-8 which expose uninfected DCs to this complex cytokines/chemokines milieu. Recently, we showed that this paracrine signaling from infected DCs induced an antiviral-primed DC state referred to as antiviral activated DCs (AVDCs, J Immunology 2008 PMID: 18981106). AVDCs are relatively resistant to virus infection in comparison with naïve DCs and achieve accelerated and augmented levels of co-stimulatory molecule expression with virus infection. Here we investigate the factors reponsible for AVDC formation. No single factor induces a similar surface marker pattern in DCs as observed in AVDCs. The effects of all possible double combinations on naive DCs have been evaluated by RNA expression pattern, surface marker expression, as well as imaging flow analysis of rate of phagocytosis and DC-T cell interaction. The results illuminate how DCs integrate multiple paracrine signals to modulate their antiviral state.
Primary human astrocytes functionally express RIG-I, a member of the retinoic acid-inducible gene-I family of viral pattern recognition receptors (133.48)
Authors: Chauhan Vinita S , Furr Samantha R , Grdzelishvili Valery Z , Marriott Ian 
Published: January 2023

Abstract
Astrocytes are ideally positioned to detect and respond to invading pathogens of the CNS and previous studies have demonstrated the ability of these cells to produce key inflammatory mediators following exposure to members of the Mononegavirales order of viruses that are the causative agents of lethal human CNS diseases including rabies. However, the mechanisms by which resident cells of the CNS perceive such viral challenges have not been defined. Recently, several cytosolic DExD/H box RNA helicases have been described that can bind early viral replicative intermediates leading to the realization that retinoic acid-inducible gene I (RIG-I)-like helicases, such as RIG-I, function as intracellular receptors for RNA viruses. In the present study, we demonstrate that cultured primary human astrocytes constitutively express RIG-I receptor protein. Interestingly, such expression is rapidly elevated following exposure to vesicular stomatitis virus (VSV), a neurotropic rhabdovirus that closely resembles rabies virus. Evidence for the functional nature of RIG-I expression in human glial cells comes from the observation that this molecule associates with its downstream effector molecule, interferon promoter stimulator-1 (IPS-1), following VSV infection as assessed by co-immunoprecipitation techniques. Furthermore, we have confirmed that this molecule functions as an intracellular pattern recognition receptor in astrocytes by demonstrating that a putative ligand for RIG-I can elicit inflammatory cytokine production by this cell type. These findings raise the exciting possibility that RIG-I plays an important role in the detection of viral CNS pathogens and the initiation of protective immune responses or, alternatively, the progression of damaging inflammation within the brain.
Targeting natural killer cell potassium channels for selective immunomodulation (134.14)
Authors: Hu Xueyou , Moore Rebecca V. , Pennington Michael W. , Beeton Christine 
Published: January 2023

Abstract
Natural killer (NK) lymphocytes play roles in the innate immune defense against tumors and viruses but also participate in graft-versus-host disease and organ transplant rejection. Selective immunomodulation of NK cell subsets would therefore prove beneficial.
We have found that human NK cells express two types of potassium channels: Kv1.3 and KCa3.1. Interestingly, NK cells adherent to plastic in the presence of cytokines up-regulate KCa3.1 channels while non-adherent NK cells up-regulate Kv1.3 channels. In going with these results, we found that selective blockers of Kv1.3 channels preferentially inhibited natural cytotoxicity, antibody-mediated cytotoxicity and Fas-mediated cytotoxicity by non-adherent NK cells while selective blockers of KCa3.1 channels preferentially targeted adherent NK cells. We observed the same dichotomy when studying the effects of potassium channel blockers on the ability of adherent and non-adherent NK cells to proliferate and produce cytokines. We have successfully used selective Kv1.3 channel blockers to inhibit autoreactive T lymphocytes for the treatment of autoimmune diseases without inducing generalized immunosuppression. Targeting NK cell potassium channels may prove beneficial for the selective immunomodulation of NK cell subsets.
Funded by the American Heart Association and Baylor College of Medicine.
Deficiency in Sphingolipids Has No Effect on Self-antigen Presentation to Invariant NKT Cells (134.17)
Authors: Pei Bo , Speak Annie , Platt Frances , Cerundolo Vincenzo , Kronenberg Mitchell 
Published: January 2023

Abstract
NKT cells with an invariant TCR (iNKT cells) represent a unique subset of T lymphocytes sharing properties of both natural killer cells and T lymphocytes. iNKT cells regulate immune responses by rapidly secreting large amount of cytokines. Their development and maturation is dependent on self-Ags presented by CD1d, a MHC class I-like antigen-presenting molecule. It is widely believed that these self-Ags are glycosphingolipids. Here, we used LY-B, a sphingolipid-deficient cell line, to study the nature of the endogenous lipid Ags that stimulate iNKT cells. With only 10% glycosphingolipid level of wild type cells, and these predominantly ganglioside GM3, mouse CD1d transfectants of LY-B still showed comparable ability to stimulate iNKT cell hybridomas. The self-Ag presentation was CD1d-dependent, because a specific antibody against mouse CD1d could block it. The finding was further confirmed by a cell-free Ag presentation assay. Surprisingly, alkaline digestion, which specifically hydrolyzes acyl fatty acids from phospholipids, dramatically reduced the antigenic activity of a cell sonicate while αGalCer was not affected. Sphingolipid ceramide N-deacylase, which specifically frees acyl fatty acids from sphingolipids, eliminated the activity of αGalCer without any effect on the activity in the cell sonicate. These data show that the endogenous Ags stimulating iNKT cells need not be glycosphingolipids.
Low T Cell Function in Preterm Neonates (PN) as Analyzed by Cylex ImmuKnow Assay (ICF) May be Responsible for a Higher Rate of Infection (134.47)
Authors: Reddy Sivapriya Thumati , Ge Shili , Puliyanda Dechu , Pao Andy , Jordan Stanley C. , Simmons Charles F. , Toyoda Mieko 
Published: January 2023

Abstract
Background: Cell mediated immunity is a critical defense mechanism against various pathogens. Lymphocyte number and function, and their links to risk for infection in neonates are not well understood. ICF measures immune function by assessing ATP levels in mitogen stimulated CD4+ cells. We investigate CD4+ cell function in neonates and the implication for infections. Methods: Heparinized cord blood from 30 term neonates (TN) and 3 PN (25-28 weeks) were submitted for ICF. Results: ATP levels were significantly lower in PN than TN (221 + 49 vs. 588 + 293 ng/ml, p&lt;0.02). All 3 PN were exposed to maternal chorioamnionitis and treated postnatally for clinical sepsis, while none of the TN showed evidence of infection. In TN, the 18 vaginally delivered (VD) had significantly higher ATP levels than 12 born by cesarean (CS) (731±255 vs. 373±206 ng/ml, p&lt;0.001). Of the 12 TN born by CS, 3 were exposed to labor and 9 were not, and showed similar ATP levels (277±110 vs. 405±225 ng/ml, NS). All 3 PN (1 CS) exposed to labor had low ATP levels. Conclusions: 1) CD4+ cell function is significantly lower in PN than TN, 2) VD in TN, but not CS w/ or w/o labor, increases ATP levels, suggesting that delivery via the birth canal is stressful for the TN and stimulates immune response, 3) ATP levels are not elevated in PN despite VD, suggesting that immune response in PN is poor, and may be partly responsible for a higher rate for infection in this patient population.
Research Sponsors: Dept. of Pediatrics & Transplant/Immunology Lab, Cedars-Sinai Medical Center, Los Angeles, CA
IL-15 and DAP-10 mediated IL-22 production by Natural Killer cells in human Mycobacterium tuberculosis-infection. (134.7)
Authors: Dhiman Rohan , Mohanalxmi Indramohan , Barnes Peter , Paidipally Padmaja , Vankayalapati Ramakrishna 
Published: January 2023

Abstract
We studied the mechanisms of IL-22 production by NK cells in human Mycobacterium tuberculosis (M. tb) infection. CD3-CD56+ NK cells from 17 healthy donors produced IL-22 upon culturing with autologous monocytes and irradiated M. tb (417 ± 99 vs 52 ± 22 pg/ml, p &lt; 0.001). In 14 healthy donors anti-IL-15 and anti-IL-23 reduced IL-22 production by NK cells from 494 ± 110 pg/ml to 193 ± 50 pg/ml (p = 0.01) and 256.1 ± 64.7 pg/ml (p = 0.03) respectively. In contrast, anti-IL-12 and anti-IL-18 had no effect. Recombinant IL-15 induced IL-23 receptor expression (18.7 ± 5.1% vs 6.7 ± 1.9%, p =0.03). Recombinant IL-15 induced IL-22 production by NK cells (4294 ± 1627 vs 43.50 ± 29 pg/ml, p=0.04), but recombinant IL-12 and 1L-18 had no effect. To identify signaling pathways involved in IL-15 mediated IL-22 production, we cultured NK cells from healthy donors with recombinant IL-15 for 48 hrs. In 5 healthy donors IL-15-stimulated NK cells expressed 12 times more DAP10 mRNA compared to control NK cells. In 8 healthy donors DAP10 siRNA inhibited IL-15-mediated IL-22 production by NK cells, compared to control siRNA-transfected NK cells (346 ± 121 vs 1248 ± 465 pg/ml, p =0.05). Studies are underway to determine the effect of IL-22 on intracellular survival of M. tuberculosis in macrophages. We conclude that IL-15 and DAP-10 are involved in IL-22 production by NK cells in human M. tb infection.
Identification of a novel IκB family member and its role in innate immune responses (134.73)
Authors: Yamauchi Shumpei , Ito Hiroaki , Miyajima Atsushi 
Published: January 2023

Abstract
The transcription factor NF-κB is a key mediator for inducible transcription in the innate immune system. While the signaling pathways from cell surface receptors to NF-κB activation have been extensively studied, the regulatory mechanisms of NF-κB transcriptional activity still remain elusive. To address this question, we performed microarray analysis of bone marrow derived dendritic cells and found a novel protein that is structurally related to the IκB family proteins. We provisionally named this molecule as IκBη and further characterized its expression and functions. IκBη was widely expressed in antigen presenting cells and predominantly localized in the nucleus. Overexpression of IκBη in NIH3T3 cells upregulated the NF-κB transcription activity. In contrast, knockdown of IκBη by siRNA in Raw264.7 cells resulted in severely impaired production of IL-6 and TNF-α in response to LPS. Biochemical study also indicated the interaction between IκBη and NF-κB on the IL-6 promoter. Taken together, it is suggested that IκBη modulates the production of proinflammatory cytokines by positively regulating the NF-κB transcription activity in innate immune responses.
Modulation of TLR4 signaling by TLR2 in the macrophage response to Mycoplasma pneumoniae (135.10)
Authors: Lai Jen-Feng , Zindl Carlene L. , Duffy Lynn B. , Atkinson Thomas P. , Chaplin David D 
Published: January 2023

Abstract
Several clinical reports suggest that Mycoplasma pneumoniae (Mp) can contribute importantly to asthma pathogenesis. As a foundation for understanding interactions between Mp and asthma, we are first studying the mechanisms by which the host normally eliminates Mp. We showed previously that macrophages are critical for elimination of Mp from the lungs of mice, and that MyD88-NFκB signaling is needed for this response. Here, we focus on the role of TLR signaling in the macrophage response to this microbe. Several mycoplasma lipoproteins have been shown to activate macrophages via TLR2, the majority through the TLR2/6 heterodimer. Interestingly, we found enhanced clearance of Mp from TLR2-/- mice, but reduced clearance of Mp from TLR1-/- or TLR6-/- mice. The enhanced clearance in TLR2-/- mice is dependent on both TLR4 signaling and the presence of macrophages. These data suggest interactions between TLR2 and TLR4 in the anti-Mp response. We extended these studies in vitro by infecting bone marrow-derived macrophages (BMM) with Mp. After infection with Mp, TLR2-/- BMM showed increased phosphorylation of IRF3 and NFκB, and up-regulation of IFN-β and IL-6 mRNA expression, compared to Mp-infected wild type BMM. These effects were TLR4-dependent. Altogether, TLR2 plays an inhibitory role in the regulation of TLR4 signaling in the macrophage response to Mp. Supported by NHLBI HL073907.
Neisserial Lipooligosaccharides (LOS) Differentially Modulate Innate Immune Responses in Human Monocytes throughTLR4 Signaling (135.17)
Authors: Liu Mingfeng , Jarvis Gary A 
Published: January 2023

Abstract
Neisseria gonorrhoeae and N. meningitidis engage innate immune receptors TLR4 and TLR2, as well as TREM1 and TREM2. In this study, we report differential innate immune activation by Neisserial LOS in monocytes. LOS differentially induced proinflammatory mediators TNF-alpha, IL-1 beta, IL-6 and IL-8 in THP1 monocytic cells as well as IL-10, IL-12, IFN-alpha, MIP-1 alpha, MIP-1 beta, and RANTES in human monocytes. Interestingly, while gonococcal LOS was not able to induce GM-CSF in monocytes, GM-CSF expression was enhanced by meningococcal LOS in both THP1 cells and monocytes. In THP1 cells, the induction of TNF-alpha by LOS was inhibited by anti-TLR4 and anti-CD14 antibody, but not by anti-TLR2, suggesting that the TLR4, but not TLR2, was responsible for the induction of cytokines. The ability of LOS to directly activate the TLR4 pathway was demonstrated by using TLR4-MD2 transfected HEK reporter cells, the activation of which was blocked by lipid IVa, a TLR4-MD2 antagonist. In monocytes, lipid IVa also inhibited the induction of all cytokines as well as CD80 expression by gonococcal LOS, but it only inhibited the activation of TNF-alpha, IL-10 and GM-CSF by meningococcal LOS. These results suggest that Neisserial LOS differentially activate innate immunity in monocytes through the TLR4 pathway, but that the induction of innate immune responses by meningococcal LOS may rely on the engagement of additional pattern recognition receptors.
Essential role of albumin in CD14-independent activation of MD-2/TLR4 by endotoxin (135.20)
Authors: Esparza Greg A , Teghanemt Athmane , Zhang De-Sheng , Gioannini Theresa , Weiss Jerrold 
Published: January 2023

Abstract
Host response to endotoxin (E) depends on the ordered interactions of LBP, CD14, MD-2 and Toll-Like Receptor (TLR) 4. CD14 is required for efficient transfer of E monomers to MD-2 (/TLR4) and for induction of TRIF-dependent signaling by activated TLR4. At high E concentrations, MD-2/TLR4-dependent cell activation by E is possible without CD14 through an unknown mechanism. We now show that incubation of purified E aggregates (Mr = 20 million) in PBS with = 0.1% albumin in the absence of the divalent cations Ca2+ and Mg2+, yields monomeric E:albumin complexes (Mr ~70,000). E monomers transfer from E:albumin to MD-2 and to MD-2/TLR4 directly and induce MD-2/TLR4-dependent, CD14-independent cell activation. Our findings suggest for the first time a mechanistic basis for CD14-independent cell activation by E. E:CD14 and E:albumin complexes should provide valuable reagents for future studies of MyD88-dependent (CD14-independent) and TRIF-dependent (CD14-dependent) TLR4 signaling by E.
Work supported by NIH/NIAID #AI59372.