bluuebunny/crossref_metadata_2025_split huggingface dataset:
HIV-1 Nef limits communication between LAT and Slp-76 to reduce formation of Slp-76 signaling microclusters (170.20)
Authors: Abraham Libin , Bankhead Peter , Pan Xiaoyu , Engel Ulrike , Fackler Oliver 
Published: January 2023

Abstract
Signal transduction through the T cell receptor (TCR) triggers actin rearrangements, receptor clustering and dynamic organization of signaling microclusters (SM) to form a stable Immunological synapse (IS). Nef, a pathogenicity factor of Human Immunodeficiency Virus (HIV), disrupts early TCR signaling in target T cells. To define the mechanism underlying this Nef-mediated signal disruption we employed quantitative microscopy to analyze the effects Nef exerts on formation and composition of TCR proximal SM. Despite marked inhibition of actin remodeling and cell spreading, the induction of SM containing the TCR itself or Zap70 was not affected by Nef. However, Nef potently inhibited the subsequent formation of SM that contained Slp-76 to reduce microcluster density in Nef expressing or HIV-1 infected T cells. Using a Nef mutant selectively defective in inhibition of actin remodeling (Nef F195I), we found that Nef-mediated disruption of actin remodeling and Slp-76 SM are independent activities. Strikingly, the effects of Nef on Slp-76 SM correlated with trans-golgi network targeting of LAT, an adaptor protein that couples Zap-70 to Slp-76. Nef-induced disruption of SM formation and composition depended on its ability to disrupt both, actin remodeling and subcellular localization of TCR-proximal machinery. Nef thus disrupts early TCR signaling by limiting the communication between LAT and Slp-76 and preventing the dynamic formation of Slp-76 SM.
Regulatory T cells decreased HIV transmission from DC to conventional T cells (170.21)
Authors: Moreno-Fernandez Maria , Chougnet Claire 
Published: January 2023

Abstract
HIV infection of CD4+ T cells is quite efficient by transfer of the virus from dendritic cells (DC) to CD4+ T cells. Activation levels of both cells play a crucial role in the efficiency of the infection. Regulatory T cells (Treg) are known to control the activation levels of both CD4+ T cells and DC. Treg frequency is increased in mucosal tissues of HIV-infected individuals and Treg can reduce HIV infection in conventional CD4+ T cells (Tcon) and macrophages. We therefore hypothesize that Treg can also control DC: Tcon HIV transmission. Monocyte derived DC were infected with the HIV R5 strains BaL and cultured for 1 day with autologous Tcon in the presence or absence of autologous Treg. Formation of Tcon:DC clusters and the percentage of infection in these clusters were determined by multicolor flow cytometry and Imaging flow cytometry (ImageStream). Culture with Treg resulted in a significant decreased of Tcon:DC cluster infection (p=0.025). Looking at the underlying mechanism we found that blockage of CTLA-4 significantly reduces Treg inhibitory function. Treg-derived cAMP also appears to be involved in Treg suppressive activity, as pharmacological decrease of cAMP levels in Treg abolished Treg suppression of HIV transmission. Our data suggest a complex role of Treg during HIV infection: they inhibit specific immune responses, but their inhibition of HIV transmission at several levels may also play a beneficial role during early HIV transmission events
Exercise modulates the immune response to influenza infection in aged mice. (170.28)
Authors: Naik Shibani , Gallup Jack , Yu Shan , Sim Young-Je , Yoon Kyoung-Jin , Nettleton Daniel , Kohut Marian 
Published: January 2023

Abstract
Exercise training prior to influenza virus infection in aged mice decreases illness severity, reduces lung viral load, and decreases inflammatory cytokine/chemokine levels in bronchoalveolar lavage (BAL) fluid. We hypothesized that an exercise-associated increase in anti-viral responses (Type I IFN and related genes, pentraxins) may contribute to reduced viral load. Exercise may also increase the rate of cell turnover in the lungs to limit the spread of virus. METHODS: Old mice (18mos) were exercised moderately 5d/wk for 10 wks, rested for 24h, and then infected with influenza A/PR/8/34 H1N1. Non-exercised old mice and young mice (2mos) were controls. Lungs were collected several times post-infection (p.i.); mRNA was detected in lungs using RT qPCR. Cytokines in BAL were measured by ELISA. Formalin Fixed Paraffin Embedded (FFPE) lungs were used to detect the presence of virus and Caspase 3 by IHC. RESULTS: After exercise training, interferon-inducible antiviral gene expression (Oas1b, B2m, BST2 & GBP1) was increased, but at 12-24 hr p.i., exercise was associated with decreased BAL IFNα & IFNβ, and reduced lung mRNA of IFNα4 and Oas1a. Exercise did not alter viral attachment or apoptosis 6hr p.i. The results suggest that exercised basal level expression of several interferon-related genes which may contribute to the early reduction in viral load.
Enhancing protection against highly pathogenic H5N1 avian influenza A viruses (170.31)
Authors: McGargill Maureen , Keating Rachael , Lukens John , Hertz Tomer , Harris Tarsha , Edwards Benjamin , Creasy Blaine , Doherty Peter , Thomas Paul 
Published: January 2023

Abstract
Highly pathogenic H5N1 avian influenza A viruses pose a serious threat for a deadly pandemic. Vaccination is the most effective strategy for controlling influenza, however it is not possible to predict which H5N1 variants may acquire the ability to transmit efficiently between humans, and conserved epitopes between different subtypes do not induce sufficient immunity. Thus, a strategy to increase the efficacy of universal vaccines is essential for preventing a deadly pandemic. Others demonstrated that the immunosuppressive drug, rapamycin, paradoxically increased the number of memory T cells during LCMV infection. Thus, we examined whether rapamycin increases the number of memory T cells during influenza infection, and consequently enhances protection against a secondary infection with a heterosubtypic H5N1 strain. Mice were immunized with HKx31 (H3N2), treated with rapamycin for 30 days, and challenged with a modified H5N1 virus, ΔVn1203. We found rapamycin protected mice from a lethal ΔVn1203 infection, but not in the absence of a primary infection. Interestingly, rapamycin increased the number of influenza-specific CD8 T cells after the primary and secondary infection. However, memory CD8 T cells were not required for protection. Rather, CD4 T cells and B cells were critical for the enhanced survival following rapamycin treatment. These data suggest that rapamycin protects against a highly pathogenic, heterosubtypic influenza infection by altering the antibody response.
Regulatory T cells control the clinical expression of viral immunopathology by acting at both the lesion site and draining lymphoid tissue (170.9)
Authors: Veiga Parga Tamara , Sparwasser Tim , Rouse Barry 
Published: January 2023

Abstract
Ocular herpes simplex virus infection can cause a blinding CD4+ T cell orchestrated immunoinflammatory lesion in the cornea called Stromal Keratitis (SK). Lesion severity can be influenced by the balance of CD4+ T effectors and Foxp3+ regulatory T cells (Treg) at the onset of infection. We have evaluated the role of Treg during the ongoing clinical phase of the disease by taking advantage of transgenic mice, which express a diphtheria toxin receptor enhanced GFP fusion protein under the control of the Foxp3 locus, permitting Treg depletion. Depleting Treg during the clinical phase of the disease resulted in significantly more severe lesions. This outcome was explained both by Treg influencing the activity of inflammatory T cells at the lesion site as well as effects in the lymphoid tissue that reduced trafficking of T cells and neutrophils to the eye, as well as the activation state of T effectors. Our results demonstrate that Treg can beneficially influence the impact of ongoing tissue damaging responses to a virus infection and imply that therapies that boost Treg function hold promise as a modality to control a lesion that is an important cause of human blindness.
Ectopic expression and presentation of diabetogenic antigens in the lymph nodes of NOD mice. (171.10)
Authors: Creusot Remi , Yip Linda , Fathman C. Garrison 
Published: January 2023

Abstract
Ectopic expression and presentation of peripheral tissue antigens (PTAs) in lymph node stromal cells has been shown to contribute to the maintenance of peripheral tolerance. During disease progression in non-obese diabetic (NOD) mice, at 12 weeks of age (the onset of destructive insulitis), expression of genes encoding many PTAs (including insulin and chromogranin A) as well as the function of the transcription regulator Deaf1, are diminished in the pancreatic lymph nodes (PLNs). We observed a defect in insulin presentation in NOD mice both in vivo (in adoptive transfer experiments) and in vitro (using purified stromal cells) compared to 12-wk old diabetes-resistant (NOD x NOD.B10) F1 mice. We identified two stromal cell subsets within the gp38+ CD31- fibroblastic reticular cells and the gp38- CD31- double negative (DN) population that can express and present insulin to CD4 T cells. Data generated to date suggest that Deaf1 controls the expression of insulin at least in DN cells. Inflammation can induce the splicing of Deaf1 mRNA into a dominant negative isoform in the PLNs. Preliminary data suggest that a substantial proportion of T cells stimulated in vivo or by stromal cells ex vivo induce Foxp3 expression. Thus, diminished PTA expression and presentation in 12-wk old NOD mice may impair the maintenance of peripheral tolerance and may explain the subsequent progression from peri-insulitis to destructive insulitis and hyperglycemia.
The Effects of Manzamine A (MZA) on Synovial Fibroblast Adhesion (173.32)
Authors: Mc Dermott Sarah , Klosowska Karolina , Zanotti Brian , Volin Michael , Woods James 
Published: January 2023

Abstract
Isolated from sponges on the ocean floor, MZA has anti-inflammatory properties which might be beneficial in treating rheumatoid arthritis (RA) or osteoarthritis (OA). Preliminary data suggested that MZA causes RA fibroblast-like synoviocytes (FLS) to detach from gelatin. We hypothesized that MZA decreased the adhesive properties of synovial fibroblasts isolated from RA, OA, or normal joints. All fibroblasts were isolated from tissues collected from patients with IRB approval. Photos of cells were taken at various time points (1, 2, 4, 8, 12, and 24 hrs) and counted for adherence after treatment with various concentrations of MZA or vehicle on gelatin, collagen, or laminin substrates. Flow cytometry was used to determine α1 integrin subunit expression on various cell types, since this subunit is important in binding to adhesive substrates. RA FLS on gelatin appeared most sensitive to MZA, in that 1 µM could significantly detach cells in as little as 8 hrs (n=4, p&lt;0.05). RA FLS were more adherent to laminin and most adherent to collagen IV. In contrast, normal or OA fibroblasts on gelatin required incubation with 10 µM MZA for 12 hrs to obtain significant detachment. Flow cytometry did not demonstrate differences in α1 integrin expression between MZA treated cell types (RA FLS, OA fibroblasts, or normals) and controls. We conclude that MZA is exerting both a concentration and time dependent effect on cell adhesion and that α1 integrin may not be involved.
Characterization of synapse-kinapse balance in CD8 T cells (173.35)
Authors: Mayya Viveka , Neiswanger Willie , Blair David , Wiggins Chris , Dustin Michael 
Published: January 2023

Abstract
T cells form stable junctions, referred to as ‘Immunological Synapses’ (IS), and also moving junctions, referred to as ‘Immunological Kinapses’ (IK), with surfaces presenting relevant adhesion and activating ligands from antigen-presenting cells (APCs). We have observed that the naïve CD8 T cells are biased towards IK, whereas antigen-experienced CD8 T cells are biased toward IS. We have also observed that naïve CD8 T cells show multiple inter-conversions between IS and IK states as previously described for naïve CD4 T cells. Further, the naïve CD8 population exhibits considerable heterogeneity in IS-IK states. Inhibition of PKCθ, myosin II, and rhoA GTPase activity promotes the IS state. The memory CD8 T cells show dispersed staining of phosphorylated ERM proteins (pERM), indicating that pERM is distributed throughout the cytoplasm. In contrast, the naïve CD8 T cells have polarized accumulation of pERM proteins, with a predominant banding pattern at one end of the cell periphery above the plane of the immunological synapse. Interestingly, the polarized accumulation of pERM is lost upon inhibition of PKCθ. These results provide a mechanistic insight into the role of PKCθ in promoting IK state in naïve CD8 T cells.
Neutrophil activities are required with hapten-primed CD8 T cell production of IFN-γ to mediate the edema of contact hypersensitivity (173.9)
Authors: Kish Danielle , Fairchild Robert 
Published: January 2023

Abstract
Contact hypersensitivity (CHS) is a CD8 T cell-mediated response to hapten skin sensitization and challenge. Effector CD8 T cell recruitment into the hapten challenged skin parenchymal tissue to elicit CHS requires prior CXCL1-directed neutrophil infiltration within 3-6 h after challenge. Depletion of neutrophils at the time sensitized mice are challenged with hapten ablates CD8 T cell infiltration into the challenge site indicating the requirement for this initial neutrophil infiltration. The current study tested whether the CHS response to 2, 4-dinitrofluorobenzene required neutrophils at times the effector CD8 T cells had infiltrated and were activated in the hapten challenged skin tissue parenchyma. Neutrophil depletion 8 h following hapten challenge of sensitized mice eliminated CHS swelling responses 16 h later despite flow cytometry and immunohistochemistry analyses of the skin challenge site indicating the presence of infiltrating T cells. ELISPOT analyses also indicated the presence of hapten-specific T cells producing IFN-γ and IL-17 in the skin challenge site of sensitized mice depleted of neutrophils 8 h after challenge and IFN-γ mRNA expression levels in the skin challenge site were similar in sensitized mice with or without the neutrophil depletion. These results indicate that neutrophil-mediated activities are required at the time of hapten-primed CD8 T cell activation in the skin challenge site parenchyma to mediate the tissue edema of the CHS response.
Catalytic inhibition of TYK2 exerts selective effects on human cytokine responses (174.13)
Authors: Sohn Sue , Barrett Kathy , Chang Christine , Kohli Pawan , Liang Jun , Blair Wade , Magnuson Steven , Wu Lawren 
Published: January 2023

Abstract
TYK2 is a JAK family protein tyrosine kinase activated in response to multiple cytokines, including Type I IFNs, IL-6, IL-10, and IL-12/23. Genetic mutation at the tyk2 locus has been linked to broad-range immune deficiency and dysregulation in a human patient, however in murine strains that lack TYK2 expression, only select pathways are compromised. We have utilized a panel of TYK2-selective small molecule inhibitors with varying degrees of selectivity against other JAK kinases to address the requirement for TYK2 catalytic function in cytokine response pathways in human cells. Our results suggest that, similar to the effects of TYK2 deficiency in murine cells, the scope of biological processes requiring TYK2 catalytic function is much more narrow and selective in human cells than previously appreciated.
Two subtypes of microvesicles can be isolated from tissue culture (174.17)
Authors: Inal Jameel , Stratton Dan , Antwi-Baffour Samuel , Grant Ryan 
Published: January 2023

Abstract
Microvesicles or MVs released from the plasma membrane of eukaryotic cells, during early apoptosis, are 100-1000 nm in diameter, rich in phosphatidylserine and important mediators of intercellular communication. Analysis of MVs revealed two distinct subtypes that can be collected from cells in culture: cMVs are constitutively released and sMVs that are stimulated for release. There are marked differences in size and composition between cMVs and sMVs, the former being smaller, denser, ‘well made’ and more slowly released from cells whereas sMVs are larger, lighter, less robust and released rapidly in response to a stress stimuli. Furthermore these differences allude to different physiological roles, indeed, analysis of calcium homeostasis having revealed MVs to contain high calcium levels, that are deliverable to cells. The implications of this research highlights that detailed characterisations of MVs should be performed to further understand the underlying mechanisms in MV biology, as the subtypes are generated through different processes and undoubtedly will perform different roles.
IL-4/IL-13 signaling responses are dictated by the extracellular/transmembrane domain of the receptor complex, not the cytoplasmic domain (174.3)
Authors: Heller Nicola , Qi Xiulan , Gesbert Franck , Keegan Achsah 
Published: January 2023

Abstract
Previously, we demonstrated that the γC subunit of type I IL-4 receptor was required for robust tyrosine phosphorylation of the downstream adapter protein, IRS-2, correlating with expression of genes (ArgI, Retnla, Chi3l3) characteristic of alternatively-activated macrophages. We hypothesized that the γC cytoplasmic domain possesses a putative I4R motif, not found in IL-13Rα1, which enhanced IRS-2 recruitment. A mutant of the key I4R motif tyrosine (Y325F) and different γC truncation mutants (γ285, γ308, γ318, γ323, γFULL LENGTH) were co-expressed in L- or CHO cells with wild-type (WT) IL-4Rα and signaling responses to IL-4 were examined. IRS-2, STAT6 and JAK3 phosphorylation was restored in CHO expressing γ323 and γFL but not in γ318 and γ285 mutants. IRS phosphorylation was not diminished in Y325F L-cell mutants. Our data suggest that Y325 is not required for IRS activation and a smaller (4 amino acid) interval than previously determined is necessary for IL-4-induced JAK3 activation/γC-mediated signaling. We predicted that cytoplasmic domain swaps between γC and IL-13Rα1 would endow signaling responses corresponding to the nature of the cytoplasmic domain. Surprisingly, IRS-2/STAT6 signaling responses were dictated solely by the nature of the extracellular/transmembrane domains in our chimeric receptor-expressing CHO or M12.4.1 cell models. A more complete understanding of receptor activation/signaling will lead to improved rational drug design for allergic disease.
Mechanism of walnut induced anaphylaxis-like shock reaction in mice (175.1)
Authors: Gangur Venugopal , Gonipeta Babu , Kim Eunjung , Parvataneni Sitaram 
Published: January 2023

Abstract
Walnut is a leading cause of life-threatening anaphylaxis in humans. Such reactions are largely thought to be mediated by the Type-I hypersensitivity mechanism. We have found that English walnut extract (EWE) upon oral or i.p., administration in naive mice without pre-sensitization results in anaphylaxis-like shock response as quantified by hypothermia. We have been studying the mechanism underlying this unusual reaction. The Fcg receptor knockout (KO) mice, IgE non-responder SJL mice and TLR4 mutant C3H/HeJ mice, all exhibited hypothermia response indicating that the reaction was antibody and LPS independent respectively. We then examined the role of complement system. The C3a receptor (C3aR) KO mice were protected from shock responses. Among the C5 deficient (DBA/1J) and C5 sufficient (DBA/2J) mice, both exhibited hypothermia responses with DBA1 being a slightly lower responder. Since the shock reaction was complement dependent, we reasoned and tested whether EWE causes hemagglutination (HA) of RBC. Using a standard HA assay protocol we evaluated the HA activity of EWE. We found that the EWE had a significant HA activity for RBC obtained from BALB/c, DBA/1J and DBA/2J mice (HA titre: 1/32; translates to ~35,555 HA units per gram of EWE protein). These data are consistent with the hypothesis that EWE causes HA in vivo leading to complement system activation with consequent C3aR dependent anaphylaxis-like shock reaction.
Lyn but not Fyn kinase controls IgG-Mediated Systemic Anaphylaxis (175.17)
Authors: Falanga Yves 
Published: January 2023

Abstract
Anaphylaxis is a rapid, life-threatening hypersensitivity reaction. Until recently, it was mainly attributed to histamine released by mast cells activated by allergen crosslinking (XL) of FcϵRI-bound allergen-specific IgE. However, recent reports established that anaphylaxis could also be triggered by basophil, macrophage and neutrophil secretion of platelet activating factor subsequent to FcγR stimulation by IgG/Ag complexes. We have investigated the contribution of Fyn and Lyn tyrosine kinases to FcγRIIb and FcγRIII signaling in the context of IgG-mediated passive systemic anaphylaxis (PSA). We found that mast cell IgG XL induced Fyn, Lyn, Akt, Erk, p38 and JNK phosphorylation. Additionally, IgG XL of mast cells, basophils and macrophages resulted in Fyn- and Lyn-regulated mediator release in vitro. FcγR-mediated activation was enhanced in Lyn-deficient (KO) cells, but decreased in Fyn KO cells, compared to wild type cells. More importantly, Lyn KO mice displayed significantly exacerbated PSA features while no change was observed for Fyn KO mice, compared to wild type littermates. Intriguingly, we establish that mast cells account for the total amount of the serum histamine in IgG-induced PSA. Taken together, our findings establish pivotal roles for Fyn and Lyn in the regulation of PSA and highlight their unsuspected functions in IgG-mediated pathologies.
Plasma cell gene expression depends on ELL2 (176.15)
Authors: Milcarek Christine , Arumemi Fortuna , Park Kyung 
Published: January 2023

Abstract
From studies with splenic B cells and cell lines ELL2, a transcription elongation factor, was found to play a vital role in the differentiation of B cells into plasma cells. It is responsible for Igh mRNA being both alternatively processed to the secretory-specific form and increased in abundance, leading to high levels of secreted Ig protein and a robust immune response. To investigate the molecular mechanisms that occur as a result of ELL2 action, we studied histone H3 methylation at K4 and K79 on the Igh in plasma cells by chromatin IP. We found that knocking out ELL2 with siRNA decreases the H3K4 di- and tri-methylation and K79 tri-methylation patterns as well as the association of CstF-64 and pTEFb, a part of the super elongation complex. Recent chromatin IP studies show that ELL2 is associated with RNA polymerase II on essential regulatory plasma cell genes including IRF-4 and blimp-1. Using luciferase transcription assays we show that ELL2 is able to increase transcription from its own and the IRF-4 promoter. Elongation is thus linked to increased mRNA production and the use of a proximal poly(A) site in the IRF-4 gene. ELL2 and ELL1 do not have identical patterns of action. Taken together, these studies define a fundamental role for ELL2 in the transcription elongation machinery and RNA processing in plasma cell differentiation. Studies on the in vivo role of ELL2 in Ig secretion are in progress.