bluuebunny/crossref_metadata_2025_split huggingface dataset:
IL-18 and CD28 Use Distinct Molecular Mechanisms to Enhance NK Cell Production of IL-12-Induced IFN-γ
Authors: Walker William , Aste-Amezaga Miguel , Kastelein Robert A. , Trinchieri Giorgio , Hunter Christopher A. 
Published: January 2023

AbstractNK cells play an important role in innate immune resistance, particularly through synthesis of the pro-inflammatory cytokine IFN-γ. This study compares the abilities of the cytokine IL-18 and the costimulatory cell surface molecule CD28 to enhance IL-12-driven IFN-γ production by NK cells. Studies with other cytokines (IL-1β, IL-6, TNF-α, IL-15) showed that IL-18 or anti-CD28 treatments were the most efficient inducers of IFN-γ when combined with IL-12. The ability of IL-18 to enhance IFN-γ was shown to be dependent on the presence of IL-12. Similarly, although anti-CD28 stimulation alone could enhance IFN-γ synthesis, this effect was significantly increased in the presence of IL-12. Although neither method of costimulation required de novo protein synthesis for their effects on IFN-γ mRNA expression, these molecules used distinct mechanisms. Specifically, nuclear run-on analysis revealed that IL-18 in combination with IL-12 enhanced the rate of transcription of the IFN-γ gene. Conversely, treatment with anti-CD28 plus IL-12 did not significantly up-regulate the rate of transcription of the IFN-γ gene, but stabilized IFN-γ mRNA expression within NK cells. These findings illustrate costimulatory pathways that result in potent IFN-γ responses by NK cells and show that although IL-18 and anti-CD28 can enhance the synthesis of IL-12-driven IFN-γ, they employ molecular mechanisms that are distinct from one another.
Expansion of Extrathymic T Cells as Well as Granulocytes in the Liver and Other Organs of Granulocyte-Colony Stimulating Factor Transgenic Mice: Why They Lost the Ability of Hybrid Resistance
Authors: Kawamura Hiroki , Kawamura Toshihiko , Kokai Yasuo , Mori Michio , Matsuura Akihiro , Oya Hiroshi , Honda Shigeru , Suzuki Susumu , Weerashinghe Anura , Watanabe Hisami , Abo Toru 
Published: January 2023

AbstractWhen we attempted to characterize the immunological state in G-CSF transgenic mice, a large number of not only granulocytes but also lymphoid cells expanded in various immune organs. Such lymphoid cells were present at unusual sites of these organs, e.g., the parenchymal space in the liver. We then determined the phenotype of these lymphoid cells by immunofluorescence tests. It was demonstrated that CD3intIL-2Rβ+ cells (i.e., extrathymic T cells), including the NK1.1+ subset of CD3int cells (i.e., NKT cells), increased in the liver and all other tested organs. These T cells as well as NK cells mediated NK and NK-like cytotoxicity, especially at youth. However, they were not able to mediate such cytotoxicity in the presence of granulocytes. This result might be associated with deficiency in the hybrid resistance previously ascribed to these mice. In other words, G-CSF transgenic mice had a large number of extrathymic T cells (including NKT cells) and NK cells that mediate hybrid resistance, but their function was suppressed by activated granulocytes. Indeed, these granulocytes showed an elevated level of Ca2+ influx upon stimulation. The present results suggest that, in parallel with overactivation of granulocytes, extrathymic T cells and NK cells are concomitantly activated in number but that their function is suppressed in G-CSF transgenic mice.
Requirement for Efficient Interactions Between CD4 and MHC Class II Molecules for Survival of Resting CD4+ T Lymphocytes In Vivo and for Activation-Induced Cell Death
Authors: Maroto Rosario , Shen Xiaoli , König Rolf 
Published: January 2023

AbstractRegulation of homeostasis in the immune system includes mechanisms that promote survival of resting T lymphocytes, and others that control activation-induced cell death (AICD). In this study, we report on the use of a transgenic mouse model to test the role of CD4-MHC class II interactions for the susceptibility of CD4+ T lymphocytes to AICD, and for the survival of resting CD4+ T cells in peripheral lymphoid organs. The only I-Aβ gene expressed in these mice is an Aβk transgene with a mutation that prevents MHC class II molecules from interacting with CD4. We show increased apoptosis in CD4+ T lymphocytes derived from wild-type, but not from mutant Aβk transgenic mice following stimulation with staphylococcal enterotoxin A. Therefore, AICD may be impaired in CD4+ T cells derived from mutant Aβk transgenic mice. Importantly, we observed much higher apoptosis in resting CD4+ T cells from mutant Aβk transgenic mice than from wild-type mice. Furthermore, resting CD4+ T cells from mutant Aβk transgenic mice expressed higher levels of cell surface CD95 (Fas, APO-1). Ab-mediated cross-linking of CD95 further increased apoptosis in CD4+ T cells from mutant Aβk transgenic mice, but not from wild-type mice, suggesting apoptosis involved CD95 signaling. When cocultured with APC-expressing wild-type MHC class II molecules, apoptosis in resting CD4+ T lymphocytes from mutant Aβk transgenic mice was reduced. Our results show for the first time that interactions between CD4 and MHC class II molecules are required for the survival of resting CD4+ T cells in peripheral lymphoid organs.
Negative Regulation by Phosphatidylinositol 3-Kinase of Inducible Nitric Oxide Synthase Expression in Macrophages
Authors: Díaz-Guerra María J. M. , Castrillo Antonio , Martín-Sanz Paloma , Boscá Lisardo 
Published: January 2023

Abstract
Triggering of the macrophage cell line RAW 264.7 with LPS promotes a transient activation of phosphatidylinositol 3-kinase (PI3-kinase). Incubation of activated macrophages with wortmannin and LY294002, two inhibitors of PI3-kinase, increased the amount of inducible nitric oxide synthase (iNOS) and the synthesis of nitric oxide. Treatment with wortmannin promoted a prolonged activation of NF-κB in LPS-treated cells as well as an increase in the promoter activity of the iNOS gene as deduced from transfection experiments using a 1.7-kb fragment of the 5′ flanking region of the iNOS gene. Cotransfection of cells with a catalytically active p110 subunit of PI3-kinase impaired the responsiveness of the iNOS promoter to LPS stimulation, whereas transfection with a kinase-deficient mutant of p110 maintained the up-regulation in response to wortmannin. These results indicate that PI3-kinase plays a negative role in the process of macrophage activation and suggest that this enzyme might participate in the mechanism of action of antiinflammatory cytokines.
Tyrphostin B42 Inhibits IL-12-Induced Tyrosine Phosphorylation and Activation of Janus Kinase-2 and Prevents Experimental Allergic Encephalomyelitis
Authors: Bright John J. , Du Caigan , Sriram Subramaniam 
Published: January 2023

AbstractIL-12 is a macrophage-derived cytokine that induces proliferation, cytokine production, and cytotoxic activity of T and NK cells. Signaling through its receptor, IL-12 induces these cellular responses by tyrosine phosphorylation and activation of Janus kinase-2 (Jak-2), Tyk-2, Stat3, and Stat4. We have used tyrphostin B42 (AG490), a Jak-2 inhibitor, to determine the role of Jak-2 kinase in IL-12 signaling and IL-12-induced T cell functions. Treatment of activated T cells with tyrphostin B42 inhibited the IL-12-induced tyrosine phosphorylation and activation of Jak-2 without affecting Tyk-2 kinase. In contrast, treatment with tyrphostin A1 inhibited the tyrosine phosphorylation of Tyk-2 but not that of Jak-2 kinase. Inhibition of either Jak-2 or Tyk-2 leads to a decrease in the IL-12-induced tyrosine phosphorylation of Stat3, but not of Stat4, protein. While inhibition of Jak-2 lead to programmed cell death, the inhibition of Jak-2 or Tyk-2 resulted a decrease in IFN-γ production. We have further tested the in vivo effects of tyrphostin B42 in experimental allergic encephalomyelitis, a Th1 cell-mediated autoimmune disease. In vivo treatment with tyrphostin B42 decreased the proliferation and IFN-γ production of neural Ag-specific T cells. Treatment of mice with tyrphostin B42 also reduced the incidence and severity of active and passive EAE. These results suggest that tyrphostin B42 prevents EAE by inhibiting IL-12 signaling and IL-12-mediated Th1 differentiation in vivo.
Inflammatory Cytokines and HIV-1-Associated Neurodegeneration: Oncostatin-M Produced by Mononuclear Cells from HIV-1-Infected Individuals Induces Apoptosis of Primary Neurons
Authors: Ensoli Fabrizio , Fiorelli Valeria , DeCristofaro Maria , Santini Muratori Donatella , Novi Arianna , Vannelli Barbara , Thiele Carol J. , Luzi Giuseppe , Aiuti Fernando 
Published: January 2023

Abstract
Neurologic abnormalities are common in HIV-1-infected patients and often represent the dominant clinical manifestation of pediatric AIDS. The neurological dysfunction has been directly related to CNS invasion by HIV-1 that is principally, if not exclusively, supported by blood-derived monocytes/macrophages and lymphocytes. By using primary long term cultures of human fetal sensory neurons as well as sympathetic precursors-like neuronal cells, we determined that blood-derived mononuclear cells from HIV-1-infected individuals spontaneously release soluble mediators that can potently inhibit the growth and survival of developing neurons as well as the viability of postmitotic neuronal cells by inducing apoptotic cell death. Analysis of the cytokines produced by lymphomonocytic cells, HIV-1 infected or activated, indicated that oncostatin M (oncM) is a major mediator of these effects. Since low TGF-β1 concentrations were capable of enhancing oncM-mediated neuronal alterations, our data indicate that by acting in concert with other cytokines, oncM may induce neuronal demise in both the developing and the mature brain. Thus, this cytokine may contribute to the setting of the neuronal cell damage observed in HIV-1-infected individuals.
Highly Cross-Reactive T Cell Responses to Myelin Basic Protein Epitopes Reveal a Nonpredictable Form of TCR Degeneracy
Authors: Loftus Christine , Huseby Eric , Gopaul Priya , Beeson Craig , Goverman Joan 
Published: January 2023

Abstract
We identified two nonoverlapping epitopes in myelin basic protein presented by I-Au that are responsible for mediating tolerance induction to this self-Ag. A large number of T cells expressing diverse TCRs are strongly cross-reactive to both epitopes. Surprisingly, the TCR contact residues in each peptide are highly dissimilar. Furthermore, functional TCR contacts cannot be interchanged between the two epitopes, indicating that the TCR contacts in each peptide can only be recognized within the context of the other amino acids present in that peptide’s sequence. This observation indicates that both buried and exposed residues of each peptide contribute to the sculpting of completely distinct antigenic surfaces. We propose that the cross-reactive TCRs adopt mutually exclusive conformations to recognize these dissimilar epitopes, adding a new dimension to TCR degeneracy. This unpredictable TCR plasticity indicates that using just the TCR contacts on a single epitope to define other cross-reactive peptides will identify only a subset of the complete repertoire of cross-reactive epitopes.
Murine Cytomegalovirus Infection Down-Regulates MHC Class II Expression on Macrophages by Induction of IL-10
Authors: Redpath Stella , Angulo Ana , Gascoigne Nicholas R. J. , Ghazal Peter 
Published: January 2023

Abstract
Herpesviruses utilize many strategies for weakening the host immune response. For CMV, this includes avoidance of NK clearance and inhibition of MHC class I and class II presentation pathways. In this study, we report that mouse CMV (MCMV) specifically causes a premature and transient activation of host IL-10 very early in the course of infection, resulting in a dramatic and selective reduction in MHC class II surface expression. The expression of IL-10 is normally late in the immune response to a pathogen, serving to dampen the response by suppression of the production of inflammatory cytokines. In infection of macrophages, we show that MCMV induces the production of IL-10, leading to an early and selective reduction in the expression of MHC class II on the surface of the cells. Inhibition of MHC class II expression was not observed in the presence of neutralizing Abs to IL-10 or in macrophages from IL-10-deficient mice. Moreover, MCMV-infected IL-10-deficient mice developed an early and significantly more robust macrophage MHC class II induction than normal mice. Altogether, our results demonstrate that viral induction of an IL-10 autocrine pathway plays an essential early role in selectively reducing MHC class II expression on the surface of APC prior to stimulation by IFN-γ.
CD38-Mediated Signaling Events in Murine Pro-B Cells Expressing Human CD38 With or Without Its Cytoplasmic Domain
Authors: Kitanaka Akira , Suzuki Toshio , Ito Chikako , Nishigaki Hikari , Coustan-Smith Elaine , Tanaka Terukazu , Kubota Yoshitsugu , Campana Dario 
Published: January 2023

AbstractTo elucidate the signaling mechanism of CD38 (a transmembrane molecule highly expressed in immature hemopoietic cells), we transfected Ba/F3 murine pro-B cells with a cDNA encoding human CD38. CD38 ligation with anti-CD38 Abs caused rapid, transient, dose-dependent tyrosine phosphorylation of several proteins, including the tyrosine kinase TEC and the adaptor molecule CBL, and association of tyrosine-phosphorylated proteins with phosphatidylinositol 3-kinase p85. Exposure to anti-CD38 Abs or their F(ab′)2 and Fab also induced tight aggregation of CD38-transfected Ba/F3 cells, which appeared to be Ca2+ and Mg2+ independent and did not involved LFA-1. Aggregation was abrogated by addition of the tyrosine kinase inhibitor herbimycin A and was delayed by the phosphatidylinositol 3-kinase inhibitor wortmannin, suggesting a link between biochemical events and cellular effects induced by CD38. Cell aggregation was accompanied by a decrease in cell recovery. After 3 days of culture on bone marrow-derived stroma, the mean (±SD) cell recovery in the presence of anti-CD38 (T16) was 10.5 ± 9.2% (n = 7) of that in parallel cultures with an isotype-matched nonreactive Ab. Finally, CD38 ligation in Ba/F3 cells expressing a mutant human CD38 lacking the cytoplasmic domain induced tyrosine phosphorylation with intensity and kinetics similar to those seen with the entire protein. It also induced cell aggregation and decreased cell recovery. We conclude that CD38 triggers remarkably similar signaling pathways in human and murine immature B cells. This signaling is independent of the CD38 cytoplasmic domain, suggesting the existence of accessory transmembrane molecules associated with CD38.
Molecular Basis of Human Complement C1s Deficiency
Authors: Endo Yuichi , Kanno Kazuko , Takahashi Minoru , Yamaguchi Ken-ichi , Kohno Yoichi , Fujita Teizo 
Published: January 2023

Abstract
This is the first report on the molecular basis of human complement C1s deficiency. Two abnormalities in the C1s gene were identified in a Japanese family, including one patient, by using exon-specific PCR, single-strand conformation polymorphism analysis, and nucleotide sequencing. A deletion of 4 bp, TTTG, was identified in exon X when using genomic DNA from the patient, his father, and his paternal grandmother. They were all heterozygous for the mutation. The mutant gene encodes a truncated C1s from the N terminus to the short consensus repeat domain. By further sequencing the PCR products, a nonsense mutation from G to T was identified at codon 608 in exon XII in the patient, his mother, and his sister. They were all heterozygous for the nonsense mutation. The mutant gene encodes a truncated form of C1s that lacks the C-terminal 80 amino acids. These results indicate that the patient was a compound heterozygote with the 4-bp deletion on the paternal allele and the nonsense mutation on the maternal allele. The levels of serum C1s seem to be correlated to the genotypes of the C1s gene in which no C1s was detected in the patient, and one-half of the normal level in the family members who are heterozygous for either mutation. The present study demonstrates that the disease is inherited in an autosomal recessive mode.
Anti-KS: Identification of Autoantibodies to Asparaginyl-Transfer RNA Synthetase Associated with Interstitial Lung Disease
Authors: Hirakata Michito , Suwa Akira , Nagai Sonoko , Kron Michael A. , Trieu Edward P. , Mimori Tsuneyo , Akizuki Masashi , Targoff Ira N. 
Published: January 2023

AbstractAutoantibodies to five of the aminoacyl-transfer RNA (tRNA) synthetases have been described, and each is associated with a syndrome of inflammatory myopathy with interstitial lung disease (ILD) and arthritis. Serum KS, from a patient with ILD and inflammatory arthritis without evidence of myositis, immunoprecipitated a tRNA that was distinct from that precipitated by any described anti-synthetase or other reported tRNA-related Abs, along with a protein of 65 kDa. KS serum and IgG fraction each showed significant (88%) inhibition of asparaginyl-tRNA synthetase (AsnRS) activity, but not of any of the other 19 aminoacyl-tRNA synthetase activities. Among 884 patients with connective tissue diseases tested, only two other sera were found to immunoprecipitate tRNAs and proteins of identical gel mobility. These two and KS showed identical immunodiffusion lines using HeLa cell extract. The new sera significantly inhibited AsnRS without significant effects on other synthetases tested. Both patients had ILD but neither had evidence of myositis. These data strongly suggest that these three sera have autoantibodies to AsnRS, representing a sixth anti-synthetase. Anti-KS was more closely associated with ILD than with myositis. Further study of this Abs might prove useful in dissecting the stimuli responsible for the genesis of anti-synthetase autoantibodies.
Determinant Spreading Associated with Demyelination in a Nonhuman Primate Model of Multiple Sclerosis
Authors: McFarland Hugh I. , Lobito Adrian A. , Johnson Michele M. , Nyswaner Jeffrey T. , Frank Joseph A. , Palardy Gregory R. , Tresser Nancy , Genain Claude P. , Mueller John P. , Matis Louis A. , Lenardo Michael J. 
Published: January 2023

AbstractDefinition of the immune process that causes demyelination in multiple sclerosis is essential to determine the feasibility of Ag-directed immunotherapy. Using the nonhuman primate, Callithrix jacchus jacchus (common marmoset), we show that immunization with myelin basic protein and proteolipid protein determinants results in clinical disease with significant demyelination. Demyelination was associated with spreading to myelin oligodendrocyte glycoprotein (MOG) determinants that generated anti-MOG serum Abs and Ig deposition in central nervous system white matter lesions. These data associate intermolecular “determinant spreading” with clinical autoimmune disease in primates and raise important issues for the pathogenesis and treatment of multiple sclerosis.
Recruitment of Pleckstrin and Phosphoinositide 3-Kinase γ into the Cell Membranes, and Their Association with Gβγ After Activation of NK Cells with Chemokines
Authors: Al-Aoukaty Ala , Rolstad Bent , Maghazachi Azzam A. 
Published: January 2023

Abstract
The role of phosphoinositide 3 kinases (PI 3-K) in chemokine-induced NK cell chemotaxis was investigated. Pretreatment of NK cells with wortmannin inhibits the in vitro chemotaxis of NK cells induced by lymphotactin, monocyte-chemoattractant protein-1, RANTES, IFN-inducible protein-10, or stromal-derived factor-1α. Introduction of inhibitory Abs to PI 3-Kγ but not to PI 3-Kα into streptolysin O-permeabilized NK cells also inhibits chemokine-induced NK cell chemotaxis. Biochemical analysis showed that within 2–3 min of activating NK cells, pleckstrin is recruited into NK cell membranes, whereas PI 3-Kγ associates with these membranes 5 min after stimulation with RANTES. Recruited PI 3-Kγ generates phosphatidylinositol 3,4,5 trisphosphate, an activity that is inhibited upon pretreatment of NK cells with wortmannin. Further analysis showed that a ternary complex containing the βγ dimer of G protein, pleckstrin, and PI 3-Kγ is formed in NK cell membranes after activation with RANTES. The recruitment of pleckstrin and PI 3-Kγ into NK cell membranes is only partially inhibited by pertussis toxin, suggesting that the majority of these molecules form a complex with pertussis toxin-insensitive G proteins. Our results may have application for the migration of NK cells toward the sites of inflammation.
Inhibition of Inducible Nitric Oxide Synthase Exacerbates Chronic Cerebral Toxoplasmosis inToxoplasma gondii-Susceptible C57BL/6 Mice But Does Not Reactivate the Latent Disease inT. gondii-Resistant BALB/c Mice
Authors: Schlüter Dirk , Deckert-Schlüter Martina , Lorenz Elke , Meyer Timothy , Röllinghoff Martin , Bogdan Christian 
Published: January 2023

AbstractInfection of C57BL/6 mice with Toxoplasma gondii leads to progressive and ultimately fatal chronic Toxoplasma encephalitis (TE). Genetic deletion or inhibition of inducible nitric oxide synthase (iNOS) from the beginning of infection increased the number of T. gondii cysts in the brain and markedly reduced the time-to-death in this mouse strain. In the present study, we addressed whether iNOS also contributes to the control of intracerebral parasites in a clinically stable latent infection that develops in T. gondii-resistant BALB/c mice after resolution of the acute phase of TE. iNOS was expressed in the inflammatory cerebral infiltrates of latently infected BALB/c mice, but the number of iNOS+ cells was significantly lower than in the brains of chronically infected T. gondii-susceptible C57BL/6 mice. In BALB/c mice with latent TE (&gt;30 days of infection), treatment with the iNOS inhibitors l-N6-iminoethyl-lysine or l-nitroarginine-methylester for ≤40 days did not result in an increase of the intracerebral parasitic load and a reactivation of the disease, despite the presence of iNOS-suppressive inhibitor levels in the brain. However, l-nitroarginine-methylester treatment had remarkably toxic effects and induced a severe wasting syndrome with high mortality. In contrast to BALB/c mice, l-N6-iminoethyl-lysine treatment rapidly exacerbated the already established chronic TE of C57BL/6 mice. Thus, the containment of latent toxoplasms in T. gondii-resistant BALB/c mice is independent of iNOS, whereas the temporary control of intracerebral parasites in T. gondii-susceptible C57BL/6 mice with chronic TE requires iNOS activity.