bluuebunny/crossref_metadata_2025_split huggingface dataset:
Glucocorticoids Promote Nonphlogistic Phagocytosis of Apoptotic Leukocytes
Authors: Liu Yuqing , Cousin Joanne M. , Hughes Jeremy , Van Damme Jo , Seckl Jonathan R. , Haslett Christopher , Dransfield Ian , Savill John , Rossi Adriano G. 
Published: January 2023

AbstractPhagocyte recognition, uptake, and nonphlogistic degradation of neutrophils and other leukocytes undergoing apoptosis promote the resolution of inflammation. This study assessed the effects of anti-inflammatory glucocorticoids on this leukocyte clearance mechanism. Pretreatment of “semimature” 5-day human monocyte-derived macrophages (Mφ) for 24 h with methylprednisolone, dexamethasone, and hydrocortisone, but not the nonglucocorticoid steroids aldosterone, estradiol, and progesterone, potentiated phagocytosis of apoptotic neutrophils. These effects were specific in that the potentiated phagocytosis of apoptotic neutrophils was completely blocked by the glucocorticoid receptor antagonist RU38486, and glucocorticoids did not promote 5-day Mφ ingestion of opsonized erythrocytes. Similar glucocorticoid-mediated potentiation was observed with 5-day Mφ uptake of alternative apoptotic “targets” (eosinophils and Jurkat T cells) and in uptake of apoptotic neutrophils by alternative phagocytes (human glomerular mesangial cells and murine Mφ elicited into the peritoneum or derived from bone marrow). Importantly, methylprednisolone-mediated enhancement of the uptake of apoptotic neutrophils did not trigger the release of the chemokines IL-8 and monocyte chemoattractant protein-1. Furthermore, longer-term potentiation by methylprednisolone was observed in maturing human monocyte-derived Mφ, with greater increases in 5-day Mφ uptake of apoptotic cells being observed the earlier glucocorticoids were added during monocyte maturation into Mφ. We conclude that potentiation of nonphlogistic clearance of apoptotic leukocytes by phagocytes is a hitherto unrecognized property of glucocorticoids that has potential implications for therapies aimed at promoting the resolution of inflammatory diseases.
Increased Generation of CD8+ T Cell Clones in p53 Mutant Mice
Authors: Zhou Xianzheng , Wong Stacey , Walter Jurgen , Jacks Tyler , Eisen Herman N. 
Published: January 2023

Abstract
Very few cultured CD8+ T cell clones can normally be obtained from a single mouse and maintained in long-term culture. To improve the yield, we immunized p53 mutant mice with peptides of Sendai virus (FAPGNYPAL) and influenza virus (ASNENMETM) origin. Substantially more clones could be derived from p53−/− mice than from similarly treated wild-type mice (p53+/+); an intermediate yield was obtained from heterozygous mice (p53+/−). CTL lines or clones from p53−/− mice exhibited greater proliferative activity and resistance to γ-irradiation than those from p53+/+ mice, and were cytolytically potent.
Gene Conversion and Hypermutation During Diversification of VH Sequences in Developing Splenic Germinal Centers of Immunized Rabbits
Authors: Schiaffella Enrico , Sehgal Devinder , Anderson Arthur O. , Mage Rose G. 
Published: January 2023

AbstractThe young rabbit appendix and the chicken bursa of Fabricius are primary lymphoid organs where the B cell Ab repertoire develops in germinal centers (GCs) mainly by a gene conversion-like process. In human and mouse, V-gene diversification by somatic hypermutation in GCs of secondary lymphoid organs leads to affinity maturation. We asked whether gene conversion, somatic hypermutation, or both occur in rabbit splenic GCs during responses to the hapten DNP. We determined DNA sequences of rearranged heavy and light chain V region gene segments in single cells from developing DNP-specific GCs after immunization with DNP-bovine γ-globulin and conclude that the changes at the DNA level that may lead to affinity maturation occur by both gene conversion and hypermutation. Selection was suggested by finding some recurrent amino acid replacements that may contribute increased affinity for antigen in the complementarity-determining region sequences of independently evolved clones, and a narrower range of complementarity-determining region 3 lengths at day 15. Some of the alterations of sequence may also lead to new members of the B cell repertoire in adult rabbits comparable with those produced in gut associated lymphoid tissues of young rabbits.
Cloning and Modeling of the First Nonmammalian CD4
Authors: Koskinen Riitta , Lamminmäki Urpo , Tregaskes Clive A. , Salomonsen Jan , Young John R. , Vainio Olli 
Published: January 2023

AbstractWe have cloned and sequenced the first nonmammalian CD4 cDNA from the chicken using the COS cell expression method. Chicken CD4 contains four extracellular Ig domains that, in analogy to mammalian CD4, are in the order V, C2, V, and C2. The molecule is 24% identical with both human and mouse sequences. The extracellular domains were modeled using human and rat CD4 crystal structures as templates. In the first domain there are two extra Cys residues that are at suitable distance to form an intra-β-sheet disulfide bridge in addition to the canonical one in the V domain. The region responsible for the interaction with MHC class II is relatively nonconserved in chicken. However, there are positively charged amino acids in the C″ region of the N-terminal domain that may mediate the association to the negatively charged residues of the MHC class II β-chain. Molecular modeling also implies that the membrane-proximal domain mediates dimerization of chicken CD4 in a similar way as it does for human CD4. Furthermore, the cytoplasmic tail is highly conserved, containing the protein tyrosine kinase p56lck recognition site that is preceded by an adjacent di-leucine motif for the internalization of the molecule. Interestingly, there are no Ser residues in the cytoplasmic part, which may explain the slow down-regulation of chicken CD4 after phorbol ester stimulation.
Regulation of Cytosolic COX-2 and Prostaglandin E2 Production by Nitric Oxide in Activated Murine Macrophages
Authors: Patel Rajesh , Attur Mukundan G. , Dave Mandar , Abramson Steven B. , Amin Ashok R. 
Published: January 2023

Abstract
Murine macrophages (RAW 264.7) when stimulated with LPS show 90% distribution of cyclooxygenase-2 (COX-2) in the nuclear fraction and ∼10% in the cytosolic fraction. Further analysis of this cytosolic fraction at 100,000 × g indicates that the COX-2 is distributed both in the 100,000 × g soluble fraction and membrane fraction. Stimulation of RAW 264.7 cells with LPS in the presence of inducible nitric oxide synthase inhibitor l-NMMA at concentrations that inhibit nitrite accumulation by ≤80% is inadequate to augment PGE2 production. However, inhibition of nitrite accumulation by ≥85% with higher concentrations of l-NMMA shows 1) up-regulation of PGE2 production, 2) accumulation of COX-2 protein in the 100,000 × g soluble and membrane fractions of the cytosolic fraction, and 3) with no significant effects on the accumulation of COX-2 mRNA. These experiments suggest that low concentrations of nitric oxide (10–15% of the total) attenuate PGE2 production in response to LPS in RAW 264.7 cells. This inhibition is, in part, due to decreased expression of cytosolic COX-2 protein.
Ligation of FcγRII (CD32) Pivotally Regulates Survival of Human Eosinophils
Authors: Kim Jin-Tack , Schimming Andrew W. , Kita Hirohito 
Published: January 2023

Abstract
The low-affinity IgG Fc receptor, FcγRII (CD32), mediates various effector functions of lymphoid and myeloid cells and is the major IgG Fc receptor expressed by human eosinophils. We investigated whether FcγRII regulates both cell survival and death of human eosinophils. When cultured in vitro without growth factors, most eosinophils undergo apoptosis within 96 h. Ligation of FcγRII by anti-CD32 mAb in solution inhibited eosinophil apoptosis and prolonged survival in the absence of growth factors. Cross-linking of human IgG bound to FcγRII by anti-human IgG Ab or of unoccupied FcγRII by aggregated human IgG also prolonged eosinophil survival. The enhanced survival with anti-CD32 mAb was inhibited by anti-granulocyte-macrophage-CSF (GM-CSF) mAb, suggesting that autocrine production of GM-CSF by eosinophils mediated survival. In fact, mRNA for GM-CSF was detected in eosinophils cultured with anti-CD32 mAb. In contrast to mAb or ligands in solution, anti-CD32 mAb or human IgG, when immobilized onto tissue culture plates, facilitated eosinophil cell death even in the presence of IL-5. Cell death induced by these immobilized ligands was accompanied by DNA fragmentation and was inhibited when eosinophil β2 integrin was blocked by anti-CD18 mAb, suggesting that β2 integrins play a key role in initiating eosinophil apoptosis. Thus, FcγRII may pivotally regulate both survival and death of eosinophils, depending on the manner of receptor ligation and β2 integrin involvement. Moreover, the FcγRII could provide a novel mechanism to control the number of eosinophils at inflammation sites in human diseases.
Augmentation of Type I IL-1 Receptor Expression and IL-1 Signaling by IL-6 and Glucocorticoid in Murine Hepatocytes
Authors: Ito Atsushi , Takii Takemasa , Matsumura Takayuki , Onozaki Kikuo 
Published: January 2023

AbstractIL-1 signal is transduced through type I receptor (IL-1RI). We have recently reported that LPS augments IL-1RI mRNA expression in the hepatocytes of mice in vivo, and the augmentation is mediated by the interaction of IL-1, IL-6, and glucocorticoid (GC). In this study, we examined whether IL-1RI mRNA expression level in the hepatocytes reflects those of cell surface molecule and IL-1 signaling. When primary cultured murine hepatocytes were treated with dexamethasone (Dex) or IL-6, these two reagents synergistically up-regulated IL-1RI mRNA expression in the cells. 125I-labeled IL-1 binding experiment showed that the level of binding was also up-regulated by the treatment with Dex and IL-6. Scatchard analysis revealed that the number of IL-1R increased. The increased binding of IL-1 was completely inhibited by an Ab against murine IL-1RI, indicating that Dex and IL-6 augmented the expression of cell surface IL-1RI molecule. When hepatocytes were pretreated with Dex and IL-6, the activation of IL-1R-associated kinase was augmented in response to IL-1, indicating that IL-1 signaling was also augmented. In addition, IL-1 treatment following administration of the combination of Dex and IL-6 into mice markedly increased the serum level of serum amyloid A. These results indicate that GC and IL-6 augment the expression of cell surface IL-1RI in hepatocytes, as well as IL-1 signaling and IL-1R-associated kinase activation, through up-regulation of IL-1RI mRNA level, which represents a novel regulatory network between IL-1, GC, and IL-6.
Evidence of Alternative or Concomitant Use of Perforin- and Fas-Dependent Pathways in a T Cell-Mediated Negative Regulation of Ig Production
Authors: Majlessi Laleh , Bordenave Guy 
Published: January 2023

Abstract
To study the possible involvement of perforin (Pfp)- and/or Fas-dependent cytotoxicity pathways in a T cell-mediated negative regulation of Ig production, we used the T cell-induced Ig-allotype suppression model. T splenocytes from Igha/a mice, when neonatally transferred into histocompatible Igha/b F1 or Ighb/b congenic hosts, are intrinsically able to totally, specifically, and chronically suppress the production of IgG2a of the Ighb haplotype (IgG2ab). It has not been established whether the suppression effectors, which are anti-IgG2ab MHC class I-restricted CD8+ T cells, cytolyse IgG2ab+ B targets or whether they only silence Ig production. In this study, using T cells from Igha/a Pfp+/+ or Pfpo/o mice, the latter obtained by crossbreeding, and B cells from Ighb/b Fas+/+ or Faslpr/lpr (lymphoproliferation) mice in appropriate adoptive transfer models, we demonstrated that: 1) under blockage of the Pfp-mediated pathway, Igha/a T cells were still able to induce suppression against wild-type IgG2ab+ B cells, 2) IgG2ab+ B cells with impaired Fas expression were also subjected to suppression by WT Igha/a T splenocytes, and 3) the suppression establishment was totally inhibited when both Pfp- and Fas-dependent mechanisms were simultaneously blocked, i.e., when Igha/a Pfpo/o T cells were used to induce suppression against Ighb/b Faslpr/lpr B cells. These results provide the first demonstration of the existence of alternative or simultaneous use of the major cytotoxic mechanisms in a T cell-mediated down-regulation of an Ig production.
Phosphorylation of CD19 Y484 and Y515, and Linked Activation of Phosphatidylinositol 3-Kinase, Are Required for B Cell Antigen Receptor-Mediated Activation of Bruton’s Tyrosine Kinase
Authors: Buhl Anne Mette , Cambier John C. 
Published: January 2023

Abstract
Bruton’s tyrosine kinase (Btk) plays a critical role in B cell Ag receptor (BCR) signaling, as indicated by the X-linked immunodeficiency and X-linked agammaglobulinemia phenotypes of mice and men that express mutant forms of the kinase. Although Btk activity can be regulated by Src-family and Syk tyrosine kinases, and perhaps by phosphatidylinositol 3,4,5-trisphosphate, BCR-coupled signaling pathways leading to Btk activation are poorly understood. In view of previous findings that CD19 is involved in BCR-mediated phosphatidylinositol 3-kinase (PI3-K) activation, we assessed its role in Btk activation. Using a CD19 reconstituted myeloma model and CD19 gene-ablated animals we found that BCR-mediated Btk activation and phosphorylation are dependent on the expression of CD19, while BCR-mediated activation of Lyn and Syk is not. Wortmannin preincubation inhibited the BCR-mediated activation and phosphorylation of Btk. Btk activation was not rescued in the myeloma by expression of a CD19 mutant in which tyrosine residues previously shown to mediate CD19 interaction with PI3-K, Y484 and Y515, were changed to phenylalanine. Taken together, the data presented indicate that BCR aggregation-driven CD19 phosphorylation functions to promote Btk activation via recruitment and activation of PI3-K. Resultant phosphatidylinositol 3,4,5-trisphosphate probably functions to localize Btk for subsequent phosphorylation and activation by Src and Syk family kinases.
TGF-β1 Prevents the Noncognate Maturation of Human Dendritic Langerhans Cells
Authors: Geissmann Frederic , Revy Patrick , Regnault Armelle , Lepelletier Yves , Dy Michel , Brousse Nicole , Amigorena Sebastian , Hermine Olivier , Durandy Anne 
Published: January 2023

Abstract
TGF-β1 is critical for differentiation of epithelial-associated dendritic Langerhans cells (LC). In accordance with the characteristics of in vivo LC, we show that LC obtained from human monocytes in vitro in the presence of TGF-β1 1) express almost exclusively intracellular class II Ags, low CD80, and no CD83 and CD86 Ags and 2) down-regulate TNF-RI (p55) and do not produce IL-10 after stimulation, in contrast to dermal dendritic cells and monocyte-derived dendritic cells. Surprisingly, while LC exhibit E-cadherin down-regulation upon exposure to TNF-α and IL-1, TGF-β1 prevents the final LC maturation in response to TNF-α, IL-1, and LPS with respect to Class II CD80, CD86, and CD83 Ag expression, loss of FITC-dextran uptake, production of IL-12, and Ag presentation. In sharp contrast, CD40 ligand cognate signal induces full maturation of LC and is not inhibited by TGF-β1. The presence of emigrated immature LCs in human reactive skin-draining lymph nodes provides in vivo evidence that LC migration and final maturation may be differentially regulated.
Therefore, due to the effects of TGF-β1, inflammatory stimuli may not be sufficient to induce full maturation of LC, thus avoiding potentially harmful immune responses. We conclude that TGF-β1 appears to be responsible for both the acquisition of LC phenotype, cytokine production pattern, and prevention of noncognate maturation.
Two Independent Calcineurin-Binding Regions in the N-Terminal Domain of Murine NF-ATx1 Recruit Calcineurin to Murine NF-ATx1
Authors: Liu Jie , Masuda Esteban S. , Tsuruta Lisako , Arai Naoko , Arai Ken-ichi 
Published: January 2023

Abstract
Intracellular calcium regulates events controlling nuclear translocation of nuclear factor of activated T cells (NF-AT). Calcium-dependent phosphatase calcineurin (CN) plays a central role in this process. Structural and functional analyses of the N-terminal domain of murine NF-ATx1, a member of the NF-AT family, have defined two distinct CN binding regions (CNBRs), CNBR1 and CNBR2, which are located in the region preceding the SP boxes of serine/proline-rich sequences and the region between the SP boxes and Rel similarity domain, respectively. The binding of murine NF-ATx1 (mNF-ATx1) to CN was abolished by deletion of these two regions, yet was unaffected by the individual deletion. In contrast, the nuclear translocation of mNF-ATx1 was much reduced when only CNBR2 was removed. Luciferase assay revealed that both regions are required for mNF-ATx1-dependent activation of the murine IL-2 promoter. Most importantly, recombinant CNBR2 bound CN with a higher affinity, and when expressed in Jurkat cells, it functioned as a dominant negative mutant that prevented the transcription driven by exogenous mNF-ATx1, probably by interfering with the function of CN. We propose that activation of mNF-ATx1 can be modulated through two distinct CN target regions. Our findings provide a new opportunity for pharmacological intervention with Ca2+-dependent signaling events.
Actinobacillus actinomycetemcomitans Immunosuppressive Protein Is a Member of the Family of Cytolethal Distending Toxins Capable of Causing a G2 Arrest in Human T Cells
Authors: Shenker Bruce J. , McKay Terry , Datar Sugandha , Miller Mark , Chowhan Rohini , Demuth Donald 
Published: January 2023

Abstract
We have previously shown that Actinobacillus actinomycetecomitans produces an immunosuppressive factor (ISF) capable of impairing human lymphocyte function by perturbing cell cycle progression. We now report that ISF is the product of the cdtB gene, one of three genes encoding the family of cytolethal distending toxins (Cdt). The ISF polypeptide exhibits ≥95% identity with Hemophilus ducreyi CdtB protein and ≤60% homology with Escherichia coli or Campylobacter jejuni CdtB. Pretreatment of PHA-activated lymphocytes with 5–25 ng ISF results in G2 arrest of CD4+ and CD8+ T cells. Similarly, treatment of HeLa cells results in G2 arrest and cell elongation and distension. However, lymphocytes are at least 5 times more sensitive to ISF than HeLa cells and do not undergo the elongation and distension that characterizes interactions of Cdts with cell lines. ISF-treated lymphocytes express normal cyclin A and B1 levels, but contain reduced levels of cell cycle-dependent kinase-1 (Cdk1). Additionally, the majority of Cdk1 is in the hyperphosphorylated, inactive, form. In contrast, PHA-induced G2 cells contain elevated levels of the hypophosphorylated, active Cdk1. Failure of ISF-treated cells to dephosphorylate Cdk1 is not associated with decreased availability of Cdc25. These studies suggest that the CdtB protein alone is capable of inducing G2 arrest in lymphocytes and cell cycle arrest, elongation, and distension of HeLa cells. Our studies also suggest that lymphocytes may be primary targets for A. actinomycetemcomitans CdtB (ISF) and possibly for other Cdt family members as well. Thus, Cdts may function to impair host immunity and contribute to the pathogenesis of disease associated with Cdt-producing organisms.
CD8+ T Cells Become Nonresponsive (Anergic) Following Activation in the Presence of Costimulation
Authors: Deeths Matthew J. , Kedl Ross M. , Mescher Matthew F. 
Published: January 2023

AbstractCD8+ T cells stimulated in vitro with anti-TCR mAb and B7-1 or ICAM-1 produce IL-2 and clonally expand. Effector function is acquired within 3 days, but proliferation ceases and the cells begin to die by apoptosis. Stimulation in vivo with B7-1-expressing allogeneic tumor results in the same sequence of events with a comparable time course. In both cases, the cells become anergic within 3 or 4 days of responding; they can no longer respond by producing IL-2 and proliferating, but can still be stimulated to proliferate in response to exogenous IL-2. This activation-induced nonresponsiveness (AINR) is not simply a consequence of ongoing cell death; cytokines that promote survival (IL-7 or IFN-α) or proliferation (human IL-2) do not restore the ability to produce IL-2 in response to costimulation. Although similar to the anergy described for CD4+ T cell clones, AINR differs in that it results from an initial stimulation with both signal 1 and signal 2. AINR appears to be an aspect of the normal differentiation of fully stimulated CD8+ T cells. It is probably important in regulating CTL responses; it limits the initial T helper-independent response and converts it to a response that requires T cell help to be sustained and further expanded. When the initial helper-independent response is not sufficient to clear Ag, and if help is not available, AINR likely results in tolerance to the Ag.
Bacterial DNA or Oligonucleotides Containing Unmethylated CpG Motifs Can Minimize Lipopolysaccharide-Induced Inflammation in the Lower Respiratory Tract Through an IL-12-Dependent Pathway
Authors: Schwartz David A. , Wohlford-Lenane Christine L. , Quinn Timothy J. , Krieg Arthur M. 
Published: January 2023

AbstractTo determine whether the systemic immune activation by CpG DNA could alter airway inflammation, we pretreated mice with either i.v. bacterial DNA (bDNA) or oligonucleotides with or without CpG motifs, exposed these mice to LPS by inhalation, and measured the inflammatory response systemically and in the lung immediately following LPS inhalation. Compared with non-CpG oligonucleotides, i.v. treatment with CpG oligonucleotides resulted in higher systemic concentrations of polymorphonuclear leukocytes, IL-10, and IL-12, but significantly reduced the concentration of total cells, polymorphonuclear leukocytes, TNF-α, and macrophage inflammatory protein-2 in the lavage fluid following LPS inhalation. The immunoprotective effect of CpG-containing oligonucleotides was dose-dependent and was most pronounced in mice pretreated between 2 and 4 h before the inhalation challenge, corresponding to the peak levels of serum cytokines. bDNA resulted in a similar immunoprotective effect, and methylation of the CpG motifs abolished the protective effect of CpG oligonucleotides. The protective effect of CpG oligonucleotides was observed in mice with either a disrupted IL-10 or IFN-γ gene, but release of cytokines in the lung was increased, especially in the mice lacking IFN-γ. In contrast, CpG DNA did not protect mice with a disrupted IL-12 gene against the LPS-induced cellular influx, even though CpG DNA reduced the release of TNF-α and macrophage inflammatory protein-2 in the lung. These findings indicate that CpG-containing oligonucleotides or bDNA are protected against LPS-induced cellular airway inflammation through an IL-12-dependent pathway, and that the pulmonary cytokine and cellular changes appear to be regulated independently.
The Specificity of a Weak γδ TCR Interaction Can Be Modulated by the Glycosylation of the Ligand
Authors: Hampl Johannes , Schild Hansjörg , Litzenberger Christa , Baron Miriam , Crowley Michael P. , Chien Yueh-hsiu 
Published: January 2023

Abstract
The γδ T cell clone LBK5 recognizes the MHC molecule IEk. Here, we demonstrate that the affinity of this interaction is weaker than those typically reported for αβ TCRs that recognize peptide/MHC complexes. Consistent with our previous finding that peptide bound to the IE molecule does not confer specificity, we show that the entire epitope for LBK5 is contained within the polypeptide chains of the molecule, centered around the polymorphic residues 67 and 70 of the IE β-chain. However, LBK5 recognition is profoundly influenced by the N-linked glycosylation at residue 82 of the IE α-chain. Since infected, stressed, or transformed cells often change the posttranslational modifications of their surface glycoproteins, this finding suggests a new way in which γδ T cell Ag recognition can be regulated.