bluuebunny/crossref_metadata_2025_split huggingface dataset:
Induction of parasite antigen-specific antibody responses in unsensitized human B cells is dependent on the presence of cytokines after T cell priming.
Authors: Garraud O , Perler F B , Bradley J E , Nutman T B 
Published: December 2022

Abstract
Using two recombinant filarial protein Ags and keyhole limpet hemocyanin, we sensitized T cells from uninfected, nonatopic individuals in such a manner that they were able to provide help for the selective induction of an Ag-specific Ab response. IL-2 and IL-4 were shown to be critical for sensitizing the T cells; once sensitized, these T cells could provide the necessary signals for B cells to produce Ag-specific Abs, provided that IL-4 (or IL-2) was supplied exogenously. Primary exposure of T cells to IFN-gamma, but not to IL-12, prevented the Ag-sensitized T cells from helping B cells to produce specific Abs, apart from the IgG2 isotype. These data suggest that Ab-producing B cells of a defined Ag specificity and isotype can be generated differentially after in vitro priming of human T cells by Ag, providing regulatory cytokines are also present.
Appropriate developmental expression of human CD8 beta in transgenic mice.
Authors: Kieffer L J , Yan L , Hanke J H , Kavathas P B 
Published: December 2022

Abstract
The human CD8 glycoprotein is expressed either as an alpha beta heterodimer or as an alpha alpha homodimer on thymocytes, mature T cells, and subpopulations of intestinal intraepithelial lymphocytes (IELs). The homodimeric form of CD8 is exclusively expressed on TCR gamma delta IELs and on subsets of NK cells and TCR alpha beta IELs. To understand the molecular mechanisms by which these genes are regulated, we created transgenic mice with a 95-kb human genomic DNA fragment containing the entire CD8 beta gene as well as a cluster of tissue-specific DNase I-hypersensitive sites 7 to 10 kb upstream of the gene. These sites were present in CD8 alpha beta+- but not CD8 alpha beta- T cell lines nor in a B cell line. We found that transgenic mice had correct developmental expression of human CD8 beta on thymocytes and mature CD8+ cells and no expression on mature CD4+ T cells or B cells. Interestingly, the percentage of mouse CD8 alpha+ cells that were human CD8 beta+ varied, depending on the founder line, from 4 to 88%, whereas the percentage among siblings was similar, indicative of a variegated phenotype resulting from site of integration effects. Expression was also observed on intestinal IELs, but only on those expressing the TCR alpha beta receptor and not the TCR gamma delta cells, which exclusively express CD8 alpha alpha. Of the TCR alpha beta+ cells, the transgene was expressed in both the CD8 alpha alpha and alpha beta subpopulations. These results indicate that this 95-kb fragment affords developmentally correct expression of the human CD8 beta gene on thymus-derived T cells in transgenic animals. Therefore, CD8 lineage-specific regulatory sequences must be located within the fragment.
HLA-DP2: self peptide sequences and binding properties.
Authors: Chicz R M , Graziano D F , Trucco M , Strominger J L , Gorga J C 
Published: December 2022

Abstract
Although self peptides bound to HLA-DQ and, especially, HLA-DR allotypes have been described in some detail, few ligands that bind to HLA-DP have been identified. Toward this aim, naturally processed peptides were isolated from immunoaffinity-purified HLA-DP2 molecules expressed in cultured B lymphocytes. The size distribution of the peptide repertoire is generally similar to those reported for self peptides bound to HLA-DR and HLA-DQ molecules. Twelve peptides representing individual sequences including two nested sets were sequenced by mass spectrometry and/or N-terminal Edman analysis. Source proteins included MHC molecules and other integral membrane proteins as well as secretory and serum proteins. No dominant amino acid markers suggestive of particular enzymatic processing events were detected. Peptide specificity and affinity were examined in binding assays using synthetic peptides and purified HLA-DP and HLA-DR molecules. Anchor residues were tentatively assigned using alanine-substituted analogues of two self peptides. Some structural features of HLA-DP2 that may relate to peptide binding are considered.
Natural killer cell cytokine production, not cytotoxicity, contributes to resistance against blood-stage Plasmodium chabaudi AS infection.
Authors: Mohan K , Moulin P , Stevenson M M 
Published: December 2022

Abstract
Our recent study showed that IL-12 treatment of susceptible A/J mice induces Th1-mediated, protective immunity against lethal blood-stage Plasmodium chabaudi AS infection. To further understand the mechanism of this protection, we examined NK cell cytotoxic (NKCC) and cytokine secretory functions in untreated and IL-12-treated A/J mice, along with resistant C57BL/6 (B6) mice. Normal A/J mice receiving six daily doses of 0.1 microg IL-12 exhibited significant increases in NKCC in total spleen cell populations. Defective NKCC evident in vitro in enriched NK cells from infected A/J mice was corrected by addition of 10 ng/ml IL-12 and was comparable with that seen in B6 mice. In vivo and in vitro analyses revealed that enriched NK cells from day 6 infected A/J mice were defective not only in NKCC, but also in IFN-gamma, and to a certain extent, TNF-alpha secretion, which could also be corrected by IL-12 treatment. Depletion of NK cells from resistant B6 mice resulted in a more severe course of infection, while NK cell-depleted, IL-12-treated A/J mice had significantly higher parasitemia, as well as 100% mortality, suggesting the importance of NK cells in IL-12-mediated protection. NKCC-defective bg/bg mice produced optimum IFN-gamma and TNF-alpha and recovered from infection similar to bg/+ controls; in vivo depletion of these cytokines resulted in significantly higher parasitemia early in infection. Based on these results, we conclude that IFN-gamma, and possibly TNF-alpha, secretion by NK cells during early infection plays a major role in protective immunity to blood-stage malaria.
Formyl peptide receptors are coupled to multiple mitogen-activated protein kinase cascades by distinct signal transduction pathways: role in activation of reduced nicotinamide adenine dinucleotide oxidase.
Authors: Rane M J , Carrithers S L , Arthur J M , Klein J B , McLeish K R 
Published: December 2022

Abstract
Formyl peptide receptor activation of three mitogen-activated protein kinase (MAPK) cascades, extracellular signal-regulated kinases (ERKs), N-terminal kinases (JNKs), and p38 MAPK was examined in differentiated HL-60 granulocytes. FMLP stimulated a concentration- and time-dependent increase in ERK, JNK, and p38 MAPK activities, all of which were dependent on a pertussis toxin-sensitive G protein. Pharmacologic inhibitors were used to examine the roles of tyrosine kinases, phosphatidylinositol 3-kinase, protein kinase C, and phospholipase C. FMLP-stimulated ERK activity was dependent on tyrosine kinases, phosphatidylinositol 3-kinase, protein kinase C, and phospholipase C; p38 MAPK activation was dependent on phosphatidylinositol 3-kinase and phospholipase C; while JNK activation was independent of all of these signaling components. The mitogen-activated protein kinase/ERK kinase inhibitor PD098059 reduced ERK activation by 90%, while an inhibitor of p38 MAPK, SB203580, inhibited p38 MAPK activation by 80%. Both PD098059 and SB203580 inhibited FMLP-stimulated superoxide release, as did inhibitors directed against protein kinase C, tyrosine kinases, and phosphatidylinositol 3-kinase. We conclude that formyl peptide receptors are coupled to three MAPK cascades by Gi proteins. ERKs, p38 MAPK, and JNKs are each activated by distinct proximal signal transduction pathways. Activation of p38 MAPK is necessary for FMLP stimulation of respiratory burst activity; however, a second signal that may involve ERK is also required for this activity.
Mechanical deformation promotes secretion of IL-1 alpha and IL-1 receptor antagonist.
Authors: Lee R T , Briggs W H , Cheng G C , Rossiter H B , Libby P , Kupper T 
Published: December 2022

Abstract
Both IL-1 alpha and IL-1 beta lack an N terminus secretory sequence, and the mechanism of secretion of these pleiotropic cytokines is incompletely understood. The epidermis contains large quantities of IL-1 alpha in keratinocytes, which may play a role in inducing endothelial adhesion molecules and promoting extravasation of leukocytes. Here we report that mechanical deformation of human keratinocytes leads to rapid release of IL-1 alpha, possibly through transient disruptions in the plasma membrane. Using a device that precisely controls the amplitude of strain on the culture substrate, we found by pulse-chase analysis, Western analysis, and ELISA that the release of IL-1 alpha is dependent on the amplitude of the strain. A cyclic strain of 14% released a small but significant quantity of IL-1 alpha, while strains of 33% released 66 +/- 9% of cytoplasmic IL-1 alpha over 1 h (p &lt; 0.001). Release of IL-1 alpha was accompanied by rapid release of large stores of IL-1R antagonist, approximately 25 to 30 times greater by mass than the quantity of IL-1 alpha released, but only a small fraction of cytoplasmic lactate dehydrogenase. Media conditioned by mechanically stimulated keratinocytes induced expression of E-selectin by human vascular endothelial cells; induction of E-selectin was completely inhibited by an Ab to IL-1 alpha. Therefore, mechanical strain promotes the secretion of IL-1 alpha, and deformation of keratinocytes in the epidermis may activate vascular endothelium through mechanically released IL-1 alpha. This pathophysiologic mechanism may play a role in the anatomic localization of some inflammatory skin diseases, such as psoriasis, which occurs more commonly in locations where the dermis is subjected to repetitive stretch or trauma.
Human monoclonal antibodies to the V3 loop of HIV-1 with intra- and interclade cross-reactivity.
Authors: Gorny M K , VanCott T C , Hioe C , Israel Z R , Michael N L , Conley A J , Williams C , Kessler J A , Chigurupati P , Burda S , Zolla-Pazner S 
Published: December 2022

Abstract
Five human anti-V3 mAbs were generated from Ab-producing cells derived from the blood of HIV-1-infected individuals from North America and selected using the V3 peptide of a divergent clade B isolate, HIV(RF). The anti-V3(RF) mAbs were mapped to a cluster of three overlapping epitopes present in the KSITKGP sequence located in the hypervariable region on the N-terminal side of the V3 loop. Broad immunochemical cross-reactivity was noted when the mAbs were tested for binding to V3 peptides derived from four clade A viruses, nine clade B viruses, and two clade C viruses. These results demonstrate antigenic relatedness in the V3 regions of these three HIV-1 clades. Affinities determined by surface plasmon resonance were higher for recombinant gp120 than for V3 peptides, suggesting that these mAbs recognize both linear and conformationally dependent epitopes of the V3 loop. Two of the mAbs neutralized four clade B T cell line-adapted and primary isolates with varying degrees of potency. The two neutralizing mAbs were the most cross-reactive with V3 peptides from several clades, had the highest affinity for V3(RF) and V3(MN), and stained HIV-infected cells. The data suggest that cross-reactivity, affinity, cell surface staining, and neutralizing activity are characteristics that describe an optimal fit between Ag and Ab. The results also demonstrate that the V3 peptides representing the sequence of several clade A, B, and C viruses share antigenic features that are recognized by the human immune response, a finding that suggests that cross-clade immunity to HIV-1 may be inducible by HIV-1 vaccines.
Prevention of immunotoxin-induced immunogenicity by coadministration with CTLA4Ig enhances antitumor efficacy.
Authors: Siegall C B , Haggerty H G , Warner G L , Chace D , Mixan B , Linsley P S , Davidson T 
Published: December 2022

Abstract
Immunotoxins have shown promise as antitumor agents in clinical trials. However, they have not become part of standard cancer therapy because of factors that include their inherent immunogenicity, which limits the duration of therapy. To address this issue, we evaluated in preclinical models the concomitant use of the immunosuppressive agent CTLA4Ig and BR96 sFv-PE40, a single-chain immunotoxin that binds to carcinoma cells expressing Le(y). Cotreatment with CTLA4Ig, an inhibitor of the CD28/CTLA4-CD80/CD86 costimulation pathway, blocked the production of Abs against BR96 sFv-PE40 in immunocompetent rodents and dogs. It also blocked hypersensitivity reactions in rats carrying colon carcinoma allografts during a second course of BR96 sFv-PE40 therapy, and the cotreatment with CTLA4Ig resulted in enhanced antitumor activity. Cotreatment with CTLA4Ig also prevented hypersensitivity reactions induced by repeat dosing of BR96 sFv-PE40 (q3dx5) in dogs. The production of anti-BR96-sFv-PE40 Abs was decreased in CTLA4Ig-cotreated rodents and dogs resulting in increased plasma levels of BR96 sFv-PE40 relative to non-CTLA4Ig-cotreated animals. These data show that cotreatment of immunotoxins with CTLA4Ig, by inhibiting the production of anti-immunotoxin Abs, can extend the duration of BR96 sFv-PE40 therapy to give greater exposure, reduced toxicities, and increased efficacy.
Distinct signal transduction pathways mediate nuclear factor-kappaB induction by IL-1beta in epithelial and lymphoid cells.
Authors: Bonizzi G , Piette J , Merville M P , Bours V 
Published: December 2022

Abstract
We previously demonstrated that IL-1beta-mediated induction of the nuclear factor-kappaB (NF-kappaB) transcription factor proceeds through the production of reactive oxygen intermediates in lymphoid cells, while it occurs independently of any oxidative stress in epithelial transformed cells. Indeed, inhibition of receptor internalization as well as NH4Cl and chloroquine blocked IL-1beta-mediated induction of NF-kappaB in OVCAR-3 and in other epithelial cell lines but not in lymphoid cells, indicating that distinct pathways are involved. Conversely, while we observed phospholipase A2 activity in both cell types following IL-1beta stimulation, specific inhibitors of this enzyme inhibited NF-kappaB induction only in lymphoid cells. Moreover, expression of the 5-lipoxygenase (5-LOX) enzyme was not detected in epithelial cells, and inhibition of this enzyme blocked NF-kappaB induction by IL-1beta only in lymphoid cells. This study thus indicates that the activation of NF-kappaB following IL-1beta treatment involves the activation of phospholipase A2 and 5-LOX and the production of reactive oxygen intermediates (ROIs) in lymphoid cells, while in epithelial cells, another pathway predominates and could involve the acid sphingomyelinase. Moreover, arachidonic acid could induce NF-kappaB in epithelial and lymphoid cells, but this activation involved the 5-LOX enzyme and the production of ROIs only in lymphoid cells. The inefficiency of the ROI pathway in epithelial cells is probably the consequence of both low ROI production due to undetectable expression of 5-LOX and rapid degradation of hydrogen peroxide due to high catalase activity.
The mucosal adjuvanticity of cholera toxin involves enhancement of costimulatory activity by selective up-regulation of B7.2 expression.
Authors: Cong Y , Weaver C T , Elson C O 
Published: December 2022

Abstract
Cholera toxin (CT) is a potent mucosal immunogen and adjuvant that can strongly prime mucosal T cells. The present study was undertaken to investigate the effects of CT on the expression and functional activity of the costimulatory molecules B7.1 and B7.2 on macrophages and the relationship of these effects to the mucosal adjuvanticity of CT. Bone marrow macrophages (BMM) were generated by culturing bone marrow with macrophage CSF or granulocyte-macrophage CSF. After treatment with either CT alone or IFN-gamma alone, B7.2 expression on BMM was moderately up-regulated and was further increased when BMM were treated with both CT and IFN-gamma together. Interestingly, CT had no effect on B7.1 expression despite the close relationship between these two molecules. Up-regulation of B7.2 expression by CT was mediated by intracellular cAMP production, in that CT-B subunit had no effect and dibutyryl cAMP could mimic the effect. CT increased functional costimulatory activity of macrophages for both anti-CD3-stimulated and allostimulated T cells, an increase that was blocked by anti-B7.2, but not anti-B7.1, Ab. B7.2 expression by Mac1+ Peyer's patch cells was increased after intraluminal exposure to CT in vivo. Treatment of mice with anti-B7.2 Ab in vivo inhibited both the mucosal adjuvanticity and the immunogenicity of CT. We conclude that CT enhances the costimulatory activity of mucosal APC by differentially up-regulating B7.2 expression, an effect that appears to be important for its mucosal adjuvanticity and immunogenicity.
Dissociation of cytokine signals for proliferation and apoptosis.
Authors: Shi Y , Wang R , Sharma A , Gao C , Collins M , Penn L , Mills G B 
Published: December 2022

Abstract
Cytokines such as IL-2 or IL-3 prevent cell death through apoptosis, either by preventing apoptosis directly or by sensitizing cells to survival factors present in serum. We demonstrate herein that BAF-B03 cells transfected with the wild-type IL-2R beta-chain undergo apoptosis when stimulated with IL-2 or IL-3 in the absence of serum. IL-2 also induced apoptosis in normal IL-2-responsive human T cell blasts in the absence of serum, and furthermore, epidermal growth factor and fibroblast growth factor induced increased rates of apoptosis in fibroblasts in the absence of serum, suggesting that cytokine-induced apoptosis in the absence of serum survival factors might represent an important biologic phenomenon. In the presence or the absence of serum, IL-2 and IL-3 induced expression of both c-Myc and Bax. In contrast, optimal cytokine-induced expression of Bcl-2 requires serum. Constitutive expression of Bcl-2 prevented cytokine-induced apoptosis. Transferrin mimicked serum by inducing an increase in Bcl-2 expression levels and concurrently prevented apoptosis. These results suggest that the balance between cytokine- and serum-induced Bcl-2 expression and cytokine-induced Bax expression may determine whether a cell undergoes cytokine-induced apoptosis. In BAF/BO3 cells expressing a mutant IL-2Rbeta with a deletion of the acidic domain, IL-2 did not induce either Bax expression or apoptosis. This suggests that the acidic domain of the IL-2R beta-chain plays an essential role in regulating IL-2-mediated Bax expression and apoptosis. Cytokine-induced apoptosis and its counterbalance by survival factors present in serum may play an important role in the regulation of cellular homeostasis during pathophysiologic processes.
Processing of engulfed apoptotic bodies yields T cell epitopes.
Authors: Bellone M , Iezzi G , Rovere P , Galati G , Ronchetti A , Protti M P , Davoust J , Rugarli C , Manfredi A A 
Published: December 2022

Abstract
Programmed death via apoptosis is the metazoan physiologic mode of cell death. Apoptotic cells are recognized by scavenger phagocytes via a number of membrane receptors and engulfed. Thereafter, little is known of their fate, or that of phagocytes. Here, we have traced apoptotic cells upon their engulfment by macrophages. After 3 h, apoptotic cells were contained in discrete well-defined vacuoles. Upon overnight chase, several small vesicles, possibly originating from the fragmentation of original vacuoles, were evident all over the macrophage body. Furthermore, Ags were diffused in the cytosol of some cells, which raises the possibility that epitopes from engulfed apoptotic cells may associate with macrophage MHC class I molecules and be recognized by T lymphocytes. Indeed, Ag-specific CTLs recognize and specifically lyse syngeneic macrophages upon phagocytosis of MHC class I-positive or -negative apoptotic cells, provided that they contain the relevant Ags. Synthesis and membrane expression of class I molecules by macrophages, together with functional transporters associated with Ag presentation, were necessary for recognition and lysis. The indirect presentation of epitopes from engulfed apoptotic cells by scavenger Ag-presenting phagocytes may, in the absence of "danger" signals, have implications for the establishment of central and peripheral self-tolerance.
Transcriptional regulation of the complement receptor 2 gene: role of a heterogeneous nuclear ribonucleoprotein.
Authors: Tolnay M , Lambris J D , Tsokos G C 
Published: December 2022

Abstract
Complement receptor 2 (CR2) has been implicated as a regulator of B cell function. In this study, we sought to identify mechanisms that control the expression of the CR2 gene in human B cells. Dibutyryl cAMP increased the DNA-binding activity of a nuclear protein that recognized specifically a CR2 promoter-defined oligonucleotide in human B cell lines. The nuclear protein was subsequently purified from B cell nuclear extracts using a biotinylated CR2 promoter-defined oligonucleotide. Partial amino acid sequence analysis of internal peptides revealed that the 42-kDa protein belongs to a family of heterogeneous nuclear ribonucleoproteins (hnRNP). Using a set of mutated double-stranded oligonucleotides, we demonstrated that the purified protein displayed sequence specificity for the CR2 promoter-defined oligonucleotide. Like some hnRNP, this protein was found to bind to single-stranded DNA. The DNA-binding activity of the purified protein increased after in vitro phosphorylation with protein kinase A. Using a CAT reporter gene driven by a single recognition site in B cell lines, dibutyryl cAMP caused a 3-fold induction of reporter gene expression. The highest induction (6.7-fold) was achieved with a combination of dibutyryl cAMP and PMA. The involvement of the nuclear protein in regulating the expression of the CR2 gene is supported by our finding that dibutyryl cAMP increased the levels of the CR2 mRNA and CR2 surface membrane protein in human B cell lines. These data strongly suggest that a cAMP-inducible hnRNP, which can recognize a novel DNA-motif, controls the expression of the CR2 gene.