bluuebunny/crossref_metadata_2025_split huggingface dataset:
Coengagement of ICAM-3 and Fc Receptors Induces Chemokine Secretion and Spreading by Myeloid Leukocytes
Authors: Kessel Julie M. , Hayflick Joel , Weyrich Andrew S. , Hoffman Patricia A. , Gallatin Michael , McIntyre Thomas M. , Prescott Stephen M. , Zimmerman Guy A. 
Published: January 2023

AbstractICAM-3 is expressed at high levels on myeloid leukocytes, but its function on these cells is unknown. We tested the hypothesis that it transduces outside-in proinflammatory signals using immobilized mAbs to engage ICAM-3 on freshly isolated human monocytes and neutrophils. Two immobilized Abs that recognize epitopes in the extracellular domain 1 of ICAM-3, which is critical for recognition by the αL/β2 integrin, potently induced secretion of MIP-1α, IL-8, and MCP-1 by monocytes and triggered IL-8 secretion by neutrophils. These chemokines are products of immediate-early genes that are induced when myeloid cells are activated. Chemokine secretion induced by “triggering” Abs was greater than that induced by isotype-matched immobilized Abs against ICAM-1, ICAM-2, PECAM-1, control Igs, or immobilized control proteins. Coengagement of ICAM-3 and Fc receptors (FcγRI or FcγRII) was required for maximal chemokine secretion by monocytes. Microscopy documented that there is also dramatic spreading of monocytes when surface ICAM-3 is engaged by immobilized Abs. Spreading was induced by Fab and F(ab′)2 fragments of triggering anti-ICAM-3 mAb, demonstrating direct outside-in signaling, but was not required for chemokine secretion. These experiments indicate that ICAM-3 may transmit outside-in signals when it is engaged by β2 integrins during myeloid cell-cell interactions in inflammatory lesions. Binding of Fc receptors by Ig in the local environment can amplify the responses.
Interaction of Vaccinia Virus Complement Control Protein with Human Complement Proteins: Factor I-Mediated Degradation of C3b to iC3b1 Inactivates the Alternative Complement Pathway
Authors: Sahu Arvind , Isaacs Stuart N. , Soulika Athena M. , Lambris John D. 
Published: January 2023

Abstract
Vaccinia virus complement control protein (VCP) is a virulence determinant of vaccinia virus that helps protect the virus from the complement attack of the host. To characterize the interaction of VCP with C3 and C4 and understand the mechanism by which VCP inactivates complement, we have expressed VCP in a yeast expression system and compared the biologic activity of the purified protein to that of human factor H and complement receptor 1 (CR1). Recombinant VCP bound to C3 and the proteolytically cleaved form of C3 (C3b), but not to the 135,300-m.w. fragment of C3 generated using elastase (C3c) and the 35,000-m.w. fragment of C3 generated using elastase (C3d) and inhibited both the classical and alternative pathways of complement activation. Although rVCP was less effective at inhibiting the alternative pathway than factor H or CR1, it was more effective than factor H at inhibiting the classical pathway. Unlike factor H, rVCP was unable discriminate between alternative pathway-mediated lysis of rabbit and sheep E. A comparison of the cofactor activity in factor I-mediated cleavage of C3b suggested that in contrast to factor H and CR1, which displayed cofactor activity for the three sites, rVCP displayed cofactor activity primarily for the first site, leading to generation of C3b cleaved by factor I between Arg1281-Ser1282 (iC3b1). Its cofactor activity for C4b cleavages was similar to that of soluble complement receptor type 1. Purification and functional analysis of iC3b1 showed that it was unable to interact with factor B to form the alternative pathway C3 convertase, C3b,Bb. These results suggest that the interaction of VCP with C3 is different from that of factor H and CR1 and that VCP-supported first cleavage of C3b by factor I is sufficient to render C3b nonfunctional.
Potassium Leakage During the Apoptotic Degradation Phase
Authors: Dallaporta Bruno , Hirsch Tamara , Susin Santos A. , Zamzami Naoufal , Larochette Nathanael , Brenner Catherine , Marzo Isabel , Kroemer Guido 
Published: January 2023

Abstract
The subcellular compartmentalization of ions is perturbed during the process of apoptosis. In this work, we investigated the impact of K+ on the apoptotic process in thymocytes and T cell hybridoma cells. Irrespective of the death-inducing stimulus (glucocorticoids, topoisomerase inhibition, or Fas-crosslinking), a significant K+ outflow was observed during apoptosis, as determined on the single-cell level by means of the K+-sensitive fluorochrome, benzofuran isophtalate. This loss of cytosolic K+ only occurs in cells that have completely disrupted their inner mitochondrial transmembrane potential. Inhibition of this mitochondrial transmembrane potential loss by Bcl-2 or by specific inhibitors acting on the mitochondrial permeability transition pore (bongkrekic acid, cyclosporin A) prevents K+ leakage. K+ drops at the same stage at which cells expose phosphatidylserine residues on the outer leaflet of the membrane and reduce the levels of nonoxidized glutathione, but before they hyperproduce reactive oxygen species, undergo massive Ca2+ influx, shrink, and lyse. In a cell-free system of apoptosis, isolated nuclei exposed to the supernatant of mitochondria that have undergone permeability transition only manifest chromatinolysis when the K+ concentration is lowered from physiologic to apoptotic levels. Accordingly, massive DNA fragmentation causing subdiploidy is confined to cells that have undergone K+ leakage. Together, these data point to the step-wise acquisition of membrane dysfunction in apoptosis and indicate an important role for the disruption of normal K+ homeostasis in apoptotic degradation. Derepression of endonucleases due to low K+ concentrations may be a decisive prerequisite for end-stage DNA fragmentation.
IL-4-Induced Eosinophil Accumulation in Rat Skin Is Dependent on Endogenous TNF-α and α4 Integrin/VCAM-1 Adhesion Pathways
Authors: Sanz Maria-Jesus , Marinova-Mutafchieva Lilia , Green Patricia , Lobb Roy R. , Feldmann Marc , Nourshargh Sussan 
Published: January 2023

AbstractIL-4 has been implicated in the pathogenesis of a number of allergic inflammatory disease states where the accumulation of eosinophils is a prominant feature. The aim of the present study was to use an isotopic in vivo model to investigate the ability of recombinant rat IL-4 in inducing eosinophil accumulation in rat skin. 111In-eosinophil accumulation in response to intradermally injected IL-4 was measured during 0 to 4 h, 24 to 28 h, and 48 to 52 h. Accumulation was detected during the first two periods, but not at the later time point. The accumulation during 24 to 28 h, which was dose dependent, was investigated in detail. Administration i.v. of an anti-rat VCAM-1 mAb, but not an anti-rat ICAM-1 mAb, inhibited the accumulation of 111In-eosinophils induced by IL-4 (maximum inhibition, 80%). Further, when the 111In-eosinophils were pretreated in vitro with an anti-β2 integrin mAb, an anti-α4 integrin mAb, or a combination of both mAbs, before their injection into recipient rats, the IL-4-induced cell accumulation was inhibited by 63, 60, and 74%, respectively. Finally, coadministration of IL-4 with the soluble TNF receptor (p55)-IgG fusion protein significantly reduced the 111In-eosinophil accumulation induced by the cytokine, and TNF-α was detected in IL-4-injected skin sites by both immunostaining and bioassay. Our results demonstrate that IL-4 is a potent inducer of eosinophil accumulation in vivo, the response being dependent on the endogenous generation of TNF-α, β2 integrins, and α4 integrin/VCAM-1 interactions.
The Effect of Deletion of the V3 Loop of gp120 on Cytotoxic T Cell Responses and HIV gp120-Mediated Pathogenesis
Authors: Kmieciak Dariusz , Wasik Thomas J. , Teppler Hedy , Pientka Janet , Hsu Susan H. , Takahashi Hidemi , Okumura Ko , Kaneko Yutaro , Kozbor Danuta 
Published: January 2023

AbstractNew strategies for improving the efficacy of HIV vaccines are of significant importance. In this study, we analyzed the effect of deletion of the hypervariable V3 loop of gp120 on envelope (env)-specific CTL responses in PBMC of HIV-infected individuals. We showed increased CTL activities against conserved epitopes of the env glycoprotein in cultures induced with the ΔV3 mutant compared with those stimulated with the full-length env gene products. In contrast to the wild-type env, the ΔV3 mutant-expressing cells were resistant to Ab-dependent cell-mediated cytotoxicity, formed no syncytia, and neither underwent nor induced apoptosis in CD4+ cells. Thus, the ΔV3 mutant may redirect immune responses toward conserved epitopes of gp160, has longer expression time due to increased resistance to Ab-dependent cell-mediated cytotoxicity, and does not trigger cytopathic effects associated with apoptosis and syncytium formation. This approach may apply to other Ags of HIV, where deletions of highly variable or immunosuppressive epitopes may improve the efficacy of HIV vaccines.
Targeting the IL-15 Receptor with an Antagonist IL-15 Mutant/Fcγ2a Protein Blocks Delayed-Type Hypersensitivity
Authors: Kim Yon Su , Maslinski Wlodzimierz , Zheng Xin Xiao , Stevens A. Christopher , Li Xian Chang , Tesch Gregory H. , Kelley Vicki R. , Strom Terry B. 
Published: January 2023

AbstractOwing to shared receptor components, the biologic activities of IL-15 are similar to those of IL-2. However, the patterns of tissue expression of IL-2/IL-2Rα and IL-15/IL-15Rα differ. The development of agents targeting the receptor and signaling elements of IL-15 may provide a new perspective for treatment of diseases associated with expression of IL-15/IL-15R. We designed, genetically constructed, and expressed a receptor site-specific IL-15 antagonist by mutating glutamine residues within the C terminus of IL-15 to aspartic acid and genetically linked this mutant IL-15 to murine Fcγ2a. These mutant IL-15 proteins specifically bind to the IL-15R, competitively inhibit IL-15-triggered cell proliferation, and do not activate the STAT-signaling pathway. Because the receptor site-specific antagonist IL-15 mutant/Fcγ2a fusion proteins had a prolonged t1/2 in vivo and the potential for destruction of IL-15R+ leukocytes, we examined the immunosuppressive activity of this agent. An IL-15 mutant/Fcγ2a fusion protein markedly attenuated Ag-specific delayed-type hypersensitivity responses and decreased leukocyte infiltration within the delayed-type hypersensitivity sites. These findings suggest that 1) IL-15/IL-15R+ cells are crucial to these T cell-dependent immune responses, and 2) treatment with IL-15 mutant/Fcγ2a protein may ameliorate T cell-dependent immune/inflammatory diseases.
Expanding Dendritic Cells In Vivo Enhances the Induction of Oral Tolerance
Authors: Viney Joanne L. , Mowat Allan M. , O’Malley Jamie M. , Williamson Eilidh , Fanger Neil A. 
Published: January 2023

Abstract
The intestine is under perpetual challenge from both pathogens and essential nutrients, yet the mucosal immune system is able to discriminate effectively between harmful and innocuous Ags. It is likely that this selective immunoregulation is dependent on the nature of the APC at sites where gut Ags are processed and presented. Dendritic cells (DC) are considered the most potent of APC and are renowned for their immunostimulatory role in the initiation of immune responses. To investigate the role of DC in regulating the homeostatic balance between mucosal immunity and tolerance, we treated mice with Flt3 ligand (Flt3L), a growth factor that expands DC in vivo, and assessed subsequent systemic immune responsiveness using mouse models of oral tolerance. Surprisingly, mice treated with Flt3L to expand DC exhibited more profound systemic tolerance after they were fed soluble Ag. Most notably, tolerance could be induced in Flt3L-treated mice using very low doses of Ag that were ineffective in control animals. These findings contrast with the generally accepted view of DC as immunostimulatory APC and furthermore suggest a pivotal role for DC during the induction of tolerance following mucosal administration of Ag.
High Frequency Apoptosis of Recent Thymic Emigrants in the Liver of Lymphopenic Diabetes-Prone BioBreeding Rats
Authors: Iwakoshi Neal N. , Goldschneider Irving , Tausche Frances , Mordes John P. , Rossini Aldo A. , Greiner Dale L. 
Published: January 2023

AbstractDiabetes-prone (DP) BioBreeding (BB) rats develop spontaneous autoimmune diabetes. DP-BB thymocyte export is reduced, and most thymic emigrants disappear rapidly from peripheral lymphoid tissues. DP-BB rats are consequently lymphopenic and circulate severely reduced numbers of T cells. Peripheral T cells present are phenotypically immature (Thy1+) and appear activated. We hypothesized that DP-BB recent thymic emigrants have a shortened life span and disappear by apoptosis. The percentage of T cells with an αβTCRlowB220+CD4−CD8− phenotype was increased in DP peripheral lymphoid tissues when compared with normal, nonlymphopenic diabetes-resistant (DR) BB rat tissues. There was no evidence of DNA fragmentation in freshly isolated DP- or DR-BB rat cells, but, after 24 h of culture, a higher proportion of DP- than DR-BB splenic T cells underwent apoptosis. We then tested the hypothesis that BB rat T cells with the αβTCRlowB220+CD4−CD8− phenotype accumulate and undergo apoptosis in the liver. Such cells were observed undergoing apoptosis in both DP- and DR-BB rats, but comprised ∼80% of intrahepatic T cells in DP vs ∼20% in DR-BB rats. Most αβTCRlowB220+CD4−CD8− cells in the liver were also Thy1+. The data suggest that T cell apoptosis in the DP-BB rat is underway in peripheral lymphoid tissues and is completed in the liver. Increased intrahepatic apoptosis of recent thymic emigrants appears in part responsible for lymphopenia in DP-BB rats and the concomitant predisposition of these animals to autoimmunity.
Exogenous and Endogenous IL-10 Regulate IFN-α Production by Peripheral Blood Mononuclear Cells in Response to Viral Stimulation
Authors: Payvandi Faribourz , Amrute Sheela , Fitzgerald-Bocarsly Patricia 
Published: January 2023

AbstractIL-10 is an important regulator of the production of proinflammatory cytokines. Its effect on IFN-α production, however, has not been reported. In this study, PBMC from healthy donors were stimulated with virus in the presence of IL-10. Human IL-10 (hIL-10) caused reductions in both the frequency of IFN-α-producing cells (IPC) and bulk IFN in response to herpes simplex virus type-1 (HSV-1), Sendai virus, Newcastle disease virus, and vesicular stomatitis virus. The inhibitory effect occurred when IL-10 was added 2 or 4 h before, or 2 h poststimulation with HSV or Sendai virus, but not when added 4 h postinduction. Unlike IL-10, IL-4 did not affect the IFN-α response to HSV. However, when PBMC were induced with Sendai virus, IFN-α production was also reduced by IL-4. IL-10 treatment of PBMC resulted in strong reductions in the steady state levels of both HSV- and Sendai virus-induced IFN-α1, -α2, and -β mRNA as determined by RT-PCR. IFN-α production to Sendai virus occurs predominantly by monocytes, whereas most enveloped viruses stimulate low frequency “natural IFN-producing cells (NIPC),” which are thought to be dendritic cells. Peripheral blood dendritic cells were found to express the IL-10 receptor, suggesting that IL-10 may directly act on the dendritic IPC. Addition of monoclonal anti-IL-10 to PBMC resulted in a significant increase in both the frequency of IPC and the amount of secreted IFN-α in response to HSV but not Sendai virus. We conclude that human IL-10 can serve as both an endogenous and exogenous regulator of IFN-α production.
A Pathogenic Role of Th2 Cells and Their Cytokine Products on the Pulmonary Metastasis of Murine B16 Melanoma
Authors: Kobayashi Makiko , Kobayashi Hiroyuki , Pollard Richard B. , Suzuki Fujio 
Published: January 2023

Abstract
The role of Th2 cells and the cytokines produced by these cells on experimental pulmonary metastasis of B16 melanoma was investigated in a murine model implanted with high metastatic (B16F10) or low metastatic (B16F1) melanoma cells. An average of 250 colonies of metastasis in the lungs was counted in mice (BF10 mice) at 14 days after the inoculation of 2 × 105 B16F10 cells/mouse, while &lt;20 colonies were detected in mice (BF1 mice) inoculated with the same number of B16F1 cells. CD4+CD11b+TCR-αβ+ T cells (BF10-Th2 cells) were produced in the spleens of BF10 mice, while these cells were not detected in BF1 mice. The BF10-Th2 cells produced IL-4 and IL-10 into culture fluids when stimulated in vitro with anti-CD3 mAb. However, IL-2 and IFN-γ were not produced. The level of a pulmonary metastasis in BF1 mice increased to the level observed in BF10 mice, when BF10-Th2 cells were adoptively transferred to BF1 mice. Also, an increase in the number of pulmonary melanoma was demonstrated in BF1 mice treated with 10 μg/kg murine rIL-4. The level of pulmonary metastasis in BF10 mice or in BF1 mice inoculated with BF10-Th2 cells decreased to the level observed in BF1 mice when mice were treated with an anti-IL-4 mAb at a dose of 250 μg/kg on days 1, 3, and 5 after tumor inoculation. These results suggest that the severity of pulmonary metastasis in mice receiving B16 melanoma cells is strongly influenced by the IL-4 released from tumor-associated Th2 cells.
CpG Oligodeoxyribonucleotides Rescue Mature Spleen B Cells from Spontaneous Apoptosis and Promote Cell Cycle Entry
Authors: Yi Ae-Kyung , Chang Ming , Peckham David W. , Krieg Arthur M. , Ashman Robert F. 
Published: January 2023

AbstractIsolated murine splenic B cells undergo spontaneous apoptosis. Motifs containing unmethylated CpG dinucleotides in bacterial DNA or in synthetic oligodeoxynucleotides (ODN) are known to activate murine B cells. Now we show that ODN that induce spleen B cell cycle entry also inhibit spontaneous apoptosis in a sequence-specific fashion. Reversal of the CG to GC abolished activity. Methylation of the central cytosine decreased activity. When CpG is preceded by a cytosine or followed by a guanine, activity was abolished. Other substitutions at the same positions had no effect. Dose-response curves for apoptosis protection and G1 entry suggested that a uniform population of ODN recognition sites controlled downstream ODN effects. A CpG ODN with a nuclease-resistant phosphorothioate backbone (S-ODN) was also active, and increased the levels of c-myc, egr-1,c-jun, bclXL, and bax mRNA and c-Myc, c-Jun, Bax, and BclXL protein in spleen B cells. Levels of c-myb, myn, c-Ki-ras, and bcl2 mRNA remained unchanged. When protein synthesis was inhibited, at 16 h ODN-induced cell cycle entry was abolished and apoptosis protection was partially preserved. Under these conditions, c-Myc was still present, but c-Jun and BclXL were not detected. Our results suggest that CpG containing ODN motifs provide signals for both survival and cell cycle entry. Single base changes determine whether this signal proceeds through a rate-limiting step governing at least two steps in apoptosis (plasma membrane transition, DNA cleavage) and two phases of the cell cycle (G1 and S phase entry). This biologic action is associated with increased c-Myc, c-Jun, and BclXL expression.
The Regulation of Murine H-2Dd Expression by Activation Transcription Factor 1 and cAMP Response Element Binding Protein
Authors: Ishiguro Nobuhisa , Brown G. Dalon , Ishizu Akihiro , Meruelo Daniel 
Published: January 2023

Abstract
Resistance to radiation leukemia virus (RadLV)-induced leukemia is correlated with an increase in H-2Dd expression on the thymocyte surface. It has been shown that elevated H-2Dd expression on infected thymocytes is a result of elevated mRNA transcription and that the transcriptional increase is correlated with elevated levels of a DNA binding activity, H-2 binding factor 1 (H-2 BF1), which recognizes the 5′-flanking sequence (5′-TGACGCG-3′) of the H-2Dd gene. Recently, it has been shown that the activation transcription factor 1 (ATF-1) homodimer is one form of the H-2 BF1 complex. Here we demonstrate that the cAMP response element binding protein (CREB) homodimer and the heterodimer of CREB/ATF-1 also recognize the cis regulatory motif and are two additional forms of the H-2 BF1 complex. The levels of mRNA encoding ATF-1 and CREB were both increased in RadLV-infected thymocytes that showed increased levels of H-2 mRNA. Also, all three H-2 BF1 binding activities, ATF-1 homodimer, CREB homodimer, and ATF-1/CREB heterodimer, were increased in RadLV-infected thymocytes that expressed high levels of H-2Dd Ag on the cell surface. Transfection experiments demonstrated that ATF-1 and CREB activated a reporter plasmid containing the H-2 BF1 motif. These observations strongly suggest that both ATF-1 and CREB are involved in the regulation of H-2 gene expression following RadLV infection of mouse thymocytes.
The Effect of γδ T Cell Depletion on Cytokine Gene Expression in Experimental Allergic Encephalomyelitis
Authors: Rajan Alice J. , Klein Jonathan D. S. , Brosnan Celia F. 
Published: January 2023

AbstractIn experimental autoimmune encephalomyelitis (EAE), a model for multiple sclerosis, we showed previously that depletion of γδ T cells using the mAb GL3 immediately before disease onset, or during the chronic phase, significantly ameliorated clinical severity. We now report on the effect of γδ T cell depletion on expression of five cytokine genes, IL-1, IL-6, TNF, lymphotoxin, and IFN-γ in spinal cords of mice during the pre-onset, onset, height, and recovery phases of EAE, and on expression of type II nitric oxide synthase. In control animals, the mRNAs for IL-1 and IL-6 rose dramatically at disease onset and peaked before disease height, whereas the mRNAs for TNF, lymphotoxin, and IFN-γ rose more slowly and peaked with peak of disease. In GL3-treated animals, a dramatic reduction in all five cytokines was noted at disease onset, but only IFN-γ remained significantly reduced at a time point equivalent to height of disease in control animals. ELISA data confirmed the reduced levels of IL-1 and IL-6 at disease onset in GL3-treated animals, and pathologic analysis demonstrated a marked reduction in meningeal infiltrates at the same time point. Studies of type II NOS also demonstrated a significant reduction in both mRNA and protein expression at the height of disease in GL3-treated animals. These results suggest that γδ T cells contribute to the pathogenesis of EAE by regulating the influx of inflammatory cells into the spinal cord and by augmenting the proinflammatory cytokine profile of the inflammatory infiltrates.
Role of Mucosal Immunity in Herpes Simplex Virus Infection
Authors: Kuklin Nelly A. , Daheshia Massoud , Chun Sangjun , Rouse Barry T. 
Published: January 2023

Abstract
This study evaluates whether the vaginal mucosal surface of immunized mice can prevent invasion by herpes simplex virus (HSV) and aims to identify immune components that affect immunity after challenge at the vaginal mucosa. Despite the induction of both IgA and IgG vaginal Ab following immunization with recombinant vaccinia virus vectors expressing either glycoproteins B or D, viral infection occurred in most animals even after minimal viral dose challenge. Challenged immune animals, including those genetically unable to generate anti-HSV Ab, survived and showed few if any clinical signs of infection. Experiments with T cell subtype knockout animals and depletion with T cell subset-specific MAb indicated that immunity following vaginal challenge was principally dependent on the function of CD4+ T cells. Our results indicate that anti-HSV vaccines may not provide barrier immunity at the vaginal mucosal site but may be adequate to minimize clinical expression of disease.