bluuebunny/crossref_metadata_2025_split huggingface dataset:
Receptor-specific induction of individual AP-1 components in B lymphocytes.
Authors: Huo L , Rothstein T L 
Published: December 2022

Abstract
The inducible nuclear transcription factor complex, AP-1, typically consists of heterodimers between Jun and Fos proteins. Although components are drawn from families of related molecules, little is known about the physiologic regulation of jun- and fos-related gene products. In particular, it is not known whether expression of individual family members is stimulus-specific or whether the same signaling pathways are responsible for induction of all subunits. To clarify these issues, AP-1 components were examined following activation of primary B lymphocytes through two separate receptors, the surface Ig Ag receptor, and the CD40 receptor for T cell influences. Both forms of stimulation led to expression of JunB and JunD mRNA and protein; however, induction of JunB mediated by anti-Ig Ab was protein kinase C (PKC)-dependent, whereas induction mediated by CD40 ligand was resistant to PKC depletion. The two forms of stimulation diverged even further with respect to Fos expression. Although both stimuli induced c-Fos, expression of FosB was stimulus specific at both the mRNA and protein levels, in that this component was induced by anti-Ig but not by CD40 ligand. Stimulated expression of c-Fos and FosB was in all cases PKC-independent. These results provide evidence for receptor-specific differences in the expression of AP-1 components, primarily with respect to FosB. They also indicate that separate intracellular pathways may be used for induction of jun and fos gene products and that the same transcription factor (junB) may be triggered by two surface receptors through separate pathways that differ in PKC dependence.
Potential involvement of IL-10 in suppressing tumor-associated macrophages. Colon-26-derived prostaglandin E2 inhibits TNF-alpha release via a mechanism involving IL-10.
Authors: Kambayashi T , Alexander H R , Fong M , Strassmann G 
Published: December 2022

Abstract
The administration of murine TNF-alpha to colon (C)-26 bearing mice, significantly protects the host against the catabolic effects of the tumor. This effect of exogenous TNF-alpha can be primarily attributed to tumor lysis rather than to a direct anticachectic action. Murine peritoneal macrophages cultured with the C-26 line or with C-26 culture supernatant do not release TNF-alpha in response to LPS stimulation. The reduction in TNF-alpha levels is associated with a significant increase in IL-10 levels. Single cell suspension of freshly disaggregated C-26 tumor (which contains host macrophages), do not produce TNF-alpha but contain significant levels of PGE2 and IL-10. In contrast, PGE2 but not TNF-alpha or IL-10 can be detected in the C-26.IVX cell line that is used to generate tumors in vivo. Neutralizing anti IL-10 Ab but not isotype-matched Ab, significantly reverses the inhibitory effect of the tumor cells and their culture supernatant on macrophage TNF-alpha release. Additional evidence is presented to indicate that the C-26-derived inhibitory activity is related to PGE2. Taken together, these results support the hypothesis that tumor-derived PGE2 prevents tumor-infiltrating macrophages from producing TNF-alpha, in part by augmenting macrophage IL-10 synthesis.
Co-localization of inducible-nitric oxide synthase and Plasmodium berghei in hepatocytes from rats immunized with irradiated sporozoites.
Authors: Klotz F W , Scheller L F , Seguin M C , Kumar N , Marletta M A , Green S J , Azad A F 
Published: December 2022

Abstract
Both CD8+ T cells and IFN-gamma (IFN-gamma) are important components in the regulation of inducible-nitric oxide synthase (iNOS) which contribute to liver stage anti-malarial activity in rodents immunized with irradiated sporozoites. IFN-gamma, provided by malaria-specific CD8+ T cells, stimulates liver cells to produce nitric oxide (NO) for the destruction of infected hepatocytes or the parasite within these cells. To identify the cell source of iNOS in livers from Brown Norway rats challenged with Plasmodium berghei sporozoites, we probed tissue sections with antisera that recognize iNOS and the malarial exoerythrocytic stage parasite. Immunofluorescence analysis of parasitized livers demonstrate that 1) iNOS was found in infected hepatocytes, not Kupffer or endothelial cells; and 2) a higher proportion of infected hepatocytes express iNOS in immunized rats compared with naive animals after challenge. There was no immunoreactivity to the iNOS antisera in liver sections of immunized rats 15 h after sporozoite challenge, however, iNOS activity was present in 18% of the infected hepatocytes by 24 h and reached 81% by 31 h. In contrast, &lt; 10% of the infected hepatocytes displayed iNOS activity in naive or immune animals 48 h after challenge. We also found a significant decrease in the ability of the immunized animals to express iNOS in response to sporozoite challenge by accelerating the removal of pre-existing irradiated-attenuated parasites from hepatocytes with the antimalarial drug, primaquine. Therefore, induction and maintenance of iNOS activity were dependent on intrahepatic persistence of the irradiated-attenuated parasite. These results suggest that liver-iNOS expression following sporozoite challenge is restricted to the infected hepatocyte and dependent on the presence of the irradiated-attenuated parasite in immune animals.
Conserved amino acids in the human granulocyte-macrophage colony-stimulating factor receptor-binding subunit essential for tyrosine phosphorylation and proliferation.
Authors: Ronco L V , Doyle S E , Raines M , Park L S , Gasson J C 
Published: December 2022

Abstract
A superfamily of growth factor and cytokine receptors has recently been identified, which is characterized by four spatially conserved cysteine residues and a tryptophan-serine motif (WSXWS) in the extracellular domain and proline-rich cytoplasmic domain. The high-affinity human granulocyte-macrophage colony-stimulating factor (GM-CSF) receptor, hGM-CSFR, consists of two subunits, alpha (hGM-CSFR alpha), which is required for ligand binding, and beta (hGM-CSFR beta), which is required for signal transduction. Both the alpha and beta subunits are members of the cytokine receptor superfamily. In this study, we analyzed mutations in the conserved amino acids of the alpha subunit to determine their function in signal transduction, as assayed by tyrosine phosphorylation and proliferation. Disruption of either of the conserved disulfide bonds in the extracellular domain abolishes low-affinity binding but not binding to a preformed heterodimeric complex with the beta-chain. Cells expressing receptors with mutations in cysteines 2 or 3 grew as well as cells expressing wild-type receptors in human GM-CSF (hGM-CSF) and phosphorylated the same proteins on tyrosine residues, although the level of phosphorylation may be attenuated; cysteine 3 appears to be required for generation of the true high-affinity binding site. The WSXWS motif and the cytoplasmic domain are required for function of the human GM-CSF receptor, as stable cell lines expressing receptors with these mutations were unable to proliferate continuously in hGM-CSF. Surprisingly, no function for the conserved proline-rich region of the cytoplasmic domain could be ascertained from these studies; cells expressing these receptors were indistinguishable from wild-type in both binding and functional assays.
Inflammatory cytokines induce AIDS-Kaposi's sarcoma-derived spindle cells to produce and release basic fibroblast growth factor and enhance Kaposi's sarcoma-like lesion formation in nude mice.
Authors: Samaniego F , Markham P D , Gallo R C , Ensoli B 
Published: December 2022

Abstract
Homosexual males often present signs of immune activation and are likely to have increased levels of inflammatory cytokines such as IL-1 beta, TNF-alpha, and IFN-gamma. These individuals develop Kaposi's sarcoma (AIDS-KS) more frequently than other HIV-1-infected groups. Our previous work demonstrated that inflammatory cytokines stimulate the growth of spindle cells derived from AIDS-KS lesions (AIDS-KS cells) and that these cells produce high levels of bFGF that mediate autocrine and paracrine (endothelial) cell growth and angiogenesis. Here we show that AIDS-KS cells constitutively produce and release bioactive bFGF in the absence of cell death, and that extracellular bFGF exist in both a soluble and a bound form; the latter can be released by treatment with trypsin, heparin, or heparinase I. Inflammatory cytokines stimulate both the synthesis and release of biologically active bFGF from KS cells and enhance their ability to induce angiogenic KS-like lesions in nude mice. Because bFGF is highly expressed in primary KS lesions, and is a mediator of KS-like lesion formation, these results suggest that the export of bFGF induced by inflammatory cytokines may play a critical role in the induction and progression of KS in HIV-1-infected homosexual men.
Analysis of murine soluble Fc epsilon RII sites of cleavage and requirements for dual-affinity interaction with IgE.
Authors: Bartlett W C , Kelly A E , Johnson C M , Conrad D H 
Published: December 2022

Abstract
The low-affinity receptor for IgE (Fc epsilon RII/CD23) is a type II integral membrane protein with an extracellular C-terminal sequence homologous to C-type animal lectins. Between this region and the membrane is a repetitive sequence predicted to form an alpha-helical coiled-coil and is termed the stalk region. The Fc epsilon RII is proteolytically cleaved when at the cell surface in this stalk region. Both the 38 Kd and 28 Kd major released fragments were isolated from culture media and N-terminal sequencing demonstrated that the cleavage sites were in the third and fourth repeat domains, respectively. The identified sites show no apparent similarity with the cleavage sites previously identified in human Fc epsilon RII. Recent studies have demonstrated that the intact Fc epsilon RII interacts with IgE with a dual-affinity, resulting from a multivalent interaction with the IgE Fc region; mutant Fc epsilon RII that have a disruption of the alpha-helical coiled-coil have a single low-affinity interaction consistent with a monomeric interaction with IgE. The soluble Fc epsilon RII were shown to interact with IgE with an affinity similar to these mutant Fc epsilon RII. Preparation of a chimeric Fc epsilon RII in which the transmembrane and cytoplasmic regions were replaced with sequences from Ly-49 revealed that these regions played no role in the multimeric association of the Fc epsilon RII necessary for dual-affinity interaction with IgE. In addition, a full-sized soluble Fc epsilon RII construct was expressed, and this molecule demonstrated increased capacity to interact with IgE.
Recently activated naive CD4 T cells can help resting B cells, and can produce sufficient autocrine IL-4 to drive differentiation to secretion of T helper 2-type cytokines.
Authors: Croft M , Swain S L 
Published: December 2022

Abstract
Development of T cells during primary responses was investigated using pigeon cytochrome C-specific naive Th from TCR transgenic mice. Naive CD4 cells did not activate and help resting B cells. This failure was found to be primarily because the resting B cells were incapable of stimulating the naive Th. Provision of a costimulatory signal such as anti-CD28, or addition of APCs that express costimulatory molecules, such as dendritic cells, activated B cells, and B7+ and B7+ICAM(+)-expressing fibroblasts, induced naive Th activation and promoted T cell-dependent help for IgM secretion. T cell activation for as little as 24 h promoted helper activity, and Ig secretion required production of small amounts of IL-4 by the activated naive Th. On initial stimulation, naive Th secrete only IL-2. By mRNA analysis, activated naive Th were also shown to produce IL-4, however induction of IL-4 message only occurred 24 h after initial activation and required additional stimulation with Ag. A single exposure of naive CD4 to Ag/APC followed by 4 to 12 days in culture led to generation of effector Th which secreted IL-2 and some IFN-gamma, and no detectable IL-4 or IL-5, and which could only help B cells to IgM secretion. In contrast, similar cultures that received Ag/APC one or more times during this period generated effector cells capable of secreting easily detectable titers of IL-4 and IL-5, as well as IL-2 and IFN-gamma, and able to now promote IgG1 and IgE responses. Generation of these Th0-like effectors was accompanied by increasing amounts of IL-4 secreted during the culture period after each restimulation, and addition of anti-IL-4 in culture inhibited development of the capacity to produce Th2 cytokines. These studies reinforce the notion that naive CD4 must interact with a costimulatory professional APC, rather than a resting B cell, for initiation of the primary response, but show that such an interaction can result in rapid development of the ability to interact with and provide cognate help to B cells. They also suggest that if activated naive CD4 cells receive multiple stimulations from Ag/APC, enough endogenous IL-4 can be produced to drive differentiation into effectors secreting type 2 cytokines. The existence of such an autocrine feedback mechanism suggests that the amount and availability of Ag could influence the nature and polarization of the Th response.
Normal adult ramified microglia separated from other central nervous system macrophages by flow cytometric sorting. Phenotypic differences defined and direct ex vivo antigen presentation to myelin basic protein-reactive CD4+ T cells compared.
Authors: Ford A L , Goodsall A L , Hickey W F , Sedgwick J D 
Published: December 2022

Abstract
Ramified microglia in the adult central nervous system (CNS) are the principal glial element up-regulating MHC class I and II expression in response to inflammatory events or neuronal damage. A proportion of these cells also express MHC class II constitutively in the normal CNS. The role of microglia as APCs for CD4+ T cells extravasating into the CNS remains undefined. In this study, using irradiation bone marrow chimeras in CD45-congenic rats, the phenotype CD45lowCD11b/c+ is shown to identify microglial cells specifically within the CNS. Highly purified populations of microglia and nonmicroglial but CNS-associated macrophages (CD45highCD11b/c+) have been obtained directly from the adult CNS, by using flow cytometric sorting. Morphologically, freshly isolated microglia vs other CNS macrophages are quite distinct. Of the two populations recovered from the normal CNS, it is the minority CD45highCD11b/c+ transitional macrophage population, and not microglia, that is the effective APC for experimental autoimmune encephalomyelitis-inducing CD4+ myelin basic protein (MBP)-reactive T cells. CD45highCD11b/c+ CNS macrophages also stimulate MBP-reactive T cells without addition of MBP to culture, suggesting presentation of endogenous Ag. This is the first study in which microglia vs other CNS macrophages have been analyzed for APC ability directly from the CNS, with substantial cross-contamination between the two populations eliminated. The heterogeneity of these populations in terms of APC function is clearly demonstrated. Evidence is still lacking that adult CNS microglia have the capacity to interact with and stimulate CD4+ T cells to proliferate or secrete IL-2.
Expression and function of mouse Fas antigen on immature and mature T cells.
Authors: Nishimura Y , Ishii A , Kobayashi Y , Yamasaki Y , Yonehara S 
Published: December 2022

Abstract
We prepared mAbs specific for the mouse Fas Ag (CD95) and used them to analyze the expression and apoptosis-inducing activity of the Fas Ag on murine immunocytes. Cytofluorometry of mouse bone marrow, thymus, and splenocytes using the mAbs indicated that cells of the T lineage, except for bone marrow cells, expressed Fas Ag on the surface. CD4-CD8- undifferentiated thymocytes expressed low levels of Fas Ag. Immature CD4+CD8+ thymocytes and mature CD4+CD8- and CD4-CD8+ thymocytes were highly positive for Fas Ag. CD4+CD8+ thymocytes were specifically sensitive to the apoptosis-inducing activity of anti-Fas, although CD4-CD8-, CD4+CD8-, and CD4-CD8+ thymocytes were resistant. Spleen T cells were resistant to anti-Fas, whereas they expressed Fas Ag. The superantigen, staphylococcal enterotoxin B (SEB) administered to BALB/c mice, induced clonal expansion and successive clonal deletion of spleen T cells bearing the V beta 8 TCR, which specifically reacts to SEB. Such clonal deletion of V beta 8 T cells was highly suppressed in lpr mice, which have defects in the Fas Ag gene. In SEB-administrated BALB/c mice, expression of Fas Ag was significantly enhanced on V beta 8, but not on V beta 6 T cells, which cannot react to SEB. Moreover, V beta 8 T cells in SEB-primed mice were sensitive to the cell-killing activity of anti-Fas, although V beta 6 T cells were resistant. These findings show that the expression level and apoptosis-inducing activity of Fas Ag on peripheral T cells are directly up-regulated by stimulation through the TCR in vivo.
B cell selection and allelic exclusion of an anti-DNA Ig transgene in MRL-lpr/lpr mice.
Authors: Roark J H , Kuntz C L , Nguyen K A , Mandik L , Cattermole M , Erikson J 
Published: December 2022

Abstract
We have used an Ig transgene (VH3H9) that increases the frequency of anti-DNA autoantibodies to address whether the production of antinuclear Abs in systemic lupus erythematosus is the consequence of a breakdown of B cell tolerance. We have shown that nonautoimmune mice regulate anti-DNA B cells, and that lupus-prone MRL-lpr/lpr mice are defective in this regulation. Here we show that a subset of anti-DNA B cells, namely those that stain nuclei in a homogeneous fashion, not only fail to be deleted in MRL-lpr/lpr mice, but undergo preferential clonal expansion. In addition, we describe a surprising finding: the VH3H9 transgene is less efficient at inhibiting endogenous heavy chain gene rearrangement on the autoimmune-prone MRL-lpr/lpr genetic background than on the nonautoimmune BALB/c background.
Retargeting of CTL by an efficiently refolded bispecific single-chain Fv dimer produced in bacteria.
Authors: Kurucz I , Titus J A , Jost C R , Jacobus C M , Segal D M 
Published: December 2022

Abstract
A single-chain bispecific Fv dimer (bs(sFv)2) having specificity for mouse CD3 epsilon chain and human transferrin receptor was produced in bacterial inclusion bodies. To overcome difficulties associated with in vitro protein folding, we used a novel renaturation approach to obtain active bs(sFv)2. The protein was dissolved in the weak ionic detergent sodium lauroylsarcosine, and disulfides were formed by oxidation in air. After oxidation, the bs(sFv)2 exhibited very little covalent aggregation and migrated as a single species in nonreducing SDS-PAGE, suggesting that disulfides were correctly paired. The detergent was removed using an ion exchange resin and the protein fractionated by size exclusion chromatography. The recovered 65-kDa protein was monomeric in non-denaturing solvent, homogeneous by SDS-PAGE, and comprised 15 to 20% of material applied to the gel filtration column. This protein bound specifically to both mouse CD3 epsilon chain and human transferrin receptor with affinities indistinguishable from those of the parental Fabs or single-chain Fvs. The bs(sFv)2 specifically redirected mouse cytotoxic T cells to lyse target cells expressing human transferrin receptor at picomolar concentrations. Bacterially produced and detergent oxidized bs(sFv)2 molecules may therefore provide the abundant amounts of homogeneous active material required to redirect cytotoxic cells against tumors and other unwanted cells in animal models and in patients.
Molecular cloning and functional characterization of human lymphotactin.
Authors: Kennedy J , Kelner G S , Kleyensteuber S , Schall T J , Weiss M C , Yssel H , Schneider P V , Cocks B G , Bacon K B , Zlotnik A 
Published: December 2022

Abstract
We describe the isolation of a cDNA that encodes human lymphotactin (Ltn), a new class of lymphocyte-specific chemokine. Human Ltn shows similarity to some members of the C-C chemokine family but has lost the first and third cysteine residues that are characteristic of the C-C and C-X-C chemokines. Ltn is chemotactic for lymphocytes but not for monocytes, a characteristic that makes it unique among chemokines. In addition, calcium flux desensitization studies indicate that Ltn uses a unique receptor. The human Ltn gene maps to a different chromosome than do the C-C and C-X-C chemokine families. Taken together, these characteristics indicate that Ltn is the first example of a new class of human chemokines with preferential effects on lymphocytes.
Genetic immunization against herpes simplex virus. Protection is mediated by CD4+ T lymphocytes.
Authors: Manickan E , Rouse R J , Yu Z , Wire W S , Rouse B T 
Published: December 2022

Abstract
Plasmid DNA encoding proteins represent a convenient novel approach to vaccination. We have investigated this "genetic immunization" approach as a means to protect against herpes simplex virus (HSV) infection using a mouse zosteriform model that mimics several aspects of reactivated HSV infection of humans. After i.m. immunization with plasmid DNA-encoding glycoprotein B (gB), (pc-gB), 80% of BALB/c mice were completely protected and lesions were delayed in the remaining animals. Upon pc-gB vaccination, the animals developed both gB- and HSV-specific IgG Ab response and the isotype examination revealed a predominance of IgG2a. These mice also have low levels (1/16) of HSV-neutralizing Abs. Immune splenocytes obtained from pc-gB-immunized mice, when restimulated in vitro with HSV resulted in production of type 1 cytokines. Evidence for CD(8+)-mediated cytotoxic T lymphocyte response was equivocal. Protection could be adoptively transferred to nude mice recipients by CD4+ T cells from pc-gB-immunized mice but not by CD8+ T cells. Our results demonstrate that genetic immunization is a potent means of inducing protection against HSV and that the mechanism of immunity responsible for clearing virus from cutaneous sites is principally by CD4+ T cells. It is likely that these cells are Th1 cells because type 1 cytokines were the major cytokines detected upon in vitro Ag stimulation.
Contribution of the TCR alpha-chain to the differential recognition of bacterial and retroviral superantigens.
Authors: Daly K , Nguyen P , Hankley D , Zhang W J , Woodland D L , Blackman M A 
Published: December 2022

Abstract
The TCR alpha-chain has been implicated in superantigen recognition by some T cells. In this study, recognition of a retroviral (minor lymphocyte stimulating Ag-1, Mls-1) and a bacterial (staphylococcal enterotoxin B, SEB) superantigen by T cells expressing an identical (transgenic) V beta 8.1 beta-chain and either a V alpha 2+ or V alpha 11+ alpha-chain have been compared. Individual hybridomas were found to vary in their recognition of the two superantigens. Whereas some T cell hybridomas recognized both superantigens comparably, other hybridomas preferentially recognized either Mls-1 or SEB, indicating that the contribution of the TCR alpha-chain to recognition of these superantigens is not equivalent. The degree of heterogeneity in recognition varied between the V alpha 2+ and V alpha 11+ hybridomas, although there were individual hybridomas within each group with distinct patterns of reactivity that varied only in CDR3 alpha. These data are consistent with recent evidence that recognition of Mls-1 and SEB involves distinct TCR/MHC interactions.