bluuebunny/crossref_metadata_2025_split huggingface dataset:
IFN-gamma and tumor necrosis factor-alpha. Cytotoxicity to murine islets of Langerhans.
Authors: Campbell I L , Iscaro A , Harrison L C 
Published: December 2022

Abstract
We have previously reported that the cytokines IFN-gamma and TNF-alpha each upregulate the expression of class I MHC proteins and, in combination, induce the expression of class II MHC proteins on pancreatic islet cells. IFN-gamma and TNF-alpha are therefore implicated in the immunologic destruction of beta-cells in insulin-dependent diabetes mellitus. The objective of the present study was to define the effects of IFN-gamma and TNF-alpha on the function and viability of murine pancreatic islet beta-cells in vitro. Exposure of islets for 3 days to 200 U/ml of either IFN-gamma or TNF-alpha did not affect glucose-stimulated insulin release, but at higher concentrations (2000 U/ml) of either cytokine there was significant inhibition of glucose-stimulated insulin release. In combination, IFN-gamma and TNF-alpha each at 200 U/ml caused significant inhibition of glucose-stimulated insulin release; at 2000 U/ml glucose-stimulated insulin release was abolished. In time-course experiments, glucose-stimulated insulin release from islets exposed to IFN-gamma and TNF-alpha each at 1000 U/ml was significantly increased at 4-h (twofold increase compared with control islets), decreased back to control levels at 18 h, significantly inhibited by 24 h (threefold decrease compared with control islets), and completely abolished by 48 h. The progressive impairment of beta-cell function mediated by IFN-gamma plus TNF-alpha was associated with morphologic derangement of the islets that were almost totally disintegrated by day 6 of exposure to the cytokines. At day 6, insulin content of the islets was significantly reduced by exposure to TNF-alpha but not IFN-gamma. The combination of IFN-gamma and TNF-alpha resulted in a further dose-dependent depletion in insulin content compared with TNF-alpha alone. The synergistic functional and cytotoxic effects of IFN-gamma and TNF-alpha are consistent with a direct role for these cytokines in the destruction of beta-cells in insulin-dependent diabetes.
Spatial and temporal characteristics of the increase in intracellular Ca2+ induced in cytotoxic T lymphocytes by cellular antigen.
Authors: Gray L S , Gnarra J R , Sullivan J A , Mandell G L , Engelhard V H 
Published: December 2022

Abstract
The increase in intracellular Ca2+ concentration [( Ca2+]i) in cytolytic T lymphocytes in response to target cell binding was investigated by ratio image fluorescence microscopy. Ca2+ mobilization from intracellular stores occurred at a site distal to target cell contact and was transient. Extracellular Ca2+ influx resulted in an increase in [Ca2+]i that was prolonged and distributed more proximal to the target cell. Oscillations in [Ca2+]i were observed after target cell contact, although the periodicity was dependent on the presence of extracellular Ca2+. The Ag-specific reorientation of cytoplasmic granules occurred well after [Ca2+]i had begun to decline to a resting level, but was dependent on extracellular Ca2+. These studies indicate that the Ag-stimulated increase in [Ca2+]i exhibits considerable spatial and temporal variation, and that these characteristics are altered by the availability of extracellular Ca2+. The results also suggest that these changes in [Ca2+]i may play a role in the cytoplasmic events that accompany T cell-mediated cytolysis.
Cell-mediated immune response toward viral envelope and core antigens in gibbon apes (Hylobates lar) chronically infected with human immunodeficiency virus-1.
Authors: Lusso P , Markham P D , Ranki A , Earl P , Moss B , Dorner F , Gallo R C , Krohn K J 
Published: December 2022

Abstract
The specific cellular immune response toward envelope and core proteins of human immunodeficiency virus-1 (HIV-1) was investigated in gibbon apes chronically infected with the HTLV-IIIB isolate. After in vitro stimulation of PBMC from infected and control animals with HIV-1 Ag, DNA synthesis, IL-2R expression and IL-2 release were assayed. Cells from infected gibbon apes demonstrated a group-specific response toward whole virus preparations from three divergent HIV-1 isolates (HTLV-IIIB, HTLV-IIIRF, HTLV-IIIMN). Consistent responses were also detected against purified HIV-1 Ag, i.e., native gp120 envelope glycoprotein, recombinant gp160 glycoprotein, a synthetic peptide (peptide 7) representing a highly conserved region of gp120, and purified native core protein p24. In addition, lymphocytes from infected gibbon apes displayed a specific, MHC-restricted, cytotoxic activity against autologous cells expressing HIV-1 envelope or gag proteins. The specific T cell reactivity toward HIV-1 proteins observed in infected gibbons contrasts with findings in HIV-1 infected humans, and may help to explain the apparent discrepancy in the natural history of the infection between the two species.
Protein synthesis in antigen processing.
Authors: Jensen P E 
Published: December 2022

Abstract
Recent studies indicate that Ag pass through a chloroquine-sensitive intracellular pathway in accessory cells before they are recognized by class II-restricted T cells. Our results indicate that this is also true for insulin. Unexpectedly, we find that protein synthesis is required for optimal accessory cell-dependent processing of insulin and other proteins by adherent macrophages. Treatment of APC with inhibitors of protein synthesis, before and during exposure to Ag, inhibits their subsequent ability to activate murine T cell hybridomas. Experiments are described which suggest that this effect is localized to intracellular processing of Ag rather than uptake or presentation, per se. Inhibition is reversible, and is not observed in special situations where intracellular processing of Ag is not required. A distinct lag period is required for inhibition of processing after inhibition of macrophage protein synthesis. One possible interpretation is that protein synthesis is necessary for maintenance of a labile protein crucial for intracellular processing of Ag. Alternatively, the susceptibility of processing to inhibitors of protein synthesis may reflect an obligate intracellular association of Ag and newly synthesized class II histocompatibility molecules.
Lectin-induced phosphatidylinositol metabolism in lymphocytes is potentiated by macrophages.
Authors: Grier C E , Mastro A M 
Published: December 2022

Abstract
The generation and hydrolysis of phosphatidylinositol 4,5-bisphosphate (PIP2) have been shown to occur early after the stimulation of a variety of cells and to trigger an array of responses, including proliferation in lymphocytes. In this study we examined the requirement for macrophages in the production and metabolism of PIP2 in lectin-stimulated lymph node lymphocytes. When lymph node cells (LNC) were stimulated by the mitogenic lectin, Con A, a two- to threefold increase in [3H]inositol-labeled PIP2 occurred within 15 min, followed by a decrease to the level of unstimulated cells by 30 min. In addition, there was also a two- to threefold increase in the accumulation of [3H]inositol-labeled inositol monophosphate (IP) 30 min after the addition of lectin. However, when the LNC were depleted of macrophages by adherence to plastic and passage over cotton columns before the addition of Con A, the PIP2 response was not seen and the IP accumulation was reduced by 40%. The macrophage-depleted, Con A-stimulated cultures failed to synthesize DNA. [3H]TdR incorporation was only 15% of that of Con A-stimulated unseparated LNC cultures. Soluble IL-2 production was also depressed to 20% of that observed in macrophage-containing cultures. Furthermore, when macrophages (2%) were added to the macrophage-depleted cultures, PIP2 production, IP accumulation, and [3H]TdR incorporation were restored to levels observed in the stimulated unseparated LNC cultures. The addition of IL-1 or the phorbol ester 12-O-tetradecanoylphorbol-13-acetate in combination with Con A also restored both [3H]TdR incorporation and IL-2 synthesis in macrophage-depleted cultures. However, they did so without a detectable increase in phosphatidylinositol metabolism. Collectively, these data suggested that the production and degradation of PIP2 in Con A-stimulated lymphocytes was potentiated by the presence of macrophages.
Impairment of in vitro natural antibacterial activity in HIV-infected patients.
Authors: Tagliabue A , Nencioni L , Mantovani A , Lazzarin A , Villa L , Romano M , Rossini S , Foppa C U , Fanetti G , Masello L C 
Published: December 2022

Abstract
Circulating PBMC of healthy subjects possess an in vitro natural antibacterial (NA) against enteropathogenic bacteria, including Salmonella species. The effector cell of NA activity is a CD: 4+, 8-, Leu-8/TQ-1+ T lymphocyte acting against bacteria via cytophylic IgA in a mechanism similar to antibody-dependent cellular activity. Because AIDS is a profound immunodeficiency caused by HIV involving primarily CD4 lymphocytes and in particular the Leu-8/TQ-1 subset, it was of interest to assess NA activity of HIV+ subjects at various stages of the disease. Results indicate that NA activity against Salmonella typhi and Salmonella paratyphi C is significantly decreased in AIDS as well as in lymphadenopathy syndrome patients. Furthermore, sera containing IgA against salmonellae were not able to arm PBMC from HIV+ patients. The humoral response against S. typhi-LPS was also greatly decreased after HIV infection, in contrast to the known hypergammaglobulinemia seen in these subjects. Defective NA activity might contribute to the increased incidence of salmonellosis observed in AIDS.
Differential functional expression of the C8 subunits. Primary role of C8 beta in assembly of intact C8.
Authors: Densen P , McRill C M 
Published: December 2022

Abstract
The eighth component of C (C8) is composed of two subunits C8 beta and C8 alpha-gamma, which are non-covalently bound in a 1/1 ratio in the intact molecule. The genes encoding the polypeptide chains composing the subunits demonstrate close genetic linkage. To assess the functional expression of these genes at the protein level, normal human serum and C8-deficient sera were electrophoresed in native polyacrylamide gels following which C8, C8 beta, and C8 alpha-gamma were detected using hemolytic overlays. These experiments demonstrated that normal sera contained free C8 alpha-gamma in addition to intact C8. Free C8 alpha-gamma was not observed when C8 was reconstituted by mixing C8 beta-deficient serum with C8 alpha-gamma-deficient serum in a ratio optimized for C8 activity, suggesting that the free C8 alpha-gamma observed in normal serum was not due to dissociation of intact C8. Inasmuch as this technique did not adequately separate C8 and C8 beta, sera were also examined by anion exchange chromatography. C8 alpha-gamma-deficient serum contained C8 beta in a single peak in the 1.4 ms/cm fall through. C8 beta-deficient serum contained a major peak of C8 alpha-gamma at 7.1 ms/cm and a lesser peak coeluting with C9 at 9.5 ms/cm. Normal serum contained both intact C8 eluting between 2.4 to 5.5 ms/cm and C8 alpha-gamma eluting at 7.1 ms/cm. Free C8 beta was not detectable in normal serum indicating that free C8 alpha-gamma was not due to C8 dissociation. Mixing aliquots from the chromatographic peak of C8 beta activity with the peaks of C8 alpha-gamma activity in C8 beta-deficient serum or in normal serum generated intact C8 hemolytic activity. Non-reducing SDS-PAGE and Western blotting with anti-C8 confirmed the presence of antigenic material of appropriate m.w. in each peak. These findings demonstrate that serum contains excess C8 alpha-gamma relative to C8 beta, despite the equimolar presence of the subunits in intact C8. Thus the availability of C8 beta determines the quantity of C8 produced. Further, these data suggest the possibility that the C8 structural genes may be differentially expressed despite their close genetic linkage.
Responsiveness to human mononuclear cell-derived histamine-releasing factor. Studies of allergic status and the role of IgE.
Authors: Baeza M L , Haak-Frendscho M , Satnick S , Kaplan A P 
Published: December 2022

Abstract
Human mononuclear cell-derived histamine-releasing factor (MNC-HRF) has m.w. of 29,000 and 23,000 and two charge species isoelectric at pH 6.9 and 7.3. Minor forms of HRF are also seen at m.w. of 12,000 to 15,000 and 60,000 to 80,000. In this manuscript we have further defined the response of human basophils to MNC-HRF in terms of atopic status of cell donors and the role of IgE antibody. We found that basophils of allergic persons, nonallergic controls, or donors who have positive skin tests but no symptoms, cannot be distinguished based upon responsiveness to HRF. Further, the response of basophils that have been desensitized to anti-IgE is retained when they are subsequently stimulated with HRF derived from human MNC. Thus an interaction with cell-surface IgE to cause histamine release is not evident. Nevertheless, one of two IgE myeloma proteins tested were capable of binding HRF and such binding could be utilized as a purification step. We conclude that MNC-HRF is heterogeneous in terms of size, charge, and affinity for a subpopulation of IgE. Histamine release is more prominent in atopic individuals but does not appear to require an interaction with IgE.
Characterization by monoclonal antibodies of a target cell antigen complex recognized by nonspecific cytotoxic cells.
Authors: Jaso-Friedmann L , Evans D L , Grant C C , St John A , Harris D T , Koren H S 
Published: December 2022

Abstract
Fish nonspecific cytotoxic cells (NCC)3 recognize and lyse a large variety of human and mouse transformed cells. In an effort to determine the Ag recognized by NCC on these targets, mAb were raised against NC-37 target cells. Four anti-NC-37 mAb were chosen for further characterization based on their effects on NCC lysis of target cells. Purified mAb 18C2 and 1E7 (IgM isotype) inhibited NCC killing of the following targets: U937, MOLT-4, K562, HL-60, DAUDI, NC-37, P815, and YAC-1. The dose-dependent inhibitory activity occurred at the target cell level and ranged from 50 to 70% at a concentration of 50 micrograms/well when compared to noninhibitory mAb 7C6 and 1D4 (IgG isotype). Similarly, mAb 18C2 protected the fish parasite Tetrahymena pyriformis from lysis by NCC when compared to mAb 7C6. Adsorption experiments demonstrated that the inhibitory effect on NC-37 lysis by NCC could be removed in a titratable fashion by incubation of mAb 1E7 with any one of the other target cell lines, but it could not be removed by incubation with effector cells. The inhibitory activity of mAb 1E7 and 18C2 was shown to be caused by the inhibition of conjugate formation between effector and NC-37 target cells. The relative membrane concentration of the antigenic determinants recognized by these mAb on the target cells was studied by flow cytometry using FITC-labeled mAb. These experiments showed that all four mAb bound to the surface of the cells tested. Biochemical analysis with Western blots and immunoprecipitation showed that mAb 18C2 and 1E7 recognize two Ag in NC-37 lysates: a larger protein of around 80 kDa and a smaller one of 42 kDa.
Induction of aggregation and enhancement of proliferation and IL-2 secretion in human T cells by antibodies to CD43.
Authors: Axelsson B , Youseffi-Etemad R , Hammarström S , Perlmann P 
Published: December 2022

Abstract
CD43 (large sialoglycoprotein) is a heavily glycosylated protein expressed on virtually all thymus-derived lymphocytes, on a subpopulation of B cells and on granulocytes. Recently, an anti-CD43 mAb (L10) was shown to induce proliferation in T cells comparable to that induced by anti-CD3. The L10 antibody was reported to react with both sialylated and desialylated CD43. In order to further elucidate the role of CD43 in various T cell functions we have studied the biologic properties of two other mAb (B1B6 and E11B, IgG1) directed against sialic acid-dependent epitopes on CD43. Addition of low amounts of antibody (5 to 10 ng/ml) to freshly isolated T cells or to T cell lines resulted in a rapid clustering of the cells. Fab fragments were also active albeit at a 10-fold higher concentration. Aggregation was dependent on active cell metabolism (inhibited by azide and at low temperatures), on the presence of divalent cations (Mg2+) and was inhibited by antibodies to CD18 but not by antibodies to CD11a (leukocyte function-associated Ag-1 alpha). B1B6 and E11B were poorly mitogenic when added alone in soluble form to PBL or to T cells. However, supernatants from cultures of PBL treated with B1B6 for 2 days contained IL-2 activity. No increase in the number of CD25+ cells was seen during the same period. Exogenously added IL-2 did not synergize with B1B6 or E11B in activation of PBL, whereas proliferation was significantly increased by the addition of the antibodies to activation systems with low endogenous production of IL-2 (PMA or soluble anti-CD3). The anti-CD43 antibodies amplified T cell proliferative responses induced by Con A or leukoagglutinin from Phaseolus vulgaris. F(ab')2 fragments enhanced proliferation significantly better than Fab fragments suggesting that cross-linking of CD43 molecules was an essential features of the amplifying signal. Compared with cultures activated by Con A alone, an increased number of CD25+ cells and of blast cells as well as an increased IL-2 production was observed in cultures activated by B1B6-Con A. The results indicate that regulatory signals, which may function to modify homo- or heterotypic T cell adhesion as well as autocrine production of IL-2, can be transduced through CD43.
Degradation of a monoclonal anti-mu chain antibody in a human surface IgM-positive B cell line starts in prelysosomal vesicle.
Authors: Ruud E , Kindberg G M , Blomhoff H K , Godal T , Berg T 
Published: December 2022

Abstract
The surface IgM-mediated endocytosis and intracellular transport of an anti-F(c mu)5 mAb was studied by using subcellular fractionation in sucrose gradients. The results of such experiments showed that antibody was initially endocytosed in vesicles of low density, and later transferred to a presumably lysosomal compartment of higher density. SDS-PAGE analysis of gradient fractions showed that high Mr degradation fragments of the endocytosed antibody were formed in the low density vesicles before terminal degradation could be recorded. The partial degradation of the antibody was not blocked by low temperature or enzyme inhibitors, such as leupeptin and benzyloxycarbonyl-phenylalanylalanine-diazomyethyl-ketone, all of which severely retarded terminal degradation. The data also suggested that the recycling of partially degraded antibody to the cell surface employed a pool of such low density prelysosomal vesicles.
IL-1 signaling for IL-2 production in T cells involves a rise in phosphatidylserine synthesis.
Authors: Didier M , Aussel C , Pelassy C , Fehlmann M 
Published: December 2022

Abstract
Activation of Jurkat T cells with anti-TCR, anti-CD3, anti-CD2, or PHA is accompanied by a strong inhibition of phosphatidylserine (PS) synthesis. The inhibition of the synthesis of this phospholipid could be partially reversed by IL-1. In Jurkat cells, IL-1 did not activate phosphodiesterases as demonstrated by the lack of change of inositol triphosphate and diacylglycerol levels as well as the lack of change in cytosolic Ca2+ concentration. Furthermore, IL-1 did not modify the intracellular level of cGMP and cAMP, suggesting that the observed rise of PS synthesis could play the role of mediator IL-1 action. As PS is a necessary cofactor for the activation of protein kinase C, our results suggest strongly that IL-1 modulate protein kinase C activity in the activated lymphocyte through its action on PS synthesis.
Endocytic pathway of recombinant murine tumor necrosis factor in L-929 cells.
Authors: Mosselmans R , Hepburn A , Dumont J E , Fiers W , Galand P 
Published: December 2022

Abstract
The fate of TNF after binding to the surface of L-929 cells was followed by using murine rTNF coupled to colloidal gold as a probe. A time-course study using electron microscopy was performed. Our results confirm previous indications obtained from biochemical studies suggesting that TNF is internalized by this cell type. They further directly show that internalization proceeds through the classical receptor-mediated endocytosis pathway, i.e., via clathrin-coated structures and endosomes before accumulation in secondary lysosomes.
Relative inefficiency of terminal complement activation.
Authors: Bhakdi S , Fassbender W , Hugo F , Carreno M P , Berstecher C , Malasit P , Kazatchkine M D 
Published: December 2022

Abstract
The efficiency of generation of fluid-phase SC5b-9 and membrane C5b-9(m) complexes relative to cleavage of C3 and C5 was studied. Fluid-phase C activation was induced through addition of purified bacterial Ag to human serum. Sephadex beads were used as particulate activators of the alternative pathway. Rabbit or antibody-coated sheep or human E were used to study formation of cytolytic C5b-9(m) complexes. The molar ratios of C3a:C5a generated in the model systems were found to be in the range of 60 to 200:1 in the case of soluble immune complex activators, and 70 to 150:1 with particulate activators and cells. The efficiency of C5 cleavage relative to C3 cleavage increased on surfaces with the density of antibody and/or C3b-binding sites. With soluble immune complexes, the efficiency of subsequent SC5b-9 generation displayed wide variations dependent on Ag and donor with molar ratios of C5a:SC5b-9 ranging from 30:1 for teichoic acid and sometimes approaching 1:1 for streptolysin-O. In contrast, activation on particles or cells always led to C5a:C5b-9 (calculated as the sum of generated moles SC5b-9 and C5b-9(m] ratios approaching 1:1. Hence, there is an overall inefficiency of terminal sequence activation in the C cascade due first to a dissociation at the level of C5 convertase formation/C5-cleavage and second, to a frequent inefficiency of C5b-utilization in the fluid-phase. The results provide an explanation for the very low levels of SC5b-9 found in plasma of healthy individuals and in patients with C-consuming immune complex disease.
Coxsackievirus B-3-induced myocarditis. Virus and actinomycin D treatment of myocytes induces novel antigens recognized by cytolytic T lymphocytes.
Authors: Huber S A , Heintz N , Tracy R 
Published: December 2022

Abstract
BALB/c mice inoculated with 6 x 10(4) plaque-forming units of a myocarditic variant of Coxsackievirus, group B, type 3 (CVB3M) developed three distinct CTL populations recognizing putative virion (virus specific CTL, VCTL), normally expressed heart (autoreactive CTL, ACTL), and aberrant metabolic (MCTL) Ag. Induction of the MCTL-specific Ag on cardiocytes correlated with the ability of the myocarditic viruses and actinomycin D to interfere with cellular metabolism as measured by 3H-uridine and 3H-leucine incorporation. ACTL specifically lysed uninfected cardiocyte targets, but ACTL Ag expression was lost soon after infection of monocytes only to reappear 6 h later. MCTL and VCTL could be separated by adsorption to myocytes treated with either actinomycin D- or UV-inactivated CVB3M. MCTL cross-reactively lysed myocytes infected with another virus suppressing 3H-uridine incorporation (encephalomyocarditis virus) but failed to react to targets infected with viruses not inhibiting cell metabolism. VCTL specifically lysed only cells infected with the homologous virus. ACTL belonged to the CD8 (Lyt-2+) T cell subset, whereas both VCTL and MCTL were CD4 (L3T4+) T cells.