bluuebunny/crossref_metadata_2025_split huggingface dataset:
Antigen processing and presentation by human trophoblast-derived cell lines.
Authors: Gobin S J , Wilson L , Keijsers V , Van den Elsen P J 
Published: December 2022

Abstract
The trophoblast-derived choriocarcinoma cell lines JEG-3 and JAR express the nonclassical MHC class I molecules HLA-G (JEG-3) or, at a low level, HLA-E (JAR), but lack expression of the classical MHC class I molecules HLA-A and HLA-B. Expression of these nonclassical MHC class I genes was found to coincide with expression of the genes encoding the peptide transporter associated with Ag processing (TAP). In immunoprecipitation studies, a physical interaction between the TAP complex and HLA-G or HLA-E could be demonstrated. To investigate whether trophoblast-derived cell lines were capable of peptide processing, transport, and loading of MHC class I molecules, HLA-A*0201-expressing transfectants of JEG-3 and JAR were used for functional studies. These transfectants were recognized by both allospecific cytotoxic T cell clones and, after viral infection, by an influenza A matrix peptide-specific cytotoxic T cell clone, indicating that these trophoblast-derived cell lines were capable of presenting endogenously derived peptides in the context of HLA-A*0201. From these observations, it can be inferred that the TAP complex and other molecules involved in Ag processing and presentation by MHC class I molecules are functionally active in these trophoblast-derived cell lines. This implies that trophoblasts are able to provide antigenic peptides for presentation by nonclassical MHC class I molecules that are naturally expressed by this cell type.
Natural killer cell cytolytic activity is inhibited by NKG2-A and activated by NKG2-C.
Authors: Houchins J P , Lanier L L , Niemi E C , Phillips J H , Ryan J C 
Published: December 2022

Abstract
NKG2 is a small family of type II transmembrane proteins possessing extracellular C-type lectin domains expressed primarily on NK cells. The function of these proteins is unknown. We have developed mAbs that recognize NKG2 family members on Western blots. Examination of cell extracts from NK cell clones demonstrates that individual NKG2 family members are expressed on subsets of NK cells. Because the anti-NKG2 mAb do not react with the cell surface Ag, signaling function was studied by generating cell lines that express a chimeric receptor consisting of a cytoplasmic and transmembrane domain from NKG2-A or NKG2-C fused to the extracellular segment of mouse NKR-P1C (NK1.1 Ag). Transfectants of the rat NK cell line, RNK-16, were tested for the effect of anti-NK1.1 mAb on cytolytic activity against the FcR+ target cell lines, P388D1 and P815. The anti-NK1.1 mAb stimulated lytic activity and calcium mobilization in the NK cell line expressing the NKG2-C/NKR-P1C chimeric receptor. By contrast, anti-NK1.1 inhibited the lytic activity and failed to stimulate a calcium response in cells expressing the NKG2-A/NKR-P1C chimeric receptor. Immunoprecipitation experiments demonstrated that the inhibitory cytoplasmic tyrosine phosphatase SHP-1 selectively associates with the NKG2-A/NKR-P1C chimeric receptor, but not with the stimulatory NKG2-C/NKR-P1C receptor. These data indicate that NKG2-A and NKG2-C deliver, respectively, inhibitory and activating transmembrane signals in NK cells.
Gamma delta T lymphocytes regulate the induction and maintenance of oral tolerance.
Authors: Ke Y , Pearce K , Lake J P , Ziegler H K , Kapp J A 
Published: December 2022

Abstract
Oral administration of Ag, over a period of several days, induces a state of tolerance that is associated with activation of CD8+ T cells that can transfer unresponsiveness to naive syngeneic hosts. We previously demonstrated that these T cells are not CTL precursors and that they inhibit responses by CD8+ CTL, as well as Ab and CD4+ T cell responses. Activation of noncytolytic, CD8+ suppressor T cells by oral Ag is a process that is not understood. In these studies, we asked whether depletion of the gamma delta T cells altered induction of oral tolerance. Injection of the anti-delta-chain Ab (GL3) down-modulated the expression of gamma delta TCR and inhibited the induction of oral tolerance to OVA, as measured by Ab, CD4+, and CD8+ T cell responses. GL3 did not activate IL-2 secretion that could be detected in the serum, nor did it induce IL-2R expression by intraepithelial lymphocytes, suggesting that GL3 inhibited the function of gamma delta T cells rather than activating them. This interpretation is supported by our observation that oral administration of Ag did not induce tolerance in TCR-delta knockout mice. These data suggest that gamma delta T cells play a critical, active role in tolerance induced by orally administered Ag.
Crossregulation between T helper cell (Th)1 and Th2: inhibition of Th2 proliferation by IFN-gamma involves interference with IL-1.
Authors: Oriss T B , McCarthy S A , Morel B F , Campana M A , Morel P A 
Published: December 2022

Abstract
The Th1-derived cytokine IFN-gamma inhibits the proliferation of Th2 lymphocytes, but the mechanism of inhibition is not known. Under certain disease conditions, an established Th2-mediated immune response is undesirable and a Th1-mediated response is beneficial. However, established Th2 cells appear to be phenotypically stable. Thus, learning more about cytokine-mediated regulation of established Th2 cells is important if deleterious immune responses are to be altered. We studied the effects of IFN-gamma on a panel of recently derived Th2 lines and clones, as well as a previously established Th2 clone, 13.26. Inhibition by IFN-gamma was observed only when there was a concomitant response to IL-1, a known costimulator of Th2. Clone 13.26 was particularly sensitive to both IL-1 and IFN-gamma, so it was studied in greater detail. We examined cytokine responses using stimulation by anti-TCR mAb-coated plates, or Ag presented by APC populations that do or do not produce IL-1. All IL-1-mediated proliferative responses of 13.26 were inhibited by IFN-gamma, whereas IL-1-independent (IL-4-associated) responses were unaffected. Our data suggest that IFN-gamma inhibits Th2 proliferation through an IL-1-dependent mechanism, and furthermore, that the costimulatory pathways used by APCs may be critical for subsequent Th cell responses to cytokines.
Contact with T cells modulates monocyte IL-10 production: role of T cell membrane TNF-alpha.
Authors: Parry S L , Sebbag M , Feldmann M , Brennan F M 
Published: December 2022

Abstract
IL-10, originally described as a cytokine synthesis inhibitory factor, is secreted by a number of cells of the immune system, including monocytes and T cells. IL-10 is a potent inhibitor of monocyte/macrophage activation, and we have shown previously this cytokine to be a major endogenous down-regulator of TNF-alpha in the rheumatoid joint. The mechanisms involved in regulating IL-10 production by cells of the monocyte/macrophage lineage are not yet clear, and most studies to date have used an exogenous triggering signal such as LPS. In this study, we have investigated the effects of cell-cell contact between human peripheral blood-derived activated T cells and monocytes in regulating monocyte IL-10 production. T cells, prestimulated with anti-CD3 mAb or with phorbol 12,13 di-butyrate and ionomycin, were fixed with glutaraldehyde and then incubated with monocytes. Fixed prestimulated T cells induced monocytes to secrete both IL-10 and TNF-alpha, and in addition, enhanced LPS-stimulated monocyte production of IL-10 and TNF-alpha in a dose-dependent manner. Stimulation of monocyte IL-10 production was abrogated when T cells were separated physically from monocytes within the tissue culture well. Using neutralizing Abs, we show that T cell contact-mediated induction of monocyte IL-10 is partially dependent on endogenous TNF-alpha and IL-1. Furthermore, T cell membrane TNF-alpha was shown to be one of the contact-mediated signals regulating monocyte IL-10 production. Endogenous IL-10 was shown to down-regulate T cell contact-mediated monocyte TNF-alpha production. Collectively, our results demonstrate that an autoregulatory loop exists involving both secreted and membrane-associated forms of IL-10 and TNF-alpha, and suggest that T cell-monocyte cognate interaction may play an important role in the regulation of monocyte cytokine production.
Identification of the rat maternally transmitted minor histocompatibility antigen.
Authors: Bhuyan P K , Young L L , Lindahl K F , Butcher G W 
Published: December 2022

Abstract
The rat maternally transmitted Ag has been previously described as a minor histocompatibility Ag composed of a mitochondrially transmitted factor (MTF) and the RT1.Aa MHC class I molecule. We compared the DNA sequences of the 13 mitochondrial open reading frames from different rat strains and identified four coding polymorphisms that correlated with this MTF. We used synthetic 17-mer peptides spanning the polymorphisms to sensitize appropriate target cells in lymphocytotoxicity assays and found that the MTF is derived from an internal region of ATPase 6. A tridecameric derivative of the ATPase 6 17 mer (termed 13N3E) could sensitize RT1.Aa-expressing target cells at picomolar concentrations and, when present on such cells, could compete fully with the natural ligand in cold-target competition assays. Comparing the 13N3E peptide with the known peptide-binding requirements of RT1.Aa suggested two possible binding conformations, placing either an internal or a C-terminal arginine in the F pocket of the peptide-binding groove. Arguments favoring a "bulging" conformation, with N- and C-terminal residues bound into their conserved pockets, are discussed.
Glucocorticoids inhibit E-selectin expression by targeting NF-kappaB and not ATF/c-Jun.
Authors: Brostjan C , Anrather J , Csizmadia V , Natarajan G , Winkler H 
Published: December 2022

Abstract
E-selectin, an adhesion molecule expressed on the surface of activated endothelial cells, is essential for leukocyte rolling on endothelium which leads to extravasation in the process of inflammation. Induction of E-selectin expression by proinflammatory stimuli such as TNF-alpha or LPS is reduced markedly in the presence of dexamethasone, a synthetic glucocorticoid and potent anti-inflammatory agent. We have investigated the molecular mechanism underlying dexamethasone-mediated E-selectin repression in porcine aortic endothelial cells. Reduced E-selectin protein expression is paralleled by a decrease in E-selectin mRNA and is based on changes in transcription rate. Analysis of the E-selectin promoter revealed that induction by proinflammatory stimuli as well as repression by dexamethasone are mediated by the same promoter region containing three closely spaced binding sites for nuclear factor (NF)-kappaB and an element, NF-ELAM-1 (endothelial leukocyte adhesion molecule-1), constitutively occupied by ATF and c-Jun. NF-ELAM-1 contributes to maximal promoter activity, but does not confer glucocorticoid inhibition, as demonstrated by site-directed mutagenesis. In contrast, transcription directed by the E-selectin NF-kappaB elements is reduced strongly in the presence of dexamethasone, thus identifying NF-kappaB as the primary target for glucocorticoid-mediated E-selectin repression.
Regulation of the expression of cyclooxygenase-2 by nitric oxide in rat peritoneal macrophages.
Authors: Habib A , Bernard C , Lebret M , Creminon C , Esposito B , Tedgui A , Maclouf J 
Published: December 2022

Abstract
Activation of rat peritoneal macrophages by LPS resulted in time-dependent production of nitric oxide and enhancement of cyclooxygenase (Cox) activity. This stimulation was accompanied by increased expression of inducible enzymes, NO synthase, and Cox-2, contrasting with no variation in constitutive Cox-1. Inhibition of NO production in LPS-treated macrophages by either the L-arginine analogue N(G)-monomethyl-L-arginine (L-NMMA) or aminoguanidine was accompanied by an additional enhancement of Cox activity parallel to the expression of Cox-2 protein analyzed by Western blot. Addition of NO donors (3-morpholinosydnonimine (Sin-1), sodium nitroprusside, or S-nitrosoglutathione) reversed the effects of L-NMMA, confirming the role of NO on Cox-2 expression. Specific immunoprecipitation of Cox-2 showed a pattern of protein expression similar to that observed in intact cells. Enzyme activity tested on the immunoprecipitates was correlated with the enzyme mass. In contrast, there was no variation in immunoprecipitated Cox-1 protein or in activity. Levels of mRNA for Cox-2 were increased in macrophages stimulated by LPS in the presence of L-NMMA compared with LPS alone. Metabolic labeling using [35S]methionine showed that inhibition of NO formation resulted in enhanced de novo synthesis of the 35S-labeled Cox-2. The amount of Cox-2 protein induced in the presence or absence of L-NMMA did not change for at least 6 h, suggesting that NO does not modify the t1/2 of the enzyme. These results provide evidence that NO participates in PG production by negative regulation of Cox-2 expression.
Direct demonstration of delayed eosinophil apoptosis as a mechanism causing tissue eosinophilia.
Authors: Simon H U , Yousefi S , Schranz C , Schapowal A , Bachert C , Blaser K 
Published: December 2022

Abstract
Nasal polyps, which often occur in association with allergic rhinitis and asthma, are characterized by a marked infiltration of eosinophils. Using a method for detecting eosinophils with DNA strand breaks, we found direct evidence for inhibition of eosinophil apoptosis in this model of tissue eosinophilia. By using Southern blot analysis linked to reverse transcription-PCR, we detected a mRNA signal specific for IL-5 in all nasal polyps. The identification of IL-5 as a major eosinophil survival factor was confirmed by ELISA measurements using tissue homogenates. Moreover, immunohistochemical analysis of the nasal polyp tissues demonstrated that IL-5 was localized in lymphocytes, mast cells, and eosinophils. Treatment of the eosinophil-infiltrated tissue with neutralizing anti-IL-5 mAb induced eosinophil apoptosis and decreased tissue eosinophilia. Therefore, IL-5 may represent an important cytokine responsible for the delay of the death process in eosinophils in nasal polyps. In addition, a previously suggested IL-4-dependent specific recruitment of eosinophils into the inflamed tissue could be excluded by our studies. Taken together, these findings suggest a novel mechanism by which eosinophils specifically accumulate in pathologic human tissues.
Biologic properties of a bispecific single-chain antibody directed against 17-1A (EpCAM) and CD3: tumor cell-dependent T cell stimulation and cytotoxic activity.
Authors: Mack M , Gruber R , Schmidt S , Riethmüller G , Kufer P 
Published: December 2022

Abstract
Anti-CD3 x anti-tumor-bispecific Abs have been used to redirect cytotoxic T cells to tumor cells in an MHC-unrestricted fashion and to induce their rejection in vivo. We have recently described a recombinant bispecific single-chain Ab that combines four different V regions of two Abs, anti-17-1A and anti-CD3, on one polypeptide chain. It folds correctly to a 60-kDa globular protein and is secreted in fully functional form by a high producer Chinese hamster ovary cell line. In this work, we report that its remarkable cytotoxicity against 17-1A+ tumor cells is exerted via T cells without an apparent engagement of a detectable costimulatory pathway. T cells are activated only by the bispecific Ab when coincubated with 17-1A+ target cells. In a chromium release assay, CD8+ T cells reach maximal tumor cell cytotoxicity within 4 h, while CD4+ T cells need about 20 h to reach similar levels of cytotoxicity. Addition of costimulatory CD28 Abs did not lead to a further increase in cytotoxicity. Its remarkable stability at 37 degrees in serum, the ease of production, and purification by affinity chromatography via polyhistidine tail make this smaller version of a bispecific Ab a promising candidate for a therapeutic trial in patients with solid tumor. Because adjuvant therapy with an intact, much less cytotoxic IgG2a Ab against the 17-1A target had already increased the 7-yr survival of colorectal cancer patients by 30%, the presented small bispecific construct lacking the immunogenic murine Fc region as well as autochthonous T lymphocyte stimulatory activity warrants a therapeutic trial in patients with minimal residual 17-1A+ cancer.
Characterization of the new immunosuppressive drug undecylprodigiosin in human lymphocytes: retinoblastoma protein, cyclin-dependent kinase-2, and cyclin-dependent kinase-4 as molecular targets.
Authors: Songia S , Mortellaro A , Taverna S , Fornasiero C , Scheiber E A , Erba E , Colotta F , Mantovani A , Isetta A M , Golay J 
Published: December 2022

Abstract
Undecylprodigiosin (UP) is the first described member of a family of related compounds showing immunosuppressive activity. We have investigated the biological effect and mechanism of action of UP in human lymphocytes. We show that UP blocks the proliferation of purified peripheral human T and B lymphocytes with an IC50 of 3 to 8 ng/ml and following stimulation by all mitogens used, with no effect on cell death. At the concentrations active on fresh lymphocytes, UP has no significant effect on the proliferation of different leukemic cell lines. UP blocks T cell activation in mid to late G1 phase and before entry into S phase, as shown by analysis of the cell cycle and of the expression of c-myc, IL-2, transferrin receptor, and B-myb. UP inhibits only partially the expression of IL-2R, suggesting that the major target of UP is localized downstream from the interaction between IL-2 and its receptor. The expression of cell cycle genes was investigated. The phosphorylation of the retinoblastoma protein was completely blocked by UP, an event alone sufficient to explain the block of S phase entry and the inhibition of proliferation. The induction of cyclin D2 and the decrease in p27 were not inhibited by UP, whereas the induction of cyclin E, cyclin A, cyclin-dependent kinase-2, and cyclin-dependent kinase-4 was strongly inhibited, potentially explaining the inhibition of retinoblastoma protein phosphorylation. These data clearly show that the site of action of UP is different from that of both cyclosporin A and rapamycin, and that this new class of compounds may, therefore, be good candidates for combined therapy.
CD28 dependence of T cell differentiation to IL-4 production varies with the particular type 2 immune response.
Authors: Gause W C , Chen S J , Greenwald R J , Halvorson M J , Lu P , Zhou X D , Morris S C , Lee K P , June C H , Finkelman F D , Urban J F , Abe R 
Published: December 2022

Abstract
T cell differentiation to effector cell function is required for the development of a type 2 immune response. The T cell surface molecule, CD28, is widely considered to be the principal costimulatory molecule involved in T cell differentiation to effector function, including IL-4 production, although this has been difficult to directly examine in vivo. We have studied in vivo differentiation to T cell effector function during two type 2 immune responses in CD28 knockout mice: the systemic immune response to goat anti-mouse IgD Ab and the mucosal immune response following oral inoculation with the nematode parasite, Heligmosomoides polygyrus. Our results show that in C57BL/6 CD28 knockout mice elevations in IL-4 gene expression and protein secretion are blocked during the immune response to goat anti-mouse IgD, and associated increases in serum IgG1 and IgE are also inhibited to untreated control levels. In marked contrast, T cell differentiation to IL-4 production is comparable in C57BL/6 CD28 -/- and CD28 +/+ H. polygyrus-inoculated mice, and elevations in both serum IgG1 and IgE levels occur. These results indicate that the specific kind of type 2 immune response determines whether T cell differentiation to IL-4 production is CD28 dependent.
Effects of blocking B7-1 and B7-2 interactions during a type 2 in vivo immune response.
Authors: Greenwald R J , Lu P , Halvorson M J , Zhou X , Chen S , Madden K B , Perrin P J , Morris S C , Finkelman F D , Peach R , Linsley P S , Urban J F , Gause W C 
Published: December 2022

Abstract
The costimulatory signal provided to T cells through CD28/CTLA-4 interactions is required for in vivo Th cell effector function associated with cytokine production. However, it is uncertain whether the two well-characterized ligands for these molecules, B7-1 and B7-2, differentially influence the consequent development of a type 1 or a type 2 primary response. We have examined the in vivo effects of blocking B7-1 and/or B7-2 ligand interactions on the type 2 mucosal immune response that follows oral infection of mice with the nematode parasite, Heligmosomoides polygyrus. Administration of the combination of anti-B7-1 and anti-B7-2 Abs inhibited H. polygyrus-induced increases in serum IgG1 and IgE levels, the expansion of mesenteric lymph node (MLN) germinal centers, in situ CD4+ T cell expansion, elevated blood eosinophils, and increased intestinal mucosal mast cells. Similarly, both Abs blocked MLN and Peyer's patch cytokine gene expression and elevations in MLN T cell-derived IL-4 protein secretion. However, in the same experiments, administration of either anti-B7-1 or anti-B7-2 Abs alone had little effect on any of these parameters. T cell and B cell activation was also blocked by the combination of anti-B7-2 and a B7-1-specific mutant Y100F CTLA-4Ig construct. These results suggest that to the extent that anti-B7-1 and anti-B7-2 mAbs block B7 interactions, either B7-1 or B7-2 ligand interactions can provide the required costimulatory signals that lead to T cell effector function during a type 2 in vivo immune response.
Shc mediates IL-6 signaling by interacting with gp130 and Jak2 kinase.
Authors: Giordano V , De Falco G , Chiari R , Quinto I , Pelicci P G , Bartholomew L , Delmastro P , Gadina M , Scala G 
Published: December 2022

Abstract
IL-6 is a multifunctional cytokine involved in hemopoiesis, immune regulation, inflammation, neural development, and infection. IL-6 belongs to a family of related cytokines that includes leukemia inhibitory factor, oncostatin M, IL-11, ciliary neurotropic factor, and cardiotropin-1, all of which initiate signaling through a receptor-associated gp130. IL-6 induces homodimerization of gp130 and activates the Jak/STAT pathway of signal transduction. In addition, IL-6 stimulates the mitogen-activated protein kinases designated ERK (extracellular signal-regulated kinase)-1 and -2. Activation of ERK-1 and -2 may involve the Src homology-2 containing proteins Shc and Grb2. Here we provide evidence that Shc could function as signaling molecules for IL-6 in DeFew-IL-6R/gp130 cells, a human B lymphoma cell line engineered to express high levels of both the IL-6R (p80) and the gp130 subunit. IL-6 was shown to promote the rapid tyrosine phosphorylation of gp130, Jak2, and Shc proteins. Moreover, Shc associated both in vivo and in vitro with phosphorylated gp130 through the Shc-Src homology-2 domain. We also report that Shc bound to activated Jak2 by using the Shc amino terminal phosphotyrosine interaction domain. Following IL-6 stimulation, Shc physically associated with Grb2. Thus, the data point to Shc proteins as a functional link between the Jak2 and Ras pathways of IL-6 signal transduction.