bluuebunny/crossref_metadata_2025_split huggingface dataset:
IFN-gamma inhibits thrombin- and endotoxin-induced plasminogen activator inhibitor type 1 in human endothelial cells.
Authors: Gallicchio M , Hufnagl P , Wojta J , Tipping P 
Published: December 2022

Abstract
The plasmin/plasminogen system of enzymes may be involved in leukocyte migration through the endothelial cell layer of the vascular wall during inflammatory processes associated with vascular injury, atherosclerosis, and sepsis. Synthesis of plasminogen activator inhibitor type 1 (PAI-1) by the endothelium may protect these cells and the subendothelial cell matrix from excessive degradation and retard leukocyte migration. We report in this work for the first time the down-regulation of both basal and thrombin- or endotoxin-induced PAI-1 in cultured human endothelial cells by the activated T cell product, IFN-gamma. Down-regulation of basal and thrombin- or endotoxin-induced endothelial PAI-1 protein by IFN-gamma was found to be both time and dose dependent. Decreases of up to 71% relative to thrombin- or endotoxin-treated controls, using an optimal IFN-gamma concentration of between 20 and 200 U/ml, were found for human macrovascular and microvascular endothelial cells. However, IFN-gamma did not appear to affect IL-1 alpha- and TNF-alpha-induced levels of PAI-1 protein or mRNA in these cells. Northern blot analysis paralleled protein results, showing decreases in specific endothelial cell thrombin- or LPS-induced PAI-1 mRNA expression, respectively, after incubation with IFN-gamma for 24 h. These results suggest a means by which the migration of circulating leukocytes through endothelial cell layers during inflammation may be facilitated.
Growth regulatory pathways in myeloma. Evidence for autocrine oncostatin M expression.
Authors: Westendorf J J , Jelinek D F 
Published: December 2022

Abstract
Expression of autocrine growth factors by myeloma cells is an important mechanism that may contribute to tumor expansion. IL-6 is one of several cytokines that uses the signal transducer gp130 as a receptor component. Of these cytokines, those that have been shown to be paracrine growth factors for some myeloma cells include IL-6, IL-11, ciliary neurotrophic factor, leukemia inhibitory factor, and oncostatin M (OSM). Only IL-6, however, has been identified as an autocrine growth factor for myeloma cells. In this study we used a panel of three IL-6-responsive myeloma cell lines to investigate the expression of other autocrine growth factor loops. Initial studies employing neutralizing mAbs to IL-6 or gp130 revealed that the growth of the DP-6 and KP-6 cell lines was inhibited by both mAbs, whereas the growth of the KAS-6/1 cell line was inhibited only by the anti-gp130 mAb. Anti-OSM neutralizing mAb also inhibited KAS-6/1 cell growth. Autocrine OSM production by the KAS-6/1 cells was confirmed using a sensitive ELISA. Although the anti-OSM mAb had no significant effects on KP-6 and DP-6 cell growth, OSM was detected in DP-6 supernatants. These results suggest that OSM production and responsiveness by myeloma cells are distinct phenotypes and not necessarily related in all myeloma cells. Finally, we analyzed the significance of OSM-mediated myeloma cell growth by assessing the effects of OSM on normal, in vitro-generated plasmablasts. OSM markedly enhanced plasmablast Ig secretion but did not affect growth. Thus, the nature of the response elicited by OSM in myeloma cells is distinct from its effects on normal B lineage cells. Moreover, because gp130-mediated signaling results in myeloma cell growth, autocrine expression of any gp130-utilizing cytokine has the potential to significantly augment tumor expansion.
Zinc enhances lipopolysaccharide-induced monokine secretion by alteration of fluidity state of lipopolysaccharide.
Authors: Wellinghausen N , Schromm A B , Seydel U , Brandenburg K , Luhm J , Kirchner H , Rink L 
Published: December 2022

Abstract
Elevated zinc serum concentrations have been shown to restore impaired immune response. Therefore, pharmacologic zinc supplementation has been used to improve immune function, particularly in intensive care patients. In these patients, Gramnegative sepsis, the symptoms of which are predominantly caused by LPS-induced release of monokines, represents a serious problem. We have recently shown that zinc enhances induction of TNF-alpha and IL-1 beta in cultures of PBMC by LPS. By fluorescence polarization and infrared spectroscopic measurements we found that zinc addition leads to decreased fluidity of the hydrocarbon chains of LPS. Experiments at different temperatures showed that the less fluid gel (beta) phase of LPS is more effective in cytokine induction than the more fluid liquid-crystalline (alpha) phase. Our studies suggest that the synergistic effect of zinc on monokine induction by LPS is caused by direct interaction of zinc with LPS altering the fluidity of the hydrocarbon chains. Although this effect is zinc specific, other divalent ions, like cobalt and nickel, with a complex structure and size comparable to those of zinc also enhance LPS-induced monokine secretion but to a much lesser extent. Our data indicate that the zinc level represents a relevant clinical parameter in the treatment of Gram-negative infection. This reveals potential risks in the therapeutic application of zinc.
Herpesvirus saimiri-transformed human CD4+ T cells can provide polyclonal B cell help via the CD40 ligand as well as the TNF-alpha pathway and through release of lymphokines.
Authors: Saha K , Ware R , Yellin M J , Chess L , Lowy I 
Published: December 2022

Abstract
We have developed human CD4+ T cell lines from the PBL of normal donors by infection with Herpesvirus saimiri (HVS), to evaluate functional properties of these immortalized lymphocytes. In this report, we characterize two such CD4+ T cell lines, CHCD4 and MHCD4, which were derived from two different donors. These cells grew independent of exogenous IL-2 stimulation for over 1 yr, and expressed surface markers (CD25+, CD69+, HLA-DR+, and B7+) associated with an activated T cell phenotype. Both lines constitutively produced and released IFN-gamma, but no IL-2 or IL-4. However, the surface expression of the two cell lines differed in that CHCD4 constitutively expressed CD40 ligand (CD40L) and membrane TNF-alpha, but MHCD4 did not. Also, CHCD4, but not MHCD4, potently induced polyclonal B cell activation and differentiation in the absence of PWM, in an MHC-unrestricted fashion. The B cell help afforded by CHCD4 included contact-dependent and soluble components. Contact-dependent help was strongly inhibited by mAb against CD40L (5C8) and to a lesser extent, by anti-TNF-alpha Ab. The CD40L-dependent helper function of CHCD4 contrasts with the recent description of other HVS-transformed CD4+ T cells that provide B cell help primarily via the membrane TNF-alpha and TNF-alphaR pathways. Furthermore, CHCD4 cells also secreted soluble factors that could mediate CD40-linked B cell differentiation into Ab-producing cells. Interestingly, this factor is not likely to be IL-2, IL-4, IL-6, IL-10, IL-15, TNF-alpha, or IFN-gamma as Abs against these cytokines were not able to inhibit the contact-independent B cell help by CHCD4. These results indicate that HVS-immortalization of CD4+ lymphocytes may produce T cell clones with a spectrum of important contact-dependent, as well as contact-independent, B cell helper function capacities.
Human umbilical vein endothelial cells possess binding sites for the globular domain of C1q.
Authors: Peerschke E I , Smyth S S , Teng E I , Dalzell M , Ghebrehiwet B 
Published: December 2022

Abstract
Binding sites for both the collagen-like and globular domains of C1q have been described on a variety of cell types. HUVEC were previously shown to express the 60- to 67-kDa receptor recognizing the collagen-like domain of C1q. This study demonstrates the presence of a distinct 28- to 33-kDa HUVEC protein (gC1qR) that interacts with the globular head domain of C1q. Polyclonal Abs raised against the Raji cell gC1qR partially inhibited HUVEC interaction with immobilized C1q and recognized a 28- to 33-kDa protein on Western blots. The Ab also reacted strongly with poly-L-lysine-immobilized, glutaraldehyde-fixed, intact HUVEC in ELISA assays. No significant difference in reactivity was noted if HUVEC were permeabilized with 0.2% Triton X-100. However, unfixed HUVEC grown on gelatin-coated microtiter wells to 80% confluence failed to express significant amounts of gC1qR Ag. Quantitation of HUVEC gC1qR by gel scanning suggested the presence of 5.7 +/- 3.8 x 10(6) molecules/cell (mean +/- SD; n = 4). A quantitative sandwich ELISA procedure, however, detected only 3.7 +/- 0.6 x 10(5) gC1qR molecules/cell (mean +/- SD; n = 4), consistent with previously described gC1qR multimerization. The capacity of endothelial cells to recognize both the collagen-like and globular domains of C1q via distinct binding sites may have implications for the role of C1q in vascular inflammatory and thrombotic lesions.
T cell-derived IL-10 antagonizes macrophage function in mycobacterial infection.
Authors: Murray P J , Wang L , Onufryk C , Tepper R I , Young R A 
Published: December 2022

Abstract
Pathogenic mycobacteria survive within macrophages despite T cell responses that activate host defenses against most pathogens. Among cytokines produced by T cells, IL-10 is known to negatively regulate Th1 cells as well as macrophages. IL-10 has been shown to inhibit the anti-mycobacterial activity of macrophages in vitro and could account for the ability of mycobacteria to survive intracellularly. To test the inhibitory functions of IL-10 in vivo, transgenic mice that secrete IL-10 from the T cell compartment were constructed and infected with Calmette-Guérin bacillus (Mycobacterium bovis). These mice were unable to clear the infection and developed large bacterial burdens. Nonetheless, their T cells produced abundant amounts of IFN-gamma and IL-2 in response to Ag challenge. These results indicate that the presence of excess IL-10 had little, if any, effect on T cell function or development during the immune response to Calmette-Guérin bacillus. Rather, the data suggest that IL-10 helps maintain mycobacterial infections by acting primarily at the level of the macrophage, overriding anti-mycobacterial signals delivered by IFN-gamma.
The maternal immune system's interaction with circulating fetal cells.
Authors: Bonney E A , Matzinger P 
Published: December 2022

Abstract
Although female mice readily reject organs from allogeneic or semiallogeneic male donors, they do not reject the fetuses sired by those same donors. An explanation for this that has been made in the past is that the fetus influences its mother's immune response by sending fetal cells into the maternal circulation. To determine the frequency and magnitude of fetal to maternal cell migration, we employed a sensitive quantitative PCR technique to assess the numbers of male cells in the thymus, spleen, liver, lymph nodes, and peripheral blood of normal mice undergoing their first pregnancy. We found that fetal cell migration is not universal but occurs in only a fraction of pregnancies. Using a kinetic analysis of normal mice mated to syngeneic or allogeneic males, a comparison of normal and SCID mice, and testing of multiparous mice for CTL against fetal Ags, we found that migrating fetal cells were cleared by the maternal immune system. Thus the mother is not continuously exposed to circulating fetal cells and, in fact, has the capacity to eliminate them without eliminating the fetus.
IgH gene rearrangements on the unexpressed allele in rabbit B cells.
Authors: Tunyaplin C , Knight K L 
Published: December 2022

Abstract
VDJ genes are assembled in two sequential DNA recombination steps, rearrangement of D and J(H) gene segments followed by rearrangement of a V(H) gene segment. In mouse and human, VDJ gene rearrangements occur in a regulated step in which D rearranges to J(H) on both alleles before V(H) rearranges to DJ. To determine how VDJ gene rearrangements are regulated in the rabbit, we studied the IgH gene rearrangements in rabbit B cells by examining the gene rearrangement on the unexpressed allele in rabbit hybridomas. By Southern blot analysis with probes from the J(H) and 3'V(H)1 regions, we found that approximately 50% of the hybridomas had DJ gene rearrangements on the unexpressed allele, whereas the remaining 50% did not rearrange either J(H) or V(H) genes. Unexpectedly, we found a VD gene rearrangement on the unexpressed allele of a rabbit B cell line, so we PCR-amplified the VD gene rearrangements from splenocyte DNA and found a few VD gene rearrangements in normal B cells as well. The data taken together show that IgH gene rearrangements in rabbit B cells are regulated differently than those in the mouse, and we hypothesize that in some B cells, VDJ gene rearrangements proceed through a VD intermediate rather than through a DJ intermediate.
Structurally similar TCRs differ in their efficiency of positive selection.
Authors: Yelon D , Berg L J 
Published: December 2022

Abstract
Studies of TCR transgenic mice have demonstrated that in these systems positive selection is not an efficient process. The capacity of the thymus to produce mature T cells is limited, even when all immature thymocytes express appropriate Ag receptors. Analysis of TCR transgenic mice expressing reduced levels of MHC molecules have shown that MHC surface density can be a limiting factor during development. Whether peptide availability in the thymus also limits the efficiency of positive selection remains controversial. Here, we examine the efficiency of positive selection in three similar lines of TCR transgenic mice, all of which express V alpha11/beta3+ TCRs specific for cytochrome c peptides bound to I-Ek. We demonstrate that thymocytes expressing these similar TCRs mature with very different efficiencies in H-2k mice. Furthermore, efficient positive selection of thymocytes expressing these three TCRs varies in its dependence on MHC density. These data suggest that similar TCRs can differ in their degree of specificity for peptide/MHC complexes during positive selection; some TCRs may require specific complexes for selection while other TCRs are more promiscuous in their thymic interactions. Alternatively, these three TCRs may differ in their affinities for positively selecting ligands.
Perforin, Fas/Fas ligand, and TNF-alpha pathways as specific and bystander killing mechanisms of hepatitis C virus-specific human CTL.
Authors: Ando K , Hiroishi K , Kaneko T , Moriyama T , Muto Y , Kayagaki N , Yagita H , Okumura K , Imawari M 
Published: December 2022

Abstract
In chronic hepatitis C, Fas expression is up-regulated in the hepatocytes, especially near liver-infiltrating lymphocytes, and Fas ligand is expressed on the lymphocytes. The presence of hepatitis C virus (HCV)-specific CTLs has been demonstrated both in peripheral blood and among liver-infiltrating lymphocytes of patients with chronic hepatitis C. We studied the killing mechanisms of HCV-specific human CTLs using target cells that were sensitive or resistant to agonistic anti-Fas Abs and TNF-alpha. We show that HCV-specific CTL clones kill non-Ag-bearing bystander cells as well as Ag-bearing cells, although the bystander killing is less efficient than the specific target cell killing, and the efficacy of the bystander killing of anti-Fas- and soluble TNF-alpha-sensitive cells is greater than that of resistant cells. We also show that the killing of Ag-presenting, sensitive cells is mediated by Fas ligand and TNF-alpha as well as perforin, although the latter plays a major role in the killing at a low E:T ratio, and that the killing of sensitive bystander cells is primarily mediated by Fas ligand and TNF-alpha on CTLs expressed upon specific Ag stimulation, which may be relevant to the bystander lysis by HCV-specific CTLs of uninfected hepatocytes, in which Fas expression is up-regulated. Activated CTLs also kill bystander cells by the perforin-based mechanism, although it requires a high E:T ratio. The effective bystander killing requires a close intercellular contact between CTLs and target cells, although TNF-alpha released from the CTLs mediates lysis of the bystander cells without a close cell-cell contact.
Role of CD19 tyrosine 391 in synergistic activation of B lymphocytes by coligation of CD19 and membrane Ig.
Authors: Li X , Sandoval D , Freeberg L , Carter R H 
Published: December 2022

Abstract
CD19 and CD21, which form a complex on B lymphocytes, are required for normal Ab responses to T-dependent Ags. Coligation of the CD21/CD19 complex with membrane IgM (mIgM) powerfully enhances B cell activation in vitro and in vivo. To determine how CD19-mIgM synergy is produced, we examined immediate and downstream signaling events after ligation of either complex alone or after CD19-mIgM coligation in normal and lymphoblastoid B cells. Ligation of mIgM alone is known to result in tyrosine phosphorylation of CD19 and association of CD19 with phosphatidylinositol 3-kinase and Vav, and these events are not enhanced by coligation. In contrast, tyrosine phosphorylation of phosphatidylinositol 3-kinase and Vav is markedly enhanced after CD19-mIgM coligation. Coligation also results in synergistic, prolonged enhancement of mitogen-activated protein kinase activity, relative to ligation of either receptor complex alone. Mutation of CD19 Y391, the site at which Vav binds, but not mutation of CD19 Y482 and Y513, the sites of association with phosphatidylinositol 3-kinase, blocks the enhancement of mitogen-activated protein kinase activation. These findings suggest that the synergistic enhancement of B cell activation following CD19-mIgM coligation results from greater tyrosine phosphorylation of Vav and Vav-dependent enhanced activation of mitogen-activated protein kinases.
IFN-gamma-deficient mice develop experimental autoimmune uveitis in the context of a deviant effector response.
Authors: Jones L S , Rizzo L V , Agarwal R K , Tarrant T K , Chan C C , Wiggert B , Caspi R R 
Published: December 2022

Abstract
Experimental autoimmune uveitis (EAU) is a T cell-mediated disease that targets the neural retina and serves as a model of human uveitis. Uveitogenic effector T cells have a Th1-like phenotype (high IFN-gamma, low IL-4), and genetic susceptibility to EAU is associated with an elevated Th1 response. Here we investigate whether the ability to produce IFN-gamma is necessary for the development of EAU by immunizing IFN-gamma-deficient (GKO) mice with the uveitogenic protein interphotoreceptor retinoid binding protein (IRBP) and characterize the associated immunologic responses. GKO mice developed EAU comparable in severity and incidence to that of their wild-type littermates. However, the cytokine profile in their uveitic eyes as well as the cytokines produced by primed lymph node cells in response to IRBP showed a distinct profile: undiminished TNF-alpha and elevated IL-5, IL-6, IL-10, and lymphotoxin (but not IL-4) responses. The inflammatory infiltrate in GKO eyes contained an excess of granulocytes and IL-5- and IL-6-producing cells, but uveitic GKO mice did not up-regulate inducible nitric oxide synthase. GKOs had enhanced lymphocyte proliferation and delayed-type hypersensitivity responses to IRBP. Histology of the delayed-type hypersensitivity lesion in GKO had superimposed elements of an allergic-like response. Anti-IRBP Ab isotypes of GKO mice showed a reduction of IgG2a, but no enhancement of IgG1. Comparison of responses in +/+ and +/- wild-type mice revealed some limited evidence of a gene-dose effect. We conclude that IFN-gamma is not required for priming of pathogenic T cells or for effecting the retinal damage and photoreceptor loss typical of EAU. However, what appears to be a grossly similar disease is caused in the GKO by a deviant type of effector response.
Conformational transitions in CD4 due to complexation with HIV envelope glycoprotein gp120.
Authors: Denisova G , Raviv D , Mondor I , Sattentau Q J , Gershoni J M 
Published: December 2022

Abstract
The binding of the surface envelope glycoprotein gp120 to its receptor, CD4, has been well characterized and is the primary basis for the cell tropism of HIV. In this study, the interaction between recombinant soluble CD4 and native membrane-associated CD4 with gp120 is probed by the use of mAbs. Complexation of gp120 with both forms of CD4 induces conformational epitopes that can be defined with specific mAbs. CG1, CG7, and CG8 are three novel mAbs that have a distinct preference for CD4 complexed over noncomplexed with gp120. The epitopes of these unique mAbs were mapped by cross-inhibition with previously characterized mAbs to a region encompassing the CDR2 and CDR3 loops in domain 1 of CD4. Systematic analysis of CG mAbs binding to CD4 and CD4/gp120 complex delineates a region in the D1 domain of CD4 that undergoes conformational rearrangements upon gp120 binding to its receptor.
Virus-specific IgD in acute viral infection of mice.
Authors: Moskophidis D , Moskophidis M , Löhler J 
Published: December 2022

Abstract
In phylogenetically diverse species with the help of T lymphocytes or soluble factors, viral infections induce the Ag-specific B lymphocytes to proliferate and terminally differentiate into IgM, IgG, IgA, IgD, or IgE Ab-secreting cells. Based on previous studies searching for IgD, it was inferred that serum IgD in the mouse is nearly undetectable, although in other species, e.g., humans, IgD is a measurable component of serum Ig. More recently, new information has been obtained indicating that IgD is secreted in minute quantities during normal B cell differentiation. We observed that IgD is secreted in significantly increased quantities in mice undergoing an acute infection with lymphocytic choriomeningitis virus or vesicular stomatitis virus compared with uninfected animals. A substantial fraction of the observed IgD was found to be virus specific. Using a solid-phase immunoenzymatic technique, virus-specific IgD Ab-forming cells were detected in the spleen; their numerical increase correlated with the level of secreted antiviral IgD. In addition, immunohistochemical staining revealed IgD+ plasma cells that occurred with a similar kinetic profile as the virus-specific IgD Ab-forming cells. These findings provide direct evidence that synthesis of IgD is a physiologic event in the mouse. Its precise function in the immune response to pathogens, however, remains to be determined.