bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effects of IL-12 on the response and susceptibility to experimental viral infections.
Authors: Orange J S , Wolf S F , Biron C A 
Published: December 2022

Abstract
Effects of administered IL-12 on immune responses to viral infection were evaluated. IL-12-mediated effects during lymphocytic choriomeningitis virus (LCMV) infection in C57BL/6 mice were contrasted to those in either uninfected mice, or mice infected with a virus inducing a more modest T cell response, murine cytomegalovirus. Mice received 0, 1, 10, 100, or 1000 ng/d of IL-12 on the day prior to infection and daily on day 0 to 6 post-infection. Responses were examined on day 7. Low doses of IL-12 enhanced immunity to LCMV infection as demonstrated by increased splenic CD8+ T cell numbers and decreased LCMV replication. Low doses of IL-12 also significantly enhanced splenic CD8+ T cell numbers in murine cytomegalovirus-infected mice. In contrast, high doses of IL-12 were detrimental to resistance against LCMV infection. Higher doses of IL-12: 1) inhibited virus-specific CTL lytic capacity per spleen by &gt; 90%; 2) inhibited virus-induced expansion of CD8+ T cells in spleen, peripheral blood, and lymph nodes by &gt; 80%; 3) induced necrotic lesions in splenic white pulp; and 4) resulted in 2 log increases in splenic and renal viral replication. Initiation of high dose IL-12 treatment on day 0, 1, 2, or 4 post-infection had similar effects. Although serum levels of IFN-gamma and TNF were normally not detectable in LCMV-infected mice, infection acted synergistically with IL-12 for cytokine induction. The IL-12-mediated reduction in CD8+ T cell numbers and synergistic enhancement of circulating cytokines levels observed during LCMV infection were unique to this infection. These results demonstrate that IL-12-mediated effects can be either protective or detrimental, depending upon the environment in which the factor is presented.
Macrophage inflammatory protein-1 alpha and monocyte chemoattractant peptide-1 elicit immediate and late cutaneous reactions and activate murine mast cells in vivo.
Authors: Alam R , Kumar D , Anderson-Walters D , Forsythe P A 
Published: December 2022

Abstract
We have previously reported that monocyte chemoattractant protein-1 (MCP-1) is the most potent histamine-releasing factor (HRF) for basophils. Macrophage inflammatory protein-1 alpha (MIP-1 alpha) has modest histamine-releasing activity. The objective of this study was to investigate whether MCP-1 and MIP-1 alpha would activate mast cells in vivo and induce a cutaneous inflammatory reaction in mice. To this goal, mouse hind footpads were separately injected with 20 microliters of human recombinant MCP-1 or MIP-1 alpha (10(-7) M). Diluent was used as a control in the second footpad. The footpad-swelling response was measured at 30 min, 1 h, and then hourly for 6 h. Both MCP-1 (2.72 +/- 0.2 vs 2.1 +/- 0.03 mm for diluent, n = 8, p &lt; 0.02) and MIP-1 alpha (3.0 +/- 0.1 vs 2.1 +/- 0.03 mm for diluent, n = 8, p &lt; 0.02) induced an immediate swelling reaction. The immediate reaction was followed by a sustained late reaction that peaked within 1 h and lasted for more than 6 h. Histologic examination of the footpads, obtained at hour 2, revealed that MCP-1 caused mild mononuclear cell infiltrates, moderate degranulation of mast cells, and soft tissue swelling. In contrast, MIP-1 alpha induced a severe inflammatory reaction that consisted of neutrophils, mononuclear cells, and degranulated mast cells. Electron microscope examination of the tissue revealed features of extensive mast cell degranulation by MIP-1 alpha and to a lesser extent by MCP-1. Thus, we conclude that mast cells are activated on injection of MCP-1, whereas degranulation of mast cells and recruitment of leukocytes contribute to the footpad reaction induced with MIP-1 alpha.
TNF-alpha binds to the N-terminal domain of fibronectin and augments the beta 1-integrin-mediated adhesion of CD4+ T lymphocytes to the glycoprotein.
Authors: Alon R , Cahalon L , Hershkoviz R , Elbaz D , Reizis B , Wallach D , Akiyama S K , Yamada K M , Lider O 
Published: December 2022

Abstract
Certain inflammatory cytokines and growth factors have been previously shown to interact with glycosaminoglycan moieties of the extracellular matrix (ECM). We have examined the association of the pleiotropic cytokine TNF-alpha with glycoprotein constituents of ECM. TNF-alpha interacted with fibronectin (FN) and laminin, and to a lesser degree with collagen. The major binding site for TNF-alpha on FN was localized to its 30-kDa N-terminal fragment (FN-N') with a Ki in the sub-nM range. The binding of 125I-labeled TNF-alpha to immobilized FN or FN-N' persisted for at least 24 h, and was specifically inhibited by antibodies to FN, mAb directed against the FN-N' domain, unlabeled TNF-alpha, and by the truncated forms of TNF-alpha receptors. Once bound to immobilized FN or FN-N', the cytokine could not be released by the soluble TNF-alpha-receptors, although it could be released by anti-TNF-alpha Ab. TNF-alpha was also found to interact with soluble FN, although with a lower affinity. Similar to the soluble cytokine, the FN-bound TNF-alpha appears to be functional; it augmented the beta 1-integrin-mediated adhesiveness of activated CD4+ human T cells to the glycoprotein. Hence, binding of TNF-alpha to immobilized FN, which modifies its functional accessibility to soluble TNF-alpha receptors, does not abolish but rather may locally restrict its activity. This study suggests that a major ECM glycoprotein can present, in a restricted manner, a functional adhesion-modulating cytokine to immune cells, and that ECM glycoproteins may regulate their intrinsic cell-adhesive properties by associating with cytokines.
Characteristics of a novel low affinity complement C3dg-binding protein of human platelets.
Authors: Chen H , Marjan J , Cox A D , Devine D V 
Published: December 2022

Abstract
The breakdown products of the complement protein C3 function in receptor-mediated immune clearance. The catabolism of the C3 molecule, mediated by factors I and H, results in the generation of the fragments C3c and C3dg. C3dg binds to human platelets in a specific and saturable manner. The direct interaction of platelets with soluble C3dg may contribute to immune-mediated platelet destruction. More importantly, platelets may interact with opsonized pathogens or complement-activating immune complexes via C3dg. In this report, we investigated the interaction of C3dg with platelets and calculated the Ka to be 3.2 x 10(6) M-1 with 1100 to 2200 specific binding sites/platelet. In the presence of 5 mM calcium, both the Ka and the number of specific binding sites were modestly decreased to Ka = 2.8 x 10(6) M-1 with 1400 to 2400 specific binding sites/platelet. The Scatchard plots demonstrated a curvilinear character. On labeling C3dg with peroxidase and visualizing platelet-bound C3dg by electron microscopy, it was shown that binding sites for C3dg were restricted to the platelet plasma membrane. Using a cell attachment assay, platelet adhesion to C3dg was readily detectable; attachment to C3dg-coated plates was not blocked by fibrinogen or fibronectin. We have characterized the C3dg-binding protein of platelets using the chemical cross-linkers, SASD and DSS, to cross-link C3dg to thrombin-stimulated platelets. Gel filtration of the 125I-labeled C3dg-platelet complex revealed the presence of a large protein complex that was absent when 125I-labeled C3dg alone was analyzed. SDS-PAGE of the radiolabeled cross-linked protein, followed by autoradiography, identified a 95-kDa membrane protein. The relationship of this C3dg-binding protein to other platelet membrane proteins has yet to be determined.
Inhibition of TNF by a TNF receptor immunoadhesin. Comparison to an anti-TNF monoclonal antibody.
Authors: Haak-Frendscho M , Marsters S A , Mordenti J , Brady S , Gillett N A , Chen S A , Ashkenazi A 
Published: December 2022

Abstract
TNF is an important mediator of inflammation, which can have deleterious effects when produced inappropriately. We have described a recombinant inhibitor of TNF, termed TNFR-IgG, or TNFR immunoadhesin, composed of the extracellular portion of the type 1 (p55) TNF receptor (TNFR) linked to the hinge and Fc regions of IgG heavy chain. This bivalent, Ab-like molecule is a potent inhibitor of TNF, exhibiting significantly higher affinity for the cytokine than soluble TNFR. Here, we compare the TNF-neutralizing capacity of TNFR-IgG to that of an anti-TNF mAb. In vitro, TNFR-IgG was 10- to 50-fold more potent than anti-TNF mAb at blocking the cytotoxic effect of exogenous TNF on actinomycin D-treated murine L-M cells. In vivo, the plasma half-life of TNFR-IgG in mice was approximately 6 days, similar to that reported for the anti-TNF mAb. However, the immunoadhesin was approximately 10-fold more effective than the Ab at neutralizing the activity of endogenous TNF, as assessed in a model for murine listeriosis. These results demonstrate a markedly greater potency of the TNFR immunoadhesin compared with the anti-TNF mAb at inhibiting TNF activity in vitro and in vivo.
Adherence of neutrophils induces release of soluble tumor necrosis factor receptor forms.
Authors: Lantz M , Björnberg F , Olsson I , Richter J 
Published: December 2022

Abstract
TNF is a potent activator of neutrophil granulocytes which acts via two cell surface receptors: the p55-TNF receptor (TNF-R55) and the p75-TNF receptor (TNF-R75). The extracellular region of the receptors can be released by proteolytic cleavage and form soluble TNF-binding proteins, TNF-R55-BP and TNF-R75-BP, respectively. The phorbol ester PMA, the chemotactic peptide FMLP, and TNF were all found to induce release of TNF-R55-BP and TNF-R75-BP from neutrophils in suspension in a time- and dose-dependent manner as measured by ELISA. Exposure of neutrophils to 10 ng/ml of PMA for 60 min resulted in release of 900 pg of TNF-R55-BP and 350 pg of TNF-R75-BP per 5 million cells, corresponding to approximately 4800 receptors per cell. In addition, adherence by itself of neutrophils to fibrinogen-coated culture plates and other surfaces resulted in a release of TNF-R55-BP of the same magnitude as seen in response of neutrophils in suspension to 1 nM TNF, whereas the release of TNF-R75-BP was less pronounced. The protein kinase C inhibitors staurosporin and calphostin C inhibited both the TNF-, PMA-, and adherence-induced release of soluble forms of TNFRs. Ab to the common beta-chain of the leukocyte integrins (CD18) did not affect adherence-induced TNF-R55-BP release, indicating that non-integrin-dependent mechanisms are involved in receptor cleavage. However, cross-linking of anti-CD18 Ab (IB4) with a Fab2 fragment resulted in a decrease of specific binding of 125I-TNF to neutrophils indicating that the leukocyte integrins can modulate TNFR expression on neutrophils. Thus, adherence to a biological surface, without additional stimuli, induces release of soluble TNFR form from neutrophils. TNFR expression can be modulated by protein kinase C as well as both leukocyte integrins and non-integrin-dependent adherence mechanisms.
Involvement of a botulinum toxin-sensitive 22-kDa G protein in stimulated exocytosis of human neutrophils.
Authors: Nath J , Powledge A , Wright D G 
Published: December 2022

Abstract
Studies of human peripheral blood neutrophils (PMNs) demonstrated that botulinum neurotoxin D (BT-D) ADP-ribosylates a 22-kDa PMN G protein (G22k) and inhibits the exocytosis of both specific and azurophilic granules stimulated by FMLP. Furthermore, this inhibition of PMN exocytosis by BT-D was found to be correlated with the degree of irreversible ADP-ribosylation of G22k by BT-D and to require modification of at least 85% of PMN G22k before significant inhibition of secretion is observed. Although both pertussis toxin and BT-D inhibited exocytosis in FMLP-stimulated PMNs, the inhibitory effects of the two toxins were found to be additive. Pertussis toxin and BT-D also inhibited Ca2+/GTP/GTP gamma S-induced secretion in digitonin-permeabilized PMNs, but there were distinct differences between the inhibitory effects of the two toxins. In contrast to BT-D, the exotoxin botulinum C3 was found to ADP-ribosylate primarily a 24- to 25-kDa PMN protein, and it was not found to inhibit Ca(2+)- and GTP-induced secretion in permeabilized PMNs. Ultrastructural studies of BT-D-treated PMNs showed an accumulation of distinct membrane-bound organelles in the periphery of the cells after FMLP stimulation, suggestive of a toxin-induced block in organelle-plasma membrane fusion. Taken together, these findings indicate that BT-D-sensitive G22k has a functional role in stimulated exocytosis of PMNs.
IFN and virus-inducible expression of an immediate early gene, crg-2/IP-10, and a delayed gene, I-A alpha in astrocytes and microglia.
Authors: Vanguri P , Farber J M 
Published: December 2022

Abstract
IFN-gamma is a potent macrophage activator and induces a number of early and delayed genes. crg-2, the presumed murine homologue of human IP-10, belongs to a family of proinflammatory chemokines and is induced as an immediate early gene in response to IFN-gamma in macrophages. In contrast, class II MHC or Ia genes which are essential for Ag presentation are induced as a delayed response to IFN-gamma. We studied the expression of crg-2 and compared it with Ia in astrocytes and microglia of the central nervous system since, like macrophages, these cells can also produce a number of cytokines, express Ia molecules, and present Ag. We showed that crg-2 mRNA was induced in astrocytes and microglia by IFN-gamma as well as a paramyxovirus, Newcastle disease virus (NDV). Crg-2 protein was detected in the cytoplasm and in the supernatants of IFN-gamma-treated astrocytes and microglia. IFN-gamma and NDV or UV irradiated-NDV (UV-NDV) also induced Ia mRNA in these cells. The kinetics of expression of crg-2 and Ia mRNA were compared in the same systems. While crg-2 mRNA appeared within 2 h and reached a maximum in 6 to 8 h, Ia mRNA was not detected before 8 h. Cycloheximide superinduced crg-2 mRNA induced by IFN-gamma or UV-NDV but it abolished Ia mRNA induction by the same stimuli. The induction of crg-2 in astrocytes and microglia likely contributes to the development of immune-mediated inflammation in response to viruses or in autoimmune diseases of the central nervous system.
Molecular analysis of IgA deficiency. Evidence for impaired switching to IgA.
Authors: Islam K B , Baskin B , Nilsson L , Hammarström L , Sideras P , Smith C I 
Published: December 2022

Abstract
The most common form of primary immunodeficiency is IgA deficiency (IgAD). However, the molecular basis of this disease remains elusive. Therefore, to address this issue we made a systematic analysis of the molecular events leading to IgA production. B lymphocytes that produce IgA have undergone somatic rearrangement that joins the switch (S) mu to S alpha region with deletion of the intervening sequences. Examination of the resulting S mu/S alpha junctions in unstimulated PBMC from IgAD patients by nested primer PCR revealed a significant decrease in the number of the S mu/S alpha fragments. To obtain the antisense primers to generate the S mu/S alpha fragments, we sequenced the human S alpha 1 and the downstream region extending to the C alpha 1 locus. Similar to previously reported switch sequences, we also found the S alpha 1 to be predominantly composed of pentameric repeats GAGCT and GGGCT. The decrease in the number of S mu/S alpha fragments is consistent with a profound decrease in the C alpha membrane mRNA expression in unstimulated PBMC, as well as in the C alpha mRNA levels and IgA production in PWM-stimulated PBMC. Sequence analysis of the switch junctions from IgA-producing cell lines, control donors, and an IgAD patient showed direct joining in 8 of 9 cases examined. TGF-beta 1, previously shown to be the switch factor for human and mouse IgA, was also examined. No difference in the TGF-beta 1 mRNA levels in unstimulated PBMC between the control subjects and the IgAD patients were detected. Our findings indicate that the failure to switch to IgA-producing B lymphocytes, or an impaired survival of such cells, may be an important molecular mechanism in IgAD.
B cells process and present lupus autoantigens that initiate autoimmune T cell responses.
Authors: Mamula M J , Fatenejad S , Craft J 
Published: December 2022

Abstract
Antibodies against U small nuclear ribonucleoprotein (snRNP) particles are a common finding in the sera of humans with SLE and in certain strains of mice with murine lupus. It is likely that Th cells are important in amplifying this autoantibody response. The focus of this work was to investigate events that might initiate autoimmune B and T cell response in non-autoimmune mice to native snRNP particles. Mice that were immunized and boosted with native mouse snRNPs failed to produce any detectable specific anti-snRNP antibody or T cell responses, suggesting that these autoreactive cells were deleted from the repertoire or were anergic to stimulation with this self Ag. In contrast, immunization with native foreign (human) snRNPs elicited both T cells and cross-reactive anti-snRNP antibodies; the latter predominantly were directed toward the A protein of the U1 snRNP. When mice were immunized with human and mouse snRNPs together in adjuvant, T cells specific for mouse snRNPs could be elicited. The results of these experiments suggested that the mechanism of breaking T cell tolerance to self snRNPs was dependent on the ability of cross-reactive B cells to process and present these autoantigens. To address this hypothesis, B cells purified from mice immunized with recombinant human A protein were transferred into naive mice. Upon boosting with native mouse snRNPs, autoreactive CD4+ T cells specific for mouse Ags, and not cross-reactive with human snRNPs, were observed. These studies support a model of molecular mimicry whereby autoantigen-presenting B cells are generated by foreign cross-reactive determinants that can, in turn, elicit an autoimmune T cell response.
T cell receptor alpha-chain repertoire of pathogenic autoantibody-inducing T cells in lupus mice.
Authors: Mao C , Osman G E , Adams S , Datta S K 
Published: December 2022

Abstract
The production of pathogenic anti-DNA autoantibodies in mice with lupus nephritis is dependent on special autoimmune Th cells that can also transfer the disease into preautoimmune mice. In previous work, these pathogenic Th cells were cloned and their TCR beta-chains were sequenced to reveal a recurrent motif of anionic residues in their CDR3 loops. Accordingly, approximately half of the Th clones were found to be specific for nucleosomal Ag that contain cationic residues. Herein, we analyzed the TCR alpha-chain repertoire of 15 of these pathogenic Th clones and found them to be heterogeneous, even among the nucleosome-specific Th clones. Most of these autoimmune TCR alpha-chains contained anionic residues in their CDR3 in addition to cationic residues. Therefore, these pathogenic Th clones of lupus probably recognize epitopes with mixed charge runs that are derived from autoantigens, such as histone-DNA complexes. Interestingly, the V alpha gene segments used by 10 of these Th clones derived from the (SWR x NZB)F1 lupus mice differed from previously reported sequences indicating that they were new members or alleles of the respective V alpha gene family. One of the Th clones used a gene from an entirely new murine V alpha gene family, identified here as V alpha 23, which consisted of approximately two members that were conserved among strains with different V alpha haplotypes. Knowledge of the primary structure of the TCR expressed by these pathogenic Th clones of lupus would help in the analysis of their antigenic specificities and also would be essential for studying their regulation in transgenic mice carrying these autoimmune TCR genes.
Variable regions of Ig heavy chain genes encoding antithyrotropin receptor antibodies of patients with Graves' disease.
Authors: Shin E K , Akamizu T , Matsuda F , Sugawa H , Fujikura J , Mori T , Honjo T 
Published: December 2022

Abstract
We have established EBV-transformed human B cell clones producing monoclonal antithyrotropin receptor antibodies from two patients with Graves' disease. We then isolated and characterized Ig H chain genes of 5 B cell clones with the thyrotropin-binding inhibitor Ig (TBII) activity and 4 B cell clones with the thyroid-stimulating antibody (TSAb) activity. We found that VH gene families used in the 5 TBII clones were all VH-III, although those of the four TSAb clones were diverse, including VH-II, -III, -IV, all -V. Most of VH segments used in TBII and TSAb are commonly used in other autoantibodies and fetal liver repertoire. The frequency of somatic mutations in TBII was higher than that in TSAb. Inasmuch as the same germline VH segment (V3-23) was used for both TBII and TSAb, the frequency and position of somatic mutations may be important for generation of TBII and TSAb.
In vitamin A deficiency multiple mechanisms establish a regulatory T helper cell imbalance with excess Th1 and insufficient Th2 function.
Authors: Cantorna M T , Nashold F E , Hayes C E 
Published: December 2022

Abstract
In hypovitaminosis A, Ab-mediated immunity is severely impaired. We reported that Trichinella spiralis infection stimulates a strong Th2 cell response in control mice but in vitamin A-deficient mice it stimulates a strong Th1 cell response. Here we investigated the immunobiologic mechanisms underlying this shift from a Th2- to a Th1-dominated response. A kinetic analysis showed that the Th1 cells developed first and IFN-gamma secretion predominated in deficient mice, whereas the Th2 cells developed later and IL-5 and IL-10 secretion predominated in control mice. The IFN-gamma-secreting cell frequencies were the same but cells from deficient mice secreted IFN-gamma sixfold faster than cells from control mice, and retinoic acid addition in vitro decreased that rate 50%. In contrast, the IL-5-secretion rates were the same but the IL-5-secreting cell frequency was lower in deficient mice than in controls, and retinoic acid addition in vitro doubled this frequency independently of its inhibitory effect on IFN-gamma. The APC from deficient mice stimulated greater IFN-gamma release than control APC and retinoic acid addition in vitro decreased this activity 50%. Together these results identify at least three vitamin A activities that balance Th1 and Th2 functions, down-regulating Th1 cell IFN-gamma secretion directly, decreasing activated APC function, and promoting Th2 cell growth and/or differentiation. In this system and perhaps others, the imbalance between regulatory Th1 and Th2 cells is one mechanism underlying poor Ab-mediated immunity in hypovitaminosis A.