bluuebunny/crossref_metadata_2025_split huggingface dataset:
Modulation of mRNA levels for urinary- and tissue-type plasminogen activator and plasminogen activator inhibitors 1 and 2 in human fibroblasts by interleukin 1.
Authors: Michel J B , Quertermous T 
Published: December 2022

Abstract
Plasminogen activators and their inhibitors are thought to play an important role in the regulation of a variety of pathologic processes including inflammation and wound healing. IL-1 is one inflammatory mediator which has been shown to increase release of plasminogen activator (PA) Ag and activity by mesenchymal cells such as chondrocytes and synoviocytes. We have found that rIL-1 beta induces a rapid and significant accumulation of both tissue-and urinary-type plasminogen activator (t-PA and u-PA) mRNA and type 1 and 2 plasminogen activator inhibitor (PAI-1 and PAI-2) mRNA in MRC-5 fetal lung fibroblasts. An SV40 transformed fibroblast cell line, XP12RO, showed an identical response of PAI-1 and t-PA message levels but revealed no change in PAI-2 or u-PA mRNA levels with rIL-1 beta stimulation. Treatment with the transcriptional inhibitor actinomycin D blocked accumulation of t-PA, u-PA, PAI-1, and PAI-2 mRNA, suggesting that RNA synthesis is required for accumulation of all four transcripts. Cycloheximide (CHX) treatment altered the rate of PAI-1 and t-PA mRNA accumulation, but both were able to increase in the absence of protein synthesis. CHX blocked the rIL-1 beta-induced increase in PAI-2 mRNA levels normally observed at 8 h, indicating that protein synthesis is required for this response to IL-1. The increase in u-PA message level was augmented in a synergistic fashion by CHX. These data for PAI-2 and u-PA provide evidence for short-lived proteins which act either to modulate transcription of these genes or regulate mRNA stability. Thus plasminogen activators and their inhibitors are regulated in a positive and complex fashion in the fibroblast by IL-1, suggesting an important role for these molecules and this cell type in the response to inflammation.
Synergistic interactions of IL-1 and IL-6 in T cell activation. Mitogen but not antigen receptor-induced proliferation of a cloned T helper cell line is enhanced by exogenous IL-6.
Authors: Mizutani H , May L T , Sehgal P B , Kupper T S 
Published: December 2022

Abstract
Recent reports have indicated that in addition to its well characterized effects on B cells and hepatocytes. IL-6 also affects murine and human T cells and thymocytes. Our study was designed to analyze the effects of IL-1 and IL-6 in providing a second signal in T cell activation in the D10.G4.1 assay. Highly purified human rIL-6 was tested. rIL-6 had modest but detectable activity in the D10.G4.1 assay. Maximal enhancement of proliferation induced by IL-6 in the presence of mitogen in the D10.G4.1 assay was always far less than that induced by IL-1. The D10.G4.1 assay was used to test the possibility of synergistic interactions between IL-1 and IL-6. Quantities of IL-6 which alone were not costimulatory to D10 cells enhanced IL-1-induced D10 proliferation significantly when Con A was used as a costimulus. This synergistic response could be partially blocked by antibodies to rIL-6 and fully blocked by a mAb to rIL-1 alpha. In contrast, when 3D3 (a clonotypic activating anti-TCR mAb) was used as a costimulus, no synergistic interaction between IL-1 and IL-6 could be detected. The proliferation of D10 cells induced by IL-1 and 3D3 was unaffected by antibodies to IL-6 but was completely neutralized by antibodies to IL-1. These data suggest that although IL-6 alone cannot substitute for IL-1 in functional assays for IL-1, the presence of IL-6 significantly enhances T cell responses to IL-1 in the context of the appropriate costimulatory signal. These observations have important implications regarding the specificity and utility of the D10.G4.1 assay for the measurement of IL-1 in biologic samples.
Bivalent binding of an anti-CD3 antibody to Jurkat cells induces association of the T cell receptor complex with the cytoskeleton.
Authors: Marano N , Holowka D , Baird B 
Published: December 2022

Abstract
Ligand binding and cross-linking of TCR/CD3 complex leads to T cell stimulation in immunologic responses. As a prelude to investigating the dynamic interactions of these receptors, we have characterized binding of the mAb OKT3 specific for CD3 on Jurkat cells. The association of both OKT3 and its Fab' fragment is rapid at 4 degrees C, and dissociation of Fab' is also rapid, but dissociation of OKT3 is slow, indicating bivalent binding in this case. Dissociation of OKT3 is substantially accelerated at 37 degrees C if internalization is prevented. From the concentration dependence, the binding of OKT3 at 4 degrees C appears to be very tight whereas binding of the Fab' fragment is weaker and biphasic. Scatchard analysis of the Fab' equilibrium binding data indicates two binding sites with KD values of 5.1 x 10(-9) M and 2.7 x 10(-8) M. The very tight binding of the bivalent antibody may be caused by inter- or intramolecular cross-linking between these sites. If Jurkat cells are warmed to 37 degrees C, there is an energy-dependent increase by about one-third of sites bound by OKT3 or its Fab' fragment over that seen at 4 degrees C. This increase may be related to a receptor recycling process because internalization of a similar number of the bound ligands occurs at similar rates. Other experiments have revealed that OKT3, but not its Fab' fragment, causes the receptor complex to become associated with the detergent-insoluble cytoskeleton, and there are also insoluble intracellular OKT3-binding sites. These cross-linking-induced receptor-cytoskeletal interactions are sensitive to moderate changes in salt concentration that should allow their molecular basis to be investigated.
Platelet-activating factor (PAF) enhances tumor necrosis factor production by alveolar macrophages. Prevention by PAF receptor antagonists and lipoxygenase inhibitors.
Authors: Dubois C , Bissonnette E , Rola-Pleszczynski M 
Published: December 2022

Abstract
The effect of platelet-activating factor (PAF) on TNF production by rat alveolar macrophages (AM) and the role of endogenous leukotriene B4 (LTB4) in this regulation were examined. When AM were cultured with PAF alone, no change in TNF production was observed. However, the concomitant addition of PAF and muramyl dipeptide to AM cultures markedly enhanced (2- to 3-fold) TNF production in a concentration-dependent fashion with peak effect at 10(-10)M PAF. This enhancement occurred when muramyl dipeptide and PAF were present together at the initiation of the 24-h culture. Stimulation of TNF production by PAF was blocked by specific, but structurally different PAF receptor antagonists, BN 52021, CV3988 and WEB 2086. Additionally, the stereoisomer of PAF, [S]PAF, and the biologically inactive precursor/metabolite of PAF, lyso-PAF failed to induce significant enhancement in TNF production. In parallel, addition of PAF to AM triggered LTB4 release in a concentration-dependent manner. Inhibition of 5-lipoxygenase by nordihydro-guaiaretic acid or AA-861 blocked the PAF-induced augmentation of both TNF and LTB4 production. This was partially reversed by addition of exogenous LTB4. Collectively, these data suggest that PAF enhances TNF production by interaction with a specific putative receptor and by subsequent induction of endogenous 5-lipoxygenase activity in AM.
Significance of the recognition of certain antigenic regions on the human thyroglobulin molecule by natural autoantibodies from healthy subjects.
Authors: Bouanani M , Piechaczyk M , Pau B , Bastide M 
Published: December 2022

Abstract
We have evaluated the epitope specificity of natural antihuman thyroglobulin (hTg) autoantibodies (aAb) in the plasma of healthy individuals. By an indirect ELISA technique, we selected 56 plasma samples with high anti-hTg antibody activity and used the IgG fraction isolated from these plasma to study the antigenic domains on the hTg molecule recognized by the natural anti-hTg aAb. A panel of 15 mAb, coupled to alkaline phosphatase and recognizing six regions (I to VI) on the hTg molecule, served to identify the domains recognized by the natural anti-hTg aAb using a competitive ELISA procedure. A total of 26 of the IgG fractions was found to interact with at least one of the regions defined by our battery of mAb. Region V was recognized by the majority of the IgG fractions. Interestingly, region II was rarely recognized by the same IgG fraction that reacted with region V. Inasmuch as we have previously shown that region II is mainly recognized by aAb in the serum of subjects with various thyroid disorders, we propose that recognition of region V reflects the normal physiologic state of the immune system with respect to the hTg molecule.
Dextran sulfate and heparin interact with CD4 molecules to inhibit the binding of coat protein (gp120) of HIV.
Authors: Lederman S , Gulick R , Chess L 
Published: December 2022

Abstract
Dextran sulfate, heparin, and certain other sulfated polysaccharides potently inhibit the adsorption of HIV to CD4+ cells. The mechanism of this inhibition is unclear and, specifically, it is unknown if these agents act at the level of CD4-gp120 binding. For example, previous reports have demonstrated that dextran sulfate does not inhibit the cell surface binding of anti-CD4 mAb known to be directed at the gp120 binding site. In order to confirm and extend these observations, in the present study, it was shown that dextran sulfate does not inhibit the binding of OKT4A, OKT4C, Leu3a, or B66.6 to CD4+ cells as measured by cytofluorography. Next, recombinant forms of CD4 (rT4) and gp120 (rgp120) were utilized to directly study their molecular interaction in the absence of other viral or cellular structures. Reciprocal solid phase ELISA assays were developed to study directly the effects of sulfated polysaccharides on the binding of rT4 to immobilized rgp120 and vice versa. Dextran sulfate, heparin, and fucoidan, but not chondroitin sulfate, inhibited the binding of rgp120 to rT4. Importantly, dextran sulfate and heparin pre-treatment of immobilized rT4, but not immobilized rgp120, inhibited rT4-rgp120 binding. Taken together, these data suggest that while both sulfated polysaccharides and anti-CD4 mAb inhibit gp120 binding, the sulfated polysaccharides interact with sites on CD4 that are distinct from those with which the antibodies bind.
The immunogenicity of soluble haptenated polymers is determined by molecular mass and hapten valence.
Authors: Dintzis R Z , Okajima M , Middleton M H , Greene G , Dintzis H M 
Published: December 2022

Abstract
T cell-independent Ag are believed to stimulate antibody formation in the relative absence of Ag processing and T cell help. Previous studies on the type 2 T cell independent (TI-2) Ag DNP-polyacrylamide, have shown that when one systematically varies the molecular mass and hapten valence, the immunogenic potential of this type of molecule depends on definable molecular characteristics. It was found that to be immunogenic, these molecules had to exceed a threshold molecular mass of 100,000 Da and a threshold hapten valence of 20. The present study was undertaken to determine whether such findings could be generalized to other molecules belonging to the TI-2 class of Ag. The molecular characteristics of five chemically different fluoresceinated (FL)-polymers were systematically varied, and their ability to stimulate an IgM antihapten immune response was measured. The polymers used as carriers were carefully size-fractionated and consisted of one natural polymer (dextran), one modified natural polymer (carboxymethyl cellulose), and three synthetic polymers (Ficoll, polyvinyl alcohol, and polyacrylamide). The carriers varied in physical structure from the highly cross-linked Ficoll, to the somewhat branched dextran, to the linear polyacrylamide, carboxymethyl cellulose, and polyvinyl alcohol. Polymers were haptenated with FL and size-fractionated so as to yield a panel of molecules with varying molecular mass, hapten valence, and hapten density. Anti-FL IgM response to these haptenated polymers was measured in vivo after i.p. injection of the FL-polymer in saline, and measured in vitro after culture with unfractionated spleen cells from naive mice. In agreement with the previous studies on DNP-polyacrylamide, it was found that to be immunogenic, each of the FL-polymers had to exceed a comparable threshold value of molecular mass and of hapten valence. Optimal immunogenicity occurred when the FL-polymers had values of mass and hapten density lying within a predictable range. Immunogenicity decreased when these optimal parameters were substantially increased or decreased. We conclude that the immunogenicity of soluble haptenated polymers depends on predictable physical molecular characteristics, and is relatively independent of the chemical composition and conformation of the carrier polymer.
Antigenicity of dextran-protein conjugates in mice. Effect of molecular weight of the carbohydrate and comparison of two modes of coupling.
Authors: Seppälä I , Mäkelä O 
Published: December 2022

Abstract
Protein conjugates of polysaccharides or their breakdown products are being used as improved "T-dependent" vaccines. We tried to define optimal characteristics of future conjugate vaccines by testing the immunogenicity of thirteen conjugates of alpha 1-6 dextran and chicken serum albumin in mice (BALB/c and CBA). All conjugates induced stronger antidextran antibody responses than the polysaccharide, and a fair proportion of these antibodies were IgG. However, there was a range of antigenicities. Consistently strong responses were obtained with conjugates that carried small dextran molecules (m.w. 1000 to 4000) coupled to the protein via the reducing end. Modification of such an "optimal" conjugate either by increasing the size of the saccharide to 40,000 Da, or by permitting multiple attachments of the saccharide molecule to the protein, reduced its antigenicity. Carbohydrate/protein ratios varying from 0.17 to 0.49 were associated with excellent antidextran responses.
Effect of conformational propensity of peptide antigens in their interaction with MHC class II molecules. Failure to document the importance of regular secondary structures.
Authors: Sette A , Lamont A , Buus S , Colon S M , Miles C , Grey H M 
Published: December 2022

Abstract
In an attempt to define some of the conformational requirements for binding of the antigenic peptide OVA 323-336 to purified IAd molecules, three distinct experimental approaches were applied. First, the effect of introducing proline or glycine residues within the region of OVA 323-336 crucial for its IAd binding capacity was analyzed. In most instances these substitutions had little or no effect, suggesting that neither alpha-helical nor beta-sheet regular structures may be strictly required for productive interaction with MHC molecules. Some of the same substitutions were also found to have no effect on the capacity of the peptide to stimulate OVA 323-336 specific T cell hybridomas, suggesting that regular structures such as alpha-helices or beta-sheets may not be strictly required for T cell stimulation, either. Second, we introduced, within the OVA 323-336 molecule, structural modifications predicted to alter its dipole characteristics and stabilize helical structures. No improvement of the IAd binding capacity was detected following these structural alterations. Surprisingly, some but not others of these analogs displayed increased antigenicity for OVA 323-336 specific T cell hybridomas. Third, a panel of analogs of OVA 323-336 were synthesized in which the crucial IAd binding core region was linked to non-native sequences of differing conformational propensities. When 22 such analogs were tested for IAd binding, it was found that these non-native sequences could drastically influence the binding capacity, but no correlation was found between their effect and their alpha-helical, beta-sheet, or beta-turn conformational propensity as calculated by the Chou and Fasman algorithm. In summary, all the data presented herein suggest that, at least in the case of OVA 323-336 and IAd, the propensity of the antigen molecule to form secondary structures such as alpha-helices, beta-sheets, or beta-turns does not correlate with its capacity to bind MHC molecules.
Different membrane anchors of Fc gamma RIII (CD16) on K/NK-lymphocytes and neutrophils. Protein- vs lipid-anchor.
Authors: Ueda E , Kinoshita T , Nojima J , Inoue K , Kitani T 
Published: December 2022

Abstract
Fc gamma RIII (CD16), the type three receptor for the Fc portion of IgG, is expressed on neutrophils, killer (K)/NK lymphocytes and macrophages. K/NK lymphocyte Fc gamma RIII, which plays a role in antibody-dependent cellular cytotoxicity, is an efficient signal transducing molecule, whereas neutrophil Fc gamma RIII, which plays a role in immune-complex clearance, seems less efficient in signal transduction. Neutrophil Fc gamma RIII has been reported to be a glycan-phosphatidylinositol-anchored membrane protein. Our studies suggest that K/NK lymphocyte Fc gamma RIII is protein-anchored rather than glycan-phosphatidylinositol-anchored. That is, K/NK lymphocyte Fc gamma RIII was resistant to phosphatidylinositol-specific phospholipase C and surface expression of Fc gamma RIII was not affected on K/NK lymphocytes from patients with paroxysmal nocturnal hemoglobinuria, a disorder of hemopoietic stem cells resulting in deficient expression of glycan-phosphatidylinositol-anchored proteins. Different membrane anchoring mechanisms of the Fc gamma RIII may account for different consequences of the ligand binding to two cell types.
Mechanisms of T cell activation by the calcium ionophore ionomycin.
Authors: Chatila T , Silverman L , Miller R , Geha R 
Published: December 2022

Abstract
We have investigated signaling mechanisms that may underlie the T cell mitogenic properties of the Ca2+ ionophore ionomycin. Ionomycin induces highly purified resting human T cells to proliferate in the presence of monocytes with accompanying IL-2R expression and IL-2 synthesis. Treatment of T cells with ionomycin triggers the hydrolysis of phosphoinositides, as evidenced by the accumulation of the hydrolytic by-products phosphatidic acid and inositol phosphates. Ionomycin also induces the activation of protein kinase C (PKC), as demonstrated by the auto-phosphorylation of PKC and the phosphorylation of the PKC target proteins CD4 and CD8. Ionomycin synergizes with PMA in enhancing the activation of PKC. It is concluded that, in addition to its putative activation of Ca2+/calmodulin-dependent signaling pathways, ionomycin induces the hydrolysis of phosphoinositides and the activation of PKC in human T cells. The synergy of ionomycin with phorbol esters in triggering T cell activation may relate, at least in part, to enhanced activation of PKC.
Functional alterations of herpes simplex virus-specific CD4+ multifunctional T cell clones following infection with human T lymphotropic virus type I.
Authors: Inatsuki A , Yasukawa M , Kobayashi Y 
Published: December 2022

Abstract
In an attempt to understand the mechanisms of immunodeficiency induced by human T lymphotropic virus type I (HTLV-I), HSV-specific CD4+ human multifunctional T cell clones were infected with HTLV-I in vitro. Early after HTLV-I infection, when their growth was still IL-2-dependent, clones were found to have almost completely lost their cytotoxic activity. At that time, their HSV-Ag-induced proliferative response and helper function for anti-HSV antibody production by B cells were only partially impaired. After this initial phase, the HTLV-I-infected clone became IL-2-independent, and the helper function was also completely lost. IL-2-dependent HTLV-I-infected clones showed degrees of proliferative response and elevation of intracellular free Ca2+ concentration induced by anti-CD3 mAb equivalent to those of HTLV-I-uninfected clones. On the other hand, during the IL-2-independent stage, expression of CD3-TCR complex on the cell surface was markedly decreased, and no significant elevation of intracellular free Ca2+ concentration was detected in response to anti-CD3 mAb. These data indicated that the loss of cytotoxic activity of HSV-specific T cell clones observed early after HTLV-I infection was not the result of impaired antigen recognition via the CD3-TCR complex, but might be due to dysfunction in the effector phase. On the other hand, the dysfunction of helper activity found late after HTLV-I infection might have mainly occurred in the recognition phase due to the decreased expression of CD3-TCR complex. The present data appear to suggest certain aspects of the pathogenesis of the immunodeficiency occurring in HTLV-I infection.
Immunologic control of a parasitic arthropod. Identification of a protective antigen from Boophilus microplus.
Authors: Willadsen P , Riding G A , McKenna R V , Kemp D H , Tellam R L , Nielsen J N , Lahnstein J , Cobon G S , Gough J M 
Published: December 2022

Abstract
Cattle can be vaccinated against the tick Boophilus microplus by inducing an immunologic reaction against Ag in the tick gut. The uptake of antibody during feeding leads to severe damage to the parasite. One of the responsible tick gut Ag has now been purified and characterized: the Bm86 Ag. It is a membrane-bound glycoprotein present in very low abundance in extracts of partially engorged adult female ticks. It has an apparent m.w. of 89,000, an isoelectric point of 5.1 to 5.6 and an affinity for wheat germ lectin. Microgram amounts of this Ag are able to induce effective protection in cattle against the parasite, as shown by the decreased survival of ticks on vaccinated cattle and a reduction in engorgement weights and egg laying capacity of the survivors. Antisera to the Ag react with the surface of digest cells in the tick gut. As a result of the reaction with antibody, the endocytotic activity of these cells, which is a critical step in bloodmeal digestion in this tick, is strongly and rapidly inhibited. A number of peptides from this Ag, produced by digestion of the reduced and alkylated protein with endoproteinase lys-C, have been sequenced. One peptide has significant amino acid sequence homology with the epidermal growth factor precursor and a second peptide has homology with a putative protective antigen from Plasmodium falciparum.