bluuebunny/crossref_metadata_2025_split huggingface dataset:
Vascular endothelial growth factor. A cytokine modulating endothelial function in rheumatoid arthritis.
Authors: Koch A E , Harlow L A , Haines G K , Amento E P , Unemori E N , Wong W L , Pope R M , Ferrara N 
Published: December 2022

Abstract
Angiogenesis is important in the proliferation of inflammatory synovial tissue. Vascular endothelial growth factor (VEGF) is an endothelial cell mitogen that is also angiogenic in vivo. We examined the potential role of VEGF in mediating chemotaxis and proliferation of endothelial cells in rheumatoid arthritis (RA) using samples of synovial tissue and synovial fluid from 55 arthritic patients. Synovial fluid VEGF by ELISA was higher in RA synovial fluids (386 +/- 122 ng/ml) (SE) compared with osteoarthritis (OA) synovial fluids (&lt; 0.8 ng/ml) (p &lt; 0.05) or synovial fluids from patients with other arthritides (6.6 +/- 2 ng/ml). In addition to its known mitogenic properties, we found that human rVEGF was chemotactic for HUVECs at concentrations above 0.02 nM. Incubation of RA synovial fluids with neutralizing anti-VEGF resulted in 23 to 66% (mean 53 +/- 4%) inhibition of HUVEC chemotaxis. Conditioned medium from four of five RA synovial tissue explants was mitogenic for bovine adrenal capillary endothelial cells. Anti-VEGF neutralized from 19 to 42% (mean 28 +/- 4%) of this mitogenic activity. To determine the cellular source of VEGF in synovial tissue, we employed immunohistochemistry. VEGF+ cells were rarely (&lt; 1%+) found in normal synovial tissues. In contrast, RA and OA synovial tissues exhibited VEGF+ lining cells (8% and 13%, respectively). A few synovial tissue macrophages were VEGF+ in both RA and OA (5% and 2%, respectively). These results elucidate a newly described function for VEGF as a potent chemotaxin for endothelial cells as well as a role for VEGF in RA-associated endothelial migration and proliferation.
60-kDa Ro protein autoepitopes identified using recombinant polypeptides.
Authors: Saitta M R , Arnett F C , Keene J D 
Published: December 2022

Abstract
The human Ro ribonucleoprotein is a clinically important yet poorly understood autoantigen. The contribution of Ro autoantibodies to pathogenesis of autoimmune disease remains unclear, as do the stimuli that initiate and maintain the response. Recent evidence suggests that patient anti-Ro responses target individual proteins, including a 60- and a 52-kDa species, within the complex in a disease-specific manner. However, Ro antisera retain considerable heterogeneity in their recognition of both continuous and discontinuous epitopes on the protein components. Previous characterization of Ro autoepitopes has primarily involved solid phase assays, which are of limited value in identifying discontinuous epitopes. To address the heterogeneity of Ro and the issue of discontinuous autoepitopes, we have generated 10 overlapping recombinant polypeptides of the human 60-kDa Ro protein and compared their reactivities using a soluble immunoprecipitation assay. Seven different epitopes, both continuous and discontinuous, were distinguished and seven distinct patterns of reactivity were discerned among the sera from 12 patients. These patterns of reactivity showed no relationship to clinical diagnosis but did correlate with the titer of Abs against recombinant 60-kDa Ro and with the concomitant presence of Abs directed against recombinant 52-kDa Ro protein. Sera that immunoprecipitated only the full-length 60-kDa protein had low or undetectable anti-60 kDa titers by ELISA and immunoblot using recombinant Ag, demonstrating a predominant recognition of discontinuous epitopes. These data indicate that autoantibody responses to the 60-kDa Ro Ag can preferentially target discontinuous epitopes and that the ability to recognize continuous epitopes is accompanied by the appearance of 52-kDa Ro autoantibodies.
Inhibition of experimental autoimmune encephalomyelitis by MHC class II binding competitor peptides depends on the relative MHC binding affinity of the disease-inducing peptide.
Authors: Wauben M H , Joosten I , Schlief A , van der Zee R , Boog C J , van Eden W 
Published: December 2022

Abstract
Blocking of the Ag presentation function of MHC molecules by competitor peptides has been proposed as a potential immunotherapy for MHC-associated autoimmune diseases. Despite the fact that successful inhibition of experimental autoimmune encephalomyelitis (EAE) by coimmunization with competitor peptides had been achieved, it remained questionable whether the in vivo activity of such peptides was solely the result of MHC blockade. In the peptide MBP72-85-induced EAE model in Lewis rats, we designed a single amino acid-substituted analogue of MBP72-85 with a superior MHC binding capacity, and with the capacity to activate encephalitogenic MBP72-85-specific T cells. Subsequently, two well-defined competitor peptides, one EAE related and one non-EAE related, were studied for their respective efficacies to inhibit the in vitro proliferation of an encephalitogenic T cell clone induced by the original MBP72-85 or the superior MHC binding analogue peptide. It appeared that the response to MBP72-85 was inhibited very efficiently by both competitor peptides, whereas the response to the superior MHC binding analogue peptide was not. Co-immunization of either the related or non-related competitor peptide together with MBP72-85 inhibited EAE induction in a concentration-dependent manner. In such protected rats, polyclonal T cell responses against MBP72-85 were dramatically decreased. However, EAE induced by the stronger MHC binding MBP72-85 analogue could not be inhibited by either of the competitor peptides. Moreover, in these rats, T cell priming for both MBP72-85 and the MBP72-85 analogue was not inhibited. These results show that competition for MHC binding in vivo could lead to inhibition of EAE induction.
Cellular and molecular mechanisms of the IL-12-induced increase in allospecific murine cytolytic T cell activity. Implications for the age-related decline in CTL.
Authors: Bloom E T , Horvath J A 
Published: December 2022

Abstract
The mechanism(s) by which IL-12 augments CTL generation and the potential for IL-12 to alter the age-related decline in CTL activity were assessed using primary CTL stimulated by allogeneic cells. IL-12 at 2 U/ml enhanced the generation of allospecific CTL response in young adult mice by 1.5- to 5-fold, and optimal augmentation was achieved and maintained with as low as 0.1 U/ml IL-12. In contrast to the enhancement of MHC-unrestricted lytic activity, which was most efficient when IL-12 was added near the end of the 5 day culture period, nearly equivalent augmentation of Ag-specific CTL was induced when IL-12 was added from 1 to 5 days before harvest. The augmentation of CTL by IL-12 was not associated with increased incorporation of [3H]TdR. Increased IFN-gamma production was not required for IL-12 to augment CTL activity because when three different Abs against mouse IFN-gamma were each included in the MLC at concentrations abolishing recoverable IFN-gamma protein, they did not inhibit the IL-12 effect but, under some conditions, further increased CTL activity. Ab to IL-2 also did not alter the IL-12 effect. Depletion of ASGM1+ cells from the responding population before stimulation did not significantly alter the response to IL-12. However, depletion of CD8+ T cells from effector cells obtained after stimulation substantially reduced the IL-12-induced augmentation of CTL. Thus, the results suggested that IL-12 augments CTL activity primarily through an effect on T cells, and the augmentation was associated with an approximate doubling of perforin levels, which was not caused by a significantly increased proportion of CD8+ cells. Finally, IL-12 was effective for moderating the age-related decrease in CTL activity, suggesting a potential role for immunomodulation by IL-12.
Recombinant CD40 ligand exerts potent biologic effects on T cells.
Authors: Fanslow W C , Clifford K N , Seaman M , Alderson M R , Spriggs M K , Armitage R J , Ramsdell F 
Published: December 2022

Abstract
Murine and human CD40 ligand (CD40L) were recently cloned, expressed, and shown to possess potent activity on human and murine B cells, including stimulation of proliferation and Ig secretion in the presence of cytokines. In addition to its action on B lymphocytes, this report demonstrates that CD40L induced both CD4+ and CD8+ T cells isolated from murine lymphoid tissues to proliferate in the presence of submitogenic dosages of Con A, PHA, CD3 mAb, and TCR-alpha beta mAb. The presence of CD40L during suboptimal TCR stimulation resulted in increased expression of the activation Ags IL-2R alpha and CD69 and increased IL-2 production. Taken together, these results show that CD40L is a potent activator of murine T cells and suggest that CD40L is involved in the regulation of T cell function mediated through T:T cell interaction.
The induction of peripheral tolerance by the chronic activation and deletion of CD4+V beta 5+ cells.
Authors: Fink P J , Fang C A , Turk G L 
Published: December 2022

Abstract
In C57BL/6 mice transgenic for a rearranged gene encoding a V beta 5+ beta-chain of the TCR, transgene expression among CD4+ cells decreases with age, such that approximately 40% of CD4+ cells express an endogenous beta-chain gene in 8-mo-old mice. A similar deletion of V beta 5+ cells is observed among CD4+ cells from nontransgenic littermates. V beta 5+ T cells are deleted intrathymically in I-E+Mtv-9+ strains of mice, but this chronic deletion occurs in the lymphoid periphery, in the absence of I-E. We now demonstrate the increased expression of the activation markers CD44 and VLA-4 among CD4+V beta 5+ cells, in the absence of either an increase in size or IL-2 receptor expression. Functional as well as phenotypic differences distinguish CD4+ from CD8+ cells in older V beta 5+ transgenic mice. Relative to their CD8+ counterparts, CD4+V beta 5+ cells are hyporesponsive to plate-bound anti-V beta 5 Abs, and this anergy is partially reversible by the addition of exogenous IL-2. These data suggest the deletion of CD4+V beta 5+ cells is the result of a process that includes their activation, loss of function, and their eventual removal. To investigate the involvement of the principal V beta 5 superantigen Mtv-9 in this chronic deletion, we have derived several lines of V beta 5+I-E-Mtv-9- mice. Transgene expression also declines with age in CD4+ T cells in these mice, clearly demonstrating that the chronic deletion of CD4+V beta 5+ cells does not require Mtv-9. There is considerable variation in the kinetics and efficiency of CD4+V beta 5+ deletion between lines of Mtv-9- transgenic mice that is not from differences in the profiles of endogenous mammary tumor proviruses nor readily explained by environmental differences that influence proviral expression. These results suggest the existence of genetic factors other than mammary tumor proviruses that influence the deletion of CD4+V beta 5+ cells in the absence of I-E.
In vivo administration of insulin-like growth factor-I stimulates primary B lymphopoiesis and enhances lymphocyte recovery after bone marrow transplantation.
Authors: Jardieu P , Clark R , Mortensen D , Dorshkind K 
Published: December 2022

Abstract
Recombinant human insulin-like growth factor-I (IGF-I) (100 micrograms/day) was infused by osmotic minipumps into mice to evaluate its effects on bone marrow B lymphopoiesis. IGF-I treatment resulted in a significant increase in the total number of bone marrow B lineage cells by 2 wk post-treatment in both normal, adult mice and animals that had been lethally irradiated and reconstituted with syngeneic bone marrow. Effects were still apparent at wk 3, even though pumps delivered IGF-I for only 14 days. In addition, the results confirm previous observations that IGF-I treatment results in an increase in numbers of splenic B cells and suggest that this is in part the result of stimulation of B cell proliferation in that organ.
Membrane-proximal Ig-like domain of Fc gamma RIII (CD16) contains residues critical for ligand binding.
Authors: Hibbs M L , Tolvanen M , Carpén O 
Published: December 2022

Abstract
Ag-Ab complexes are cleared from the circulation through a complex system of receptors for the Fc portion of Ig (FcRs). Fc gamma RIII (CD16) is a low affinity FcR for IgG that is composed of two highly homologous Ig-like extracellular domains. Using secondary structure predictions, we located a strongly hydrophilic region in the second Ig-like domain of Fc gamma RIII that is predicted to lie between beta-strands C and C'. Substitutions of seven out of eight amino acids in this region abolished binding to IgG. Substitution of a conformationally adjacent amino acid in a bend just before beta-strand F and an amino acid in the B-C loop also affected ligand binding. However, amino acid substitutions in two different predicted loops in the second Ig-like domain as well as substitutions to three predicted loops in the first Ig-like domain had no effect on function. A chimeric Fc gamma RIII molecule lacking the second Ig-like domain was unable to bind IgG further, suggesting the presence of the binding site in the second domain. Neutralizing mAbs that inhibit Fc gamma RIII interaction with IgG were mapped to the E-F loop in the membrane proximal domain of Fc gamma RIII, providing further evidence of the importance of this region of the molecule in ligand interaction.
HLA class II antigens and the HIV envelope glycoprotein gp120 bind to the same face of CD4.
Authors: Houlgatte R , Scarmato P , el Marhomy S , Martin M , Ostankovitch M , Lafosse S , Vervisch A , Auffray C , Platier-Tonneau D 
Published: December 2022

Abstract
Although the HIV gp120 binding site of CD4 is well characterized, its interaction site with HLA class II molecules is still controversial. Sixty-seven mutations within the four extracellular domains of CD4 were examined for their effects on cell surface expression and conformational changes and for adhesion of HLA class II-expressing B lymphocytes and HIV gp120 binding to CD4-transfected COS cells. Mutations within the gp120 binding site affected both assays similarly, indicating that the two sites fully overlap. A few additional substitutions of residues mapping on the same face of domains 1 and 2 induced decreased rosette formation. Molecular modeling studies indicated that this is likely to be the consequence of conformational changes induced by the mutations. Thus, CD4 appears to interact with HLA class II molecules mainly through the HIV gp120 binding site and possibly through a second minor interaction site mapping on the same face of the molecule.
An isotype switched and somatically mutated rheumatoid factor clone isolated from a MRL-lpr/lpr mouse exhibits limited intraclonal affinity maturation.
Authors: Jacobson B A , Sharon J , Shan H , Shlomchik M , Weigert M G , Marshak-Rothstein A 
Published: December 2022

Abstract
Employing site-directed mutagenesis we have reconstructed and expressed the germ-line precursor of an expanded rheumatoid factor (RF) clone. This RF clone, designated clone F, was isolated from an autoimmune MRL/MpJ-lpr/lpr mouse. Most of the clone members were extensively mutated and isotyped-switched. The predominant isotype of clone F was gamma 3. The RF bound specifically to the MRL gamma 2 a allotype (Igh-1j) but not to the B6 gamma 2a allotype (Igh-1b). The germ-line antibody was also found to bind gamma 2a in an RF assay. The affinities of the germ-line RF and representative members of the clone were measured in an ELISA-based equilibrium binding assay. The dissociation constant (Kd) of the germ-line RF was 2.5 x 10(-6) M. All of the expressed clone members had affinities within a two- to sixfold range of the germ line, indicating that the mechanisms of somatic hypermutation and selection resulted in only limited affinity maturation of this autoantibody clone.
Fc gamma receptor cross-linking down-regulates IL-1 receptor antagonist and induces IL-1 beta in mononuclear phagocytes stimulated with endotoxin or Staphylococcus aureus.
Authors: Marsh C B , Pope H A , Wewers M D 
Published: December 2022

Abstract
The cross-linking of monocyte Fc gamma R is a potent stimulus for IL-1ra production but does not induce IL-1 beta. However, during systemic infection, IgG-coated bacteria can activate mononuclear phagocytes via both cell wall components and opsonized IgG. Therefore, we analyzed the effect of combinations of Fc gamma R cross-linking and bacterial cell wall components on mononuclear phagocyte IL-1 beta and IL-1ra production. Human mononuclear cells and monocytes were cultured either alone or with combinations of immobilized IgG, LPS, or heat-killed Staphylococcus aureus (HKSA). Cells cultured on immobilized IgG released large amounts of IL-1ra but no detectable IL-1 beta. In response to LPS, mononuclear cells released IL-1ra at 1000-fold lower doses of LPS than was required to induce IL-1 beta. However, when measured in the presence of immobilized IgG, the LPS sensitivity for IL-1 beta release increased 100-fold, whereas IL-1ra release correlated inversely with the LPS dose. Furthermore, HKSA, a nonendotoxin stimulus, affected mononuclear cell IL-1 beta and IL-1ra release similarly. In addition, polymyxin B, a specific endotoxin inhibitor, blocked the LPS, but not the HKSA-induced changes in IL-1 beta and IL-1ra secretion, irrespective of immobilized IgG co-stimulation. In summary, these results suggest that mononuclear phagocyte stimulation with immobilized IgG favors IL-1ra over IL-1 beta production. Conversely, the addition of LPS or HKSA to the Fc gamma R-stimulated cells augments IL-1 beta but suppresses IL-1ra production.
Epitopes on proteinase-3 recognized by antibodies from patients with Wegener's granulomatosis.
Authors: Williams R C , Staud R , Malone C C , Payabyab J , Byres L , Underwood D 
Published: December 2022

Abstract
The 228 amino acid primary sequence of proteinase-3 (PR3) was studied for antigenic epitopes, which react with IgG Ab in sera of patients with Wegener's granulomatosis, by synthesizing overlapping 7 mers of PR3 linear sequence on pins. Main regions of linear sequence reactivity included GHEAQPH (at residues 4-10), QPHSRPY (8-14), TQEPTQQ (65-71), ATVQLPQ (108-114), QLPQQDQ (111-117), PVPHGTQ (118-124), RVGAHDP (132-138), FCRPHNI (154-160), PRRKAGI (165-171), FGDSGGP (173-179), and IDSFVIW (189-195). All of these regions were surface accessible and seemed to be on the outside of the molecule. By substituting a glycine or an alanine for each residue within each reactive epitope, we identified the arginine at 12, valine at 119, proline at 120, histidine at 121, arginine at 132, alanine at 135, histidine at 136, and glycine at 178 as major immunodominant single residues that contribute to antigenic determinants. Visualization of these reactive regions on a three-dimensional computer-generated carbon PR3 trace diagram showed that one aspect of the molecule on the inferolateral surface comprised most of the antigenic regions. Two peptides, ATVQLPQ and RVGAHDP, when preincubated with Wegener's granulomatosis sera, produced almost complete inhibition of Wegener's granulomatosis IgG Abs either binding to PR3 on the ELISA plate or by reacting with polymorphonuclear leukocyte azurophilic granules in immunofluorescence assays for cANCA. FGDSGGP (at residues 173-179), one epitope that was recognized by Wegener's patient sera Abs, included part of the active catalytic triad for PR3. Rabbit Abs against the PR3 peptides ATVQLPQ or RVGAHDP showed a cANCA cytoplasmic granular pattern of immunofluorescence staining when they were incubated with polymorphonuclear leukocytes. These findings indicate that it is possible to identify various antigenic sites on PR3 by using overlapping 7 mers of portions of the solvent, accessible linear sequence.
Quantitative differences in cell surface expression of class I MHC antigens on murine epidermal Langerhans cells.
Authors: Sharrow S O , Barden L A , Singer A , Katz S I 
Published: December 2022

Abstract
Epidermal Langerhans cells are derived from cells of bone marrow origin and, as the primary APC population in the skin, are responsible for initiation of many immune responses. Consequently, cell surface expression of MHC Ags by Langerhans cells is central to their function. Although murine Langerhans cells express class II MHC Ags at high levels, their level of expression of class I MHC has been controversial. In this study, cell surface expression of multiple individual class I MHC Ags on murine epidermal Langerhans cells was analyzed using quantitative immunofluorescence. It was found that Langerhans cells differentially express products of distinct class I genes. Langerhans cells expressed low cell surface amounts of H-2K and Qa-2, whereas expression of surface H-2D and H-2L by the same cells was high. Murine epidermal Langerhans cells therefore express low cell surface amounts of some but not all class I MHC Ags. Differential surface expression of products of distinct class I MHC genes by Langerhans cells may have a profound effect on cutaneous immune responses.
Expression cloning of a human IL-12 receptor component. A new member of the cytokine receptor superfamily with strong homology to gp130.
Authors: Chua A O , Chizzonite R , Desai B B , Truitt T P , Nunes P , Minetti L J , Warrier R R , Presky D H , Levine J F , Gately M K 
Published: December 2022

Abstract
A cDNA encoding a human IL-12R subunit was isolated by expression cloning. This subunit is a 662 amino acid type I transmembrane protein with an extracellular domain of 516 amino acids and a cytoplasmic domain of 91 amino acids. It is a member of the hemopoietin receptor superfamily and is most closely related over its entire length to gp130 and the receptors for granulocyte-CSF (G-CSF) and leukemia-inhibitory factor. When expressed in COS cells, this IL-12R subunit binds both human and murine IL-12 with an apparent affinity of 2 to 5 nM. The transfected COS cells express both monomers and disulfide-linked dimers or oligomers of the IL-12R subunit on their surface. However, unlike the IL-6-induced dimerization of gp130, the oligomerization of the IL-12R subunit is not dependent on binding of IL-12. Only the IL-12R subunit dimers/oligomers but not the monomers bind IL-12 with an affinity of 2 to 5 nM. A polyclonal antiserum raised against this receptor subunit specifically inhibits IL-12-induced proliferation of PHA-activated PBMC. The data are consistent with the hypotheses that 1) a dimer/oligomer of the cloned IL-12R subunit (IL-12R-beta) represents the low affinity IL-12 binding site identified on human lymphoblasts, 2) the cloned receptor subunit is involved in IL-12 signal transduction, and 3) an additional, as of yet unidentified subunit is required to generate a high affinity IL-12R complex.