bluuebunny/crossref_metadata_2025_split huggingface dataset:
Murine and human antibodies to native DNA that cross-react with the A and D SnRNP polypeptides cause direct injury of cultured kidney cells.
Authors: Koren E , Koscec M , Wolfson-Reichlin M , Ebling F M , Tsao B , Hahn B H , Reichlin M 
Published: December 2022

Abstract
Murine monoclonal and human affinity-purified Abs to native DNA (anti-nDNA) that cross-react with the A and D SnRNP polypeptides were analyzed for direct injurious effects against cultured pig kidney (PK15) cells under ordinary cell-culture conditions. Of the two murine nephritogenic Abs derived from NZB/NZW F1 mice (BWds1 and BWds3), BWds1 initially bound to the cell surface and subsequently penetrated into cells localizing in nuclei and cytoplasm. BWds3 was consistently and abundantly associated with the surface of live cells without penetration. In the presence of rabbit C, BWds3 caused massive cell lysis (85% dead cells) whereas BWds1 had only a modest lytic effect (24% dead cells). One of the nonpathogenic murine anti-nDNA Abs (5GD5) that did not cross-react with the A and D polypeptides showed no interaction with PK-15 cells and had no injurious effects. Affinity-purified autoantibodies to nDNA isolated from two SLE patients with high anti-nDNA titers and clinically active lupus nephritis showed properties similar to the murine mAbs. They both strongly cross-reacted with the A and D SnRNP polypeptides and interacted with live PK-15 cells. One of them (Cr) penetrated into live cells and localized within cytoplasm and nuclei whereas the other (Pe) bound mostly to the cell surface and caused significant cell lysis in the presence of C. Results of this study suggest that the nephritogenic murine anti-nDNA as well as subpopulations of human anti-nDNA Abs could exert their injurious influence through direct interactions with kidney cells using two different pathogenic mechanisms (i.e., C-mediated cytotoxicity and potential cell cycle dysfunctions. Interestingly, cross-reactivity of anti-nDNA Abs with the A and D SnRNP polypeptides appears to be a prerequisite for their direct pathogenicity.
Induction of experimental autoimmune sialoadenitis by immunization of PL/J mice with carbonic anhydrase II.
Authors: Nishimori I , Bratanova T , Toshkov I , Caffrey T , Mogaki M , Shibata Y , Hollingsworth M A 
Published: December 2022

Abstract
Experimental autoimmune sialoadenitis was induced in PL/J (H-2u) mice by intradermal immunization with human carbonic anhydrase II (CAII) and adjuvant containing monophosphoryl lipid A and trehalose diorynomycolate. Mice immunized with CAII showed a significant increase in the number and size of foci with lymphocytic infiltration in the salivary gland compared with mice immunized with adjuvant alone and untreated mice. In mice immunized with CAII, lymphocytic foci were observed around intercalated and intralobular ducts in the salivary glands, resulting in atrophy and replacement of acinar units. The epithelial cells of salivary ducts adjacent to the lymphocytic foci showed both degenerative and regenerative changes. Similar lymphocytic infiltrations were observed in the pancreas and kidney of a few mice immunized with CAII. Among several mouse strains with different H-2 haplotypes (p, q, r, s, and u), strains bearing H-2s and H-2u were susceptible to CAII-induced sialoadenitis. These results indicate that sialoadenitis induced by the immunization of CAII in mice may serve as a disease model of Sjögren's syndrome and that CAII or its derived peptides in association with the MHC may be one Ag recognized by an autoimmune response in this syndrome.
CD82, member of the tetra-span-transmembrane protein family, is a costimulatory protein for T cell activation.
Authors: Lebel-Binay S , Lagaudrière C , Fradelizi D , Conjeaud H 
Published: December 2022

Abstract
It is now well documented that full activation of T cells requires a two-signal triggering that can be mimicked, in the absence of accessory cells, by co-immobilization of mAbs directed to stimulatory/accessory molecules (CD2, CD3, CD28, adhesion molecules, etc.). In this report, we describe that engagement of CD82 can delivery such a costimulatory signal for full activation of the human T cell line Jurkat, leading to strong IL-2 production and cell differentiation. The CD82 Ag, which belongs to the new tetra-span-transmembrane family (CD9, CD37, CD53, CD63, and CD81 (TAPA-1)), has been identified originally in our laboratory for its enhanced expression on three LAK-susceptible cell lines, and has been characterized as an activation/differentiation marker of mononuclear cells. Jurkat cells, stimulated in vitro by co-immobilization of anti-CD82 and anti-CD3 mAbs, produced high levels of IL-2, became strongly adherent to plastic dishes, and developed dendritic processes. These morphologic changes, associated with a total arrest of cell proliferation, were not the result of cell death but rather of cell differentiation, as shown by an increase in their metabolic activity. Costimulation through both CD82 and CD3 induced up-regulation of both IL-2 and IFN-gamma mRNA synthesis (but not of IL-4) and an increased expression of HLA class I molecules at the cell surface, which was inhibited by anti-IFN-gamma Ab.
IL-12 inhibits the production of IL-4 and IL-10 in allergen-specific human CD4+ T lymphocytes.
Authors: Marshall J D , Secrist H , DeKruyff R H , Wolf S F , Umetsu D T 
Published: December 2022

Abstract
IL-12 influences cytokine synthesis in unprimed CD4+ T cells by enhancing IFN-gamma synthesis and enhancing the development of Th1 cells, but its effects upon Ag-primed T cells, which are thought to have relatively fixed cytokine profiles, is less clear. We investigated the capacity of IL-12 to modify cytokine synthesis in allergen-specific human CD4+ T lymphocytes from allergic donors after in vitro stimulation. CD4+ T cells were obtained from the peripheral blood of subjects with allergic rhinitis, depleted of activated T cells, and cultured with APCs and allergen. IL-12 dramatically inhibited the development of IL-4 and IL-10 synthesis, while it enhanced T cell secretion of IFN-gamma and IL-2, and enhanced Ag-specific T cell proliferation. The inhibitory effect of IL-12 on IL-4 synthesis was not dependent on the presence of IFN-gamma, was greatest when IL-12 was added at the initiation of culture, and was minimal when added late, indicating that resting memory CD4+ T cells were more sensitive than activated CD4+ T cells to the effects of IL-12. The effect of IL-12 on IL-4 and IL-10 synthesis was not dependent on the APC type, because IL-12 decreased IL-4 synthesis when either B cells or monocytes served as APCs. These results indicate that IL-12 may be therapeutically beneficial in the treatment of allergic diseases in which allergen-specific T cells characteristically produce enhanced quantities of IL-4 and IL-10.
Antigen-presenting T cells induce the development of cytotoxic CD4+ T cells. I. Involvement of the CD80-CD28 adhesion molecules.
Authors: Mauri D , Wyss-Coray T , Gallati H , Pichler W J 
Published: December 2022

Abstract
The development of cytotoxic CD4+ T lymphocytes that can kill target cells in a MHC class II-restricted manner was evaluated by comparing different APCs. B-lymphoblasts (B-LCL) pulsed with the superantigen staphylococcus enterotoxin B or allogeneic B-lymphoblasts induce CD4+ T cells without cytotoxic activity. In contrast, superantigen-pulsed, MHC class II+ T cell blasts or allogeneic T cell blasts preferentially induce the development of specific, MHC class II-restricted CD4+ cytotoxic effector cells. CD4+ T cell clones generated with T or B cell blasts as APCs (T- or B-APCs) differ in their cytolytic potential, but secrete a similar cytokine pattern. Our data implicate that activated T-APCs preferentially induce a cytotoxic, CD8+ and CD4+ T cell response. Because the density of CD80 expression is lower on activated T-APCs than on B-APCs, we studied the involvement of CD28 and CD80 adhesion molecules in the generation of CD4+ CTLs. Partial blockade of the CD80 molecule with a CTLA4-Ig fusion protein and with specific anti-CD80 mAbs on B-APCs enhanced the generation of CD4+ CTLs. Specific anti-CD86 mAbs, on the contrary, had no effect on the generation of CD4+ CTLs. In contrast, stimulation of CD28, the CD80 counter-receptor, with a cross-linked B7-Ig fusion protein or with an anti-CD28 mAb, inhibited the generation of CD4+ CTLs. Thus, a reduced interaction between CD80 and CD28 may be relevant for the induction of CD4+ CTLs. This shows a new and not yet described function of these adhesion molecules. This induction of a cytotoxic immune response by T cells as APCs may be relevant for the anticlonotypic regulation of T cells and for the depletion of CD4+ T cells in HIV infection.
B cell superstimulatory influenza virus activates peritoneal B cells.
Authors: Rott O , Charreire J , Mignon-Godefroy K , Cash E 
Published: December 2022

Abstract
We evaluated the potential of B cell "superstimulatory" influenza viruses to activate peritoneal B cells (PBC) from BALB/c mice containing both CD5+ and CD5- "sister" cells. Like conventional B cells, PBCs responded to influenza viruses in a hemagglutinin glycoprotein (HA) subtype-specific manner with proliferation and vigorous Ig synthesis. However, a number of HA subtypes that are highly stimulatory for conventional B cells failed to induce significant responses of PBC. Isotype-determination revealed a high predominance of IgM and only very low production of IgA and IgG. HA-activated CD5+ B cells showed a hyperexpression of various activation markers, including MHC class II, intercellular adhesion molecule 1 (CD54), and B7-1 molecules. In contrast to conventional B cells, where activation by HA is antagonized by phorbol esters (PMA), HA and PMA acted synergistically on PBC, suggesting differential activation requirements of B-2 cells vs PBC in response to HA. Like HA stimulation of B-2 cells, virus-triggered proliferation of PBC was abrogated by a simultaneous treatment with F(ab')2 fragments of anti-Ig Ab and exhibited synergistic effects with LPS stimulation. HA-mediated proliferative responses of PBC, but not of B-2 cells, were positively controlled by various cytokines, including IL-4 and IL-10, and to a lesser extent by IL-6. In conclusion, our data present the first example of a stimulation of peritoneal B cells by a polyclonal-activating virus, findings that call for considering infections with polyclonal B cell-stimulatory viruses as a means of expanding the pool of potentially autoreactive CD5+ B cells.
Expression of CD45RB and CD27 identifies subsets of CD4+ memory T cells with different capacities to induce B cell differentiation.
Authors: Tortorella C , Schulze-Koops H , Thomas R , Splawski J B , Davis L S , Picker L J , Lipsky P E 
Published: December 2022

Abstract
The capacity of four subsets of CD4+ memory T cells, defined by expression of CD45RB and CD27, to provide help for B cells was examined. Larger amounts of Ig were induced by CD45RBdimCD27- cells compared with the CD45RBdimCD27+ population, whereas CD45RBbrightCD27+ or CD27- cells were poor inducers of Ig synthesis. Mitomycin C treatment, which prevents suppressive activity, markedly enhanced Ig production supported by each subset except for CD45RBbrightCD27- cells. Mitomycin C-treated CD45RBdim cells remained the most efficient inducers of Ig production, but no difference was detected between CD27+ and CD27- cells. The subsets also differed in their ability to proliferate and secrete cytokines, but these differences did not explain variations in the capacity to provide help for B cells. Both CD27- subsets exhibited decreased proliferation and uniquely secreted IL-4, with the CD45RBdimCD27- subset producing the greatest quantities of IL-4. No differences in IL-2 and IFN-gamma production were found. IL-10 secretion increased with the acquisition of the CD45RBdim phenotype and, within the CD45RBdim cells, with the loss of CD27. Staining for cytoplasmic cytokines indicated that individual populations of CD27-CD4+ helper T cells produced either IL-4 or IFN-gamma, whereas more than half of the IL-4 producers also synthesized IL-2. Finally, the different abilities of CD4+ memory T cell subsets to support B cell differentiation did not relate to variations in the expression of CD40 ligand. These results indicate that within the CD4+ memory T cell population an increase of helper activity associates with the shift from a CD45RBbright to a CD45RBdim phenotype. Within the CD45RBdim subset, the loss of CD27 is associated with a reduction of suppressive activity.
The extracellular neutral cysteine proteinase of Entamoeba histolytica degrades anaphylatoxins C3a and C5a.
Authors: Reed S L , Ember J A , Herdman D S , DiScipio R G , Hugli T E , Gigli I 
Published: December 2022

Abstract
We have shown previously that the extracellular cysteine proteinase of Entamoeba histolytica trophozoites activates the alternative pathway of complement by specifically cleaving C3. This unique mechanism of complement activation leads to passive lysis of nonpathogenic, but not of pathogenic strains. In an attempt to investigate the relationship between the cleavage of complement components C3 and C5 and the pathogenesis of amebiasis, we investigated the production of the anaphylatoxins C3a and C5a, which have diverse effects on the host immune response. The concentration of proteinase required to cleave purified C5 was at least 5 to 10 times that needed for C3 cleavage, but these levels are easily obtainable as demonstrated by cleavage of 125I-labeled C5 during incubation with purified trophozoites. When the C3a-like cleavage fragments were purified by gel filtration, they were found to be extensively degraded during a 1-h incubation of C3 with the proteinase. Subsequent evaluations of the C3a- and C5a-like cleavage products generated earlier in the reaction using immunoblots and cellulose acetate electrophoresis revealed rapid degradation, even during incubation periods as short as 5 min. Because C-terminal fragments as small as 20 amino acid residues can mimic the biologic functions of C3a or C5a, we tested cleavage products for activity. In sensitive bioassays, including guinea pig platelet aggregation for C3a activity and chemotaxis for C5a activity, we demonstrated that proteolysis renders these molecules inactive. These studies suggest that the extracellular cysteine proteinase of E. histolytica, which is capable of activating the complement system, may also provide a mechanism to circumvent normal host immunity by inactivating the proinflammatory factors C3a and C5a.
Expression of functional receptors for human C5a anaphylatoxin (CD88) on the human hepatocellular carcinoma cell line HepG2. Stimulation of acute-phase protein-specific mRNA and protein synthesis by human C5a anaphylatoxin.
Authors: Buchner R R , Hugli T E , Ember J A , Morgan E L 
Published: December 2022

Abstract
Acute inflammation is characterized by increased production of acute phase proteins in the liver. The induction of the hepatocytic response is primarily mediated through soluble cytokines such as IL-1, IL-6, TNF-alpha, and transforming growth factor beta, which bind to specific cell surface receptors and regulate gene expression of acute-phase proteins. Hepatoma cell lines, such as HepG2, represent a model system for studying acute-phase protein synthesis. HepG2 is induced to produce a variety of acute-phase proteins, including alpha 1-antitrypsin, alpha 1-antichymotrypsin, fibrinogen, alpha 1-acid glycoprotein, and haptoglobin, upon stimulation with cytokines. Analysis of HepG2 by reverse transcriptase PCR indicated that this cell line synthesized mRNA specific for the human C5a receptor (CD88). Flow cytometric analysis of HepG2 cells indicated that these cells bound anti-CD88 Ab, thus confirming our RT-PCR data by demonstrating that these cells also express the C5a receptor. Because C5a has been shown to be a potent mediator of inflammation and HepG2 cells express CD88, we assessed the possibility that C5a was capable of stimulating acute-phase protein synthesis by HepG2 cells. The results indicate that binding of human C5a to CD88 on HepG2 cells resulted in an increased production of alpha 1-antitrypsin- and alpha 1-antichymotrypsin-specific mRNA as assayed by RT-PCR. Analysis of culture supernatants derived from C5a-stimulated HepG2 cells showed an increased production of alpha 1-antitrypsin as measured by solid-phase ELISA. alpha 1-antitrypsin production by HepG2 cells was a direct result of C5a stimulation as evidenced by the fact that anti-C5a receptor Ab inhibited the response. These results suggest that C5a may be an important mediator of APP production in the regulation of the inflammatory response.
Identification of complement regulatory domains in human factor H.
Authors: Gordon D L , Kaufman R M , Blackmore T K , Kwong J , Lublin D M 
Published: December 2022

Abstract
Factor H, a regulator of complement activation, contains 20 short consensus repeat (SCR) domains common among the family of C3b/C4b-binding proteins. Chinese hamster ovary cells transfected with cDNA corresponding to the N-terminal tryptic fragment of factor H (containing SCR 1-5 and part of SCR 6) secreted protein with cofactor activity for factor I-dependent cleavage of C3b. A series of deletion mutants, each lacking one of the first five SCR, were constructed, and the supernatants of transfected Chinese hamster ovary cells were tested for cofactor activity. Supernatants of Chinese hamster ovary cells transfected with SCR 1, SCR 4, and SCR 5 deletion mutants retained cofactor function, although the SCR 1 deletion had reduced cofactor activity. Deletion of SCR 2 or 3 totally abolished cofactor activity. Expression and functional analysis of SCR units 1-3, 2-3, and 2-4 demonstrated that the SCR 1-3 unit is sufficient for cofactor activity, but SCR 1-4 is required for full activity. For assays involving cell protection, a construct linking SCR 1-5 to the glycosyl-phosphatidylinositol anchor of decay-accelerating factor was prepared, and stable transfectants were obtained. These cells were protected against complement-mediated cytotoxicity, similarly to decay-accelerating factor- and membrane cofactor protein-transfected cells. These studies define the complement regulatory domains in factor H and suggest that the general complement functional unit for C3 convertase regulation involves three or four consecutive SCR units.
A novel canine leukointegrin, alpha d beta 2, is expressed by specific macrophage subpopulations in tissue and a minor CD8+ lymphocyte subpopulation in peripheral blood.
Authors: Danilenko D M , Rossitto P V , Van der Vieren M , Le Trong H , McDonough S P , Affolter V K , Moore P F 
Published: December 2022

Abstract
The beta 2 or leukointegrin family is comprised of three structurally related leukocyte surface heterodimers: LFA-1 (CD11a/CD18), Mac-1/Mo-1 (CD11b/CD18), and p150,95 (CD11c/CD18). In this work, we describe a novel canine beta 2 (CD18)-associated leukointegrin, designated alpha d. Expression of alpha d in tissues was prominent in macrophages in splenic red pulp, lymph node medullary regions, and bone marrow. In peripheral blood, alpha d expression was limited to a minor subpopulation of CD8+ T cells, which included small lymphocytes and large granular lymphocytes. A minor subpopulation of either CD8+ or CD4-CD8- splenic red pulp lymphocytes also expressed alpha d. Immunoprecipitation of alpha d from canine splenocytes revealed a heterodimer of 155 kDa and 95 kDa. Prior clearance of splenocyte extracts with an anti-CD18 mAb resulted in complete removal of alpha d. In addition, prior clearance of canine splenocyte extracts with anti-CD11a, anti-CD11b, or anti-CD11c mAb failed to clear alpha d. These immunoclearance data indicated that canine alpha d was antigenically distinct from the three known CD11 molecules, and occurred as an alpha d beta 2 heterodimer. Amino acid sequencing of canine alpha d affinity isolated from spleen further suggested that canine alpha d beta 2 probably represented a fourth member of the canine leukointegrin family via its homology to a subsequently discovered, novel human leukointegrin, alpha d beta 2, which further supported the uniqueness of the canine protein. The discovery of canine alpha d, and the demonstration of its highly restricted cell and tissue distribution, support a re-evaluation of leukointegrin-dependent inflammatory and immunologic interactions that involve cells now known to express alpha d.
Lung macrophage uptake of unopsonized environmental particulates. Role of scavenger-type receptors.
Authors: Kobzik L 
Published: December 2022

Abstract
The receptors responsible for avid alveolar macrophage (AM) phagocytosis of unopsonized environmental particulates have not been well defined. This study used flow cytometry to quantitate the effects of a panel of soluble ligands for macrophage adhesion receptors on AM binding of unopsonized environmental dusts (titanium dioxide, TiO2; iron oxide, Fe2O3; alpha-quartz, SiO2; diesel engine exhaust dust) or fluorescent latex beads. Polyanionic ligands of the macrophage scavenger receptor (SR) for acetylated-LDL caused marked inhibition of AM binding of the oxide particles and latex beads (e.g., TiO2 binding; polyinosinic acid (polyl), 10 micrograms/ml: 70.2 +/- 1.5% inhibition, mean +/- SE, n = 11). In contrast, no inhibition was seen with the polyanions heparin and chondroitin sulfate (chond-S), or dextran, consistent with the known inhibitor profile of macrophage SRs for acetylated-LDL AM uptake of latex or SiO2 beads instilled into lungs of hamsters was inhibited by administration of polyl but not chondroitin sulfate (AM beads per cell: control, 6.1 +/- 0.7; polyl, 3.5 +/- 0.2; chond-S, 5.1 +/- 0.7, n &gt; or = 4, p &lt; 0.05 for control vs polyl) indicating macrophages SRs operate in vivo as well as in vitro. In contrast, AM binding of the carbonaceous diesel dust particles was not inhibited by any ligand tested. AM uptake of unopsonized TiO2, SR ligands or acetylated LDL caused no significant activation of AM respiratory burst or TNF production, consistent with past observations that opsonin-independent phagocytosis of inert particles by normal AMs is not accompanied by pro-inflammatory activation. These data implicate macrophage-type SRs in AM binding of charged environmental particles and indicate that distinct mechanisms mediate binding of carbonaceous dusts.