bluuebunny/crossref_metadata_2025_split huggingface dataset:
Platelet activating factor and endotoxin increase the enzyme activity and gene expression of type II phospholipase A2 in the rat intestine. Role of polymorphonuclear leukocytes.
Authors: Tan X D , Wang H , Gonzalez-Crussi F X , Chang H , Gonzalez-Crussi F , Hsueh W 
Published: December 2022

Abstract
Type II phospholipase A2 (PLA2-II) may regulate eicosanoid synthesis; is involved in various inflammatory processes, septic shock, and inflammatory bowel disease; and is up-regulated by LPS and inflammatory cytokines in vitro. We have previously shown that the platelet-activating factor (PAF)-induced intestinal injury is attenuated by peptido-leukotriene antagonists, suggesting a role of PLA2. The purpose of this study is to examine the regulation of intestinal PLA2-II by PAF and LPS. Using synthesized competitor RNA as competitor, we quantified PLA2-II transcripts by competitive reverse transcription-PCR. We found that PLA2-II gene is constitutively expressed in the rat ileum. PAF at a dose (1.5 micrograms/kg) below that causing intestinal injury rapidly up-regulated intestinal PLA2-II at both transcriptional and post-transcriptional levels, almost tripling its transcripts and significantly increasing enzyme activity in 30 min. LPS (5 mg/kg) also up-regulated PLA2-II. This effect could not be blocked by PAF antagonist. Depletion of circulating polymorphonuclear leukocytes (PMNs) abolished the effect of PAF on PLA2-II gene expression and enzyme activation. In contrast, PMN depletion prevented LPS-induced PLA2-II enzyme activity but enhanced the gene expression. We conclude that: 1) both PAF and LPS induce gene transcription and enzyme activation of PLA2-II in the small intestine; 2) PAF up-regulates PLA2-II via PMN activation; 3) LPS effect is independent of endogenous PAF formation; and 4) different pathways exist for PAF and LPS in the regulation of intestinal PLA2-II gene expression in vivo.
Localization of monocyte chemoattractant peptide-1 expression in the central nervous system in experimental autoimmune encephalomyelitis and trauma in the rat.
Authors: Berman J W , Guida M P , Warren J , Amat J , Brosnan C F 
Published: December 2022

Abstract
Monocyte chemoattractant protein-1 (MCP-1) is a member of the chemokine beta family of chemoattractants that has been shown to play a major role in the initiation of monocyte and T cell inflammation to sites of tissue injury. In this study, we have examined the distribution of MCP-1 expression in inflammation in the central nervous system (CNS) associated with the autoimmune disease experimental autoimmune encephalomyelitis (EAE) and compared the results with those detected in inflammation associated with trauma. In EAE, MCP-1 expression was detected at the onset of inflammation, prior to clinical expression of disease, in lymphocytes and endothelial cells in subarachnoid locations. Monocyte infiltration into these areas appeared 24 h later. After the onset of clinical signs, MCP-1 expression was widely distributed in the spinal cord with levels increasing and decreasing in association with disease activity. Lymphocytes, macrophages, astrocytes, and endothelial cells could be identified as sources of MCP-1 by immunoreactivity and in situ hybridization. A similar close correlation between macrophage infiltration and the levels of mRNA for MCP-1 was found in the CNS of rats subjected to trauma, and in these animals MCP-1 was detected by immunohistochemistry in macrophages and endothelial cells. The results support the conclusion that MCP-1 is an important mediator of inflammation in the CNS.
Functional differentiation of dendritic cells in rheumatoid arthritis: role of CD86 in the synovium.
Authors: Thomas R , Quinn C 
Published: December 2022

Abstract
Dendritic cells (DC) are the major APC in human peripheral blood (PB) and rheumatoid synovium. We previously identified in PB a population of CD33dim-CD14dim DC precursors, as well as a smaller population of CD33bright CD14dim mature DC. Neither PB DC population expressed the CD28/CTLA4 ligands, suggesting that additional signals are required for full functional DC differentiation. Because rheumatoid synovium is characterized by an ongoing immune response, the expression and function of CD80, CD86, and other markers of DC differentiation by rheumatoid arthritis synovial APC were examined. The phenotype of a large subset of freshly isolated rheumatoid arthritis synovial fluid (SF) DC resembled that of the mature PB DC. These DC expressed CD45R0, CD11c, CMRF-44, and high levels of CD33. Whereas CD80 expression by rheumatoid SF DC and monocytes was minimal, CD86 was expressed by a subset of SF monocytes and by CMRF-44+SF DC. Furthermore, sorted CD86- SF DC spontaneously up-regulated CD86 in vitro. CD80 was expressed diffusely and at low levels by rheumatoid synovial tissue cells, whereas CD86 was expressed by perivascular HLA-DR+HLA-DQ+CD80+CMRF-44+ DC, and by some CD14+ monocytes. Anti-CD86 mAb and CTLA4 Ig, but not anti-CD80 mAb, inhibited the MLR stimulated by SF DC. Both CMRF-44+ and CMRF-44- SF DC were efficient stimulators of the allogeneic MLR, which was in each case blocked by CTLA4 Ig. The data indicate that rheumatoid synovial DC can undergo full functional differentiation, associated with CD86 expression, in vitro and in situ. Synovial DC expressing high levels of MHC molecules and CD86 are strategically located to present arthritogenic Ag to T cells after transendothelial migration.
Continuous administration of Il-13 to mice induces extramedullary hemopoiesis and monocytosis.
Authors: Lai Y H , Heslan J M , Poppema S , Elliott J F , Mosmann T R 
Published: December 2022

Abstract
IL-13, a recently identified Th2 cytokine, shares some, but not all, IL-4 functions, including inhibition of monocyte and macrophage activation, stimulation of human B cells, and induction of growth and differentiation of mouse bone marrow cells in vitro. We have now tested the in vivo effects of recombinant mouse IL-13 (rIL-13) from stably transfected, high expressing BW5147 thymoma cells. After purification by anion exchange chromatography, rIL-13 was administered in the peritoneal cavity of BALB/c mice via osmotic pump for 7 days. Spleens from the rIL-13-treated mice were significantly enlarged compared with control spleens due to increased cellularity. In particular, increased numbers of immature erythroblasts and megakaryocytes were observed in splenic sections after rIL-13 treatment. Spleen cells from rIL-13-treated mice showed greatly increased responsiveness in vitro to recombinant forms of mouse IL-3, mouse granulocyte-macrophage CSF, or human CSF-1 and, to a lesser extent, to mouse IL-4 or IL-13. Moreover, the rIL-13-treated mice also showed significant increases in CFU-E, CFU-C, and erythroid burst colonies in the spleen, further indicating the presence of increased numbers of hemopoietic precursors. Hematologic analyses indicated that rIL-13 treatment induced slight anemia and striking monocytosis. Finally, spleen cells from rIL-13-treated mice produced significantly more IL-6 upon LPS stimulation. Interestingly, the strong Th2 response induced by Nippostrongylus brasiliensis infection was also accompanied by an increase in hemopoietic precursor frequencies in the spleen. Collectively, these data indicate that exogenous rIL-13 induces extramedullary hemopoiesis in mice and suggest that endogenous IL-13 may contribute to replenishment of effector cells during strong Th2 responses.
Kinetically coordinated induction of TAP1 and HLA class I by IFN-gamma: the rapid induction of TAP1 by IFN-gamma is mediated by Stat1 alpha.
Authors: Min W , Pober J S , Johnson D R 
Published: December 2022

Abstract
Transporter associated with Ag processing-1 (TAP1) is induced by IFN-gamma more rapidly than is HLA class I. Kinetic analysis of transfectants reveals that IFN-gamma activates the TAP1 promoter more rapidly than the HLA-B7 class I promoter. A gamma-activating sequence (GAS) in the TAP1 promoter is necessary for the rapid induction by IFN-gamma. Two overlapping IFN consensus sequences contribute to the constitutive and TNF-induced expression of TAP1 but are not necessary for the IFN-gamma response. Moreover, IFN-gamma activates the GAS-binding protein Stat1 alpha much more rapidly than it induces the IFN consensus sequence-binding protein IRF-1, which mediates the response of the HLA-B7 class I promoter. We conclude that IFN-gamma uses different transcription factors to regulate the sequence of appearance of these interacting gene products.
HLA-DQ8 transgenic mice lacking endogenous class II molecules respond to house dust allergens: identification of antigenic epitopes.
Authors: Neeno T , Krco C J , Harders J , Baisch J , Cheng S , David C S 
Published: December 2022

Abstract
We have introduced HLA-DQ8 (HLADQB*0302 and HLA-DQA*0301) genes into A beta 0 knockout mice. Transgenic animals were immunized with a whole body extract of Dermatophagoides pteronyssinus (Der p), one of the causative agents of house dust mite allergy. Transgenic mice expressing HLA-DQ8 genes elicited HLA-DQ8-restricted responses driven by CD4+ T cells. Synthetic-overlapping peptides representing a major allergen of house dust mite (Der p 2) were synthesized and used as immunogens. HLA-DQ8+ mice responded to three peptides: 8 (residues 61-80), 11 (residues 91-110), and 13 (residues 111-129). The mice produced IL-2, IL-4, and IL-6 response to Der p challenge, suggesting a mixed Th1/Th2 response. These mice represent a new model for studies of the immune basis of allergy.
Tolerance of single, but not multiple, amino acid replacements in antibody VH CDR 2: a means of minimizing B cell wastage from somatic hypermutation?
Authors: Brown M , Rittenburg M B , Chen C , Roberts V A 
Published: December 2022

Abstract
Mutations in the heavy chain complementarity determining region 2 (CDR2) of the phosphocholine-specific T15 Ab can have a dramatic effect on the ability of the Ab to bind Ag. A panel of multisite mutants that had lost detectable binding to phosphocholine-containing Ags was previously created by saturation mutagenesis of the CDR2 region of T15. Based on the predicted importance of amino acid changes represented in the multisite mutants, we have created single-site mutations, yielding a panel of Abs with which to test 17 of the 19 CDR2 residues. Of the 17 positions examined, only one, Arg52, is intolerant to change, yielding a nonbinder phenotype even with conservative amino acid replacement. Mutation at two other sites, Ala50 and Tyr55, can yield a nonbinder phenotype depending on the amino acid replacement. Single-site mutations of the remaining 14 positions allowed retention of binding ability. Thus, except for positions 50, 52, and 55, multiple mutations must be introduced into the CDR2 region to create a nonbinder phenotype. We provide a newly refined model of T15, illustrating the structure and the interactions of the CDR2 region. Our results imply that introduction of point mutations would not normally delete Ag-binding ability until two or more mutations had accumulated. This would minimize potentially harmful effects of somatic mutation on Ig V region genes and improve the chance of survival for an Ab such as T15, which in its unmutated form is already well suited to bind Ag.
MHC class I-dependent presentation of exoerythrocytic antigens to CD8+ T lymphocytes is required for protective immunity against Plasmodium berghei.
Authors: White K L , Snyder H L , Krzych U 
Published: December 2022

Abstract
T lymphocytes are believed to play a major role in protection against malaria. Previous experiments using in vivo depletion of CD8+ T cells, reconstitution with CD8+ T splenic cells, and adoptive transfer of CD8+ CTL clones demonstrated that protection against the exoerythrocytic stage of the murine strain, Plasmodium berghei malaria, was CD8+ T cell-dependent. Despite evidence for the critical role of CD8+ CTL, neither the cellular nor the molecular requirements for CD8+ T cell induction or for recognition of malaria Ags are known. In this study, we wished to define the role of CD8+ T cells and MHC class I molecules by using the P. berghei malaria attenuated sporozoites (SPZ) protection model in beta 2-microglobulin (beta 2m) knockout (-/-) mice. In contrast to observations that beta 2m-/- mice are resistant to many infectious diseases by compensatory mechanisms involving non-class I-restricted T cells, we found that beta 2m-/- mice failed to be protected against P. berghei SPZ, although immunization with attenuated SPZ induced production of IL-2, INF-gamma, anti-circumsporozoite protein IgG, and proliferative T cells. The lack of compensatory mechanisms involving non-CD8+ T cells was particularly evident in the failure to adoptively transfer protective immunity with wild-type SPZ-immune splenic T cells. From our data it can be concluded that CD8+ T cells induced during immunization with attenuated SPZ must recognize liver-expressed Ags presented by class I molecules to engage effectively in a response leading to destruction of the malaria parasites.
Chemotactic factors stimulate CD18-dependent canine neutrophil adherence and motility on lung fibroblasts.
Authors: Burns A R , Simon S I , Kukielka G L , Rowen J L , Lu H , Mendoza L H , Brown E S , Entman M L , Smith C W 
Published: December 2022

Abstract
The mechanisms by which neutrophils migrate through the alveolar interstitium during acute lung inflammation are unknown. We wished to determine whether platelet-activating factor (PAF) and IL-8, two important mediators in neutrophil transendothelial migration, stimulated neutrophil adherence and motility on lung fibroblasts. Canine fibroblasts grown from lung explants were characterized by light and electron microscopy, and flow cytometry. Unstimulated neutrophils adhered poorly (less than 2%) to cultured fibroblasts. However, neutrophils stimulated with PAF (20-200 nM) showed a dose-dependent increase in adherence that was largely (70%) mediated by the beta 2 (CD11/CD18) integrins; adherence was less dependent (50%) on fibroblast intercellular adhesion molecule-1. Conversely, neutrophils stimulated with canine rIL-8 did not increase their adherence to fibroblasts. PAF-stimulated neutrophils were nonmotile on the surface of the fibroblast, but subsequent addition of rIL-8 (10(-8) M) induced motility that was entirely CD1 8 dependent. Fibroblasts stimulated with human rTNF-alpha or Escherichia coli endotoxin (LPS) were a significant source of IL-8 mRNA. In response to rTNF-alpha (50 U/ml), IL-8 mRNA was detected at 2 h by northern blot analysis; it peaked at 6 h and returned to baseline by 24 h. Fibroblasts stimulated with rTNF-alpha secreted IL-8 protein into the culture medium; secreted IL-8 was chemotactic for neutrophils. These data suggest that fibroblasts can function not only as an adhesive substrate, but also as a source of stimulation for neutrophil migration through the inflamed alveolar interstitium.
Heat shock mimics glucocorticoid effects on IFN-gamma-induced Fc gamma RI and Ia messenger RNA expression in mouse peritoneal macrophages.
Authors: Sivo J , Harmon J M , Vogel S N 
Published: December 2022

Abstract
Glucocorticoids activate or repress the expression of different genes. In murine macrophages, glucocorticoids exert opposing effects on the IFN-gamma-induced expression of Fc gamma RI and Ia mRNA and cell surface expression; they enhance IFN-gamma-induced Fc gamma RI mRNA and protein expression, yet inhibit IFN-gamma-induced Ia mRNA and protein expression. Recently, in transfected cell lines, heat shock (HS) has been shown to promote nuclear accumulation of the glucocorticoid receptor (GR), resulting in potentiation of certain GR-mediated responses. In this study, we compared the effects of HS and dexamethasone (DEX) treatment on the IFN-gamma induction of Fc gamma RI and Ia mRNA in murine primary peritoneal macrophages. Our results show that HS exerted the same opposing effects on these IFN-gamma-responsive genes as DEX at 37 degrees C. The glucocorticoid antagonist RU 486 blocked both DEX and HS-induced enhancement of IFN-gamma induction of Fc gamma RI, suggesting a common GR-mediated mechanism. While RU 486 also reversed DEX-induced repression of Ia mRNA expression, supporting a GR-mediated action, it did not affect HS-mediated repression, raising the possibility of a ligand-independent HS response pathway.
Regulation of cytokine production during development of autoimmune diabetes induced with multiple low doses of streptozotocin.
Authors: Herold K C , Vezys V , Sun Q , Viktora D , Seung E , Reiner S , Brown D R 
Published: December 2022

Abstract
Cytokines have been shown to play an important role in regulating tolerance to islet Ags and provoking destructive islet lesions. However, data from a number of experimental systems have been conflicting, and the role of cytokines produced by T lymphocytes at various stages of diabetes has not been clearly defined. We have studied the production of cytokines in the pancreas during the development of autoimmune diabetes induced in mice by administration of (5) low doses of streptozotocin (STZ) (MDSDM). Diabetes in this model is T lymphocyte dependent. We used techniques of semiquantitative PCR to identify and quantitate cytokines that are produced. We have found that IL-2, IL-4, TNF-alpha, and IFN-gamma are expressed by the time the fourth dose of STZ is given. In the same pancreas, all of these cytokines (including IL-4) may be found. However, expression of IFN-gamma, but not IL-4, was limited to intrapancreatic lymphocytes and was not detectable at extrapancreatic lymphoid sites. Moreover, mAbs against IFN-gamma, but not against IL-4 or IL-2, prevent hyperglycemia and insulitis in MDSDM, suggesting that IFN-gamma regulates development of disease. Cells in the pancreases of nondiabetic mice treated with anti-IFN-gamma mAb and STZ show enhanced expression of IL-4, but the prevention of disease is due to blockade of the IFN-gamma itself, and not due to secretion of IL-4, because systemic administration of IL-4 does not prevent MDSDM. Thus, our findings indicate that cytokines produced by Th1 (or T cytolytic 1) and Th2 (or T cytolytic 2) cells are found in the pancreases of mice developing autoimmune diabetes. IFN-gamma is responsible for progression to diabetes, and its production is limited to lymphocytes only at that site.
Blockade of platelet endothelial cell adhesion molecule-1 protects against myocardial ischemia and reperfusion injury in cats.
Authors: Murohara T , Delyani J A , Albelda S M , Lefer A M 
Published: December 2022

Abstract
Polymorphonuclear leukocytes have been shown to play an important role in myocardial ischemia (MI) and reperfusion (R) injury. Since blockade of platelet-endothelial cell adhesion molecules (PECAM-1) inhibits neutrophil transmigration in vitro and in vivo, the effects of a polygonal Ab directed against PECAM-1 were examined in a feline model of Ml/R. We established cross-reactivity of our anti-human PECAM-1 Ab to cat coronary vasculature and neutrophils by immunohistochemistry and flow cytometry. The anti-PECAM-1 Ab markedly blocked leukocyte transmigration into the peritoneal cavity of cats after glycogen-induced peritonitis. Then, anti-PECAM-1 Ab (1 mg/kg) was tested to determine whether it attenuates MI/R injury in a well characterized feline model of Ml and R. Anti-PECAM-1 Ab administered 10 min before R significantly inhibited the myocardial necrosis seen 4.5 h post-R compared with that in MI/R cats treated with control isotype rabbit IgG (12 +/- 2 vs 29 +/- 4% of area at risk; p less than 0.01) and significantly attenuated the rise in plasma creatine kinase activity (p less than 0.05). The Ab did not prevent increases in cardiac myeloperoxidase activity within the affected regions and did not significantly inhibit autologous neutrophil adhesion to coronary endothelium after stimulation of either neutrophils (by leukotriene B4) or coronary endothelium (by thrombin) in vitro. These results indicate that in vivo blockade of PECAM-1 significantly attenuates MI/R injury, presumably by inhibiting transendothelial migration of neutrophils.
Human CD4-internal antigen anti-idiotypic monoclonal antibody: induction of a CD4-specific response in humans.
Authors: Perosa F , Scudeletti M , Imro M A , Dammacco F , Indiveri F 
Published: December 2022

Abstract
We previously showed that anti-idiotypic mAb (mAb2) F16-16D7 (16D7) to the paratope (or paratope-related idiotope) of the anti-CD4 mAb HP2/6 induces anti-CD4 Abs in BALB/c mice. In view of the potential ability of 16D7 to induce anti-CD4 Ab in humans and the potential benefits of anti-CD4 Abs in the treatment of autoimmune diseases, we evaluated the immunologic response to and assessed the safety of four 2-mg 16D7 s.c. injections in one patient with systemic lupus erythematosus (SLE) and one with rheumatoid arthritis (RA). 16D7 induced anti-isotypic and anti-anti-idiotypic Abs (Ab3), which were almost exclusively of the IgG isotype. Ab3 specifically reacted with 16D7 as they inhibited its binding to mAb HP2/6. Although Ab3 did not react with cellular or recombinant CD4 (rCD4), single-cell enzyme-linked immunospot assays of anti-CD4 Ab production revealed many more spot-forming cells in rCD4- and 16D7-coated wells than in wells coated with BSA or 16D7 isotype-matched MK2-23. Spot-forming anti-CD4 Abs were specifically induced by 16D7, since rCD4-dependent spot formation 1) was not observed with PBL from one patient with SLE, one with mixed connective tissue disease, and one with melanoma immunized with MK2-23; and 2) was inhibited by 16D7 and not by MK2-23. Spot-forming anti-CD4 Abs recognize a CD4 epitope identical (or closely related) to that seen by HP2/6, since this specifically inhibited spot formation. A substantial, although transient, CD4+ T cell depletion was only observed in the RA patient. Local and/or general toxicity and laboratory and/or clinical signs indicative of immunodepression or diseases relapse were not observed during an 18-month follow-up.
Rheumatoid factor idiotypic and antigenic specificity is strongly influenced by the light chain VJ junction.
Authors: Zhang M , Spey D , Ackerman S , Majid A , Davidson A 
Published: December 2022

Abstract
The aim of this study was to define the structural basis for rheumatoid factor (RF) specificity and for the expression of the RF light chain-associated Ids, 4C9 and 6B6.6, by determining the reactivity of recombined heavy and light chains of Ig derived from monoclonal B cell lines of patients with rheumatoid arthritis and of light chains with site-directed mutations. We found that expression of the 4C9 and 6B6.6 Ids resulted from use of the VkIIIa genes Humkv 328 and Vg, but only in the presence of a permissive VJ junction. Expression of the Ids was independent of heavy chain use for the Humkv328-encoded light chains, but was highly dependent on the associated heavy chain for the Vg-encoded light chains. The RF specificity of the Abs was primarily heavy chain dependent, but the light chain VJ junction was critical in determining the relative avidity of the Abs for Fc. Our study points to the critical contribution of the somatically generated VJ junction to RF autoantibody specificity and to the expression of the two RF-associated Ids studied.