bluuebunny/crossref_metadata_2025_split huggingface dataset:
Site-directed mutagenesis of the phosphocholine-binding site of human C-reactive protein: role of Thr76 and Trp67.
Authors: Agrawal A , Lee S , Carson M , Narayana S V , Greenhough T J , Volanakis J E 
Published: December 2022

Abstract
We have reported previously that residues Lys57, Arg58, and Trp67 of human C-reactive protein (CRP) contribute to the structure of the phosphocholine (PCh)-binding site. In this study, based on the three-dimensional structures of human CRP and serum amyloid P, we constructed an additional mutant, T76Y, to probe the structural determinants of the PCh-binding site of CRP. Binding properties of four mutant CRPs, K57Q/R58G, W67K, K57Q/R58G/W67K, and T76Y were compared. Wild-type (wt) and all mutant CRPs were purified by affinity chromatography on PCh-, pneumococcal C-polysaccharide (PnC)-, or phosphoethanolamine-conjugated agarose columns. Purified mutant CRPs, K57Q/R58G/W67K and T76Y failed to bind to solid phase, PCh-substituted BSA. They did, however, bind to immobilized PnC, although with substantially decreased avidity compared with wt CRP. W67K, K57Q/R58G/W67K, and T76Y CRP required a 10-fold higher Ca2+ concentration than wt CRP to bind PnC and exhibited decreased avidity for mAb EA4.1, which recognizes a Ca2+-dependent epitope. We conclude that Thr76 is a determinant of the PCh-binding site, probably interacting with the choline group. This conclusion is supported by recent crystallographic data indicating that this residue participates in the formation of a hydrophobic pocket that constitutes the binding site for choline. Trp67, Lys57, and Arg58 do not directly contact PCh, but appear to be required for the proper conformation of the binding site.
Mouse bone marrow-derived mast cells undergo exocytosis, prostanoid generation, and cytokine expression in response to G protein-activating polybasic compounds after coculture with fibroblasts in the presence of c-kit ligand.
Authors: Ogasawara T , Murakami M , Suzuki-Nishimura T , Uchida M K , Kudo I 
Published: December 2022

Abstract
Polycationic mast cell activators, such as compound 48/80 and substance P, have been reported to activate connective tissue-type mast cells specifically by interacting directly with the Gi family of trimeric GTP-binding protein. We now demonstrate that mouse bone marrow-derived mast cells (BMMC) developed in IL-3, an immature mast cell population lacking responsiveness to the Gi-coupled polycationic mast cell activators, underwent maturation toward a connective tissue-type mast cells-like phenotype that responded to polycationic compounds after only 4 to 6 days of coculture with Swiss 3T3 fibroblasts in concert with recombinant soluble c-kit ligand (KL), whereas 3T3 or KL alone was insufficient to mediate this process. Under optimal conditions, cocultured BMMC released approximately 30% beta-hexosaminidase and generated approximately 1 ng of PGD2/10(6) cells within a few minutes in response to compound 48/80 or substance P. Furthermore, these cells expressed cytokines, such as IL-1beta and IL-6, and PG endoperoxide synthase-2 1 to 4 h after stimulation with compound 48/80 or substance P. All these responses were suppressed effectively by pertussis toxin, implicating functional Gi coupling. Regardless of the remarkable change in polycationic compound sensitivity, there was only a minimal change in the constitutive expression of Gi3 alpha after coculture. These results together with the observation that before coculture BMMC responded to thrombin through its Gi-coupled receptor suggest that the alteration in a certain step(s) distinct from the level of Gi3 alpha protein expression is important for the acquisition of responsiveness to the polycationic compounds by the synergistic action of KL and 3T3 fibroblast-derived factor. Several lines of evidence have revealed that 3T3-derived factor appears to differ from the known cytokines, prostanoids, and adhesion molecules and is a labile soluble substance.
Involvement of 26-kDa cell-associated TNF-alpha in experimental hepatitis and exacerbation of liver injury with a matrix metalloproteinase inhibitor.
Authors: Solorzano C C , Ksontini R , Pruitt J H , Hess P J , Edwards P D , Kaibara A , Abouhamze A , Auffenberg T , Galardy R E , Vauthey J N , Copeland E M , Edwards C K , Lauwers G Y , Clare-Salzler M , MacKay S L , Moldawer L L , Lazarus D D 
Published: December 2022

Abstract
TNF-alpha is a pleiotropic cytokine that exists both as a 26-kDa cell-associated and a 17-kDa soluble form. Recently, a class of matrix metalloproteinase inhibitors has been identified that can prevent the processing by TNF convertase of 26-kDa TNF-alpha to its 17-kDa form and can reduce mortality from normally lethal doses of D-galactosamine plus LPS (D-GalN/LPS). Here we report that a matrix metalloproteinase inhibitor, GM-6001, improves survival but does not protect against liver injury from D-GalN/LPS-induced shock in the mouse. In Con A-induced hepatitis, GM-6001 actually exacerbates hepatocellular necrosis and apoptosis despite greater than 90% reduction in plasma TNF-alpha concentrations. Treatment with GM-6001 also has minimal effect on the concentration of membrane-associated TNF-alpha in the livers of animals with Con A induced hepatitis. In contrast, a TNF binding protein (TNF-bp), which neutralizes both membrane-associated and soluble TNF-alpha, prevents D-GalN/LPS- and Con A-induced hepatitis. Our studies suggest that cell-associated TNF-alpha plays a role in the hepatocellular necrosis and apoptosis that accompany D-GalN/LPS- or Con A-induced hepatitis, and that matrix metalloproteinase inhibitors are ineffective in preventing this hepatic injury.
Chemotaxis and IL-8 receptor expression in B cells from normal and HIV-infected subjects.
Authors: Jinquan T , Møller B , Storgaard M , Mukaida N , Bonde J , Grunnet N , Black F T , Larsen C G , Matsushima K , Thestrup-Pedersen K 
Published: December 2022

Abstract
To date, the activities of the alpha chemokines for human peripheral B cells from normal subjects (N-B cells) or from HIV-infected subjects (HIV-B cells) are not well established. No report on the IL-8R expression on N-B cells and HIV-B cells has been seen. We report in this work that the alpha chemokines IL-8 and growth-regulatory oncogene-alpha (GRO-alpha) induce a chemotactic migration of N-B cells and HIV-B cells via stimulating the IL-8RB on these cells. The chemotaxis of N-B cells can be inhibited by IFN-gamma and IL-2, and augmented by IL-4 and IL-13, whereas TNF-alpha and IL-10 have no influence. The chemotaxis of HIV-B cells can be inhibited by IFN-gamma and IL-2, and augmented by TNF-alpha, IL-4, and IL-10, whereas IL-13 has no influence. IL-8R are expressed more abundantly on freshly isolated HIV-B cells than N-B cells (51% and 15%, respectively). The IL-8R on N-B cells can be down-regulated by IFN-gamma, IL-2, and TNF-alpha (selectively on IL-8RA), and up-regulated by IL-4 and IL-13, whereas IL-10 has no influence. The IL-8R on HIV-B cells can be down-regulated by IFN-gamma and IL-2, and up-regulated by TNF-alpha, IL-4, and IL-10, whereas IL-13 has no influence. Importantly, N-B cell and HIV-B cell chemotaxis toward IL-8 and GRO-alpha can be blocked by anti-IL-8RB polyclonal Ab, but not by anti-IL-8RA polyclonal Ab. Our results demonstrate that IL-8 and GRO-alpha are important inflammatory mediators that stimulate the directional migration and recruitment of B lymphocytes. The migratory behavior and the expression of IL-8R on HIV-B cells and some of the reactions to Th1- and Th2-like cytokines are modified significantly during HIV infection.
IL-16 represses HIV-1 promoter activity.
Authors: Maciaszek J W , Parada N A , Cruikshank W W , Center D M , Kornfeld H , Viglianti G A 
Published: December 2022

Abstract
IL-16 is produced by CD8+ lymphocytes and has been reported to inhibit HIV-1 and SIV replication in infected PBMCs. CD4 serves as a receptor for the secreted form of IL-16, and IL-16 binding to CD4 induces signal transduction, which affects the activation state of the cell. We hypothesized, therefore, that the effect of IL-16 on HIV-1 replication might occur at the level of virus expression. In transient transfection studies with HIV-1 LTR-reporter gene constructs we found that pretreatment of CD4+ lymphoid cells with recombinant IL-16 repressed HIV-1 promoter activity up to 60-fold, preventing both PMA and Tat activation. This effect of IL-16 required sequences contained within the core enhancer, but was not simply due to the down-regulation of transcription factors binding to this element.
Beryllium induces IL-2 and IFN-gamma in berylliosis.
Authors: Tinkle S S , Kittle L A , Schumacher B A , Newman L S 
Published: December 2022

Abstract
Chronic beryllium disease (CBD) provides a model for study of the Ag-stimulated, cell-mediated immune response that, over time, progresses to granulomatous lung disease. Using cells obtained with bronchoalveolar lavage from patients with CBD and normal individuals, we evaluated beryllium salt-stimulated T lymphocyte proliferation and production of proinflammatory cytokines. Our findings demonstrate that beryllium sulfate stimulates production of both IL-2 and IFN-gamma, not IL-4 and IL-7. We observed a brief time course for IL-2 protein (6-48 h after BeSO4 stimulation) and mRNA production (3-6 h) and a protracted time course for IFN-gamma protein (24-168 h) and mRNA (0.25-168 h). Beryllium-stimulated T lymphocyte proliferation and IFN-gamma release were only partially inhibited by neutralization of IL-2. On the basis of these findings, we hypothesized that IFN-gamma and the IL-2/IFN-gamma-inducible alpha subunit of the soluble IL-2 receptor were elevated in serum and bronchoalveolar lavage fluid of individuals with disease and were molecular markers of granulomatous disease. The data demonstrate that levels of the alpha subunit of the soluble IL-2 receptor, but not IFN-gamma, are elevated in the serum (median = 1428 U/ml; interquartile range = 823-2137 U/ml) and bronchoalveolar lavage fluid (median = 1.56 U/ml, interquartile range = 1.04-4.22 U/ml) of patients with CBD and correlate with the degree of pulmonary lymphocytosis and clinical measures of disease severity. We conclude that IL-2 and IFN-gamma are produced in the beryllium-stimulated, cell-mediated immune response with different time courses and that the alpha subunit of the soluble IL-2 receptor may serve as a biomarker of disease progression.
Phenotypic and functional maturation of TCR gammadelta cells in the human thymus.
Authors: Offner F , Van Beneden K , Debacker V , Vanhecke D , Vandekerckhove B , Plum J , Leclercq G 
Published: December 2022

Abstract
In contrast to thymic differentiation of TCR alphabeta cells, differentiation stages of TCR gammadelta cells are largely unknown. This report shows that CD1, a known marker of immature TCR alphabeta thymocytes, was expressed on some postnatal TCR gammadelta thymocytes. Only CD1+ TCR gammadelta thymocytes expressed recombination-activating gene-1 mRNA, and they were shown to differentiate into CD1- TCR gammadelta thymocytes. Functionally, sorted CD1- TCR gammadelta thymocytes proliferated in the presence of immobilized anti-CD3 Ab plus exogenous rIL-2 or rIL-15. Interestingly, in contrast to CD1- TCR alphabeta cells, CD1- TCR gammadelta thymocytes also proliferated extensively when cultured with exogenous rIL-2 or rIL-15 alone. FACS analysis as well as reverse transcription-PCR analysis showed that only CD1- TCR gammadelta thymocytes expressed IL-2Rbeta protein and mRNA. The differential expression of maturation markers, such as CD27, CD45RO, and CD45RA, as a function of expression of CD1 was similar in TCR gammadelta and TCR alphabeta thymocytes. An important exception is the expression of CD4 and CD8. Whereas TCR alphabeta thymocytes are mainly CD4-CD8 double positive at the immature CD1+ stage and CD4 or CD8 single positive at the mature CD1- stage, CD1(bright) TCR gammadelta thymocytes all expressed CD4, but only some of them expressed CD8. Some CD1- TCR gammadelta thymocytes also expressed CD8, but were negative for CD4. Collectively, our data clearly show that CD1 is a useful marker to distinguish immature human TCR gammadelta thymocytes from functional mature gammadelta cells based on recombination-activating gene-1 expression, in vitro differentiation, and phenotypic and functional characteristics.
T cell deletion induced by chronic infection with mouse mammary tumor virus spares a CD25-positive, IL-10-producing T cell population with infectious capacity.
Authors: Papiernik M , Leite-de-MoraesM do Carmo , Pontoux C , Joret A M , Rocha B , Penit C , Dy M 
Published: December 2022

Abstract
We found that T cells recognizing viral superantigen (vSAG) can be subdivided into two distinct functional subsets based on IL-2R alpha (CD25) expression. CD4+Vbeta6+CD25- and CD4+Vbeta6+CD25+ T cells were sensitive to vSAG activation. When obtained from BALB/c(SW) mice, both subsets were infected and capable to induce the tolerance process when transferred into noninfected recipients. However, in contrast to CD4+Vbeta6+CD25- cells, which were gradually deleted in MMTV(SW)-infected mice, the pool of CD4+Vbeta6+CD25+ lymphocytes was constant even at the end of the deletion process, and maintained a limited reactivity to vSAG-induced activation. The constant number of Vbeta6+CD25+ observed in infected mice could not be explained by their rapid turnover (deletion and renewal), as their proliferative rate measured by BrdU incorporation was similar in infected and naive mice, as well as in virus-nonspecific (Vbeta8.2+) cells. Neither was the Vbeta6+CD25+ subset dependent on vSAG activation since it was also present in MMTV-free mice and was not generated from Vbeta6+CD25- cells upon in vivo vSAG stimulation. Vbeta6+CD25+ T cells constitutively expressed IL-4 and IL-10 mRNA. IL-10 has been shown to be associated with viral, bacterial, and parasitic infections. This permanent CD25+ subpopulation may play a role in the control of viral infection and tolerance induction via vSAG recognition and IL-10 production.
Apoptosis within spontaneously accepted mouse liver allografts: evidence for deletion of cytotoxic T cells and implications for tolerance induction.
Authors: Qian S , Lu L , Fu F , Li Y , Li W , Starzl T E , Fung J J , Thomson A W 
Published: December 2022

Abstract
MHC-mismatched liver grafts are accepted spontaneously between many mouse strains. The underlying mechanism(s) is unclear. In the B10 (H2(b)) to C3H (H2(k)) strain combination used in this study, donor T cells within the liver were rapidly replaced within 2 to 4 days of transplantation with those of the recipient. Freshly isolated liver graft-infiltrating cells harvested on days 4 and 7 exhibited strong CTL responses against donor alloantigens. CTL activity was reduced substantially, however, by day 14, although levels of CTL precursors in the spleen and liver remained high. Examination of the liver allografts by in situ terminal deoxynucleotidyltransferase-catalyzed dUTP-digoxigenin nick end labeling on days 4, 7, and 14 after transplantation revealed prominent apoptotic cells dispersed throughout the nonparenchymal cell population. When acute liver allograft rejection was induced by administration of IL-2 from days 0 to 4 post-transplant (median survival time, 5 days), apoptotic activity (day 4) was reduced substantially, whereas CTL activity was enhanced. Nonparenchymal cells isolated from allografts of unmodified recipients 4, 7, and 14 days after transplantation exhibited significantly higher DNA fragmentation after 18-h culture than cells from liver isografts. Moreover, the level was 4 to 5 times higher than that of cells from IL-2-treated mice (on day 4). These observations suggest that T cell deletion, not regulation, may be responsible for spontaneous liver allograft acceptance. The molecular recognition events that cause apoptosis of infiltrating T cells and why this occurs within liver grafts, but not heart or skin grafts, remain to be elucidated.
Impaired lymphokine secretion in anergic CD4+ T cells leads to defective help for B cell growth and differentiation.
Authors: Telander D G , Mueller D L 
Published: December 2022

Abstract
The ability of anergic helper T cells to interact with resting B cells was examined in vitro. B cell growth and differentiation in cocultures were found to be dependent on the expression of CD40 ligand (CD40L) on the cloned T cells, and the expression of this molecule was only marginally blocked by the induction of anergy. In contrast, secretion of IL-3, IL-4, IL-5, and IL-6 within the cocultures was found to be significantly reduced following the induction of anergy, and this correlated with the development of a 3- to 10-fold decrease in the ability of the T cells to induce B cell proliferation and IgG secretion. In contrast to the B cells, the activation of the T cells in these cocultures did not result in proliferation; thus, the effects of T cell anergy observed on the B cell responses were independent of an ability of clonal anergy to block T cell clonal expansion. In one T cell clone (E6), lymphokine production was reduced in part because of an increased propensity to undergo apoptosis; nevertheless, two other clones (A.E7 and 16B.2) showed no reduced viability after anergy induction. Finally, the addition of rIL-2 to the anergic T cells significantly improved their helper activity relative to control cells; this was associated with a partial reversal of the IL-3, - 4, and -5 production defects. Therefore, clonal anergy can interfere with the delivery of helper lymphokines by T cells, resulting in a decreased capacity to stimulate the growth and differentiation of B cells.
B7-blocking agents, alone or in combination with cyclosporin A, induce antigen-specific anergy of human memory T cells.
Authors: Yi-qun Z , Lorré K , de Boer M , Ceuppens J L 
Published: December 2022

Abstract
T cell anergy refers to a functional state in which the cells are alive but unable to produce IL-2 after appropriate triggering. Lack of CD28 costimulation through CD80 and CD86 molecules on APC might play a causative role in anergy induction, as previously shown with T cell clones. We now developed a model of anergy induction in cultures of freshly isolated memory T cells. Addition of either CTLA-4Ig or blocking anti-CD80 and anti-CD86 mAbs, in combination with cyclosporin A, to cultures of PBMC with soluble Ag consistently resulted in Ag-specific unresponsiveness, as evidenced upon antigenic rechallenge. In most experiments, the presence of cyclosporin A was not required, and blocking the B7-CD28 interaction during antigenic stimulation was sufficient to induce unresponsiveness. Unresponsiveness was apparent at the level of T cell proliferation as well as at the level of IL-2 and IFN-gamma production, and T cell responses to unrelated Ags were intact. Induction of unresponsiveness correlated with lack of T cell proliferation in the induction culture and could largely be prevented by supplementing the induction cultures with rIL-2, indicating that lack of IL-2 was responsible for this altered functional state. Unresponsive T cells did not suppress the proliferation of autologous T cells in response to original or third-party Ags. On the other hand, culture with IL-2 and Ag could reverse established T cell unresponsiveness, pointing to anergy rather than deletion as the underlying mechanism. Anergy induction in freshly isolated memory T cells opens perspectives for treatment of autoimmune and allergic diseases.
CD40 cross-linking induces Ig epsilon germline transcripts in B cells via activation of NF-kappaB: synergy with IL-4 induction.
Authors: Iciek L A , Delphin S A , Stavnezer J 
Published: December 2022

Abstract
Transcription of unrearranged (germline) Ig heavy chain C region (C(H)) genes is required before Ab class switch recombination. Although the cytokine IL-4 is well known to induce transcription of unrearranged C epsilon and C gamma1 genes, it has been shown recently that CD40 signaling also induces these transcripts in mouse B cells. We report in this study that treatment of mouse M12.4.1 B lymphoma cells with soluble CD40 ligand (CD40L)-CD8alpha fusion protein modestly induces the promoter for germline epsilon transcripts, and that this induction synergizes with IL-4. CD40L induces binding of nuclear factor (NF)-kappaB/Rel proteins to two tandem kappaB sites located immediately 3' to the IL-4-responsive region of the mouse germline epsilon promoter. The epsilon-124/-56 promoter segment containing the IL-4 response region and the two kappaB sites is sufficient to transfer CD40L and IL-4 inducibility to a minimal c-fos promoter when transiently transfected into M12.4.1 cells. Mutation of the two kappaB sites eliminates induction by CD40L or by IL-4, and treatment of M12.4.1 cells with inhibitors of NF-kappaB activation prevents induction of endogenous germline epsilon transcripts in M12.4.1 cells. In addition to the NF-kappaB/Rel complexes induced by CD40L, two nuclear complexes, each which contain both STAT6 and NF-kappaB/Rel proteins, are induced in splenic B cells by a combination of CD40L and IL-4, and bind to the CD40L/IL-4-responsive region of the germline epsilon promoter. The presence of these complexes may explain the synergistic induction of transcription by CD40L and IL-4 mediated through this promoter segment.
Borrelia burgdorferi outer surface protein A (OspA) activates and primes human neutrophils.
Authors: Morrison T B , Weis J H , Weis J J 
Published: December 2022

Abstract
Lyme disease is caused by infection with the spirochete Borrelia burgdorferi and is characterized by bacterial persistence and inflammation of many host tissues. B. burgdorferi express outer surface lipoproteins, including OspA, with inflammatory properties that could contribute to the localized tissue inflammation. Neutrophils are the predominant infiltrate into the inflamed arthritic joints, and are crucial for controlling the spirochete infection. They may also contribute to the joint pathology associated with Lyme arthritis. This study examines the effect of OspA on the activities of the neutrophil. Picomolar concentrations of OspA induce surface markers associated with neutrophil activation: increased CD10 and CD11b expression; decreased CD62-L expression; and an increased adherence to extracellular matrix. These events were similar in kinetics and magnitude to those induced by the strong activators LPS and FMLP. Like LPS, OspA could prime neutrophils for FMLP-induced release of lysosomal granules and production of superoxide. Thus, models of Lyme arthritis should include the possible contribution of direct activation of neutrophils to both defense and disease.