bluuebunny/crossref_metadata_2025_split huggingface dataset:
TNF-alpha stimulation of fibroblast proliferation. Dependence on platelet-derived growth factor (PDGF) secretion and alteration of PDGF receptor expression.
Authors: Battegay E J , Raines E W , Colbert T , Ross R 
Published: December 2022

Abstract
TNF-alpha stimulates DNA synthesis and proliferation of cultured human fibroblasts. Maximal DNA synthesis in response to TNF-alpha occurs approximately 28 h after addition of TNF-alpha to quiescent fibroblasts, a delay of about 12 to 14 h as compared with DNA synthesis elicited by platelet-derived growth factor (PDGF). TNF-alpha induces PDGF A chain gene expression with a maximum at 4 h. DNA synthesis is abrogated in response to TNF-alpha by a goat anti-PDGF IgG but not by nonimmune goat IgG, suggesting induction of an autocrine PDGF-AA loop by TNF-alpha. The response to PDGF-AA requires the presence of PDGF receptor alpha-receptors. TNF-alpha does not significantly affect PDGF alpha-receptor mRNA or protein expression, nor does it alter the proliferative response to externally added PDGF-AA. In contrast, TNF-alpha reduces the levels of PDGF beta-receptor mRNA, protein expression, and cell proliferation in response to PDGF-BB. Thus, DNA synthesis in response to TNF-alpha depends upon autocrinely induced PDGF-AA. At the same time, TNF-alpha may alter the response to PDGF-BB from exogenous sources.
Expression and biologic characterization of the murine chemokine KC.
Authors: Bozic C R , Kolakowski L F , Gerard N P , Garcia-Rodriguez C , von Uexkull-Guldenband C , Conklyn M J , Breslow R , Showell H J , Gerard C 
Published: December 2022

Abstract
KC, the product of an immediate early gene induced in mouse fibroblasts by platelet-derived growth factor, was expressed in Escherichia coli by using a maltose binding protein vector and biochemically characterized as a ligand for both murine and human polymorphonuclear neutrophils (PMN). On murine PMN, KC is both a potent chemoattractant and up-regulator of Mac-1 cell surface expression. On human PMN, in contrast, KC exhibits dissociation of its chemoattractant and Mac-1 up-regulatory activities. Although KC strongly increases Mac-1 expression on human PMN, it does not induce chemotaxis in vitro. 125I-KC-Tyr binds to both mouse and human PMN with two classes of binding sites, including high affinity sites of 0.8 and 2 nM, with approximately 9,000 and 10,000 sites per cell, respectively. On mouse PMN, human macrophage inflammatory protein (MIP)-2 alpha and MIP-2 beta compete for 125I-KC-Tyr binding with high affinity, whereas the murine beta-chemokine TCA-3 does not compete. KC binds to human PMN by the IL-8 type B receptor and to murine PMN by a murine IL-8 type B receptor homologue. 125I-KC-Tyr also binds to human RBC with a single class of high affinity sites. KC mRNA is constitutively expressed in multiple murine tissues. With human IL-8 and KC cDNA as probes, a mouse neutrophil exudate library was screened: KC and MIP-2 were the dominant chemokine species found. Thus, KC appears to be intimately involved in murine inflammation and its constitutive expression may have a role in the basal trafficking of neutrophils.
Human skin mast cells express functional beta 1 integrins that mediate adhesion to extracellular matrix proteins.
Authors: Columbo M , Bochner B S , Marone G 
Published: December 2022

Abstract
We have evaluated the adhesion of human cutaneous mast cells to several components of the extracellular matrix (plasma fibronectin, laminin, collagen type I and IV) and studied whether these cells express the beta 1 integrins potentially involved in the adhesion to these proteins. Human skin mast cells (5.1 +/- 1.5% pure) spontaneously adhered to fibronectin and laminin (0.1 to 10 micrograms/ml) immobilized on plastic surfaces (e.g., 14 +/- 7.2% and 14 +/- 4.4% adhesion at 10 micrograms/ml, respectively). Similar results were obtained with a 90% pure mast cell preparation. In contrast, cutaneous mast cells did not adhere to collagen type I (1.6 +/- 0.5% adhesion) or type IV (1.2 +/- 0.8% adhesion). Control adhesion in BSA-coated wells was &lt; 5%. Mast cell adhesion to fibronectin was optimal after an incubation period of 60 to 90 min (t1/2 = 28.2 +/- 6.2 min), whereas adhesion to laminin was faster (t1/2 = 10.1 +/- 1.2 min), being nearly optimal after a 15-min incubation period. Human skin mast cell adhesion to fibronectin and laminin was found to be dependent on the presence of divalent cations in the extracellular medium. Dual-color immunofluorescence and flow cytometry were used to evaluate whether human skin mast cells (51.3 +/- 3.9% pure) express beta 1 integrins that may mediate cell adhesion to extracellular matrix proteins. These mast cells were found to express VLA (very late Ag)-3 (75.3 +/- 35.6 specific fluorescence intensity) and, to lesser degree, VLA-4 and VLA-5 receptors (8.0 +/- 2.5 and 6.9 +/- 3.2 specific fluorescence intensity, respectively). In contrast, VLA-1, VLA-2, and VLA-6 integrins were not expressed significantly. mAb to VLA-3, VLA-4, and VLA-5 each inhibited by 70% skin mast cell adhesion to fibronectin. mAb to VLA-3 nearly abolished mast cells adhesion to laminin, whereas anti-VLA-4 and anti-VLA-5 were ineffective. Finally, immunosuppressant cyclosporin A (100 nM) and FK-506 (10 nM) significantly inhibited mast cell adhesion to both fibronectin and laminin (p &lt; 0.05). Our data demonstrate that human skin mast cells spontaneously adhere to fibronectin and laminin, and that this adhesion is mediated by VLA-3, VLA-4, and/or VLA-5 integrins on these cells. Interactions between these beta 1 integrins and extracellular matrix proteins may be involved in perivascular tissue localization of human mast cells in vivo.
Macrophage inflammatory protein-1 alpha and IL-8 stimulate the motility but suppress the resorption of isolated rat osteoclasts.
Authors: Fuller K , Owens J M , Chambers T J 
Published: December 2022

Abstract
Cells of the osteoblastic lineage play a major role in the regulation of osteoclastic bone resorption. Recent studies have demonstrated production of chemokines by osteoblastic cells. Although these phagocyte-stimulating and proinflammatory cytokines act as chemoattractants and activators for other members of the hemopoietic lineage, their actions on osteoclasts have not been characterized. We found that macrophage inflammatory protein-1 alpha (MIP-1 alpha) and IL-8 inhibited bone resorption by rat osteoclasts, primarily through reduction in the proportion of osteoclasts resorbing bone, a pattern of inhibition previously observed in response to macrophage CSF (M-CSF). MIP-2, RANTES, MIP-1 beta, and monocyte chemotactic protein-1 were without effect on resorption. MIP-1 alpha and IL-8, but not the other chemokines, also stimulated osteoclastic motility and increased the osteoclast spread area in a dose-dependent manner, over the same concentration range as that which inhibited bone resorption. In addition, MIP-1 alpha induced osteoclast orientation in a gradient of the chemokine, and stimulated osteoclast migration. We detected no effect of chemokines on osteoclast formation or survival. Our data suggest that chemokines can promote osteoclast orientation and migration, processes that might be involved in chemotaxis; it seems appropriate that resorptive functions should be suppressed during migration. Because chemokines are proinflammatory, their actions on osteoclasts might represent mechanisms by which bone resorption is modulated by the inflammatory process when this occurs in bone. However, given that chemokines are increasingly recognized to be multifunctional and that they are produced by cells of the osteoblastic lineage, they may also be components of the physiologic regulation of bone resorption.
A unique member of the thymidylate kinase family that is induced during macrophage activation.
Authors: Lee C G , O'Brien W E 
Published: December 2022

Abstract
LPS, a bacterial endotoxin, induces the expression of many genes in macrophages. We report the cloning of a novel 3.3-kb cDNA that is a member of the thymidylate kinase family of genes. This clone, which we have designated TYKi, was obtained by screening a cDNA library prepared from RNA isolated from the murine cell line RAW264.7 after bacterial LPS treatment. TYKi is quite similar to all thymidylate kinases for which there are sequence data. It conserves two very important domains in these kinases, namely, the catalytic domain or P-loop and the nucleotide binding domain. After LPS exposure, the TYKi message appears at 2 h, peaks at 6 h, and declines at 8 h. LPS induction of TYKi is dependent on de novo protein synthesis. Increasing cytosolic cAMP with forskolin attenuates the LPS induction of TYKi. However, treatment with 8-(4-chlorophenylthio)-cAMP (CPT-cAMP) or dibutyryl-cAMP did not affect the LPS induction of TYKi. In contrast, activation of protein kinase C with phorbol ester augmented the LPS response, whereas inhibiting protein kinase C with 1-(5-isoquinolinylsulfonyl)-2-methylpiperazine (H7) suppressed the LPS response. Removing extracellular Ca2+ with EGTA inhibited LPS induction of TYKi, whereas increasing intracellular calcium with the calcium ionophore A23187 had little effect on the levels of the TYKi transcript. Inhibiting tyrosine kinase with genistein suppressed the induction of TYKi by LPS.
A dominant T cell receptor beta-chain in response to a short ragweed allergen, Amb a 5.
Authors: Huang S K , Yi M , Palmer E , Marsh D G 
Published: December 2022

Abstract
HLA-DR alpha, beta 1 *1501 (and the closely related DR alpha, beta 1 *1502) heterodimers are the primary class II MHC restriction elements controlling T cell responses to a ragweed pollen allergen, Amb a 5 (M(r) = 5000). Using a novel, quantitative, competitive PCR (QC-PCR) assay and a TCR beta-gene internal standard (IS), we have examined the TCR beta-gene use in Amb a 5-specific T cells. Multiple TCR V beta (and V alpha) genes were found in polyclonal T cell lines from two unrelated subjects, and 30% of the cells were stained positive for V beta 5.2/5.3 as judged by a flow cytometry analysis. An Amb a 5-specific Th2 clone (AP1.2) was found to express V beta 5.2 (and V alpha 8) and to have a unique V-D-J junctional region sequence. To determine the relative frequency of clone AP1.2 beta-gene expression in the polyclonal T cell lines and in the PBMC using a QC-PCR assay, we first created a TCR IS by duplicating the J beta 1.5 gene segment of the AP1.2 beta-gene. A QC-PCR assay was performed using the modified AP1.2 beta-gene as a competitor and a V beta 5.2 or a D beta-specific primer, each paired with a C beta primer. Results showed the presence of 30% of AP1.2 beta transcripts in the polyclonal T cell lines, but no detectable amplified products were found in the total RNAs (200 ng) of autologous PBMC. These findings were confirmed by sequencing independent clones of PCR-amplified V beta 5.2-C beta fragments (from two unrelated subjects) from each cell line, which suggested that the frequency of the clone AP1.2 beta sequence is quite low in the PBMC but is dominant in polyclonal Amb a 5-specific cell lines.
Oligoclonal CD8+ T cells are preferentially expanded in the CD57+ subset.
Authors: Morley J K , Batliwalla F M , Hingorani R , Gregersen P K 
Published: December 2022

Abstract
A number of recent reports have established that oligoclonality and/or clonal expansion is a common feature of the CD8+ T cell population. Oligoclonal expansion has also been observed in bone marrow transplant recipients and rheumatoid arthritis patients, disease states in which CD57+CD8+ T cells are occasionally elevated. In this study we have compared the TCR repertoire of the CD57+ and CD57- subsets of CD8+ T cells in normal persons by using three-color FACS analysis with a panel of 16 mAbs specific for TCR V segments. The CD57 surface marker was highly variable in frequency but generally present on a minority of CD8+CD3+ T cells (mean 16.3%, SD 12.7) in a group of 41 normal volunteers. Dramatic oligoclonal expansion was present in the CD57+CD8+ T cell population in 15 of 41 (37%) of our study population and thus is a characteristic feature of the normal immune system. No such prominent oligoclonal expansions were observed in the CD57-CD8+ subset, although preliminary experiments suggest that oligoclonality per se is occasionally present at a lower frequency in CD57- cells. The reasons for this persistent accumulation of oligoclonal CD8+CD57+ T cells and their function in immune homeostasis are unclear.
Two mechanisms of antigen-specific apoptosis of myelin basic protein (MBP)-specific T lymphocytes derived from multiple sclerosis patients and normal individuals.
Authors: Pelfrey C M , Tranquill L R , Boehme S A , McFarland H F , Lenardo M J 
Published: December 2022

Abstract
Several stimuli induce mature T cells to undergo apoptosis or programmed cell death (PCD) including specific Ag. We have demonstrated previously that Ag induces the death of encephalitogenic T cells in vitro and deletion in vivo, leading to amelioration of autoimmune encephalomyelitis. We have now examined whether activated, myelin basic protein (MBP)-specific human T cells may be eliminated by Ag-induced PCD. We demonstrate that activated MBP-specific T cell lines (TCL) undergo the classic nuclear morphologic changes and DNA fragmentation characteristic of apoptosis when given a TCR challenge. We found evidence that two mechanisms led to apoptosis: a propriocidal mechanism that was highly Ag-specific and dependent on the dose of exogenously added rIL-2, and a cytolytic mechanism in which MBP-specific TCL lysed B cell targets and engaged in considerable "fratricidal" cytolysis of other MBP-specific T cells. These two pathways leading to MBP-specific apoptotic death could be distinguished by their glucocorticoid sensitivity. Glucocorticoid treatment significantly blocked MBP-induced propriocidal apoptosis but had no effect on T cell cytolysis of B cell targets. Although it has been proposed that autoimmune disease could result from the failure of normal deletional mechanisms, this preliminary survey of MBP-reactive mature TCL from multiple sclerosis patients revealed that such cells are highly susceptible to TCR-induced PCD and comparable with TCL from normal subjects. Thus, therapeutic strategies based on Ag-induced PCD of T lymphocytes may be feasible in man.
CD4+ T cells anergized by high dose feeding establish oral tolerance to antibody responses when transferred in SCID and nude mice.
Authors: Hirahara K , Hisatsune T , Nishijima K , Kato H , Shiho O , Kaminogawa S 
Published: December 2022

Abstract
The cellular mechanism for oral tolerance in specific Ab response was investigated by cell-transfer experiments, using severe combined immunodeficiency (SCID) and BALB/c nu/nu mice. High dose feeding with bovine alpha s1-casein, a major allergen in milk, to BALB/c mice induced Ag-specific oral tolerance to the specific Ab response. This state of oral tolerance was successfully transferred to SCID mice with splenocytes from orally tolerant BALB/c mice. In SCID mice that were transferred with tolerant T cells and normal B cells before being immunized with alpha s1-casein, oral tolerance to the Ab responses was generated. In addition, only the T cells established the tolerant state in nude mice. A decreased proliferative response of the splenic T cells from BALB/c mice against alpha s1-casein was also shown, indicating that the decreased Ab responses were attributed to the unresponsiveness of the splenic T cells. Next, the tolerant splenic T cells were further separated into CD4+ T cells and CD8+ T cells, remixed with normal cells, and then transferred to nude mice, which revealed that the tolerant state in the nude mice was principally generated by the CD4+ T cells. When tolerant CD4+ T cells were cotransferred with normal CD4+ T cells to nude mice, there was no significant reduction in the specific Ab responses. These results demonstrate that splenic CD4+ T cells anergized by high dose feeding established oral tolerance to the Ab responses when transferred to SCID and nude mice.
Differential susceptibility to tolerance induction in vitro of splenic B cells from several transgenic mouse lines. Role of B1 cells.
Authors: Liou L B , Colosia A , Corley R B , Clarke S H , Scott D W 
Published: December 2022

Abstract
Spleen cells from transgenic mice, whose rearranged Ig receptors reflect the repertoires of B1 (CD5+ and "sister" B cells) or normal B2 cells, were examined for their ability to be rendered unresponsive. By using an anti-Ig tolerance protocol that is independent of receptor specificity, we previously reported that peritoneal B cells, containing primarily CD5+ and "sister" B cells, were not susceptible to unresponsiveness. Herein, we show that splenic B cells from two separate transgenic mouse lines, each expressing a B1-type receptor, are resistant to tolerance induction in vitro. In contrast, splenic B cells from two other transgenic mouse lines with a large representation of conventional B cells were sensitive to anti-lg-mediated unresponsiveness. This difference does not reside in the surface Ig density, cell cycle, or activation stage of these cells, but is reflected in the initial calcium mobilization and tyrosine phosphorylation after surface Ig cross-linking. Therefore, these results support the hypothesis that the antigenic specificity of B cell receptors may drive cells toward the B1 subset, as suggested by Cong et al. (Cong, Y-Z., E. Rabin, and H. H. Wortis. 1991. Int. Immunol. 3:467-476), and that B1 cell characteristics confer the ability of B cells to withstand in vitro tolerance induction, irrespective of their anatomical location. The possibility that this results from previous antigenic experience is discussed.
Evidence for lineage commitment and initiation of positive selection by thymocytes with intermediate surface phenotypes.
Authors: van Meerwijk J P , O'Connell E M , Germain R N 
Published: December 2022

Abstract
Previous studies have shown that both MHC class I and class II molecules can stimulate CD4+CD8+ thymocytes to develop into TCRint cells with surface phenotypes, suggesting initial differentiation along either the CD4 or CD8 developmental pathways. In accord with the view that these cells have undergone lineage commitment, we show here that CD4intTCRint cells generated by recognition of either MHC class show the same partial down-regulation of CD8 from the level on precursor double positive thymocytes as do almost mature CD4intTCRhigh cells positively selected only by MHC class I recognition. As expected of cells undergoing positive selection, we find that either class I or class II MHC molecules on radioresistant thymic stromal cells alone are sufficient for generation of both types of transitional phenotype cells. Biases in V beta representation associated with allele-dependent positive selection are seen only in the TCRhigh and not the TCRint cohorts, however. These findings are consistent with the hypothesis that transitional phenotype thymocytes have begun but not completed positive selection, and that entry into the CD4 vs CD8 pathways is not uniquely determined by the specific coreceptor-MHC molecule interaction involved in precursor thymocyte activation.
Changes of liver-resident NK cells during liver regeneration in rats.
Authors: Vujanovic N L , Polimeno L , Azzarone A , Francavilla A , Chambers W H , Starzl T E , Herberman R B , Whiteside T L 
Published: December 2022

Abstract
To determine the role of NK cells in regulation of tissue growth, the phenotype and function of liver-resident NK cells were studied after 70% partial hepatectomy in rats. The process of liver regeneration was generally completed by day 14. In contrast, the number of liver-resident NK cells (NKR-P1bright) was restored as early as day 3 after partial hepatectomy. However, spontaneous functions of liver-resident NK cells, including killing of YAC-1 and P815 targets, Ab-dependent cellular cytotoxicity, and redirected killing via NKR-P1, were continuously suppressed throughout the entire period of liver regeneration (from 3 h to 14 days). Augmentation of NK cytotoxicity against P815 targets and induction of NK cell adherence to plastic following 24 h of IL-2 stimulation showed a similar pattern of suppression. However, IL-2-induced augmentation of YAC-1 killing, proliferation and generation of adherent NK cells, and LAK activity in 5- to 7-day cultures were found to be suppressed only during the first 24 h and increased between days 2 and 7 after hepatectomy. Sorted NK cells (&gt; or = NKR-P1bright) from liver-resident mononuclear leukocytes 24 h after partial hepatectomy showed the same pattern of suppression as unsorted mononuclear leukocytes. In contrast to liver-resident NK cells, no significant changes were detected in peripheral blood or spleen NK cells of rats following partial hepatectomy. Of particular interest, in normal liver, hepatocytes were resistant to NK lysis, while resident NK cells were cytotoxic for various NK-sensitive targets. In contrast, during the early period of liver regeneration, when hepatocytes were sensitive to lysis by liver-resident NK cells of normal rats, NK cells obtained from regenerating liver tissues were unable to mediate cytotoxicity. At the final phase of liver regeneration (days 7-14 after hepatectomy), both resistance of hepatocytes to killing by NK cells and cytotoxicity of liver-resident lymphocytes against hepatocytes from regenerating liver were simultaneously restored. In vivo depletion of NK cells by injection of rats with anti-NKR-P1 mAb resulted in a significant augmentation of liver regeneration subsequent to partial hepatectomy. Our data suggest that liver-resident NK cells may be involved in regulation of the extent of liver regeneration.
Calcineurin activation protects T cells from glucocorticoid-induced apoptosis.
Authors: Zhao Y , Tozawa Y , Iseki R , Mukai M , Iwata M 
Published: December 2022

Abstract
In T cell hybridomas, TCR/CD3 complex-mediated stimulation induces apoptosis but inhibits that induced by glucocorticoids. A combination of ionomycin (IM), a calcium ionophore, and PMA, a protein kinase C activator, mimics the effects of the TCR/CD3-mediated stimulation. Glucocorticoid-induced apoptosis is, however, markedly inhibited by IM alone, and less markedly by PMA alone. The immunosuppressant FK506 canceled the inhibition by IM but not that by PMA. As calcineurin (CN) is one of the target molecules of FK506, we examined whether CN activation might have an anti-apoptotic effect. BOG8, a T cell hybridoma, was stably transfected with a mutant CN catalytic subunit with Ca2+/calmodulin-independent, constitutive but FK506-sensitive phosphatase activity. The transfectant clones were fairly resistant to glucocorticoid-induced death. Their resistance, however, was hardly affected by FK506 when added simultaneously with glucocorticoid, but was lost after a prolonged preincubation with FK506. In the parent BOG8 cells, FK506 failed to cancel the inhibitory effect of IM on glucocorticoid-induced death when the addition of FK506 was delayed for 1 h or more. These results suggest that CN activation is required for the resistance only as an early event. The transfectant clones produced IL-2 but failed to undergo apoptosis upon stimulation with PMA alone, whereas apoptosis was induced by a combination of IM and PMA. These results suggest that activation-induced cell death may require a higher level of CN activity than IL-2 production or may require another Ca(2+)-dependent pathway.