bluuebunny/crossref_metadata_2025_split huggingface dataset:
Characterization of T cell clones derived from lymph nodes and lungs ofPseudomonas aeruginosa-susceptible and resistant mice following immunization with heat-killed bacteria
Authors: Kondratieva T K , Kobets N V , Khaidukov S V , Yeremeev V V , Lyadova I V , Apt A S , Tam M F , Stevenson M M 
Published: March 2003

SUMMARYPseudomonas aeruginosa-resistant BALB/c and susceptible C57Bl/6 (B6) mice were immunized with heat-killed Pseudomonas either in the foot pad or via the trachea, and panels of Pseudomonas-specific T cell clones were developed from lymph nodes and lungs. All clones from either strain, whether of lymph node or lung origin, were CD3+CD4+CD8−TCRαβ+. The efficacy of cloning from lymph node cells was comparable between BALB/c and B6 mice. All lymph node BALB/c clones proliferated in response to Pseudomonas antigen in a dose-dependent manner, and this response was MHC class II-restricted. Vigorous proliferation by a considerable proportion of B6 T cell clones occurred in the absence of specific antigen. Lymph node clones from either strain could be categorized as either Th1 or Th0 on the basis of interferon-gamma (IFN-γ)/IL-4 production. In either mouse strain the efficacy of cloning from lung tissue was substantially lower than from lymph nodes, but the efficacy of cloning from BALB/c compared with B6 lungs was higher. Four lung T cell clones from BALB/c and two from B6 mice were expanded for further analyses, and an interstrain difference was observed in cytokine production. Both B6 lung T cell clones were Th1-like and produced IFN-γ but not IL-4 and IL-10, whereas four BALB/c lung T cell clones were Th2-like and produced IL-4 and IL-10 but not IFN-γ. These observations suggest that differences in the CD4+ Th response in the lung may contribute to differences among inbred mouse strains in the level of resistance to bronchopulmonary Pseudomonas infection.
Influence of fluticasone and salmeterol on airway effects of inhaled organic dust;anin vivoandex vivostudy
Authors: Ek A , Palmberg L , Larsson K 
Published: March 2003

SUMMARYInhalation of dust from swine confinement buildings induces airway inflammation with an increase in both inflammatory cell numbers and secretion of proinflammatory cytokines in the lungs. It is not known whether anti-asthma drugs, which influence airway inflammation in asthma, also influence the airway reaction to inhaled organic dust. In the present study we examined the effects of a ß2-agonist (salmeterol) and an inhaled steroid (fluticasone) on the swine dust-induced cell and cytokine content of the lower airways, and cytokine release in cultured alveolar macrophages. Healthy volunteers were pretreated with inhaled salmeterol (n = 8), fluticasone propionate (n = 8) or placebo (n = 8) for about 2 weeks and exposed to dust in a pig house. Bronchoalveolar lavage was performed both before medication and after dust exposure. Cell differential counts and cytokine analyses in bronchoalveolar lavage fluid (BALF) were examined. Alveolar macrophages were cultured and cytokine release was studied, both in unstimulated cells and after lipopolysaccharide (LPS) stimulation. Unstimulated alveolar macrophages from swine dust-exposed individuals released less IL-6, IL-8 and tumour necrosis factor-alpha (TNF-α) after, than before, exposure (P &lt; 0.01). Medication did not influence basal cytokine production. Fluticasone inhibited LPS-induced IL-6 and IL-8 release (P &lt; 0.05). There was no significant difference between the groups. There was a large and significant increase (P &lt; 0.05) in alveolar macrophage, granulocyte, lymphocyte numbers, and IL-6 and TNF-α content in BALF in all three groups following dust exposure, with no significant difference between the groups. These findings suggest that drugs which are known to influence and control airway inflammation in asthma do not have major effects on airway inflammation induced by the inhalation of organic dust.
The C5a receptor is expressed by human renal proximal tubular epithelial cells
Authors: Zahedi R , Braun M , Wetsel R A , Ault B H , Khan A , Welch T R , Frenzke M , Davis A E 
Published: March 2003

SUMMARYThe C5a receptor is expressed by a variety of cell types. These studies demonstrate by immunohistochemistry that the receptor is present on the surface of proximal and distal tubular epithelial cells from normal kidney. In addition, the receptor was detected on transitional epithelial cells of the ureter and bladder. Primary proximal tubular cultures and a proximal tubular cell line both also expressed the C5a receptor, as demonstrated by immunofluorescence and by FACS analysis. The presence of mRNA encoding the receptor was confirmed by reverse transcriptase-polymerase chain reaction analysis. As opposed to its effect on glomerular mesangial cells, the receptor did not mediate a proliferative response by the proximal tubular cells. C5a also did not enhance the synthesis/secretion of transforming growth factor-beta 1, monocyte chemoattractant protein-1, platelet-derived growth factor-AB or tumour necrosis factor-alpha by cultured proximal tubular cells. Therefore, although the C5a receptor clearly is expressed by proximal tubular cells, clarification of its functional relevance on this cell type awaits further studies.
Accumulation of CD4+CD7− T cells in inflammatory skin lesions: evidence for preferential adhesion to vascular endothelial cells
Authors: Liu L , Abken H , Pföhler C , Rappl G , Tilgen W , Reinhold U 
Published: March 2003

SUMMARYThe CD7− subset of CD4+ memory T cells reflects a stable differentiation state of post-thymic helper T cells and represents a small subpopulation in circulating blood. We here demonstrate that CD7− T cells preferentially accumulate in skin lesions under chronic inflammatory conditions irrespective of the particular disease. As adhesion to vascular endothelial cells (EC) is required for migration of circulating lymphocytes into tissues, we analysed the adherence of purified subsets of CD4+ memory T cells to endothelial cells in vitro. Compared with CD4+CD7+ T cells, cells of the CD4+CD7− subset preferentially adhere to EC, which is moreover increased after prestimulation of EC with tumour necrosis factor-alpha (TNF-α). Stimulated EC increase expression of intercellular adhesion molecule-1 (CD54) and E-selectin (CD62E), the ligand of which, cutaneous lymphocyte-related antigen (CLA), is highly expressed in CD4+CD7− T cells but not in CD4+CD7+ T cells. LFA-1 is expressed in a bimodal distribution on CD4+CD7− T cells in contrast to CD4+CD7+ cells, whereas VLA-1, VLA-3, and VLA-5 are nearly similarly expressed in both T cell subsets. Our results imply that the preferred adherence of CD4+CD7− memory T cells to vascular EC, which is increased after long-term EC stimulation with TNF-α, is likely to facilitate their accumulation in various inflammatory skin lesions.
Induction of necrosis and apoptosis of neutrophil granulocytes byStreptococcus pneumoniae
Authors: Zysk G , Bejo L , Schneider-Wald B K , Nau R , Heinz H-P 
Published: March 2003

SUMMARYApoptosis followed by macrophage phagocytosis is the principal mechanism by which neutrophil granulocytes (PMN) are removed from the site of inflammation. To investigate whether Streptococcus pneumoniae causes apoptosis of PMN, we exposed PMN to viable and heat-killed pneumococci and purified pneumococcal cell walls (PCW). The occurrence of PMN cell death was quantified by flow cytometry using annexin V/propidium iodide labelling of the cells. Intracellular histone-associated DNA fragments were quantified by ELISA. The presence of apoptosis was confirmed by in situ tailing. Exposure of PMN to viable pneumococci caused necrosis of the cells. The pneumococcal cytotoxin pneumolysin, the bacterial production of hydrogen peroxide, and PCW contributed to necrosis. Heat-killed pneumococci accelerated the process of apoptosis observed in cultivated non-stimulated PMN in vitro. These results demonstrated that pneumococci induce PMN cell death. Depending on the intensity of the stimulus, PMN necrosis and apoptosis were observed.
Humoral hyporesponsiveness to a conjugate contraceptive vaccine and its bypass by diverse carriers using permissible adjuvant
Authors: Mandokhot A , Pal R , Nagpal S , Chauhan V S , Ahlawat S , Singh Om 
Published: March 2003

SUMMARYA contraceptive vaccine directed against human chorionic gonadotropin (hCG) has previously undergone clinical testing that demonstrated the feasibility of the approach in preventing pregnancy in women. Some immunized volunteers however, did not respond with an adequate anti-hCG antibody response despite employing highly immunogenic bacterial toxoids as carriers. Since there is some evidence that T cell responses to a complex protein typically focus on a few immunodominant epitopes, we investigated the responsiveness to hCG in mice of different haplotypes using the protein carrier diphtheria toxoid (DT). Our data showed a differential carrier effect of DT. With the aim of making a more potent immunogen employing promiscuous pathogen-derived Th peptides as carriers, peptide:antigen stoichiometric ratios were optimized. When tested individually using alum as the adjuvant, three such peptide conjugates improved the anti-hCG response, though not consistently to levels higher than the DT conjugate. Immunization with a combination of these synthetic epitopes generated anti-hCG responses higher than those achieved with DT or with the individual peptides. Antibodies were of high affinity and capable of neutralizing the bioactivity of hCG, but were devoid of anti-peptide reactivity. These results support our view that differential hyporesponsiveness in a diverse population may arise from inadequate carrier effect and that it can be overcome by use of pathogen-derived broadly reactive non-B Th epitopes employing only alum, a permissible adjuvant.
Renal cytokine responses in acuteEscherichia colipyelonephritis in IL-6-deficient mice
Authors: Khalil A , Tullus K , Bartfai T , Bakhiet M , Jaremko G , Brauner A 
Published: March 2003

SUMMARYThe aim of this study was to investigate the influence of IL-6 on mortality, bacterial growth and cytokine expression in experimental acute pyelonephritis. Female IL-6-deficient mice and their wild-type counterparts, 8–10 weeks old, were infected with Escherichia coli CFT 073 or injected with NaCl 0·9% (w/v) via the urethra and thereafter obstructed for 6 h. Animals were killed at 48 h, 6 days or 8 weeks and cytokine and bacterial renal levels were assessed at each time point. We found that IL-6-deficient mice had increased mortality and extensive renal bacterial growth on day 6, compared with wild-type mice (P &lt; 0·05) and the histopathological changes were generally more severe and widespread in the IL-6-deficient mice. Peak mRNA expression of IL-1β, IL-4, IL-10, IL-12 and interferon-gamma (IFN-γ) occurred 48 h after infection in both IL-6 knock out and wild-type mice. Transforming growth factor-beta (TGF-β) levels also peaked at 48 h in E. coli-infected wild-type mice, while in the IL-6-deficient strain both TGF-β mRNA and protein levels were significantly lower at 48 h than wild-type levels (P &lt; 0·0008 and P &lt; 0·03, respectively) and remained stationary throughout the study period. Animals injected with NaCl 0·9% (w/v) displayed a similar decrease in TGF-β expression (P &lt; 0·02). When splenocytes from the IL-6-deficient mice were incubated with murine recombinant IL-6, TGF-β levels increased to those of wild-type mice. No increase was observed when splenocytes from wild-type mice were incubated with the same doses of rIL-6. We therefore conclude that IL-6 plays an important role in bacterial clearance and directly influences the TGF-β levels in experimental acute pyelonephritis. We also demonstrate that urethral obstruction per se induces an increase in TGF-β the magnitude of which is decreased in IL-6-deficient mice.
Induction of lymphocyte apoptosis in rat liver allograft with ongoing rejection by FTY720
Authors: Li X-K , Tamura A , Fujino M , Guo L , Kakefuda T , Funeshima N , Enosawa S , Amari M , Naoe S , Amemiya H , Suzuki S 
Published: March 2003

SUMMARYThe action mechanism of FTY720, a novel immunosuppressant, is completely different from conventional immunosuppressants. The drug, which triggers apoptosis in murine and human lymphocytes, has a potent immunosuppressive activity to prevent allograft rejection without any severe side-effect. The present study was designed to determine whether FTY720 induces apoptotic cell death in activated lymphocytes infiltrated into liver grafts with ongoing rejection. FTY720 was orally administered at 5 mg/kg to the recipients on day 3 and day 4 after grafting, when the graft rejection was histologically confirmed. The intragraft patterns of IL-2, interferon-gamma (IFN-γ), perforin, and granzyme B gene expression were detected by reverse transcriptase-polymerase chain reaction. The treatment reversed ongoing rejection and significantly prolonged recipient survival time compared with the control group. Light microscopic observation of the graft sections stained with the DNA nick-end labelling method showed that the apoptosis in the control allografts was mainly induced in hepatocytes, while that in the FTY720-treated allografts was in infiltrated lymphocytes. The rejection therapy with FTY720 did not alter the expression of IL-2, IFN-γ, and perforin mRNAs, but slightly decreased granzyme B expression. Our results suggest that FTY720 does not alter the intrinsic lymphocyte function to produce the rejection-related cytokines, but strongly induces apoptotic cell death in the activated lymphocytes. Thus, FTY720 affords new insight into the mechanisms underlying improvements in immunosuppressive treatments.
The impact of platelet-activating factor (PAF)-like mediators on the functional activity of neutrophils: anti-inflammatory effects of human PAF-acetylhydrolase
Authors: Kuijpers T W , Van Den BERG1 J M , Tool A T J , Roos D 
Published: March 2003

SummaryPlatelet-activating factor (PAF) is a proinflammatory agent in infectious and inflammatory diseases, partly due to the activation of infiltrating phagocytes. PAF exerts its actions after binding to a monospecific PAF receptor (PAFR). The potent bioactivity is reflected by its ability to activate neutrophils at picomolar concentrations, as defined by changes in levels of intracellular Ca2+ ([Ca2+]i), and induction of chemotaxis and actin polymerization at nanomolar concentration. The role of PAF in neutrophil survival is, however, less well appreciated.In this study, the inhibitory effects of synthetic PAFR-antagonists on various neutrophil functions were compared with the effect of recombinant human plasma-derived PAF-acetylhydrolase (rPAF-AH), as an important enzyme for PAF degradation in blood and extracellular fluids. We found that endogenously produced PAF (–like) substances were involved in the spontaneous apoptosis of neutrophils. At concentrations of 8 µg/ml or higher than normal plasma levels, rPAF-AH prevented spontaneous neutrophil apoptosis (21 ± 4% of surviving cells (mean ± SD; control) versus 62 ± 12% of surviving cells (mean ± SD; rPAF-AH 20 µg/ml); P &lt; 0·01), during overnight cultures of 15 h. This effect depended on intact enzymatic activity of rPAF-AH and was not due to the resulting product lyso-PAF. The anti-inflammatory activity of rPAF-AH toward neutrophils was substantiated by its inhibition of PAF-induced chemotaxis and changes in [Ca2+]i.In conclusion, the efficient and stable enzymatic activity of rPAF-AH over so many hours of coculture with neutrophils demonstrates the potential for its use in the many inflammatory processes in which PAF (–like) substances are believed to be involved.
The release of leukotriene B4 from human skin in response to substance P: evidence for the functional heterogeneity of human skin mast cells among individuals
Authors: Okabe T , Hide M , Koro O , Nimi N , Yamamoto S 
Published: March 2003

SUMMARYSubstance P is located in cutaneous nerve fibres and induces wheal and flare responses, accompanied by granulocyte infiltration, upon intradermal injection. Studies with animal skin and rat peritoneal mast cells have suggested that substance P induces the release of histamine and leukotriene B4 (LTB4), a potent chemoattractant for granulocytes, from skin mast cells. However, the release of LTB4 has not been detected from mast cells enzymatically isolated from human skin. In order to investigate the mechanism of granulocyte infiltration induced by substance P in human skin, we studied the release of LTB4 and histamine in response to substance P, and the effect of dexamethasone using human skin obtained from 22 nonallergic individuals. Histamine was released from all skin tissue samples in a dose-dependent manner. However, the amount of LTB4 release, both constitutive and inducible, was variable among skin preparations. Substance P induced a large release of LTB4 from the skin of eight donors (twice to six times that of the spontaneous release), but no or only negligible release from the skin of 14 donors. The amount of constitutive release of LTB4 correlated with the amount of tissue histamine. Dexamethasone selectively abolished the inducible release of LTB4, without an effect on histamine release and the constitutive release of LTB4. These results suggest that substance P induces the release of LTB4 in a certain population of human individuals by a glucocorticosteroid-dependent mechanism, and plays an important role in neurogenic inflammation with granulocyte infiltration.
HLA-DRB1 gene transcripts in rheumatoid arthritis
Authors: Kerlan-Candon S , Combe B , Vincent R , Clot J , Pinet V , Eliaou J -F 
Published: March 2003

SUMMARYSusceptibility to rheumatoid arthritis (RA) is associated with defined HLA-DRB1 alleles. However the molecular basis of this association is not known. Peculiarities in the expression of disease-linked DRB1 alleles could be involved since in healthy controls HLA-DRB1 gene expression varies according to the alleles in B cells. Peripheral blood B cells of healthy controls and RA patients were examined for their level of allelic DRB1 transcripts using a competitive PCR approach. Levels of DRB1 transcripts were greatly modified in RA and influenced by HLA-DRB1 genotype: patients with double dose of RA-associated alleles displayed up-regulated amounts of DRB1 gene transcripts whereas patients carrying either a single or no at risk allele had low levels of DRB1 transcripts, compared to control individuals. These differential levels of DRB1 gene expression were not influenced in any way by clinical, biological or therapeutic features of the patients. Various amounts of DRB1 mRNA may be related to variations of the density of DR molecules on B cells and consequently could influence the response of CD4 T cells. This particular regulation of DRB1 gene expression in RA patients could therefore represent one of the molecular mechanisms involved in the association of HLA DRB1 genes to RA.
Identification of ricin A-chain HLA class II-restricted epitopes by human T-cell clones
Authors: Tommasi M , Castelletti D , Pasti M , Fracasso G , Lorenzetti I , Sartoris S , Pera C , Ferrara G B , Tridente G , Colombatti M 
Published: March 2003

SummaryThe identification of ricin toxin A-chain (RTA) epitopes and the molecular context in which they are recognized will allow strategies to be devised that prevent/suppress an anti-RTA immune response in patients treated with RTA-based immunotoxins. RTA-specific human T-cell lines and T-cell clones were produced by in vitro priming of PBMC. The T-cell clones used a limited set of Vβ chains (Vβ1, Vβ2 and Vβ8) to recognize RTA epitopes. The use of RTA deletion mutants demonstrated that T-cell lines and T-cell clones from three out of four donors responded to RTA epitopes within the domain D124-Q223, whereas one donor recognized the region I1-D124. The response to RTA peptides of T-cell lines and T-cell clones from two donors allowed the identification of immunogenic segments (D124-G140 and L161-T190) recognized in the context of different HLA-DRB1 alleles (HLA-DRB1*0801, and HLA-DRB1*11011 and B1*03011, respectively). The response to L161-T190 was investigated in greater detail. We found that the HLA-DRB1*03011 allele presents a minimal epitope represented by the sequence I175-Y183 of RTA, whereas the HLA-DRB1*11011 allele presents the minimal epitope M174-I184. RTA peptides and an I175A RTA point mutant allowed us to identify I175 as a crucial residue for the epitope(s) recognized by the two HLA-DRB1 alleles. Failure of T-cell clones to recognize ribosome inactivating proteins (RIPs) showing sequences similar but not identical to RTA further confirmed the role of I175 as a key residue for the epitope recognized in the context of HLA-DRB1*11011/03011 alleles.
N-acetylcysteine induces shedding of selectins from liver and intestine during orthotopic liver transplantation
Authors: Taut F J H , Schmidt H , Zapletal C M , Thies J C , Grube C , Motsch J , Klar E , Martin E 
Published: March 2003

SUMMARYIn orthotopic liver transplantation (OLT), N-acetylcysteine (NAC) reduces ischaemia/reperfusion (I/R) injury, improves liver synthesis function and prevents primary nonfunction of the graft. To further elucidate the mechanisms of these beneficial effects of NAC, we investigated influence of high-dose NAC therapy on the pattern of adhesion molecule release from liver and intestine during OLT. Nine patients receiving allograft OLT were treated with 150 mg NAC/kg during the first hour after reperfusion; 10 patients received the carrier only. One hour after reperfusion, samples of arterial, portal venous and hepatic venous plasma were taken and blood flow in the hepatic artery and the portal vein was measured. Absolute concentrations of sICAM-1, sVCAM-1, sP-selectin and sE-selectin were not markedly different. However, balance calculations showed release of selectins from NAC-treated livers as opposed to net uptake in controls (P ≤ 0.02 for sP-selectin). This shedding of selectins might be a contributing factor to the decrease in leucocyte adherence and improved haemodynamics found experimentally with NAC-treatment.
Skin T cell proliferative response to M protein and other cell wall and membrane proteins of group A streptococci in chronic plaque psoriasis
Authors: Baker B S , Brown D W , Fischetti V A , Ovigne J-M , Porter W , Powles A , Fry L 
Published: March 2003

SUMMARYTo determine and compare the T cell response to M protein and other group A streptococcal (GAS) antigens, T cell lines (TCL) were cultured from the lesional skin of 33 psoriatic patients and 17 disease controls. GAS-reactive skin TCL were tested in proliferation assays with recombinant M6 protein, and extracts of cell wall and membrane from type M6 GAS and its corresponding M gene deletion mutant. Initially, GAS-reactive skin TCL were obtained from 16 of 25 (64%) psoriasis, and from seven of 17 (41%) control patients. Eleven psoriatic and four control GAS-reactive TCL proliferated to M6 cell wall extract, whereas all the TCL from both groups responded to the extract of M6 membrane proteins. This difference in response to the two extracts was significant for both groups of patients (psoriasis, P = 0·0335, controls, P = 0·0156). GAS-reactive TCL from a further eight psoriasis patients showed no difference in response to cell wall extract from M6 GAS (containing the M protein minus its C-terminus) compared to that of its corresponding M gene deletion mutant. Furthermore, GAS-reactive TCL did not proliferate to recombinant M6 protein. However, a small, but significant reduction in proliferation by the eight psoriatic GAS-reactive TCL to the M-negative (lacking the M protein C-terminus) compared to M6-positive membrane extract was observed (P = 0·01). These findings suggest that GAS-reactive T cells in skin lesions of chronic plaque psoriasis proliferate to streptococcal membrane and, to a lesser extent, cell wall proteins. However, psoriatic skin T cells do not recognize cell wall M protein.