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排序方式: 共有4224条查询结果,搜索用时 218 毫秒
21.
Matthias Niedrig Katrin Leitmeyer Wilina Lim Malik Peiris John S Mackenzie Maria Zambon 《Journal of clinical virology》2005,34(1):22-25
To confirm an infection with the new coronavirus (SARS-CoV) causing the severe acute respiratory syndrome (SARS) diagnostic assays for detection of SARS-CoV specific antibody are necessary. To evaluate the diagnostic performance of laboratories an external quality assurance (EQA) study was performed in 2004. Participating laboratories (9/20) correctly detected anti-SARS antibodies in serum samples without false positive results in an immunofluorescence assay. In contrast, only 4/13 laboratories detected most of the anti-SARS antibody positive samples without false positive results using enzyme immunoassays (EIA) and/or immunoblot. The overall results clearly demonstrate that serological diagnosis of SARS-CoV remains at an early stage of development, with further technical improvements required, particularly with respect to the use of SARS specific EIAs. 相似文献
22.
Hubert Sch?fer Katrin Klippert Petra Meuer Bettina Borsdorf Albrecht F Kiderlen Reinhard Burger 《Journal of interferon & cytokine research》2007,27(4):305-315
Interferon-gamma (IFN-gamma) plays a key role in the induction and maintenance of immunity against intracellular infectious agents. Compared to other species, little is known about the biology of this cytokine in the guinea pig (Cavia porcellus). We found that in contrast to humans and mice, IFN-gamma in the guinea pig did not induce the antiviral state, which in other species leads to protection of IFN-gamma -stimulated fibroblasts from the cytopathic effect (CPE) of subsequent viral infections. As an alternative strategy to detect and quantify guinea pig IFN-gamma activity in vitro, a reporter system using guinea pig fibroblasts transfected with a luciferase gene, which is regulated by an IFN-stimulated response element (ISRE), was established. With the help of the highly sensitive reporter assay system, the biologic activity of recombinant guinea pig IFN-gamma (GpIFN-gamma, from prokaryotic and eukaryotic expression systems was detected. The response to both native and recombinant GpIFN-gamma was inhibited by a rabbit antiserum directed against the recombinant cytokine expressed in Escherichia coli, demonstrating structural and functional homology of native and recombinant GpIFN-gamma. Stimulation with GpIFN-gamma, obtained from transfected cells, induced upregulation of MHC class I expression in a guinea pig fibroblast line. The restricted activity of GpIFN-gamma might have implications for this species' ability to control infections with intracellular pathogens. 相似文献
23.
24.
Warncke B Valtink M Weichel J Engelmann K Schäfer H 《Virchows Archiv : an international journal of pathology》2004,444(1):74-81
Transplantation of retinal pigment epithelial (RPE) cells is discussed as a possible therapeutic approach for retinal degeneration. Xenogeneic transplantation of human RPE cells in animal models has been studied extensively. Various methods have been used to identify the graft cells, but these methods interfere with cell behaviour so that the monitored physiological post-transplantation course may be influenced. In the present study, we applied a method for an unequivocal identification of the graft cells without interfering cell metabolism or behaviour using in situ hybridisation (ISH) of human specific Alu sequences. Visualisation of the strong extended nuclear signal of Alu sequences was much easier than that of the small nuclear signals of donor-specific sex chromosome probes. With Alu probe, even single graft cells can be identified and their development can be observed in short-term and long-term studies. With this procedure, we could prove that donor cells were injected correctly into the subretinal space by a special injection technique that we developed previously. In combination with immunohistochemistry, donor cells could be clearly discriminated from macrophages, which contained phagocytosed donor cell fragments. Application of these ISH methods for species-specific identification was valuable for follow-up-studies of RPE transplantation. 相似文献
25.
26.
Will Katrin; Stuhrmann Manfred; Dean Michael; Schmidtke Jorg 《Human molecular genetics》1993,2(3):231-235
27.
28.
Acute and long-term humoral immunity following active immunization of rabbits with inacctivated spores of various Encephalitozoon species 总被引:1,自引:0,他引:1
Sobottka I Iglauer F Schüler T Schmetz C Visvesvara GS Albrecht H Schwartz DA Pieniazek NJ Bartscht K Laufs R Schottelius J 《Parasitology research》2001,87(1):1-6
Microsporidia of the genus Encephalitozoon are increasingly being reported as a cause of severe, often disseminated infections, mainly in patients with acquired immunodeficiency
syndrome (AIDS). Immunological identification of each of the three recognized species (E. cuniculi, E. hellem, and E. intestinalis) requires the availability of specific immune sera. All sera available thus far have been generated by direct inoculation
of rabbits with virulent microsporidian spores. This study demonstrates for the first time that subcutaneous immunization
with inactivated spores of E. cuniculi, E. hellem, or E. intestinalis is capable of generating highly active rabbit hyperimmune sera to the homologous antigens, with maximal titers being 1:5,120,
1:1,280, and 1:2,560, respectively, as determined by the indirect immunofluorescence technique (IIF). Broad cross-reactivity
of the rabbit antisera with all heterologous Encephalitozoon antigens was determined by IIF and immunogold electron microscopy; however, only the E. hellem immune serum strongly cross-reacted with spores of Enterocytozoon bieneusi. During the 35-month follow-up period the antibody titers to the homologous antigens declined to 1:640, 1:160, and 1:320,
respectively. The observed decay curves for antibody titers against E. cuniculi, E. hellem, and E. intestinalis were fitted using mathematical modeling, resulting in a predicted duration for specific immune responses of about 7 years
on average. Knowledge of the magnitude and duration of specific immune responses is a prerequisite for further evaluation
of the concept of using inactivated microsporidian spores in the quest for vaccines against microsporidian infections.
Received: 10 April 2000 / Accepted: 18 July 2000 相似文献
29.
The specificity of the αβ T cell receptor for class I or class II major histocompatibility complex (MHC) molecules determines whether a mature T cell will be of the CD4?CD8+ or CD4+CD8? phenotype, respectively. We show here that a human CD4 transgene can rescue a significant fraction of CD4?CD8+ T cells in β2-microglobulin-deficient mice. Cells with this phenotype could be induced to become potent killers of targets expressing allogeneic MHC antigens, indicating that lineage commitment can precede the rescue of developing cells by the T cell receptor for antigen and the CD4 coreceptor. 相似文献
30.
Hematopoietic progenitor cells and cellular microenvironment: behavioral and molecular changes upon interaction 总被引:2,自引:0,他引:2
Wagner W Saffrich R Wirkner U Eckstein V Blake J Ansorge A Schwager C Wein F Miesala K Ansorge W Ho AD 《Stem cells (Dayton, Ohio)》2005,23(8):1180-1191
Cell-cell contact between stem cells and cellular determinants of the microenvironment plays an essential role in controlling cell division. Using human hematopoietic progenitor cells (CD34+/CD38-) and a stroma cell line (AFT024) as a model, we have studied the initial behavioral and molecular sequel of this interaction. Time-lapse microscopy showed that CD34+/CD38- cells actively migrated toward and sought contact with stroma cells and 30% of them adhered firmly to AFT024 stroma through the uropod. CD44 and CD34 are colocalized at the site of contact. Gene expression profiles of CD34+/CD38- cells upon cultivation with or without stroma for 16, 20, 48, or 72 hours were analyzed using our human genome cDNA microarray. Chk1, egr1, and cxcl2 were among the first genes upregulated within 16 hours. Genes with the highest upregulation throughout the time course included tubulin genes, ezrin, c1qr1, fos, pcna, mcm6, ung, and dnmt1, genes that play an essential role in reorganization of the cytoskeleton system, stabilization of DNA, and methylation patterns. Our results demonstrate directed migration of CD34+/CD38- cells toward AFT024 and adhesion through the uropod and that upon interaction with supportive stroma, reorganization of the cytoskeleton system, regulation of cell division, and maintenance of genetic stability represent the most essential steps. 相似文献