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排序方式: 共有324条查询结果,搜索用时 31 毫秒
71.
Control of Epstein–Barr virus reactivation by activated CD40 and
viral latent membrane protein 1 总被引:1,自引:0,他引:1 下载免费PDF全文
72.
Theiss HD Kofler DM Büning H Aldenhoff AL Kaess B Decker T Baumert J Hallek M Wendtner CM 《Experimental hematology》2003,31(12):1223-1229
OBJECTIVE: Transduction of primary B-cell chronic lymphocytic leukemia (B-CLL) cells with recombinant adeno-associated virus (rAAV) vectors is dependent on preactivation of leukemic cells by CD40L. CpG-oligodeoxynucleotides (CpG-ODNs) are able to activate cytokine production and proliferation of B-CLL cells. Therefore CpG-ODNs were tested for their potential to enhance transgene expression in CLL cells. MATERIALS AND METHODS: Using an optimized adenovirus-free packaging system, rAAV vectors coding for the enhanced green fluorescent protein (AAV/EGFP) were packaged and highly purified resulting in infectious titers up to 5 x 10(9)/mL. Cells obtained from patients with B-CLL were infected with AAV/EGFP at a multiplicity of infection of 100 while being stimulated with CpG-ODNs and/or CD40L-expressing HeLa/SF cells. Transgene expression was assessed after 48 hours by flow cytometry. RESULTS: Stimulation of B-CLL cells by CpG-ODNs resulted in up-regulation of costimulatory molecules and G(1)/S-phase transition at similar levels compared to activation by HeLa/SF cells, but use of CpG-ODNs alone did not result in any efficient AAV/EGFP transduction. Combined stimulation of B-CLL cells with HeLa/SF cells and CpG-ODNs during AAV/EGFP transduction significantly enhanced transgene expression compared to feeder stimulation alone (p=0.004). In addition, the copy number per single cell was significantly increased by addition of CpG-ODNs as detected by quantitative real-time PCR (p=0.04). Use of self-complementary AAV vectors that are not dependent on target cell DNA synthesis did not result in increased transgene expression compared to single-stranded AAV vectors (p=0.30). CONCLUSION: Stimulation by CD40L is crucial for efficient gene transfer into B-CLL cells by rAAV vectors, whereas transduction efficiency can be significantly enhanced by CpG-ODNs. 相似文献
73.
A large-scale,gene-driven mutagenesis approach for the functional analysis of the mouse genome 总被引:12,自引:0,他引:12 下载免费PDF全文
Hansen J Floss T Van Sloun P Füchtbauer EM Vauti F Arnold HH Schnütgen F Wurst W von Melchner H Ruiz P 《Proceedings of the National Academy of Sciences of the United States of America》2003,100(17):9918-9922
A major challenge of the postgenomic era is the functional characterization of every single gene within the mammalian genome. In an effort to address this challenge, we assembled a collection of mutations in mouse embryonic stem (ES) cells, which is the largest publicly accessible collection of such mutations to date. Using four different gene-trap vectors, we generated 5,142 sequences adjacent to the gene-trap integration sites (gene-trap sequence tags; http://genetrap.de) from >11,000 ES cell clones. Although most of the gene-trap vector insertions occurred randomly throughout the genome, we found both vector-independent and vector-specific integration "hot spots." Because >50% of the hot spots were vector-specific, we conclude that the most effective way to saturate the mouse genome with gene-trap insertions is by using a combination of gene-trap vectors. When a random sample of gene-trap integrations was passaged to the germ line, 59% (17 of 29) produced an observable phenotype in transgenic mice, a frequency similar to that achieved by conventional gene targeting. Thus, gene trapping allows a large-scale and cost-effective production of ES cell clones with mutations distributed throughout the genome, a resource likely to accelerate genome annotation and the in vivo modeling of human disease. 相似文献
74.
75.
Different mechanisms of cyclin D1 overexpression in multiple myeloma revealed by fluorescence in situ hybridization and quantitative analysis of mRNA levels 下载免费PDF全文
Specht K Haralambieva E Bink K Kremer M Mandl-Weber S Koch I Tomer R Hofler H Schuuring E Kluin PM Fend F Quintanilla-Martinez L 《Blood》2004,104(4):1120-1126
76.
Epstein-Barr virus latent membrane protein 2A is a B-cell receptor mimic and essential for B-cell survival 下载免费PDF全文
Many cells latently infected with Epstein-Barr virus (EBV), including certain virus-associated tumors, express latent membrane protein 2A (LMP2A), suggesting an important role for this protein in viral latency and oncogenesis. LMP2A mimics B-cell receptor signaling but can also act as a decoy receptor blocking B-cell receptor (BCR) activation. Studies of peripheral B cells have not resolved this apparent contradiction because LMP2A seems to be dispensable for EBV-induced transformation of these B cells in vitro. We show here that LMP2A is essential for growth transformation of germinal center B cells, which do not express the genuine BCR because of deleterious somatic hypermutations in their immunoglobulin genes. BCR-positive (BCR(+)) and BCR-negative (BCR(-)) B cells are readily transformed with a recombinant EBV encoding a conditional, floxed LMP2A allele, but the survival and continued proliferation of both BCR(+) and BCR(-) B cells is strictly dependent on LMP2A. These findings indicate that LMP2A has potent, distinct antiapoptotic and/or transforming characteristics and point to its role as an indispensable BCR mimic in certain B cells from which human B-cell tumors such as Hodgkin lymphoma originate. 相似文献
77.
Peters A Schneider A Greven S Bellander T Forastiere F Ibald-Mulli A Illig T Jacquemin B Katsouyanni K Koenig W Lanki T Pekkanen J Pershagen G Picciotto S Rückerl R Rosario AS Stefanadis C Sunyer J;AIRGENE Study Group 《Inhalation toxicology》2007,19(Z1):161-175
Ambient air pollution has been associated with an increased risk of hospital admission and mortality in potentially susceptible subpopulations, including myocardial infarction (MI) survivors. The multicenter epidemiological study described in this report was set up to study the role of air pollution in eliciting inflammation in MI survivors in six European cities, Helsinki, Stockholm, Augsburg, Rome, Barcelona, and Athens. Outcomes of interest are plasma concentrations of the proinflammatory cytokine interleukin 6 (IL-6) and the acute-phase proteins C-reactive protein (CRP) and fibrinogen. In addition, the study was designed to assess the role of candidate gene polymorphisms hypothesized to lead to a modification of the short-term effects of ambient air pollution. In total, 1003 MI survivors were recruited and assessed with at least 2 repeated clinic visits without any signs of infections. In total, 5813 blood samples were collected, equivalent to an average of 5.8 repeated clinic visits per subject (97% of the scheduled 6 repeated visits). Subjects across the six cities varied with respect to risk factor profiles. Most of the subjects were nonsmokers, but light smokers were included in Rome, Barcelona, and Athens. Substantial inter- and intraindividual variability was observed for IL-6 and CRP. The study will permit assessing the role of cardiovascular disease risk factors, including ambient air pollution and genetic polymorphisms in candidate genes, in determining the inter- and the intraindividual variability in plasma IL-6, CRP, and fibrinogen concentrations in MI survivors. 相似文献
78.
OBJECTIVE: CD23 is constitutively and atypically expressed on malignant B cells in patients with chronic lymphocytic leukemia (B-CLL). Here, we investigated whether CD23-derived peptides might function as B-CLL-specific tumor-associated antigen (TAA). PATIENTS AND METHODS: Using IFN-gamma-ELISPOT assays and HLA-A2/dimer-peptide staining we identified autologous, CD23-specific HLA-A0201-restricted T cells after 4 weeks of in vitro culture. RESULTS: We were able to expand autologous T cells from 8/11 B-CLL patients by using native and CD40L-activated B-CLL cells as antigen-presenting cells (APCs) in 5 cases whereas for 3 samples an autologous T cell response could only be evoked by use of CD40L-stimulated B-CLL cells as APCs. The number of CD8(+) T cells could be expanded during 4 weeks of in vitro culture with native or CD40L-activated B-CLL cells. We could demonstrate that the expanded T cells were also able to secrete IFN-gamma upon recognition of the antigen using IFN-gamma-ELISPOT assays. Furthermore, these T cells not only recognized HLA-A0201-binding CD23-derived peptides presented by T2 cells, but also CD23-overexpressing autologous B-CLL cells in an MHC-I-restricted manner. CONCLUSION: In sum, CD23-derived peptides were shown to be naturally processed and presented as TAA in primary B-CLL, enabling the expansion of autologous tumor-specific T cells. 相似文献
79.
The receptor tyrosine kinase (RTK) Flt3 is expressed in early hematopoietic progenitor cells and stimulates their growth.
Due to frequent mutations in the Flt3 gene in patients with acute myeloid leukemia (AML), Flt3 is regarded as a potential
therapeutic target, but the underlying mechanisms are still poorly understood. Therefore, we investigated interactions of
Flt3 and some Src family tyrosine kinases (SFKs), which are expressed predominantly or exclusively in hematopoietic cells
and known to be involved in signal transduction by various RTKs. Employing sets of wt and mutant Flt3 and Hck, we analyzed
protein binding as well as Flt3 phosphorylation and maturation in HEK-293 cells cotransfected with expression constructs encoding
both binding partners. Kinase-inactive Hck-K269R was recruited to phosphotyrosine residues located in the juxtamembrane (JM)
region of activated Flt3 via its SH2 domain. Several of the JM domain tyrosines were phophorylated by Hck and other SFKs.
As apparent from the distribution of mature and hypoglycosylated Flt3, SFKs interfered with Flt3 maturation in a kinase-dependent
manner. Together, these findings show a complex role of SFKs in Flt3 signaling and reveal a new function of SFKs in the maturation
of RTKs. 相似文献
80.
Laura Caggiari Massimo Guidoboni Emanuela Vaccher Luigi Barzan Giovanni Franchin Annunziata Gloghini Debora Martorelli Paola Zancai Maria Teresa Bortolin Mario Mazzucato Diego Serraino Antonino Carbone Paolo De Paoli Riccardo Dolcetti 《Infectious agents and cancer》2007,2(1):1-11