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- Cerboni, C, et al.
(författare)
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Human cytomegalovirus strain-dependent changes in NK cell recognition of infected fibroblasts
- 2000
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Ingår i: Journal of immunology (Baltimore, Md. : 1950). - : The American Association of Immunologists. - 0022-1767 .- 1550-6606. ; 164:9, s. 4775-4782
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Tidskriftsartikel (refereegranskat)abstract
- NK cells play a key role in the control of CMV infection in mice, but the mechanism by which NK cells can recognize and kill CMV-infected cells is unclear. In this study, the modulation of NK cell susceptibility of human CMV (hCMV)-infected cells was examined. We used a human lung and a human foreskin fibroblast cell line infected with clinical isolates (4636, 13B, or 109B) or with laboratory strains (AD169, Towne). The results indicate that all three hCMV clinical isolates confer a strong NK resistance, whereas only marginal or variable effects in the NK recognition were found when the laboratory strains were used. The same results were obtained regardless of the conditions of infection, effector cell activation status, cell culture conditions, and/or donor-target cell combinations. The NK cell inhibition did not correlate with HLA class I expression levels on the surface of the target cell and was independent of the leukocyte Ig-like receptor-1, as evaluated in Ab blocking experiments. No relevant changes were detected in the adhesion molecules ICAM-I and LFA-3 expressed on the cell surface of cells infected with hCMV clinical and laboratory strains. We conclude that hCMV possesses other mechanisms, related neither to target cell expression of HLA-I or adhesion molecules nor to NK cell expression of leukocyte Ig-like receptor-1, that confer resistance to NK cell recognition. Such mechanisms may be lost during in vitro passage of the virus. These results emphasize the differences between clinical hCMV isolates compared with laboratory strains.
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- Li, S. Y., et al.
(författare)
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Universal toxin-based selection for precise genome engineering in human cells
- 2021
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Ingår i: Nature Communications. - : Springer Science and Business Media LLC. - 2041-1723. ; 12:1
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Tidskriftsartikel (refereegranskat)abstract
- Prokaryotic restriction enzymes, recombinases and Cas proteins are powerful DNA engineering and genome editing tools. However, in many primary cell types, the efficiency of genome editing remains low, impeding the development of gene- and cell-based therapeutic applications. A safe strategy for robust and efficient enrichment of precisely genetically engineered cells is urgently required. Here, we screen for mutations in the receptor for Diphtheria Toxin (DT) which protect human cells from DT. Selection for cells with an edited DT receptor variant enriches for simultaneously introduced, precisely targeted gene modifications at a second independent locus, such as nucleotide substitutions and DNA insertions. Our method enables the rapid generation of a homogenous cell population with bi-allelic integration of a DNA cassette at the selection locus, without clonal isolation. Toxin-based selection works in both cancer-transformed and non-transformed cells, including human induced pluripotent stem cells and human primary T-lymphocytes, as well as it is applicable also in vivo, in mice with humanized liver. This work represents a flexible, precise, and efficient selection strategy to engineer cells using CRISPR-Cas and base editing systems. Genome engineering in cell lines or human stem cells often has poor efficiency, limiting the development of research and therapeutic applications. Here, the authors use a toxin-based selection system for precise bi-allelic engineering in cells and in vivo.
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- Romania, P., et al.
(författare)
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Identification of a Genetic Variation in ERAP1 Aminopeptidase that Prevents Human Cytomegalovirus miR-UL112-5p-Mediated Immunoevasion
- 2017
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Ingår i: Cell Reports. - : Elsevier BV. - 2211-1247. ; 20:4, s. 846-853
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Tidskriftsartikel (refereegranskat)abstract
- Herein, we demonstrate that HCMV miR-UL112-5p targets ERAP1, thereby inhibiting the processing and presentation of the HCMV pp65495-503 peptide to specific CTLs. In addition, we show that the rs17481334 G variant, naturally occurring in the ERAP1 30 UTR, preserves ERAP1 from miR-UL1125p-mediated degradation. Specifically, HCMV miRUL112-5p binds the 30 UTR of ERAP1 A variant, but not the 30 UTR of ERAP1 G variant, and, accordingly, ERAP1 expression is reduced both at RNA and protein levels only in human fibroblasts homozygous for the A variant. Consistently, HCMV-infected GG fibroblasts were more efficient in trimming viral antigens and being lysed by HCMV-peptide-specific CTLs. Notably, a significantly decreased HCMV seropositivity was detected among GG individuals suffering from multiple sclerosis, a disease model in which HCMV is negatively associated with adultonset disorder. Overall, our results identify a resistance mechanism to HCMV miR-UL112-5p-based immune evasion strategy with potential implications for individual susceptibility to infection and other diseases.
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- Sjolin, H, et al.
(författare)
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Pivotal role of KARAP/DAP12 adaptor molecule in the natural killer cell-mediated resistance to murine cytomegalovirus infection
- 2002
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Ingår i: The Journal of experimental medicine. - : Rockefeller University Press. - 0022-1007 .- 1540-9538. ; 195:7, s. 825-834
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Tidskriftsartikel (refereegranskat)abstract
- Natural killer (NK) cells are major contributors to early defense against infections. Their effector functions are controlled by a balance between activating and inhibiting signals. To date, however, the involvement of NK cell activating receptors and signaling pathways in the defense against pathogens has not been extensively investigated. In mice, several NK cell activating receptors are coexpressed with and function through the immunoreceptor tyrosine-based activation motif (ITAM)-bearing molecule KARAP/DAP12. Here, we have analyzed the role of KARAP/DAP12 in the early antiviral response to murine cytomegalovirus (MCMV). In KARAP/DAP12 mutant mice bearing a nonfunctional ITAM, we found a considerable increase in viral titers in the spleen (30–40-fold) and in the liver (2–5-fold). These effects were attributed to NK cells. The formation of hepatic inflammatory foci appeared similar in wild-type and mutant mice, but the latter more frequently developed severe hepatitis with large areas of focal necrosis. Moreover, the percentage of hepatic NK cells producing interferon γ was reduced by 56 ± 22% in the absence of a functional KARAP/DAP12. This is the first study that shows a crucial role for a particular activating signaling pathway, in this case the one induced through KARAP/DAP12, in the NK cell–mediated resistance to an infection. Our results are discussed in relation to recent reports demonstrating that innate resistance to MCMV requires the presence of NK cells expressing the KARAP/DAP12-associated receptor Ly49H.
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- Sjostrom, A, et al.
(författare)
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Acquisition of external major histocompatibility complex class I molecules by natural killer cells expressing inhibitory Ly49 receptors
- 2001
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Ingår i: The Journal of experimental medicine. - : Rockefeller University Press. - 0022-1007 .- 1540-9538. ; 194:10, s. 1519-1530
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Tidskriftsartikel (refereegranskat)abstract
- Murine natural killer (NK) cells express inhibitory Ly49 receptors specific for major histocompatibility complex (MHC) class I molecules. We report that during interactions with cells in the environment, NK cells acquired MHC class I ligands from surrounding cells in a Ly49-specific fashion and displayed them at the cell surface. Ligand acquisition sometimes reached 20% of the MHC class I expression on surrounding cells, involved transfer of the entire MHC class I protein to the NK cell, and was independent of whether or not the NK cell expressed the MHC class I ligand itself. We also present indirect evidence for spontaneous MHC class I acquisition in vivo, as well as describe an in vitro coculture system with transfected cells in which the same phenomenon occurred. Functional studies in the latter model showed that uptake of H-2Dd by Ly49A+ NK cells was accompanied by a partial inactivation of cytotoxic activity in the NK cell, as tested against H-2Dd-negative target cells. In addition, ligand acquisition did not abrogate the ability of Ly49A+ NK cells to receive inhibitory signals from external H-2Dd molecules. This study is the first to describe ligand acquisition by NK cells, which parallels recently described phenomena in T and B cells.
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