| 1. |
- Aranburu, Alaitz, et al.
(författare)
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Age-associatedBcells expanded in autoimmune mice are memory cells sharing H-CDR3-selected repertoires
- 2018
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Ingår i: European Journal of Immunology. - : Wiley. - 0014-2980 .- 1521-4141. ; 48:3, s. 509-521
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Tidskriftsartikel (refereegranskat)abstract
- Age-associated Bcells (ABCs) represent a distinct cell population expressing low levels of CD21 (CD21 −/low ). The Ig repertoire expressed by ABCs in aged mice is diverse and exhib its signs of somatic hypermutation (SHM). A CD21 −/low B-cell population is expanded in autoimmune diseases, e.g. systemic lupus erythematosus, as well as in lupus-prone NZB/W mice and in mice lacking a pre-Bcell receptor (SLC −/− ). However, the nature of the CD21 −/low Bcells (hereafter ABCs) in autoimmunity is not well understood. Here we show that in young SLC −/− mice, the vast majority of the ABCs express memory B-cell (MBC) markers in contrast to wild-type controls. A similar population is present in lupus-prone MRL mice before and at disease onset. In SLC −/− mice, a majority of the ABCs are IgM + , their V H genes have undergone SHM, show clonal diversification and clonal restriction at the H-CDR3 level. ABC hybridomas, established from SLC −/− mice, secrete typical lupus autoantibodies, e.g. anti-Smith antigen, and some of those that bind to DNA comprise a H-CDR3 that is identical to previously described IgM anti-DNA antibodies from lupus-prone mice. Together, these results reveal that ABCs in autoimmune mice are comprised of autoreactive MBCs expressing highly restricted H-CDR3 repertoires.
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| 2. |
- Bergmann, B., et al.
(författare)
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Memory B Cells in Mouse Models
- 2013
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Ingår i: Scandinavian Journal of Immunology. - : Wiley. - 0300-9475. ; 78:2, s. 149-156
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Tidskriftsartikel (refereegranskat)abstract
- One of the principles behind vaccination, as shown by Edward Jenner in 1796, and host protection is immunological memory, and one of the cells central to this is the antigen-experienced memory B cell that responds rapidly upon re-exposure to the initiating antigen. Classically, memory B cells have been defined as progenies of germinal centre (GC) B cells expressing isotype-switched and substantially mutated B cell receptors (BCRs), that is, membrane-bound antibodies. However, it has become apparent over the last decade that this is not the only pathway to B cell memory. Here, we will discuss memory B cells in mice, as defined by (1) cell surface markers; (2) multiple layers; (3) formation in a T cell-dependent and either GC-dependent or GC-independent manner; (4) formation in a T cell-independent fashion. Lastly, we will touch upon memory B cells in; (5) mouse models of autoimmune diseases.
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| 3. |
- Chen, Hai-Xia, et al.
(författare)
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A comparative study of nemertean complete mitochondrial genomes, including two new ones for Nectonemertes cf. mirabilis and Zygeupolia rubens, may elucidate the fundamental pattern for the phylum Nemertea
- 2012
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Ingår i: Bmc Genomics. - : Springer Science and Business Media LLC. - 1471-2164. ; 13
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Tidskriftsartikel (refereegranskat)abstract
- Background: The mitochondrial genome is important for studying genome evolution as well as reconstructing the phylogeny of organisms. Complete mitochondrial genome sequences have been reported for more than 2200 metazoans, mainly vertebrates and arthropods. To date, from a total of about 1275 described nemertean species, only three complete and two partial mitochondrial DNA sequences from nemerteans have been published. Here, we report the entire mitochondrial genomes for two more nemertean species: Nectonemertes cf. mirabilis and Zygeupolia rubens. Results: The sizes of the entire mitochondrial genomes are 15365 bp for N. cf. mirabilis and 15513 bp for Z. rubens. Each circular genome contains 37 genes and an AT-rich non-coding region, and overall nucleotide composition is AT-rich. In both species, there is significant strand asymmetry in the distribution of nucleotides, with the coding strand being richer in T than A and in G than C. The AT-rich non-coding regions of the two genomes have some repeat sequences and stem-loop structures, both of which may be associated with the initiation of replication or transcription. The 22 tRNAs show variable substitution patterns in nemerteans, with higher sequence conservation in genes located on the H strand. Gene arrangement of N. cf. mirabilis is identical to that of Paranemertes cf. peregrina, both of which are Hoplonemertea, while that of Z. rubens is the same as in Lineus viridis, both of which are Heteronemertea. Comparison of the gene arrangements and phylogenomic analysis based on concatenated nucleotide sequences of the 12 mitochondrial protein-coding genes revealed that species with closer relationships share more identical gene blocks. Conclusion: The two new mitochondrial genomes share many features, including gene contents, with other known nemertean mitochondrial genomes. The tRNA families display a composite substitution pathway. Gene order comparison to the proposed ground pattern of Bilateria and some lophotrochozoans suggests that the nemertean ancestral mitochondrial gene order most closely resembles the heteronemertean type. Phylogenetic analysis proposes a sister-group relationship between Hetero- and Hoplonemertea, which supports one of two recent alternative hypotheses of nemertean phylogeny.
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| 4. |
- Georgiou, Konstantinos, et al.
(författare)
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Genetic basis of PD-L1 overexpression in diffuse large B-cell lymphomas
- 2016
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Ingår i: Blood. - : American Society of Hematology. - 0006-4971 .- 1528-0020. ; 127:24, s. 3026-3034
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Tidskriftsartikel (refereegranskat)abstract
- Diffuse large B-cell lymphoma (DLBCL) is one of the most common and aggressive types of B-cell lymphoma. Deregulation of proto-oncogene expression after a translocation, most notably to the immunoglobulin heavy-chain locus (IGH), is one of the hallmarks of DLBCL. Using whole-genome sequencing analysis, we have identified the PD-L1/PD-L2 locus as a recurrent translocation partner for IGH in DLBCL. PIM1 and TP63 were also identified as novel translocation partners for PD-L1/PD-L2. Fluorescence in situ hybridization was furthermore used to rapidly screen an expanded DLBCL cohort. Collectively, a subset of samples was found to be affected by gains (12%), amplifications (3%), and translocations (4%) of the PD-L1/PD-L2 locus. RNA sequencing data coupled with immunohistochemistry revealed that these cytogenetic alterations correlated with increased expression of PD-L1 but not of PD-L2. Moreover, cytogenetic alterations affecting the PD-L1/PD-L2 locus were more frequently observed in the non-germinal center B cell-like (non-GCB) subtype of DLBCL. These findings demonstrate the genetic basis of PD-L1 overexpression in DLBCL and suggest that treatments targeting the PD-1-PD-L1/PD-L2 axis might benefit DLBCL patients, especially those belonging to the more aggressive non-GCB subtype.
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| 5. |
- Grimsholm, Ola, 1979, et al.
(författare)
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Absence of surrogate light chain results in spontaneous autoreactive germinal centres expanding V(H)81X-expressing B cells
- 2015
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Ingår i: Nature Communications. - : Springer Science and Business Media LLC. - 2041-1723. ; 6
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Tidskriftsartikel (refereegranskat)abstract
- Random recombination of antibody heavy- and light-chain genes results in a diverse B-cell receptor (BCR) repertoire including self-reactive BCRs. However, tolerance mechanisms that prevent the development of self-reactive B cells remain incompletely understood. The absence of the surrogate light chain, which assembles with antibody heavy chain forming a pre-BCR, leads to production of antinuclear antibodies (ANAs). Here we show that the naive follicular B-cell pool is enriched for cells expressing prototypic ANA heavy chains in these mice in a non-autoimmune background with a broad antibody repertoire. This results in the spontaneous formation of T-cell-dependent germinal centres that are enriched with B cells expressing prototypic ANA heavy chains. However, peripheral tolerance appears maintained by selection thresholds on cells entering the memory B-cell and plasma cell pools, as exemplified by the exclusion of cells expressing the intrinsically self-reactive V(H)81X from both pools.
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| 6. |
- Nie, Man, et al.
(författare)
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The dual role of CD70 in B‐cell lymphomagenesis
- 2022
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Ingår i: Clinical and Translational Medicine. - : John Wiley & Sons. - 2001-1326. ; 12:12
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Tidskriftsartikel (refereegranskat)abstract
- BackgroundCD70 is a costimulatory molecule that is transiently expressed on a small set of activated lymphocytes and is involved in T-cell-mediated immunity. However, the role of CD70 in B-cell malignancies remains controversial.MethodsWe investigated the clinical relevance of CD70 genetic alterations and its protein expression in two diffuse large B-cell lymphoma (DLBCL) cohorts with different ethnic backgrounds. We also performed transcriptomic analysis to explore the role of CD70 alterations in tumour microenvironment. We further tested the blockade of CD70 in combination with PD-L1 inhibitor in a murine lymphoma model.ResultsWe showed that CD70 genetic aberrations occurred more frequently in the Chinese DLBCL cohort (56/233, 24.0%) than in the Swedish cohort (9/84, 10.8%), especially in those with concomitant hepatitis B virus (HBV) infection. The CD70 genetic changes in DLBCL resulted in a reduction/loss of protein expression and/or CD27 binding, which might impair T cell priming and were independently associated with poor overall survival. Paradoxically, we observed that over-expression of CD70 protein was also associated with a poor treatment response, as well as an advanced disease stage and EBV infection. More exhausted CD8+ T cells were furthermore identified in CD70 high-expression DLBCLs. Finally, in a murine lymphoma model, we demonstrated that blocking the CD70/CD27 and/or PD1/PD-L1 interactions could reduce CD70+ lymphoma growth in vivo, by directly impairing the tumour cell proliferation and rescuing the exhausted T cells.ConclusionsOur findings suggest that CD70 can play a role in either tumour suppression or oncogenesis in DLBCL, likely via distinct immune evasion mechanisms, that is, impairing T cell priming or inducing T cell exhaustion. Characterisation of specific dysfunction of CD70 in DLBCL may thus provide opportunities for the development of novel targeted immuno-therapeutic strategies.
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| 7. |
- Pecori, Riccardo, et al.
(författare)
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ADAR1-mediated RNA editing promotes B cell lymphomagenesis
- 2023
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Ingår i: iScience. - : Cell Press. - 2589-0042. ; 26:6
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Tidskriftsartikel (refereegranskat)abstract
- Diffuse large B cell lymphoma (DLBCL) is one of the most common types of aggressive lymphoid malignancies. Here, we explore the contribution of RNA editing to DLBCL pathogenesis. We observed that DNA mutations and RNA editing events are often mutually exclusive, suggesting that tumors can modulate pathway outcomes by altering sequences at either the genomic or the transcriptomic level. RNA editing targets transcripts within known disease-driving pathways such as apoptosis, p53 and NF-kappa B signaling, as well as the RIG-I-like pathway. In this context, we show that ADAR1-mediated editing within MAVS transcript positively correlates with MAVS protein expression levels, associating with increased interferon/NF-kappa B signaling and T cell exhaustion. Finally, using targeted RNA base editing tools to restore editing within MAVS 3 ' UTR in ADAR1-deficient cells, we demonstrate that editing is likely to be causal to an increase in downstream signaling in the absence of activation by canonical nucleic acid receptor sensing.
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| 8. |
- Ren, Weicheng, et al.
(författare)
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Complete genome sequence of acute viral necrosis virus associated with massive mortality outbreaks in the Chinese scallop, Chlamys farreri.
- 2013
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Ingår i: Virology journal. - 1743-422X. ; 10:1
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Acute viral necrosis virus (AVNV) is the causative agent of a serious disease resulting in high mortality in cultured Chinese scallops, Chlamys farreri. We have sequenced and analyzed the complete genome of AVNV. RESULTS: The AVNV genome is a linear, double-stranded DNA molecule of 210,993 bp with a nucleotide composition of 38.5% G + C. A total of 123 open reading frames were predicted to encode functional proteins, ranging from 41 to 1,878 amino acid residues. The DNA sequence of AVNV is 97% identical to that of ostreid herpesvirus 1 (OsHV-1), and the amino acid sequences of the encoded proteins of these two viruses are 94-100% identical. The genomic organization of AVNV is similar to that of OsHV-1, and consists of two unique regions (170.4 kb and 3.4 kb, respectively), each flanked by two inverted repeats (7.6 kb and 10.2 kb, respectively), with a third unique region (1.5 kb) situated between the two internal repeats. CONCLUSIONS: Our results indicate that AVNV is a variant of OsHV-1. The AVNV genome sequence provides information useful for understanding the evolution and divergence of OsHV-1 in marine molluscs.
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| 9. |
- Ren, Weicheng, et al.
(författare)
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Genetic and transcriptomic analyses of diffuse large B-cell lymphoma patients with poor outcomes within two years of diagnosis
- 2024
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Ingår i: Leukemia. - : Springer Nature. - 0887-6924 .- 1476-5551. ; 38:2, s. 438-441
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Tidskriftsartikel (refereegranskat)abstract
- Despite the improvements in clinical outcomes for DLBCL, a significant proportion of patients still face challenges with refractory/relapsed (R/R) disease after receiving first-line R-CHOP treatment. To further elucidate the underlying mechanism of R/R disease and to develop methods for identifying patients at risk of early disease progression, we integrated clinical, genetic and transcriptomic data derived from 2805 R-CHOP-treated patients from seven independent cohorts. Among these, 887 patients exhibited R/R disease within two years (poor outcome), and 1918 patients remained in remission at two years (good outcome). Our analysis identified four preferentially mutated genes (TP53, MYD88, SPEN, MYC) in the untreated (diagnostic) tumor samples from patients with poor outcomes. Furthermore, transcriptomic analysis revealed a distinct gene expression pattern linked to poor outcomes, affecting pathways involved in cell adhesion/migration, T-cell activation/regulation, PI3K, and NF-kappa B signaling. Moreover, we developed and validated a 24-gene expression score as an independent prognostic predictor for treatment outcomes. This score also demonstrated efficacy in further stratifying high-risk patients when integrated with existing genetic or cell-of-origin subtypes, including the unclassified cases in these models. Finally, based on these findings, we developed an online analysis tool (https://lymphprog.serve.scilifelab.se/app/lymphprog) that can be used for prognostic prediction for DLBCL patients.
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| 10. |
- Ren, Weicheng, et al.
(författare)
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Surrogate light chain is required for central and peripheral B-cell tolerance and inhibits anti-DNA antibody production by marginal zone B cells
- 2015
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Ingår i: European Journal of Immunology. - : Wiley. - 0014-2980 .- 1521-4141. ; 45:4, s. 1228-1237
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Tidskriftsartikel (refereegranskat)abstract
- Selection of the primary antibody repertoire takes place in pro-/pre-B cells, and subsequently in immature and transitional B cells. At the first checkpoint, μ heavy (μH) chains assemble with surrogate light (SL) chain into a precursor B-cell receptor. In mice lacking SL chain, μH chain selection is impaired, and serum autoantibody levels are elevated. However, whether the development of autoantibody-producing cells is due to an inability of the resultant B-cell receptors to induce central and/or peripheral B-cell tolerance or other factors is unknown. Here, we show that receptor editing is defective, and that a higher proportion of BM immature B cells are prone to undergoing apoptosis. Furthermore, transitional B cells are also more prone to undergoing apoptosis, with a stronger selection pressure to enter the follicular B-cell pool. Those that enter the marginal zone (MZ) B-cell pool escape selection and survive, possibly due to the B-lymphopenia and elevated levels of B-cell activating factor. Moreover, the MZ B cells are responsible for the elevated IgM anti-dsDNA antibody levels detected in these mice. Thus, the SL chain is required for central and peripheral B-cell tolerance and inhibits anti-DNA antibody production by MZ B cells.
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