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| 2. |
- Björkander, Sophia, et al.
(författare)
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Staphylococcus aureus-derived factors induce IL-10, IFN-gamma and IL-17A-expressing FOXP3(+)CD161(+) T-helper cells in a partly monocyte-dependent manner
- 2016
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Ingår i: Scientific Reports. - : Springer Science and Business Media LLC. - 2045-2322. ; 6
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Tidskriftsartikel (refereegranskat)abstract
- Staphylococcus aureus (S. aureus) is a human pathogen as well as a frequent colonizer of skin and mucosa. This bacterium potently activates conventional T-cells through superantigens and it is suggested to induce T-cell cytokine-production as well as to promote a regulatory phenotype in T-cells in order to avoid clearance. This study aimed to investigate how S. aureus impacts the production of regulatory and pro-inflammatory cytokines and the expression of CD161 and HELIOS by peripheral CD4(+)FOXP3(+) T-cells. Stimulation of PBMC with S. aureus 161:2-cell free supernatant (CFS) induced expression of IL-10, IFN-gamma and IL-17A in FOXP3(+) cells. Further, CD161 and HELIOS separated the FOXP3(+) cells into four distinct populations regarding cytokine-expression. Monocyte-depletion decreased S. aureus 161:2-induced activation of FOXP3(+) cells while pre-stimulation of purified monocytes with S. aureus 161:2-CFS and subsequent co-culture with autologous monocyte-depleted PBMC was sufficient to mediate activation of FOXP3(+) cells. Together, these data show that S. aureus potently induces FOXP3(+) cells and promotes a diverse phenotype with expression of regulatory and pro-inflammatory cytokines connected to increased CD161-expression. This could indicate potent regulation or a contribution of FOXP3(+) cells to inflammation and repression of immune-suppression upon encounter with S. aureus.
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| 3. |
- Lasaviciute, Gintare, et al.
(författare)
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Deficits in the IgG+ memory B‐cell recovery after anthracycline treatment is confined to the spleen of rhesus macaques
- 2020
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Ingår i: Clinical & Translational Immunology (CTI). - : Wiley. - 2050-0068. ; 9:7
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Tidskriftsartikel (refereegranskat)abstract
- Objectives. Loss of vaccine-induced antibodies (Abs) after chemotherapy against paediatric acute lymphoblastic leukaemia (ALL) is common and often necessitates re-immunisation after cessation of treatment. Even so, some ALL survivors fail to mount or to maintain protective Abs. Germinal centres (GCs) are clusters of proliferating B cells in follicles of secondary lymphoid tissues (SLTs) formed during adaptive immune responses and the origins of long-lived memory B and plasma cells that are the source of Abs. Furthermore, productive GC reactions depend on T follicular helper (TFH) cells. To understand why chemotherapy induces deficits in Ab responses, we examined how SLTs were affected by chemotherapy. Methods. Rhesus macaques were infused with either three cycles of the anthracycline doxorubicin or saline, followed by immunisation with a de novo and booster antigen. Spleen and lymph nodes were removed, and memory B, bulk T and TFH cells were examined. Results. Despite adequate GC morphology, a diminished memory and IgG+ B-cell population along with diminished total and booster vaccine-specific IgGproducing memory B cells were noted in the spleens of macaques with past doxorubicin exposure compared to the saline-treated controls (P < 0.05). Intact bulk T and TFH cells were found in the SLTs of treated macaques, which displayed higher CD40L upregulation capacity by their splenic CXCR5+ helper T cells (P < 0.01). In contrast to the spleen, the immune cell populations studied were comparable between the lymph nodes of both saline- and doxorubicin-treated macaques. Conclusion. Our findings suggest that the splenic memory B-cell subset, compared to its lymph node counterpart, is more severely altered by anthracycline treatment.
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| 6. |
- Lasaviciute, Gintare, et al.
(författare)
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Epstein-Barr Virus, but Not Cytomegalovirus, Latency Accelerates the Decay of Childhood Measles and Rubella Vaccine Responses-A 10-Year Follow-up of a Swedish Birth Cohort
- 2017
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Ingår i: Frontiers in Immunology. - : Frontiers Media SA. - 1664-3224. ; 8
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Tidskriftsartikel (refereegranskat)abstract
- Background: Epstein-Barr virus (EBV) and cytomegalovirus (CMV) are ubiquitous and persistent herpesviruses commonly acquired during childhood. Both viruses have a significant impact on the immune system, especially through mediating the establishment of cellular immunity, which keeps these viruses under control for life. Far less is known about how these viruses influence B-cell responses. Objectives: To evaluate the impact of latent EBV and CMV infection on rubella- and measles-specific antibody responses as well as on the B-cell compartment in a prospective birth cohort followed during the first 10 years of life. Methods: IgG titers against rubella and measles vaccines were measured in plasma obtained from the same donors at 2, 5, and 10 years of age. Peripheral B-cell subsets were evaluated ex vivo at 2 and 5 years of age. Factors related to optimal B-cell responses including IL-21 and CXCL13 levels in plasma were measured at all-time points. Results: EBV carriage in the absence of CMV associated with an accelerated decline of rubella and measles-specific IgG levels (p = 0.003 and p = 0.019, respectively, linear mixed model analysis), while CMV carriage in the absence of EBV associated with delayed IgG decay over time for rubella (p = 0.034). At 5 years of age, EBV but not CMV latency associated with a lower percentage of plasmablasts, but higher IL-21 levels in the circulation. Conclusion: Our findings suggest that EBV carriage in the absence of CMV influences the B-cell compartment and the dynamics of antibody responses over time during steady state in the otherwise healthy host.
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| 7. |
- Lasaviciute, Gintare, 1990-
(författare)
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Functions and memory features of adaptive- and innate immune cells in physiological and inflammatory settings
- 2022
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The immune system is a complex but well-regulated network which cooperates with the microbiota to maintain optimal homeostasis under physiological settings. A number of factors display the capacity to alter the immune system and thus microbiota crosstalk including host genetics, diet, environmental influences and drugs such as antibiotics or chemotherapeutic agents.We and others have previously demonstrated immune regulatory capacities of the gut commensal Limosilactobacillus reuteri (L. reuteri) that seem to act via myeloid cells. In paper I, we have further shown that priming of blood dendritic cells (DCs) or monocytes with L. reuteri-derived cell free supernatant (CFS) modifies how these cells respond to future stimulus challenge, even after monocytes differentiation to DCs (mo-DCs). Notably, priming conditions in mo-DCs skewed subsequent T-helper cell responses. In paper II, we continued to elaborate on whether microbial and gut-associated metabolites modify chemotherapy-induced effects. Thus far, we could show that the CFS from probiotic bacteria might imprint immune cells to modulate inflammatory responses when intestinal epithelial cells are compromised by chemotherapy exposure. In paper III, we investigated how chemotherapy agent Doxorubicin (Doxo) affects bone marrow resident mesenchymal stromal cells (BM MSCs) which support antibody secreting cells (ASCs) responsible for serological memory. Our findings have shown that Doxo-induced alterations in BM MSCs are not sufficient to disrupt their support to ASCs, thus alternative or additional factors might be implicated in ASC preservation during chemotherapy. Lastly, in paper IV, we investigated how Doxo affects secondary lymphoid organs and we found that splenic compartment is more prominently affected by Doxo treatment compared to its lymph node counterpart in an animal model of rhesus macaques.Collectively, this thesis outlines novel perceptions on innate immune memory-like capacity and how gut-associated factors influence such recall responses in innate immune cells. Further, this thesis increases our knowledge on how adaptive immune cells, required for long-term serological memory, are preserved during toxic conditions such as those induced by chemotherapy treatment.
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| 8. |
- Lasaviciute, Gintare, et al.
(författare)
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Gut commensal Limosilactobacillus reuteri induces atypical memory-like phenotype in human dendritic cells in vitro
- 2022
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Ingår i: Gut microbes. - : Informa UK Limited. - 1949-0976 .- 1949-0984. ; 14:1
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Tidskriftsartikel (refereegranskat)abstract
- Memory-like responses in innate immune cells confer nonspecific protection against secondary exposures. A number of microbial agents have been found to induce enhanced or diminished recall responses in innate cells, however, studies investigating the ability of probiotic bacteria to trigger such effects are lacking. Here, we show that priming of human monocytes with a secretome from the gut probiotic bacterium Limosilactobacillus (L.) reuteri induces a mixed secondary response phenotype in monocyte-derived dendritic cells (mo-DCs), with a strong IL-6 and IL-1β response but low TNFα, IL-23 and IL-27 secretion. Instead, blood DC priming with L. reuteri-secretome resembles a tolerant state upon secondary exposure. A similar pattern was found in conventional and gut-like (retinoic acid exposed) DCs, although retinoic acid hampered TNFα and IL-6 production and enrichment of histone modifications in L. reuteri-secretome primed mo-DC cultures. Further, we show that the memory-like phenotype of mo-DCs, induced by priming stimuli, is important for subsequent T helper (Th) cell differentiation pathways and might determine the inflammatory nature of Th cells. We also show enhanced recall responses characterized by robust inflammatory cytokines and lactate production in the gut-like mo-DCs derived from β-glucan primed monocytes. Such responses were accompanied with enriched histone modifications at the promoter of genes associated with a trained phenotype in myeloid cells. Altogether, we demonstrate that a gut commensal-derived secretome prompts recall responses in human DCs which differ from that induced by classical training agents such as β-glucan. Our results could be beneficial for future therapeutic interventions where T cell responses are needed to be modulated.
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| 9. |
- Lasaviciute, Gintare, 1990-, et al.
(författare)
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Human Bone Marrow Mesenchymal Stromal Cell-Derived CXCL12, IL-6 and GDF-15 and Their Capacity to Support IgG-Secreting Cells in Culture Are Divergently Affected by Doxorubicin
- 2021
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Ingår i: Hemato. - : MDPI AG. - 2673-6357. ; 2:1, s. 154-166
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Tidskriftsartikel (refereegranskat)abstract
- Various subsets of bone marrow mesenchymal stromal cells (BM MSCs), including fibroblasts, endothelial, fat and reticular cells, are implicated in the regulation of the hematopoietic microenvironment and the survival of long-lived antibody-secreting cells (ASCs). Nowadays it is widely acknowledged that vaccine-induced protective antibody levels are diminished in adults and children that are treated for hematological cancers. A reason behind this could be damage to the BM MSC niche leading to a diminished pool of ASCs. To this end, we asked whether cell cytotoxic treatment alters the capacity of human BM MSCs to support the survival of ASCs. To investigate how chemotherapy affects soluble factors related to the ASC niche, we profiled a large number of cytokines and chemokines from in vitro-expanded MSCs from healthy donors or children who were undergoing therapy for acute lymphoblastic leukemia (ALL), following exposure to a widely used anthracycline called doxorubicin (Doxo). In addition, we asked if the observed changes in the measured soluble factors after Doxo exposure impacted the ability of the BM niche to support humoral immunity by co-culturing Doxo-exposed BM MSCs with in vitro-differentiated ASCs from healthy blood donors, and selective neutralization of cytokines. Our in vitro results imply that Doxo-induced alterations in BM MSC-derived interleukin 6 (IL-6), CXCL12 and growth and differentiation factor 15 (GDF-15) are not sufficient to disintegrate the support of IgG-producing ASCs by the BM MSC niche, and that serological memory loss may arise during later stages of ALL therapy.
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