| 1. |
- Badolati, Isabella, et al.
(författare)
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Staphylococcus aureus-derived factors promote human Th9 cell polarization and enhance a transcriptional program associated with allergic inflammation
- 2023
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Ingår i: European Journal of Immunology. - : Wiley. - 0014-2980 .- 1521-4141. ; 53:3
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Tidskriftsartikel (refereegranskat)abstract
- T helper (Th) 9 cells, characterized by robust secretion of IL-9, have been increasingly associated with allergic diseases. However, whether and how Th9 cells are modulated by environmental stimuli remains poorly understood. In this study, we show that in vitro exposure of human PBMCs or isolated CD4 T-cells to Staphylococcus (S.) aureus-derived factors, including its toxins, potently enhances Th9 cell frequency and IL-9 secretion. Furthermore, as revealed by RNA sequencing analysis, S. aureus increases the expression of Th9-promoting factors at the transcriptional level, such as FOXO1, miR-155, and TNFRSF4. The addition of retinoic acid (RA) dampens the Th9 responses promoted by S. aureus and substantially changes the transcriptional program induced by this bacterium, while also altering the expression of genes associated with allergic inflammation. Together, our results demonstrate a strong influence of microbial and dietary factors on Th9 cell polarization, which may be important in the context of allergy development and treatment.
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| 2. |
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| 4. |
- Björkander, Sophia, 1987-
(författare)
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Immune maturation and lymphocyte characteristics in relation to early gut bacteria exposure
- 2016
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- At birth, the immune system is immature and the gut microbiota influences immune maturation. Staphylococcus aureus (S. aureus) and lactobacilli are part of the neonatal gut microbiota and have seemingly opposite effects on the immune system. S. aureus is a potent immune activator and early-life colonization associates with higher immune responsiveness later in life. Lactobacilli-colonization associates with reduced allergy-risk and lower immune responsiveness. Further, lactobacilli modulate immune-activation and have probiotic features.Here, we investigated S. aureus-induced activation of human lymphocytes, including T regulatory cells (Tregs), conventional T-cells (CD4+ and CD8+), unconventional T-cells (γδ T-cells and MAIT-cells) and NK-cells from children and adults, together with the modulatory effect of lactobacilli on immune-activation. Further, early-life colonization with these bacteria was related to lymphocyte-maturation, plasma cytokine- and chemokine-levels and allergy. S. aureus cell free supernatant (CFS) and staphylococcal enterotoxin (SE) A induced an increased percentage of FOXP3+ Tregs and of CD161+, IL-10+, IFN-γ+ and IL-17A+ Tregs (Paper I). The same pattern was observed in children with a lower degree of activation, possibly due to lower CD161-expression and poor activation of naive T-cells (Paper II). S. aureus-CFS induced IFN-γ-expression, proliferation and cytotoxic capacity in conventional and unconventional T-cells, and NK-cells. SEA, but not SEH, induced activation of unconventional T-cells and NK-cells by unknown mechanism(s) (Paper III, extended data). Lactobacilli-CFS reduced S. aureus-induced lymphocyte activation without the involvement of IL-10, Tregs or monocytes, but possibly involving lactate (Paper III). Early-life colonization with S. aureus associated with increased percentages of CD161+ and IL-10+ Tregs while lactobacilli-colonization negatively correlated with the percentage of IL-10+ Tregs later in life (Paper II). Allergic disease in childhood associated with double allergic heredity, being born wintertime and with higher plasma levels of TH2-, TH17- and TFH-related chemokines early in life. Lactobacilli-colonization associated with lower prevalence of allergy, reduced chemokine-levels and increased levels of IFN-γ in plasma (Paper IV). This thesis provides novel insights into S. aureus- and SE-mediated activation of Tregs, unconventional T-cells and NK-cells and suggests an overall impairment of immune-responsiveness towards this bacterium in children. Further, S. aureus-colonization may influence the maturation of peripheral Tregs. Our data show that lactobacilli potently dampen lymphocyte-activation in vitro and that colonization associates with Treg-responsiveness, altered plasma cytokine- and chemokine-levels and with remaining non-allergic, thereby supporting the idea of lactobacilli as important immune-modulators.
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| 5. |
- Björkander, Sophia, et al.
(författare)
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SARS-CoV-2-specific B- and T-cell immunity in a population-based study of young Swedish adults
- 2022
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Ingår i: Journal of Allergy and Clinical Immunology. - : Elsevier BV. - 0091-6749 .- 1097-6825. ; 149:1, s. 65-75
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Tidskriftsartikel (refereegranskat)abstract
- Background: Young adults are now considered major spreaders of coronavirus disease 2019 (COVID-19) disease. Although most young individuals experience mild to moderate disease, there are concerns of long-term adverse health effects. The impact of COVID-19 disease and to which extent population-level immunity against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) exists in young adults remain unclear.Objective: We conducted a population-based study on humoral and cellular immunity to SARS-CoV-2 and explored COVID-19 disease characteristics in young adults.Methods: We invited participants from the Swedish BAMSE (Barn [Children], Allergy Milieu, Stockholm, Epidemiology) birth cohort (age 24-27 years) to take part in a COVID-19 followup. From 980 participants (October 2020 to June 2021), we here present data on SARS-CoV-2 receptor-binding domain-specific IgM, IgA, and IgG titers measured by ELISA and on symptoms and epidemiologic factors associated with seropositivity. Further, SARS-CoV-2-specific memory B-and T-cell responses were detected for a subpopulation (n 5 108) by ELISpot and FluoroSpot.Results: A total of 28.4% of subjects were seropositive, of whom 18.4% were IgM single positive. One in 7 seropositive subjects was asymptomatic. Seropositivity was associated with use of public transport, but not with sex, asthma, rhinitis, IgE sensitization, smoking, or body mass index. In a subset of representative samples, 20.7% and 35.0% had detectable SARSCoV-2 specific B-and T-cell responses, respectively. B-and T-cell memory responses were clearly associated with seropositivity, but T-cell responses were also detected in 17.2% of seronegative subjects.Conclusions: Assessment of IgM and T-cell responses may improve population-based estimations of SARS-CoV-2 infection. The pronounced surge of both symptomatic and asymptomatic infections among young adults indicates that the large-scale vaccination campaign should be continued. (J Allergy Clin Immunol 2022;149:65-75.)
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| 6. |
- 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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| 7. |
- Björkander, Sophia, et al.
(författare)
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The allergic phenotype during the first 10 years of life in a prospective cohort
- 2019
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Ingår i: Immunity, Inflammation and Disease. - : Wiley. - 2050-4527. ; 7:3, s. 170-182
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Tidskriftsartikel (refereegranskat)abstract
- BackgroundHeredity and environmental parameters jointly affect allergy development. Here, we used a Swedish prospective cohort to study the influence of heredity and factors usually associated with allergic disease and the development of allergic manifestations in combination with immunoglobulin E (IgE) sensitization at four different time points until 10 years of age.MethodsParents‐to‐be were characterized concerning allergy and their children (n = 281) were divided based on allergic heredity and followed from birth and clinically examined for IgE‐associated allergic symptoms until 10 years of age. The relation between allergy and early‐life parameters was analyzed by logistic regression. Group‐wise comparisons were made by nonparametrical tests.ResultsEarly life eczema and/or asthma in combination with IgE sensitization, was a strong indicator of allergy at a later time point. Further, the early occurrence of multiple allergic symptoms among IgE‐sensitized children predisposed for a more complex allergic phenotype at later ages, independently of allergic heredity. At 10 years of age, allergic children had higher fractional exhaled nitrogen oxide (FeNO) levels, regardless of asthma, and FeNO levels were also influenced by heredity. Birth season was strongly associated with allergy development, but only in children with two allergic parents.ConclusionAllergic eczema/asthma in early life, being born during the autumn/winter, having multiple allergic symptoms and two allergic parents were all strong predictors for having allergic diseases at 5 and 10 years of age. However, the allergic march seems to be independent of heredity, as IgE‐mediated allergies follow the same trajectories in children with and without allergic heredity.
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| 8. |
- Fergusson, Joannah R., et al.
(författare)
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CD161 Defines a Transcriptional and Functional Phenotype across Distinct Human T Cell Lineages
- 2014
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Ingår i: Cell Reports. - : Elsevier BV. - 2211-1247. ; 9:3, s. 1075-1088
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Tidskriftsartikel (refereegranskat)abstract
- The C-type lectin CD161 is expressed by a large proportion of human T lymphocytes of all lineages, including a population known as mucosal-associated invariant T (MAIT) cells. To understand whether different T cell subsets expressing CD161 have similar properties, we examined these populations in parallel using mass cytometry and mRNA microarray approaches. The analysis identified a conserved CD161++/MAIT cell transcriptional signature enriched in CD161+CD8+ T cells, which can be extended to CD161+ CD4+ and CD161+TCR gamma delta+ T cells. Furthermore, this led to the identification of a shared innate-like, TCR-independent response to interleukin (IL)-12 plus IL-18 by different CD161-expressing T cell populations. This response was independent of regulation by CD161, which acted as a costimulatory molecule in the context of T cell receptor stimulation. Expression of CD161 hence identifies a transcriptional and functional phenotype, shared across human T lymphocytes and independent of both T cell receptor (TCR) expression and cell lineage.
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| 9. |
- Haileselassie, Yeneneh, et al.
(författare)
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Lactobacilli Regulate Staphylococcus aureus 161:2-Induced Pro-Inflammatory T-Cell Responses In Vitro
- 2013
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Ingår i: PLOS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 8:10
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Tidskriftsartikel (refereegranskat)abstract
- There seems to be a correlation between early gut microbiota composition and postnatal immune development. Alteration in the microbial composition early in life has been associated with immune mediated diseases, such as autoimmunity and allergy. We have previously observed associations between the presence of lactobacilli and Staphylococcus (S.) aureus in the early-life gut microbiota, cytokine responses and allergy development in children. Consistent with the objective to understand how bacteria modulate the cytokine response of intestinal epithelial cell (IEC) lines and immune cells, we exposed IEC lines (HT29, SW480) to UV-killed bacteria and/or culture supernatants (-sn) from seven Lactobacillus strains and three S. aureus strains, while peripheral blood mononuclear cells (PBMC) and cord blood mononuclear cells (CBMC) from healthy donors were stimulated by bacteria-sn or with bacteria conditioned IEC-sn. Although the overall IEC response to bacterial exposure was characterized by limited sets of cytokine and chemokine production, S. aureus 161: 2-sn induced an inflammatory response in the IEC, characterized by CXCL1/GROa and CXCL8/IL-8 production, partly in a MyD88-dependent manner. UV-killed bacteria did not induce a response in the IEC line, and a combination of both UV-killed bacteria and the bacteria-sn had no additive effect to that of the supernatant alone. In PBMC, most of the Lactobacillus-sn and S. aureus-sn strains were able to induce a wide array of cytokines, but only S. aureus-sn induced the T-cell associated cytokines IL-2, IL-17 and IFN-gamma, independently of IEC-produced factors, and induced up regulation of CTLA-4 expression and IL-10 production by T-regulatory cells. Notably, S. aureus-sn-induced T-cell production of IFN-gamma and IL-17 was down regulated by the simultaneous presence of any of the different Lactobacillus strains, while the IEC CXCL8/IL-8 response was unaltered. Thus these studies present a possible role for lactobacilli in induction of immune cell regulation, although the mechanisms need to be further elucidated.
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| 10. |
- Johansson, Maria A., et al.
(författare)
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Probiotic Lactobacilli Modulate Staphylococcus aureus-Induced Activation of Conventional and Unconventional T cells and NK Cells
- 2016
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Ingår i: Frontiers in Immunology. - : Frontiers Media SA. - 1664-3224. ; 7
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Tidskriftsartikel (refereegranskat)abstract
- Lactobacilli are probiotic commensal bacteria and potent modulators of immunity. When present in the gut or supplemented as probiotics, they beneficially modulate ex vivo immune responsiveness. Further, factors derived from several lactobacilli strains act immune regulatory in vitro. In contrast, Staphylococcus aureus (S. aureus) is known to induce excessive T cell activation. In this study, we aimed to investigate S. aureus-induced activation of human mucosal-associated invariant T cells (MAIT cells), gamma delta T cells, NK cells, as well as of conventional CD4(+) and CD8(+) T cells in vitro. Further, we investigated if lactobacilli-derived factors could modulate their activation. PBMC were cultured with S. aureus 161: 2 cell-free supernatants (CFS), staphylococcal enterotoxin A or CD3/CD28-beads alone, or in combination with Lactobacillus rhamnosus GG-CFS or Lactobacillus reuteri DSM 17938-CFS and activation of T and NK cells was evaluated. S. aureus-CFS induced IFN-gamma and CD107a expression as well as proliferation. Costimulation with lactobacilli-CFS dampened lymphocyte-activation in all cell types analyzed. Preincubation with lactobacilli-CFS was enough to reduce subsequent activation, and the absence of APC or APC-derived IL-10 did not prevent lactobacilli-mediated dampening. Finally, lactate selectively dampened activation of unconventional T cells and NK cells. In summary, we show that molecules present in the lactobacilli-CFS are able to directly dampen in vitro activation of conventional and unconventional T cells and of NK cells. This study provides novel insights on the immune-modulatory nature of probiotic lactobacilli and suggests a role for lactobacilli in the modulation of induced T and NK cell activation.
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