| 1. |
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| 2. |
- Gebremariam, Hanna G., et al.
(author)
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Lactobacillus gasseri Suppresses the Production of Proinflammatory Cytokines in Helicobacter pylori-Infected Macrophages by Inhibiting the Expression of ADAM17
- 2019
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In: Frontiers in Immunology. - : Frontiers Media SA. - 1664-3224. ; 10
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Journal article (peer-reviewed)abstract
- The ability of Helicobacter pylori to evade the host immune system allows the bacterium to colonize the host for a lifetime. Long-term infection with H. pylori causes chronic inflammation, which is the major risk factor for the development of gastric ulcers and gastric cancer. Lactobacilli are part of the human microbiota and have been studied as an adjunct treatment in H. pylori eradication therapy. However, the molecular mechanisms by which lactobacilli act against H. pylori infection have not been fully characterized. In this study, we investigated the anti-inflammatory effects of Lactobacillus strains upon coincubation of host macrophages with H. pylori. We found that Lactobacillus gasseri Kx110A1 (L. gas), a strain isolated from a human stomach, but not other tested Lactobacillus species, blocked the production of the proinflammatory cytokines TNF and IL-6 in H. pylori-infected macrophages. Interestingly, L. gas also inhibited the release of these cytokines in LPS or LTA stimulated macrophages, demonstrating a general anti-inflammatory property. The inhibition of these cytokines did not occur through the polarization of macrophages from the M1 (proinflammatory) to M2 (anti-inflammatory) phenotype or through the altered viability of H. pylori or host cells. Instead, we show that L. gas suppressed the release of TNF and IL-6 by reducing the expression of ADAM17 (also known as TNF-alpha-converting enzyme, TACE) on host cells. Our findings reveal a novel mechanism by which L. gas prevents the production of the proinflammatory cytokines TNF and IL-6 in host macrophages.
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| 3. |
- Govindaraj, Dhanapal, et al.
(author)
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Effects of extremely preterm birth on cytokine and chemokine responses induced by T-cell activation during infancy
- 2024
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In: Clinical & Translational Immunology (CTI). - : WILEY. - 2050-0068. ; 13:5
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Journal article (peer-reviewed)abstract
- Objectives: Extremely preterm (EPT; gestational week < 28 + 0, < 1000 g) neonates are vulnerable to infections and necrotising enterocolitis, important contributors to mortality and morbidity. However, knowledge regarding their immune maturation remains limited. We here investigated the longitudinal development of functional T-cell capacity in EPT infants. Methods: Peripheral blood mononuclear cells were isolated at 14th and 28th day (D) and at gestational week 36 + 0 (Gw36) from EPT infants, participated in a randomised, double-blind, placebo-controlled study of Lactobacillus reuteri DSM 17938 probiotic supplementation. Blood collected from 25 full-term (FT) infants at D14 was used as control. The secretion of immune mediators was determined through comprehensive Luminex panels after stimulation with human T-cell activator CD3/CD28 beads. Results: The levels of many mediators were low in EPT infants at D14, whereas the secretion of several chemokines was higher in EPT than in FT infants. Furthermore, Th2:Th1 cytokine ratios were higher in EPT than in FT infants. Progressively elevated secretion of, for example, IFN-gamma, TNF and IL-17A in EPT infants was observed from D14 to D28 and then at Gw36. Elevated levels were observed for many proinflammatory mediators at D28. Probiotic supplementation or perinatal factors (e.g. clinical chorioamnionitis, preeclampsia and delivery mode) did not influence the cytokine and chemokine responses. Conclusions: Immune mediators induced by T-cell activation in EPT infants were mainly reduced at D14 and Th2 skewed compared to those in FT infants, but mostly recovered at Gw36, indicating immune maturation. Increased proinflammatory responses at D28 may be related to the heightened risk of severe immune-associated complications seen in EPT infants.
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| 4. |
- Haileselassie, Yeneneh, et al.
(author)
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Lactobacillus reuteri and Staphylococcus aureus differentially influence the generation of monocyte-derived dendritic cells and subsequent autologous T cell responses
- 2016
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In: Immunity, Inflammation and Disease. - : Wiley. - 2050-4527. ; 4:3, s. 315-326
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Journal article (peer-reviewed)abstract
- Introduction: In early-life, the immature mucosal barrier allows contact between the gut microbiota and the developing immune system. Due to their strategic location and their ability to sample luminal antigen, dendritic cells (DC) play a central role in the interaction of microbes and immune cells in the gut. Here, we investigated how two bacteria associated with opposite immune profiles in children, that is, Lactobacillus (L.) reuteri and Staphylococcus (S.) aureus, influenced the differentiation of monocytes in vitro as well how the generated DC impacted T cell responses.Methods: We exposed monocyte cultures to cell-free supernatants (CFS) from these bacteria during their differentiation to DC.Results: The presence of L. reuteri-CFS during DC differentiation resulted in DC with a more mature phenotype, in terms of up-regulated surface markers (HLA-DR, CD86, CD83, CCR7) and enhanced cytokine production (IL6, IL10, and IL23), but had a reduced phagocytic capacity compared with non-treated monocyte-derived DC (Mo-DC). However, upon LPS activation, L. reuteri-CFS-generated DC displayed a more regulated phenotype than control Mo-DC with notable reduction of cytokine responses both at mRNA and protein levels. In contrast, S. aureus-CFS-generated DC were more similar to control Mo-DC both without and after LPS stimulation, but they were still able to induce responses in autologous T cells, in the absence of further T cell stimulation.Conclusions: We show that bacterial signals during DC differentiation have a profound impact on DC function and possibly also for shaping the T cell pool.
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| 5. |
- Haileselassie, Yeneneh, 1983-, et al.
(author)
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Postbiotic Modulation of retinoic acid imprinted Mucosal-like Dendritic cells by Probiotic Lactobacillus reuteri 17938 In Vitro
- 2016
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In: Frontiers in Immunology. - : Frontiers Media SA. - 1664-3224. ; 7, s. 1-11
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Journal article (peer-reviewed)abstract
- Lactobacilli are widely used as probiotics with beneficial effects on infection-associated diarrhea, but also used in clinical trials of e.g., necrotizing enterocolitis and inflammatory bowel diseases. The possibility of using probiotic metabolic products, so-called postbiotics, is desirable as it could prevent possible side effects of live bacteria in individuals with a disturbed gut epithelial barrier. Here, we studied how Lactobacillus reuteri DSM 17938 cell-free supernatant (L. reuteri-CFS) influenced retinoic acid (RA)-driven mucosal-like dendritic cells (DC) and their subsequent effect on T regulatory cells (Treg) in vitro. RA clearly imprinted a mucosal-like DC phenotype with higher IL10 production, increased CD103 and CD1d expression, and a downregulated mRNA expression of several inflammatory-associated genes (NFκB1, RELB, and TNF). Treatment with L. reuteri-CFS further influenced the tolerogenic phenotype of RA-DC by downregulating most genes involved in antigen uptake, antigen presentation, and signal transduction as well as several chemokine receptors, while upregulating IL10 production. L. reuteri-CFS also augmented CCR7 expression on RA-DC. In cocultures, RA-DC increased IL10 and FOXP3 expression in Treg, but pre-treatment with L. reuteri-CFS did not further influence the Treg phenotype. In conclusion, L. reuteri-CFS modulates the phenotype and function of mucosal-like DC, implicating its potential application as postbiotic.
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| 6. |
- Johansson, Maria A., et al.
(author)
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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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In: Frontiers in Immunology. - : Frontiers Media SA. - 1664-3224. ; 7
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Journal article (peer-reviewed)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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| 7. |
- Kupferschmidt, Natalia, et al.
(author)
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Mesoporous silica particles potentiate antigen-specific T-cell responses
- 2014
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In: Nanomedicine. - 1743-5889 .- 1748-6963. ; 9:12, s. 1835-1846
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Journal article (peer-reviewed)abstract
- Aim: To study the adjuvant effect of mesoporous silica particles and their capability of modifying an already existing allergic Th2-like immune response. Materials & methods: The adjuvant effect of Santa Barbara Amorphous-15 (SBA-15) mesoporous silica particles was studied in an antigen-specific ovalbumin (OVA) system in vitro and in vivo. The capacity of the OVA-loaded SBA-15 particles (SBA-15-OVA) to modify an existing immune response was assessed in a murine allergy model. Results: SBA-15-OVA induced significantly stronger OVA-specific splenocyte proliferation compared with OVA alone. Significantly higher IFN-gamma production was observed in ex vivo OVA-stimulated splenocytes from SBA-15-OVA-immunized mice compared with mice injected with only SBA-15 or OVA. Treatment of OVA-sensitized mice with SBA-15-OVA modified the immune response with significantly lower serum levels of OVA-specific IgE and higher IgG levels compared with the alum-OVA-treated group. Conclusion: The results are promising for the continued development of mesoporous silica materials for therapeutic applications.
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| 8. |
- Kupferschmidt, Natalia, et al.
(author)
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Mesoporous silica particles potentiate antigen specific T cell responses
- 2014
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In: Nanomedicine. - : Future Medicine Ltd. - 1743-5889 .- 1748-6963. ; 9:12, s. 1835-1846
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Journal article (peer-reviewed)abstract
- Aim: To study the adjuvant effect of mesoporous silica particles and their capability of modifying an already existing allergic Th2-like immune response. Materials & methods: The adjuvant effect of Santa Barbara Amorphous-15 (SBA-15) mesoporous silica particles was studied in an antigen-specific ovalbumin (OVA) system in vitro and in vivo. The capacity of the OVA-loaded SBA-15 particles (SBA-15-OVA) to modify an existing immune response was assessed in a murine allergy model. Results: SBA-15-OVA induced significantly stronger OVA-specific splenocyte proliferation compared with OVA alone. Significantly higher IFN-γ production was observed in ex vivo OVA-stimulated splenocytes from SBA-15-OVA-immunized mice compared with mice injected with only SBA-15 or OVA. Treatment of OVA-sensitized mice with SBA-15-OVA modified the immune response with significantly lower serum levels of OVA-specific IgE and higher IgG levels compared with the alum-OVA-treated group. Conclusion: The results are promising for the continued development of mesoporous silica materials for therapeutic applications. Original submitted 18 January 2013; Revised submitted 30 August 2013
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| 9. |
- Petursdottir, Dagbjort H., et al.
(author)
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Early-Life Human Microbiota Associated With Childhood Allergy Promotes the T Helper 17 Axis in Mice
- 2017
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In: Frontiers in Immunology. - : Frontiers Media SA. - 1664-3224. ; 8
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Journal article (peer-reviewed)abstract
- The intestinal microbiota influences immune maturation during childhood, and is implicated in early-life allergy development. However, to directly study intestinal microbes and gut immune responses in infants is difficult. To investigate how different types of early-life gut microbiota affect immune development, we collected fecal samples from children with different allergic heredity (AH) and inoculated germ-free mice. Immune responses and microbiota composition were evaluated in the offspring of these mice. Microbial composition in the small intestine, the cecum and the colon were determined by 16S rRNA sequencing. The intestinal microbiota differed markedly between the groups of mice, but only exposure to microbiota associated with AH and known future allergy in children resulted in a T helper 17 (Th17)-signature, both systemically and in the gut mucosa in the mouse offspring. These Th17 responses could be signs of a particular microbiota and a shift in immune development, ultimately resulting in an increased risk of allergy.
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| 10. |
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| 11. |
- Qazi, Khaleda Rahman, et al.
(author)
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Extremely Preterm Infants Have Significant Alterations in Their Conventional T Cell Compartment during the First Weeks of Life
- 2020
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In: Journal of Immunology. - : AMER ASSOC IMMUNOLOGISTS. - 0022-1767 .- 1550-6606. ; 204:1, s. 68-77
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Journal article (peer-reviewed)abstract
- Extremely preterm neonates are particularly susceptible to infections, likely because of severely impaired immune function. However, little is known on the composition of the T cell compartment in early life in this vulnerable population. We conducted a comprehensive phenotypic flow cytometry-based longitudinal analysis of the peripheral conventional T cell compartment of human extremely low gestational age neonates (ELGAN) with extremely low birth weight (ELBW; amp;lt;1000 g) participating in a randomized placebo-controlled study of probiotic supplementation. PBMCs from ELGAN/ELBW neonates were collected at day 14, day 28, and postmenstrual week 36. Comparisons were made with full-term 14-d-old neonates. Total CD4(+) and CD8(+) T cell frequencies were markedly lower in the preterm neonates. The reduction was more pronounced among the CD8(+) population, resulting in an increased CD4/CD8 ratio. The preterm infants were also more Th2 skewed than the full-term infants. Although the frequency of regulatory T cells seemed normal in the ELGAN/ELBW preterm neonates, their expression of the homing receptors alpha 4 beta 7, CCR4, and CCR9 was altered. Notably, ELGAN/ELBW infants developing necrotizing enterocolitis before day 14 had higher expression of CCR9 in CD4(+)T cells at day 14. Chorioamnionitis clearly associated with reduced T regulatory cell frequencies and functional characteristics within the preterm group. Finally, probiotic supplementation with Lactobacillus reuteri did not impose any phenotypic changes of the conventional T cell compartment. In conclusion, notable immaturities of the T cell compartment in ELGAN/ELBW neonates may at least partially explain their increased susceptibility to severe immune-mediated morbidities.
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| 12. |
- Qazi, Khaleda Rahman, 1972-
(author)
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Heat shock proteins as vaccine adjuvants
- 2005
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Doctoral thesis (other academic/artistic)abstract
- New efficient vaccines against infectious diseases are in demand. Some important factors impeding the vaccine development are the poor immunogenicity and the MHC restriction of the immune responses to a number of antigens. The use of novel vaccine adjuvants or carrier proteins, which are known to enhance the immunogenicity of the subunit antigens and provide T-cell help, can circumvent these problems. The potential of heat shock proteins (HSPs) to function as adjuvants when fused to or co-delivered with protein antigens, make them attractive vaccine candidates. In this thesis we have evaluated the potency of heat shock protein 70 (HSP70) as a possible vaccine adjuvant and studied the mechanisms behind the adjuvanticity.The first article aims to evaluate the carrier effect of glutathione-S-transferase (GST) on a malarial antigen EB200 that induces a MHC restricted response in mice. Immunization of CBA and C57BL/6 mice, high and low responders to EB200, respectively, with the GST-EB200 fusion protein elicited EB200 specific antibody responses in both strains of mice, which indicated that MHC restriction was broken in C57BL/6 mice. However, the antibody affinity and the magnitude of the response were lower in the C57BL/6 mice compared with that in CBA. To improve the response, the efficacy of various adjuvants like alum, HSP70 from Trypanosoma cruzi, and the adjuvant combination (HSP70 and cholera toxin) was evaluated. The results indicated that cholera toxin and HSP70 act synergistically and improve the immunogenicity of EB200 antigen by increasing the affinity and magnitude of the response.HSP belongs to a family of conserved molecules and the maximum homology lies on the N-terminal region of the protein, therefore there is a risk that use of a complete molecule would give rise to autoimmunity. Thus, in our second study we first evaluated the adjuvant effect of the less conserved portion of HSP70 derived from Plasmodium falciparum (Pf70C). We found that the Pf70C exhibited similar adjuvant properties as the whole molecule. We further analyzed the adjuvant potential of Pf70C against EB200 formulated as a chimeric DNA vaccine construct. These constructs alone failed to generate substantial levels of EB200 specific antibodies in mice. However, the DNA immunization efficiently primed the immune system. This was evident as the subsequent boosting with the corresponding recombinant fusion proteins Pf70C-EB200 elicited strong EB200 specific Th-1 antibody responses. In contrast, no such priming effect was observed for ex vivo IFN-γ production, however stimulation with the Pf70C-EB200 fusion protein induced an enhanced secretion of IFN-γ in vitro.During the infection process, the synthesis of bacterial HSP is up-regulated, which is known to sensitize T cells in the infected host. Since a high degree of homology exists within the phylogenetic families of HSPs, we postulated that exposure of mice to microorganisms could prime the immune system for evolutionary diverse HSPs and for any antigen coupled to them. We tested this hypothesis by priming mice with different microorganisms such as BCG, Mycobacterium vaccae or Chlamydia pneumoniae and boosted with a recombinant fusion protein Pf70C-EB200 or with a panel of HSPs. We found that BCG and M. vaccae but not C. pneumoniae could provide priming of the immune system to induce secondary IgG responses to Pf70C as well as to other HSPs tested. The priming effect was also observed when the EB200 antigen was coupled to Pf70C. Analysis of the IgG1 and IgG2a profiles and IFN-g production induced against the HSPs revealed a mixture of Th1/Th2 type of responses. We also observed that HSP70 specific sera cross-reacted some extent with certain autoreactive antigens. However, no deposits were observed in the kidneys of HSP treated animals.Finally, we investigated the role of TLR2 and TLR4 on HSP70-mediated adjuvanticity. We found that HSPs displayed different degrees of adjuvanticity regarding both the strength and the profile of the induced immune response. Also, they possessed different requirements for signaling through TLRs. While HSP70 from T. cruzi induced antigen-specific humoral responses in wild type as well as in both the TLR2 and TLR4 knockout mice, the response was diminished in the TLR4 knockout mice when both the whole and C-terminal fragment of HSP70 from Mycobacterium tuberculosis was used. However, the C-terminal fragment of P. falciparum HSP70 elicited responses only in wild type mice but not in TLR2 or TLR4 knockout mice indicating that the adjuvant function differ for phylogenetically related HSPs. Taken together our data suggest that HSPs can be promising candidates in future vaccines.
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| 15. |
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| 16. |
- Rahman Qazi, Khaleda, et al.
(author)
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Extreme prematurity and sepsis strongly influence frequencies and functional characteristics of circulating gamma delta T and natural killer cells
- 2021
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In: Clinical & Translational Immunology (CTI). - : Wiley. - 2050-0068. ; 10:6
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Journal article (peer-reviewed)abstract
- Objectives. Extremely low gestational age neonates with extremely low birthweight (ELGAN/ELBW) are highly susceptible to infection. This is linked to their relatively immature immune system which is not yet fully compatible with an extra-uterine environment. Here, we performed a longitudinal characterisation of unconventional T and natural killer (NK) cells in ELGAN/ELBW during their first months of life. Methods. Peripheral blood mononuclear cells were collected from 97 ELGAN/ELBW at 14 and 28 days of life and at a time point corresponding to postmenstrual week 36 + 0. gamma delta T-cell, NKT-cell, mucosa-associated invariant T-cell and NK cell frequencies and characteristics were analysed by flow cytometry. As control, cells from 14-day-old full-term (FT) infants were included. Results. Extreme prematurity had significant bearing on gamma delta T-cell and NK cell frequencies and characteristics. ELGAN/ELBW had significantly higher proportions of gamma delta T cells that were skewed towards effector and effector memory phenotypes, characteristics that were maintained throughout the study period. Expression of the gut homing receptor CCR9 was also more common in gamma delta T cells from ELGAN/ELBW. Conversely, NK cell frequencies were markedly lower and skewed towards a cytotoxic phenotype in the ELGAN/ELBW group at 14 days of age. Culture-proven sepsis with an onset during the first 14 days after birth further manifested these differences in the gamma delta T- and NK cell populations at 14 days of age. Conclusion. Prematurity strongly influences the levels of gamma delta T and NK cells, in particular in cases where sepsis debuts during the first 2 weeks of life.
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| 17. |
- van der Heiden, Marieke, et al.
(author)
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Characterization of the gamma delta T-cell compartment during infancy reveals clear differences between the early neonatal period and 2 years of age
- 2020
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In: Immunology and Cell Biology. - : Wiley. - 0818-9641 .- 1440-1711. ; 98:1, s. 79-87
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Journal article (peer-reviewed)abstract
- gamma delta T cells are unconventional T cells that function on the border of innate and adaptive immunity. They are suggested to play important roles in neonatal and infant immunity, although their phenotype and function are not fully characterized in early childhood. We aimed to investigate gamma delta T cells in relation to age, prematurity and cytomegalovirus (CMV) infection. Therefore, we used flow cytometry to characterize the gamma delta T-cell compartment in cord blood and peripheral blood cells from 14-day-, 2-year- and 5-year-old children, as well as in peripheral blood samples collected at several time points during the first months of life from extremely premature neonates. gamma delta T cells were phenotypically similar at 2 and 5 years of age, whereas cord blood was divergent and showed close proximity to gamma delta T cells from 14-day-old neonates. Interestingly, 2-year-old children and adults showed comparable V delta 2(+) gamma delta T-cell functionality toward both microbial and polyclonal stimulations. Importantly, extreme preterm birth compromised the frequencies of V delta 1(+) cells and affected the functionality of V delta 2(+) gamma delta T cells shortly after birth. In addition, CMV infection was associated with terminal differentiation of the V delta 1(+) compartment at 2 years of age. Our results show an adult-like functionality of the gamma delta T-cell compartment already at 2 years of age. In addition, we demonstrate an altered gamma delta T-cell phenotype early after birth in extremely premature neonates, something which could possible contribute to the enhanced risk for infections in this vulnerable group of children.
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