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- Bartsch, Yannic C, et al.
(författare)
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IgG Fc sialylation is regulated during the germinal center reaction upon immunization with different adjuvants
- 2020
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Ingår i: The Journal of Allergy and Clinical Immunology. - : Elsevier BV. - 1097-6825 .- 0091-6749. ; 146:3, s. 652-666
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Effector functions of IgG antibodies (Abs) are regulated by their Fc N-glycosylation pattern. IgG Fc glycans that lack galactose and terminal sialic acid residues correlate with the severity of inflammatory (auto)immune disorders and have also been linked to the protection against viral infection and discussed in the context of vaccine-induced protection. In contrast, sialylated IgG Abs have shown immunosuppressive effects.OBJECTIVE: We sought to investigate IgG glycosylation programming during the germinal center (GC) reaction upon immunization of mice with a foreign protein antigen and different adjuvants.METHODS: Mice were analyzed for GC T, B cell and plasma cell responses as well as antigen-specific serum IgG subclass titers and Fc glycosylation patterns.RESULTS: Different adjuvants induce distinct IgG+ GC B cell responses with specific transcriptomes and expression levels of the α2,6-sialyltransferase responsible for IgG sialylation that correspond to distinct serum IgG Fc glycosylation patterns. Low IgG Fc sialylation programming in GC B cells was overall highly dependent on the T follicular helper (TFH) cell-inducing cytokine IL-6, especially induced by water-in-oil adjuvants and Mycobacterium tuberculosis (Mtb). Furthermore, low IgG Fc sialylation programming was dependent on adjuvants that induced IL-27R-dependent IFNγ+ TFH1 cells, IL-6/IL-23-dependent IL-17A+ TFH17 cells and high TFH/T follicular regulatory (TFR) cell ratios. The two latter were here dependent on Mtb and its cord factor.CONCLUSION: These findings on adjuvant-dependent GC responses and IgG glycosylation programming may aid the development of novel vaccination strategies to induce IgG Abs with both high affinity and defined Fc glycosylation patterns.
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- Gorski, Mathias, et al.
(författare)
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Meta-analysis uncovers genome-wide significant variants for rapid kidney function decline
- 2021
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Ingår i: Kidney International. - : Elsevier. - 0085-2538 .- 1523-1755. ; 99:4, s. 926-939
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Tidskriftsartikel (refereegranskat)abstract
- Rapid decline of glomerular filtration rate estimated from creatinine (eGFRcrea) is associated with severe clinical endpoints. In contrast to cross-sectionally assessed eGFRcrea, the genetic basis for rapid eGFRcrea decline is largely unknown. To help define this, we meta-analyzed 42 genome-wide association studies from the Chronic Kidney Diseases Genetics Consortium and United Kingdom Biobank to identify genetic loci for rapid eGFRcrea decline. Two definitions of eGFRcrea decline were used: 3 mL/min/1.73m2/year or more ("Rapid3"; encompassing 34,874 cases, 107,090 controls) and eGFRcrea decline 25% or more and eGFRcrea under 60 mL/min/1.73m2 at follow-up among those with eGFRcrea 60 mL/min/1.73m2 or more at baseline ("CKDi25"; encompassing 19,901 cases, 175,244 controls). Seven independent variants were identified across six loci for Rapid3 and/or CKDi25: consisting of five variants at four loci with genome-wide significance (near UMOD-PDILT (2), PRKAG2, WDR72, OR2S2) and two variants among 265 known eGFRcrea variants (near GATM, LARP4B). All these loci were novel for Rapid3 and/or CKDi25 and our bioinformatic follow-up prioritized variants and genes underneath these loci. The OR2S2 locus is novel for any eGFRcrea trait including interesting candidates. For the five genome-wide significant lead variants, we found supporting effects for annual change in blood urea nitrogen or cystatin-based eGFR, but not for GATM or LARP4B. Individuals at high compared to those at low genetic risk (8-14 vs 0-5 adverse alleles) had a 1.20-fold increased risk of acute kidney injury (95% confidence interval 1.08-1.33). Thus, our identified loci for rapid kidney function decline may help prioritize therapeutic targets and identify mechanisms and individuals at risk for sustained deterioration of kidney function.
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- Jost, Etta, et al.
(författare)
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Variants of the Acyltransferase from Mycobacterium smegmatis Enable Enantioselective Acyl Transfer in Water
- 2020
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Ingår i: ACS Catalysis. - : American Chemical Society (ACS). - 2155-5435. ; 10:18, s. 10500-10507
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Tidskriftsartikel (refereegranskat)abstract
- The acyltransferase from Mycobacterium smegmatis (MsAcT) complements the well-established acylation activity of hydrolases in organic solvents with its activity to perform acylation reactions (among other reactions) in an aqueous environment. The enzyme’s potential is however limited, due to its poor regio- and stereoselectivity with enantioselectivities (E-values) below 20 for bulky (aromatic) substrates. By applying computer-guided rational design, a library of single variants was designed that allowed conversion of a set of previously challenging substrates with good activity and E-values up to >200. The computational predictions were found to be in agreement with experimental data, which in turn allowed for the generation of even more active and selective double variants. Overall, the produced set of variants provides a toolbox for the enantioselective acylation of challenging alcohols in water, effectively contributing to an alternative to reactions in organic solvents.
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- Oefner, Carolin M., et al.
(författare)
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Tolerance induction with T cell-dependent protein antigens induces regulatory sialylated IgGs
- 2012
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Ingår i: Journal of Allergy and Clinical Immunology. - : Elsevier BV. - 1097-6825 .- 0091-6749. ; 129:6, s. 1647-1647
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Tidskriftsartikel (refereegranskat)abstract
- Background: Under inflammatory conditions, T cell-dependent (TD) protein antigens induce proinflammatory T-and B-cell responses. In contrast, tolerance induction by TD antigens without costimulation triggers the development of regulatory T cells. Under both conditions, IgG antibodies are generated, but whether they have different immunoregulatory functions remains elusive. Objective: It was shown recently that proinflammatory or anti-inflammatory effector functions of IgG molecules are determined by different Fc N-linked glycosylation patterns. We sought to examine the Fc glycosylation and anti-inflammatory quality of IgG molecules formed on TD tolerance induction. Methods: We administered chicken ovalbumin (OVA) with or without costimulus to mice and analyzed OVA-reactive IgG Fc glycosylation. The anti-inflammatory function of differentially glycosylated anti-OVA IgGs was further investigated in studies with dendritic cell cultures and in an in vivo model of allergic airway disease. Additionally, we analyzed the Fc glycosylation pattern of birch pollen-reactive serum IgGs after successful allergen-specific immunotherapy in patients. Results: Stimulation with TD antigens under inflammatory conditions induces plasma cells expressing low levels of alpha 2,6-sialyltransferase and producing desialylated IgGs. In contrast, plasma cells induced on tolerance induction did not downregulate alpha 2,6-sialyltransferase expression and secreted immunosuppressive sialylated IgGs that were sufficient to block antigen-specific T- and B-cell responses, dendritic cell maturation, and allergic airway inflammation. Importantly, successful specific immunotherapy in allergic patients also induced sialylated allergen-specific IgGs. Conclusions: Our data show a novel antigen-specific immunoregulatory mechanism mediated by anti-inflammatory sialylated IgGs that are formed on TD tolerance induction. These findings might help to develop novel antigen-specific therapies for the treatment of allergy and autoimmunity. (J Allergy Clin Immunol 2012;129:1647-55.)
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