| 1. |
- Ali, Abukar, 1988, et al.
(författare)
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CTLA4-Ig but not anti-TNF therapy promotes staphylococcal septic arthritis in mice.
- 2015
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Ingår i: The Journal of infectious diseases. - : Oxford University Press (OUP). - 1537-6613 .- 0022-1899. ; 212:8, s. 1308-1316
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Tidskriftsartikel (refereegranskat)abstract
- The development of biologics has greatly increased the quality of life as well as the life expectancy of many RA patients. However, a large number of these patients are at an increased risk of developing serious infections. The aim of this study was to examine differential effects of anti-TNF versus CTLA4-Ig treatment on both immunological response and host defense in a murine model of septic arthritis.
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| 2. |
- Ali, Abukar, 1988, et al.
(författare)
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IL-1 Receptor Antagonist Treatment Aggravates Staphylococcal Septic Arthritis and Sepsis in Mice.
- 2015
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Ingår i: PloS one. - : Public Library of Science (PLoS). - 1932-6203. ; 10:7
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Tidskriftsartikel (refereegranskat)abstract
- Interleukin-1 receptor antagonist (IL-1Ra) is the primary therapy against autoinflammatory syndromes with robust efficacy in reducing systemic inflammation and associated organ injury. However, patients receiving IL-1Ra might be at increased risk of acquiring serious infections.
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| 3. |
- Amirbeagi, Firoozeh, et al.
(författare)
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Determination of Subset-Restricted Anti-neutrophil Cytoplasmic Antibodies (ANCA) by Immunofluorescence Cytochemistry.
- 2019
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Ingår i: Methods in molecular biology (Clifton, N.J.). - New York, NY : Springer New York. - 1940-6029. ; , s. 63-77
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Bokkapitel (refereegranskat)abstract
- Neutrophils have long been considered a homogeneous cell type where all circulating cells of a particular individual express the same proteins. Lately, however, this view is changing and distinct neutrophil subsets, defined by the presence or absence of different proteins, are being increasingly recognized. At least two separate protein markers, CD177 and Olfactomedin-4 (OLFM4) are known to be expressed by some, but not all, circulating neutrophils of a given individual. We recently described the existence of subset-restricted serum autoantibodies targeting OLFM4; these were discovered during clinical testing for anti-neutrophil cytoplasmic antibodies (ANCAs). ANCA testing is part of the clinical examinations routinely carried out to support diagnosis of suspected autoimmune conditions, especially vasculitis. Positive sera typically react with all neutrophils from a single donor, whereas subset-restricted ANCA sera (such as those containing anti-OLFM4 antibodies) only react with a fraction of neutrophils. Described in this chapter is an indirect immunofluorescence (IIF) approach to test human sera for the presence of subset-restricted ANCA as well as instructions for costaining experiments using sera and purified antibodies directed against established subset markers.
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| 4. |
- Amirbeagi, Firoozeh, et al.
(författare)
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Olfactomedin-4 autoantibodies give unusual c-ANCA staining patterns with reactivity to a subpopulation of neutrophils.
- 2015
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Ingår i: Journal of leukocyte biology. - 1938-3673. ; 97:1, s. 181-189
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Tidskriftsartikel (refereegranskat)abstract
- Testing for the presence of ANCAs in circulation is part of the clinical examinations routinely performed upon suspected autoimmune disorders, mainly vasculitis. The autoantibodies are typically directed toward neutrophil MPO or PR3. These are major granule-localized proteins, and similar to all hitherto-described ANCA antigens, they are expressed by all neutrophils, and ANCA-containing sera thus give rise to uniform reactivity toward all neutrophils in a sample. In this paper, we describe sera from 2 unrelated patients with diffuse inflammatory symptoms that gave rise to peculiar c-ANCA patterns, only reacting with a subpopulation (roughly 30%) of human neutrophils. By immunoblotting, both sera reacted to the same antigen, which was expressed in intracellular granules. The antigen could be released to the extracellular milieu through secretion but also through the formation of NETs. Neutrophils have long been considered a homogenous cell population, but it is becoming increasingly clear that distinct subpopulations, defined by the presence or absence of certain proteins, exist. One such marker that defines a neutrophil subset is the granule protein OLFM4. The unusual, subset-restricted c-ANCA sera reacted only with OLFM4-positive neutrophils, and MS analysis revealed that the autoantigen was, in fact, OLFM4. These data describe for the first time a c-ANCA pattern reactive to only a subpopulation of neutrophils and identify the granule protein OLFM4 as a novel autoantigen.
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| 5. |
- Andersson, Karin, 1972, et al.
(författare)
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Survivin co-ordinates formation of follicular T-cells acting in synergy with Bcl-6
- 2015
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Ingår i: Oncotarget. - : Impact Journals, LLC. - 1949-2553. ; 6:24, s. 20043-20057
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Tidskriftsartikel (refereegranskat)abstract
- Follicular T helper (Tfh) cells are recognized by the expression of CXCR5 and the transcriptional regulator Bcl-6. Tfh cells control B cell maturation and antibody production, and if deregulated, may lead to autoimmunity. Here, we study the role of the proto-oncogene survivin in the formation of Tfh cells. We show that blood Tfh cells of patients with the autoimmune condition rheumatoid arthritis, have intracellular expression of survivin. Survivin was co-localized with Bcl-6 in the nuclei of CXCR5(+)CD4 lymphocytes and was immunoprecipitated with the Bcl-6 responsive element of the target genes. Inhibition of survivin in arthritic mice led to the reduction of CXCR5(+) Tfh cells and to low production of autoantibodies. Exposure to survivin activated STAT3 and induced enrichment of PD-1(+)Bcl-6(+) subset within Tfh cells. Collectively, our study demonstrates that survivin belongs to the Tfh cell phenotype and ensures their optimal function by regulating transcriptional activity of Bcl-6.
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| 6. |
- Björkman, Lena, 1965, et al.
(författare)
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Neutrophil recruitment to inflamed joints can occur without cellular priming.
- 2019
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Ingår i: Journal of leukocyte biology. - 1938-3673. ; 105:6, s. 1123-1130
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Tidskriftsartikel (refereegranskat)abstract
- Recruitment of neutrophils from blood to tissues is a cardinal event in inflammation during which neutrophils switch from a resting, naive state to a preactivated, primed phenotype; the priming process is characterized by alterations in the composition of cell surface adhesins, for example, shedding of l-selectin and mobilization of granule-stored integrins to the cell surface. Ligation of chemotactic receptors and interactions with the endothelial lining are established triggers of neutrophil priming and in line with this, in vivo transmigrated neutrophils obtained from tissues are typically highly primed. We here characterize the priming of neutrophils brought about by in vivo recruitment from blood to inflamed joints by the analyses of synovial fluid and blood from patients with inflammatory arthritis. For comparisons, we used controlled in vivo models of neutrophil transmigration to skin of healthy subjects. In contrast to the residing view and in vivo transmigrated neutrophils from skin models, neutrophils from synovial fluid were often surprisingly resting and phenotypically very similar to naive cells isolated from peripheral blood; synovial fluid cells often retained l-selectin and had undergone minimal up-regulation of integrin receptors. In complete agreement with our in vivo findings, cell-free synovial fluid was potently chemotactic without triggering alteration of surface receptors also in vitro. We conclude that tissue recruitment of neutrophils does not by default trigger l-selectin shedding and granule mobilization, and the chemoattractant(s) guiding neutrophils to synovial fluid apparently operate without inducing cellular priming.
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| 7. |
- Björnsdottir, Halla, et al.
(författare)
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Inhibition of phospholipase A(2) abrogates intracellular processing of NADPH-oxidase derived reactive oxygen species in human neutrophils.
- 2013
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Ingår i: Experimental cell research. - : Elsevier BV. - 1090-2422 .- 0014-4827. ; 319:5, s. 761-774
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Tidskriftsartikel (refereegranskat)abstract
- Upon activation of human neutrophils, superoxide can be produced at two cellular sites; either in the plasma membrane, giving extracellular release of oxidants, or in intracellular organelles, resulting in oxidants being retained in the cell. The involvement of phospholipase A(2) (PLA(2)) in phorbol myristate acetate (PMA)-induced activation of the two pools of NADPH-oxidase was investigated using a variety of PLA(2) inhibitors and the oxidase activity was measured by luminol/isoluminol-amplified chemiluminescence (CL). Two of the seven inhibitors were without effect, two inhibitors inhibited both intra- and extracellular ROS production equally, and three inhibitors inhibited intracellular but not extracellular CL. Using another technique to measure ROS, PHPA oxidation, we found that intracellular ROS production was unaltered with the three last inhibitors, indicating that PLA(2) is not involved in the NADPH-oxidase activity per se, but in the intracellular processing of the radicals necessary for the CL reaction to take place. The PLA(2) inhibitors did not abolish the activity of myeloperoxidase (MPO), an enzyme necessary for intracellular CL to occur. Instead, we suggest that these PLA(2) inhibitors block heterotypic granule fusion and prohibit the colocalization of ROS and MPO needed for intracellular CL activity.
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| 8. |
- Björnsdottir, Halla, et al.
(författare)
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Neutrophil NET formation is regulated from the inside by myeloperoxidase-processed reactive oxygen species.
- 2015
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Ingår i: Free radical biology & medicine. - : Elsevier BV. - 1873-4596 .- 0891-5849. ; 89, s. 1024-1035
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Tidskriftsartikel (refereegranskat)abstract
- Neutrophil extracellular traps (NETs) are mesh-like DNA fibers clad with intracellular proteins that are cast out from neutrophils in response to certain stimuli. The process is thought to depend on reactive oxygen species (ROS) generated by the phagocyte NADPH-oxidase and the ROS-modulating granule enzyme myeloperoxidase (MPO), but when, how, and where these factors contribute is so far uncertain. The neutrophil NADPH-oxidase can be activated at different cellular sites and ROS may be produced and processed by MPO within intracellular granules, even in situations where a phagosome is not formed, e.g., upon stimulation with phorbol myristate acetate (PMA).
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| 9. |
- Björnsdottir, Halla, et al.
(författare)
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Phenol-soluble Modulin α Peptide Toxins from aggressive Staphylococcus aureus induce rapid Formation of neutrophil extracellular Traps through a reactive Oxygen species-independent Pathway
- 2017
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Ingår i: Frontiers in Immunology. - : Frontiers Media SA. - 1664-3224. ; 8
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Tidskriftsartikel (refereegranskat)abstract
- Neutrophils have the ability to capture and kill microbes extracellularly through the formation of neutrophil extracellular traps (NETs). These are DNA and protein structures that neutrophils release extracellularly and are believed to function as a defense mechanism against microbes. The classic NET formation process, triggered by, e.g., bacteria, fungi, or by direct stimulation of protein kinase C through phorbol myristate acetate, is an active process that takes several hours and relies on the production of reactive oxygen species (ROS) that are further modified by myeloperoxidase (MPO). We show here that NET-like structures can also be formed by neutrophils after interaction with phenol-soluble modulin alpha (PSM alpha) that are cytotoxic membrane-disturbing peptides, secreted from community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA). The PSMa-induced NETs contained the typical protein markers and were able to capture microbes. The PSMa-induced NET structures were disintegrated upon prolonged exposure to DNase-positive S. aureus but not on exposure to DNase-negative Candida albicans. Opposed to classic NETosis, PSMa-triggered NET formation occurred very rapidly, independently of ROS or MPO, and was also manifest at 4 degrees C. These data indicate that rapid NETs release may result from cytotoxic membrane disturbance by PSMa peptides, a process that may be of importance for CA-MRSA virulence.
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| 10. |
- Björnsdottir, Halla, et al.
(författare)
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Quantification of heterotypic granule fusion in human neutrophils by imaging flow cytometry.
- 2016
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Ingår i: Data in brief. - : Elsevier BV. - 2352-3409. ; 6, s. 386-93
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Tidskriftsartikel (refereegranskat)abstract
- Human neutrophils are filled with intracellular storage organelles, called granules and secretory vesicles, which differ in their content of soluble matrix proteins and membrane-bound molecules. To date, at least four distinct granule/vesicle subsets have been identified. These organelles may secrete their content extracellularly following mobilization to and fusion with the plasma membrane, but some of them may also fuse with internal membrane-enclosed organelles, typically a plasma membrane-derived phagosome. There are also instances where different granules appear to fuse with one another, a process that would enable mixing of their matrix and membrane components. Such granule fusion enables e.g., myeloperoxidase-processing of intragranular oxygen radicals, a key event in the formation of neutrophil extracellular traps (Björnsdottir et al., 2015)[1]. Described herein are data that show the quantification of such heterotypic granule-granule fusion by the use of imaging flow cytometry, a technique that combines flow cytometry with microscopy. The analysis described is based on immunofluorescent staining of established granule markers (lactoferrin and/or NGAL for one granule subset; the specific granules, and CD63 for another granule subset, the azurophil granules) and calculation of a colocalization score for resting and PMA-stimulated neutrophils.
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