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26 results on '"Thulin, Pontus"'

10. The neutrophil subset defined by CD177 expression is preferentially recruited to gingival crevicular fluid in periodontitis.

Author

Dahlstrand Rudin, Agnes, Amirbeagi, Firoozeh, Davidsson, Lisa, Khamzeh, Arsham, Thorbert Mros, Sara, Thulin, Pontus, Welin, Amanda, Björkman, Lena, Christenson, Karin, and Bylund, Johan

Subjects
GINGIVAL fluid, PERIODONTITIS, SYNOVIAL fluid, CELL membranes, NEUTROPHILS
Abstract

In recent years, the concept of distinct subpopulations of human neutrophils has attracted much attention. One bona fide subset marker, exclusively expressed by a proportion of circulating neutrophils in a given individual, and therefore dividing neutrophils in two distinct subpopulations, is the glycoprotein CD177. CD177 is expressed on the plasma and granule membranes of 0–100% of circulating neutrophils depending on the donor. Several in vitro studies have linked CD177 to neutrophil transmigration, yet very few have looked at the role of CD177 for tissue recruitment in vivo. We investigate whether the CD177+ and CD177– neutrophil subsets differ in their propensity to migrate to both aseptic‐ and microbe‐triggered inflamed human tissues. Microbe‐triggered neutrophil migration was evaluated in samples of gingival crevicular fluid (GCF) from patients with periodontitis, whereas neutrophil migration to aseptic inflammation was evaluated in synovial fluid from patients with inflammatory arthritis, as well as in exudate from experimental skin chambers applied on healthy donors. We found that the proportion of CD177+ neutrophils was significantly higher in GCF from patients with periodontitis, as compared to blood from the same individuals. Such accumulation of CD177+ neutrophils was not seen in the two models of aseptic inflammation. Moreover, the proportion of CD177+ neutrophils in circulation was significantly higher in the periodontitis patient group, as compared to healthy donors. Our data indicate that the CD177+ neutrophil subset is preferentially recruited to the gingival crevice of periodontitis patients, and may imply that this subtype is of particular importance for situations of microbe‐driven inflammation. [ABSTRACT FROM AUTHOR]

Published
2021
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12. Evaluation of the applicability of security testing techniques in continuous integration environments

Author

Thulin, Pontus

Subjects
Automated security testing, Datavetenskap (datalogi), Computer Sciences, Continuous Integration, Agile Security, Security Testing
Abstract

Agile development methodologies are becoming increasingly popular, especially in projects that develop web applications. However, incorporation of software security in lightweight approaches can be difficult. Using security testing techniques throughout a complete agile development process by running automated tests in continuous integration environments is one approach that strives to improve security in agile projects. Instead of performing security testing at the end of the development cycle, such methods enables early and continuous detection of security risks and vulnerabilities. The purpose of this thesis is to study how existing security testing techniques operate in continuous integration environments and what level of security they can help assure. The work is a qualitative analysis of dierent security testing techniques and evaluates how they technically fit into a continuous integration environment as well as how they adhere to agile principles. These techniques are also analyzed with the use of OWASP Top Ten to determine which security requirements they can verify. The outcome of the analysis is that no existing security testing technique is a perfect fit for usage in continuous integration testing. Each technique has its distinct advantages and drawbacks that should be taken into consideration when choosing a technique to work with in continuous integration environments.

Published
2015

20. LL-37 at the local site of streptococcal skin and soft-tissue infections

Author

Thulin, Pontus, primary, Johansson, Linda, additional, Sendi, Parham, additional, Hertzén, Erika, additional, Linder, Adam, additional, Åkesson, Per, additional, Christensson, Bertil, additional, Kotb, Malak, additional, Low, Donald, additional, Agerberth, Birgitta, additional, and Norrby-Teglund, Anna, additional

Published
2007
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23. Olfactomedin‐4 autoantibodies give unusual c‐ANCA staining patterns with reactivity to a subpopulation of neutrophils

Author

Amirbeagi, Firoozeh, Thulin, Pontus, Pullerits, Rille, Pedersen, Bo, Andersson, Bengt A., Dahlgren, Claes, Welin, Amanda, and Bylund, Johan

Abstract

Atypical c‐ANCA staining patterns with reactivity to some neutrophils can be explained by auto‐antibodies directed to subtype marker OLFM4. 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.

Published
2015
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24. Cathelicidin LL-37 in Severe Streptococcus pyogenesSoft Tissue Infections in Humans

Author

Johansson, Linda, Thulin, Pontus, Sendi, Parham, Hertzén, Erika, Linder, Adam, Åkesson, Per, Low, Donald E., Agerberth, Birgitta, and Norrby-Teglund, Anna

Abstract

ABSTRACTSevere soft tissue infections, such as necrotizing fasciitis and severe cellulitis, caused by group A streptococci (GAS) are rapidly progressing life-threatening infections characterized by massive bacterial loads in the tissue even late after the onset of infection. Antimicrobial peptides are important components of the innate host defense, and cathelicidins have been shown to protect against murine necrotic skin infections caused by GAS. However, it has been demonstrated that the streptococcal cysteine protease SpeB proteolytically inactivates the human cathelicidin LL-37 in vitro. Here we have investigated the expression of LL-37 and its interaction with GAS and SpeB during acute severe soft tissue infections by analyses of patient tissue biopsy specimens. The results showed large amounts of LL-37, both the proform (hCAP18) and the mature peptide, in the tissue. Confocal microscopy identified neutrophils as the main source of the peptide. A distinct colocalization between the bacteria and LL-37 could be noted, and bacterial loads showed positive correlation to the LL-37 levels. Areas with high LL-37 levels coincided with areas with large amounts of SpeB. Confocal microscopy confirmed strong colocalization of GAS, SpeB, and LL-37 at the bacterial surface. Taken together, the findings of this study provide in vivo support of the hypothesis that SpeB-mediated inactivation of LL-37 at the streptococcal surface represents a bacterial resistance mechanism at the infected tissue site in patients with severe GAS tissue infections.

Published
2008
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26. Determination of Subset-Restricted Anti-neutrophil Cytoplasmic Antibodies (ANCA) by Immunofluorescence Cytochemistry.

Author

Amirbeagi F, Welin A, Thulin P, and Bylund J

Subjects
Antibodies, Antineutrophil Cytoplasmic isolation & purification, Biomarkers metabolism, Ethanol, Humans, Neutrophils metabolism, Serum metabolism, Antibodies, Antineutrophil Cytoplasmic analysis, Fluorescent Antibody Technique methods
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.

Published
2019
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