Interleukin 15 and 17 in Staphylococcus aureus arthritis

Staphylococcus aureus–induced arthritis leads to severe joint destruction and high mortality despite antibiotic treatment. Thus, there is a need to identify new treatment targets in addition to antibiotic therapy. Interleukin (IL)-15 has been implicated both in osteoclastogenesis and in bacterial clearance – two important issues in S. aureus−induced joint destruction. Interleukin-17A has been discovered as an important mediator of aseptic arthritis both in mice and men, while its function in S. aureus–induced arthritis is largely unknown. The aim of this thesis was to investigate the importance of IL-15 and IL-17A and in addition, the interaction between IL-17A and interleukin-23 in S. aureus−induced arthritis. Wildtype, IL-15 knockout and IL-17A knockout mice were inoculated (systemically or locally) with a defined number of toxic shock syndrome toxin-1 (TSST-1) producing S. aureus. At sacrifice, tissues were collected and further analysed. We found that mice genetically lacking IL-15 or treated with anti-IL-15 antibodies developed less severe and destructive arthritis compared with control mice. In neither situation the bacterial clearance was negatively influenced. Furthermore, the IL-15 knockout mice had fewer osteoclasts in the joints compared with wildtype mice. We suggest that due to IL-15 absence, the mice developed milder arthritis probably because of less bone and cartilage destruction. We observed that IL-17A was of minor importance in systemic S. aureus arthritis but played a major role in local S. aureus arthritis. In the systemic model of arthritis we found elevated levels of IL-17F in the IL-17A knockout mice, suggesting that IL-17F compensates for the absence of IL-17A and that IL-17F in a normal wildtype mice is inhibited by IL-17A. Furthermore we found that IL-17A regulates the production of IL-23, a cytokine that is known to regulate the production of IL-17A, in a negative feedback manner, which means that IL-17A may have regulatory properties. Thus, we have found that IL-15, but not IL-17A, could represent a promising treatment target along with antibiotics in S. aureus−induced arthritis, and that IL-17A negatively regulates its upstream inducer, IL-23

Förskollärares reflektioner kring litteraturanvändning i förskolan

Syftet med denna uppsats var att undersöka förskollärares reflektioner kring litteraturanvändning i verksamheten. Studien var uppbyggd utifrån tre frågeställningar. Dessa frågeställningar har fokus att ta reda på hur lärare reflekterar kring högläsning, boksamtal och litteratur. Vi använde oss av enkätundersökning för att få fram denna information. Antalet medverkande var 5 förskolor och det samlades in 12 enkäter från förskollärare. Det framkom att förskolorna använder sig av högläsning i olika grad och då främst beroende på den tid som fanns samt ålder på barngruppen. Resultatet visar också att boksamtal inte prioriteras men att materialet finns då resultaten visar att litteratur finns på varje förskola som medverkat i studien. Litteraturen väljs utefter vad som är aktuellt i verksamheten samt barnens intressen

Antigen-Specific Gene Therapy after Immunisation Reduces the Severity of Collagen-Induced Arthritis

Reestablishment of tolerance induction in rheumatoid arthritis (RA) would be an optimal treatment with few, if any, side effects. However, to develop such a treatment further insights in the immunological mechanisms governing tolerance are needed. We have developed a model of antigen-specific tolerance in collagen type II (CII) induced arthritis (CIA) using lentivirus-based gene therapy. The immunodominant epitope of CII was inserted into a lentivirus vector to achieve expression on the MHC class II molecule and the lentiviral particles were subsequently intravenously injected at different time points during CIA. Injection of lentiviral particles in early phases of CIA, that is, at day 7 or day 26 after CII immunisation, partially prevented development of arthritis, decreased the serum levels of CII-specific IgG antibodies, and enhanced the suppressive function of CII-specific T regulatory cells. When lentiviral particles were injected during manifest arthritis, that is, at day 31 after CII immunisation, the severity of arthritis progression was ameliorated, the levels of CII-specific IgG antibodies decreased and the proportion of T regulatory cells increased. Thus, antigen-specific gene therapy is effective when administered throughout the inflammatory course of arthritis and offers a good model for investigation of the basic mechanisms during tolerance in CIA

Interleukin-17A during Local and Systemic Staphylococcus aureus-Induced Arthritis in Mice▿

Staphylococcus aureus is one of the dominant pathogens that induce septic arthritis in immunocompromised hosts, e.g., patients suffering from rheumatoid arthritis treated with immunosuppressive drugs. S. aureus-induced arthritis leads to severe joint destruction and high mortality despite antibiotic treatment. Recently, interleukin-17A (IL-17A) has been discovered to be an important mediator of aseptic arthritis both in mice and humans, but its function in S. aureus-induced arthritis is largely unknown. Here, we investigated the role of IL-17A in host defense against arthritis following systemic and local S. aureus infection in vivo. IL-17A knockout mice and wild-type mice were inoculated systemically (intravenously) or locally (intra-articularly) with S. aureus. During systemic infection, IL-17A knockout mice lost significantly more weight than the wild-type mice did, but no differences were found in the mortality rate. The absence of IL-17A had no impact on clinical arthritis development but led to increased histopathological erosivity late during systemic S. aureus infection. Bacterial clearance in kidneys was increased in IL-17A knockout mice compared to the level in wild-type mice only 1 day after bacterial inoculation. During systemic S. aureus infection, serum IL-17F protein levels and mRNA levels in the lymph nodes were elevated in the IL-17A knockout mice compared to the level in wild-type mice. In contrast to systemic infection, the IL-17A knockout mice had increased synovitis and erosions and locally decreased clearance of bacteria 3 days after local bacterial inoculation. On the basis of these findings, we suggest that IL-17A is more important in local host defense than in systemic host defense against S. aureus-induced arthritis

Spiroplasma ixodetis Infections in Immunocompetent and Immunosuppressed Patients after Tick Exposure, Sweden

We report 2 cases of Spiroplasma ixodetis infection in an immunocompetent patient and an immunocompromised patient who had frequent tick exposure. Fever, thrombocytopenia, and increased liver aminotransferase levels raised the suspicion of anaplasmosis, but 16S rRNA PCR and Sanger sequencing yielded a diagnosis of spiroplasmosis. Both patients recovered after doxycycline treatment

Serotonin transporter gene polymorphisms: Effect on serotonin transporter availability in the brain of suicide attempters

The efficacy of serotonin reuptake inhibitors in depression and anxiety disorders suggests the gene coding for the serotonin transporter (5-HTT), SLC6A4, as a candidate of importance for these conditions. Positive findings regarding associations between polymorphisms in SLC6A4 have been reported, indicating that these polymorphisms may influence anxiety-related personality traits, as well as the risk of developing depression and suicidality. Serotonin 5-HTT availability was assessed with single photon emission computed tomography (SPECT), using I-123-beta-CIT as ligand, in a population of unmedicated male suicide attempters (n=9) and in matched controls (n=9). Two polymorphisms in SLC6A4 were assessed, including the 5-HTTLPR located in the promoter region and a variable number of tandem repeats (VNTR) polymorphism in intron 2 (STin2). In suicide attempters, but not in controls, low 5-HTT availability was associated with the S allele of 5-HTTLPR and with the 12 repeat allele of STin2. Data suggest that polymorphisms in SLC6A4 may influence the expression of the brain serotonin transporter in suicide attempters

Collagen epitope expression on B cells is sufficient to confer tolerance to collagen-induced arthritis

Background: The mechanisms underlying tolerance induction and maintenance in autoimmune arthritis remain elusive. In a mouse model of rheumatoid arthritis, collagen type II (CII)-induced arthritis, we explore the contribution of B cells to antigen-specific tolerance. Methods: To generate expression of the CII-peptide specifically on B-cell major histocompatibility complex type II, lentiviral-based gene therapy including a B-cell-specific Igk promoter was used. Results: Presentation of the CII-peptide on B cells significantly reduced the frequency and severity of arthritis as well as the serum levels of CII -specific IgG antibodies. Further, both frequency and suppressive function of regulatory T cells were increased in tolerized mice. Adoptive transfer of regulatory T cells from tolerized mice to naive mice ameliorated the development of CII-induced arthritis. Conclusion: Our data suggest that endogenous presentation of the CII-peptide on B cells is one of the key contributors to arthritis tolerance induction and maintenance

Disease-Dependent Local IL-10 Production Ameliorates Collagen Induced Arthritis in Mice

<div><p>Rheumatoid arthritis (RA) is a chronic destructive autoimmune disease characterised by periods of flare and remission. Today’s treatment is based on continuous immunosuppression irrespective of the patient’s inflammatory status. When the disease is in remission the therapy is withdrawn but withdrawal attempts often results in inflammatory flares, and re-start of the therapy is commenced when the inflammation again is prominent which leads both to suffering and increased risk of tissue destruction. An attractive alternative treatment would provide a disease-regulated therapy that offers increased anti-inflammatory effect during flares and is inactive during periods of remission. To explore this concept we expressed the immunoregulatory cytokine interleukin (IL)-10 gene under the control of an inflammation dependent promoter in a mouse model of RA - collagen type II (CII) induced arthritis (CIA). Haematopoetic stem cells (HSCs) were transduced with lentiviral particles encoding the IL-10 gene (LNT-IL-10), or a green fluorescence protein (GFP) as control gene (LNT-GFP), driven by the inflammation-dependent IL-1/IL-6 promoter. Twelve weeks after transplantation of transduced HSCs into DBA/1 mice, CIA was induced. We found that LNT-IL-10 mice developed a reduced severity of arthritis compared to controls. The LNT-IL-10 mice exhibited both increased mRNA expression levels of IL-10 as well as increased amount of IL-10 produced by B cells and non-B APCs locally in the lymph nodes compared to controls. These findings were accompanied by increased mRNA expression of the IL-10 induced suppressor of cytokine signalling 1 (SOCS1) in lymph nodes and a decrease in the serum protein levels of IL-6. We also found a decrease in both frequency and number of B cells and serum levels of anti-CII antibodies. Thus, inflammation-dependent IL-10 therapy suppresses experimental autoimmune arthritis and is a promising candidate in the development of novel treatments for RA.</p> </div

Lentiviral gene constructs and clinical development of arthritis.

<p>(<b>A</b>) Lentiviral constructs: LNT-GFP and LNT-IL-10. LTR; long terminal repeat, cPPT; central polypurine tract, pA; polyadenylic acid tail, WPRE; Woodchuck post-transcriptional regulatory element, IL-1E; Interleukin-1 enhancer, IL-6 promoter. (<b>B</b>) Severity of arthritis (mean arthritis score ± SEM). LNT-GFP (day 0–42 n = 18, day 44–49 n = 10) and LNT-IL-10 (day 0–42 n = 25, day 44–49 n = 14)). (<b>C</b>) Histopathological severity of synovitis and cartilage and bone erosivity measured as histological severity score (Y-axis) ranging from 0–3. Data in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0049731#pone-0049731-g001" target="_blank">figure 1B and C</a> were analysed by Mann-Whitney U-test. Closed circles represents LNT-GFP and open circles LNT-IL-10 mice. Bars in 1C represent the median.</p

Levels of IL-6 and anti-CII antibodies

<p>(<b>A</b>) Serum protein levels of IL-6 (<b>B</b>) and serum levels of anti-CII IgG were analysed at days 29 and 42 after CII immunisation. Analysed by Mann-Whitney U-test. Closed circles represents LNT-GFP and open circles LNT-IL-10 mice.</p