| 1. |
- Christensson, Marta, et al.
(författare)
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Serum sFAS levels are elevated in ANCA-positive vasculitis compared with other autoimmune diseases
- 2002
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Ingår i: Journal of Clinical Immunology. - 0271-9142 .- 1573-2592. ; 22:4, s. 220-227
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Tidskriftsartikel (refereegranskat)abstract
- The role of the Fas/FasL system in ANCA-associated vasculitis is unclear. We therefore assessed levels of soluble Fas (sFas) in sera and Fas expression on mononuclear cells from patients with ANCA-positive vasculitis and compared the results with those found in other rheumatic diseases. Serum levels of sFas were determined by ELISA. The ANCA-positive vasculitis patients studied included 29 at onset, 17 in first remission while on therapy, and 12 in quiescence. For comparison, 10 patients with Sjogren’s syndrome (SS), 14 patients with systemic lupus erythematosus (SLE), 29 patients with rheumatoid arthritis (RA), 7 patients on dialysis (DP), and 26 healthy controls (HC) were studied. In addition, Fas expression in mononuclear cells was examined at the mRNA level using reverse transcriptase (RT)-PCR in 6 vasculitis patients at onset and in first remission. The expression of CD95 on the surface of leukocytes was determined by flow cytometry in 6 vasculitis patients at onset of the disease, in 6 patients in clinical remission, and in 6 HC. Expression of Fas and FasL in renal biopsy specimens was studied using immunohistochemistry. Patients with vasculitis had high sFas levels irrespective of disease phase. Both vasculitis patients and patients with RA and SLE had significantly increased sFas levels compared with healthy controls. All patient groups had sFas levels, which correlated with raised serum creatinine values. However, the sFas levels in vasculitis patients in first remission and in quiescence were increased despite a lower serum creatinine compared with onset. Some of the vasculitis patients showed an increased mRNA expression of Fas in mononuclear cells after treatment, suggesting that Fas production fluctuates with the intensity of the disease. The expression of CD95 on leukocytes was slightly decreased in vasculitis patients compared to healthy controls. No alterations of Fas and FasL expression were seen in renal biopsy specimens. These results show that ANCA-positive vasculitis patients have high sFas levels and that the levels remain elevated even in clinical remission. The findings indicate that perturbations in the Fas/Fas ligand system may play a role in the disease process in ANCA vasculitis.
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| 2. |
- Eneslätt, Kjell, et al.
(författare)
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Persistence of cell-mediated immunity three decades after vaccination with the live vaccine strain of Francisella tularensis
- 2011
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Ingår i: European Journal of Immunology. - Weinheim : Wiley-VCH Verlagsgesellschaft. - 0014-2980 .- 1521-4141. ; 41:4, s. 974-980
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Tidskriftsartikel (refereegranskat)abstract
- The efficacy of many vaccines against intracellular bacteria depends on the generation of cell-mediated immunity, but studies to determine the duration of immunity are usually confounded by re-exposure. The causative agent of tularemia, Francisella tularensis, is rare in most areas and, therefore, tularemia vaccination is an interesting model for studies of the longevity of vaccine-induced cell-mediated immunity. Here, lymphocyte proliferation and cytokine production in response to F. tularensis were assayed in two groups of 16 individuals, vaccinated 1-3 or 27-34 years previously. As compared to naïve individuals, vaccinees of both groups showed higher proliferative responses and, out of 17 cytokines assayed, higher levels of MIP-1β, IFN-γ, IL-10, and IL-5 in response to recall stimulation. The responses were very similar in the two groups of vaccinees. A statistical model was developed to predict the immune status of the individuals and by use of two parameters, proliferative responses and levels of IFN-γ, 91.1% of the individuals were correctly classified. Using flow cytometry analysis, we demonstrated that during recall stimulation, expression of IFN-γ by CD4(+) CCR7(+) , CD4(+) CD62L(+) , CD8(+) CCR7(+) , and CD8(+) CD62L(+) cells significantly increased in samples from vaccinated donors. In conclusion, cell-mediated immunity was found to persist three decades after tularemia vaccination without evidence of decline.
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| 3. |
- Eneslätt, Kjell, et al.
(författare)
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Signatures of T cells as correlates of immunity to Francisella tularensis
- 2012
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Ingår i: PLOS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 7:3, s. e32367-
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Tidskriftsartikel (refereegranskat)abstract
- Tularemia or vaccination with the live vaccine strain (LVS) of Francisella tularensis confers long-lived cell-mediated immunity. We hypothesized that this immunity depends on polyfunctional memory T cells, i.e., CD4(+) and/or CD8(+) T cells with the capability to simultaneously express several functional markers. Multiparametric flow cytometry, measurement of secreted cytokines, and analysis of lymphocyte proliferation were used to characterize in vitro recall responses of peripheral blood mononuclear cells (PBMC) to killed F. tularensis antigens from the LVS or Schu S4 strains. PBMC responses were compared between individuals who had contracted tularemia, had been vaccinated, or had not been exposed to F. tularensis (naive). Significant differences were detected between either of the immune donor groups and naive individuals for secreted levels of IL-5, IL-6, IL-10, IL-12, IL-13, IFN-gamma, MCP-1, and MIP-1 beta. Expression of IFN-gamma, MIP-1 beta, and CD107a by CD4(+)CD45RO(+) or CD8(+) CD45RO(+) T cells correlated to antigen concentrations. In particular, IFN-gamma and MIP-1 beta strongly discriminated between immune and naive individuals. Only one cytokine, IL-6, discriminated between the two groups of immune individuals. Notably, IL-2- or TNF-alpha-secretion was low. Our results identify functional signatures of T cells that may serve as correlates of immunity and protection against F. tularensis.
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| 4. |
- Eneslätt, Kjell, et al.
(författare)
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The regulation of FasL expression : a distinguishing feature between monocytes and T lymphocytes/NK cells with possible implications for SLE
- 2001
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Ingår i: Journal of Clinical Immunology. - 0271-9142 .- 1573-2592. ; 21:3, s. 183-192
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Tidskriftsartikel (refereegranskat)abstract
- Monocytes and lymphocytes from patients with systemic lupus erythematosus (SLE) had a higher cell surface expression of Fast than the corresponding cells from healthy individuals. Inhibitors of metalloproteases upregulated the surface expression of Fast in peripheral blood lymphocytes (PBL), indicating that a metalloprotease is responsible for the cleavage of FasL. The level of sFasL in serum was slightly increased in the patient group compared to the controls. Therefore, the possible contribution of various mononuclear cell types to the release of Fast was analyzed. Isolated NK cells and T lymphocytes released Fast into the medium and the release was prevented by inhibitors of metalloproteases. In contrast, isolated monocytes did not release Fast. FasR expression was elevated in patients with inverted CD4/CD8 ratio, while Fast expression showed no relationship to CD4/CD8 ratio. The absence of Fast release by isolated cells and a high level of surface expression of Fast distinguish monocytes and T lymphocytes/NK cells.
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| 5. |
- Eneslätt, Kjell, et al.
(författare)
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Vaccine-mediated mechanisms controlling replication of Francisella tularensis in human peripheral blood mononuclear cells using a co-culture system
- 2018
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Ingår i: Frontiers in Cellular and Infection Microbiology. - : Frontiers Media S.A.. - 2235-2988. ; 8
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Tidskriftsartikel (refereegranskat)abstract
- Cell-mediated immunity (CMI) is normally required for efficient protection against intracellular infections, however, identification of correlates is challenging and they are generally lacking. Francisella tularensis is a highly virulent, facultative intracellular bacterium and CMI is critically required for protection against the pathogen, but how this is effectuated in humans is poorly understood. To understand the protective mechanisms, we established an in vitro co-culture assay to identify how control of infection of F. tularensis is accomplished by human cells and hypothesized that the model will mimic in vivo immune mechanisms. Non-adherent peripheral blood mononuclear cells (PBMCs) were expanded with antigen and added to cultures with adherent PBMC infected with the human vaccine strain, LVS, or the highly virulent SCHU S4 strain. Intracellular numbers of F. tularensis was followed for 72 h and secreted and intracellular cytokines were analyzed. Addition of PBMC expanded from naïve individuals, i.e., those with no record of immunization to F. tularensis, generally resulted in little or no control of intracellular bacterial growth, whereas addition of PBMC from a majority of F. tularensis-immune individuals executed static and sometimes cidal effects on intracellular bacteria. Regardless of infecting strain, statistical differences between the two groups were significant, P < 0.05. Secretion of 11 cytokines was analyzed after 72 h of infection and significant differences with regard to secretion of IFN-γ, TNF, and MIP-1β was observed between immune and naïve individuals for LVS-infected cultures. Also, in LVS-infected cultures, CD4 T cells from vaccinees, but not CD8 T cells, showed significantly higher expression of IFN-γ, MIP-1β, TNF, and CD107a than cells from naïve individuals. The co-culture system appears to identify correlates of immunity that are relevant for the understanding of mechanisms of the protective host immunity to F. tularensis.
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| 6. |
- Eriksson, Catharina, 1955-, et al.
(författare)
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Abnormal expression of chemokine receptors on T-cells from patients with systemic lupus erythematosus
- 2003
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Ingår i: Lupus. - : SAGE Publications. - 0961-2033 .- 1477-0962. ; 12:10, s. 766-774
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Tidskriftsartikel (refereegranskat)abstract
- The expression of chemokine receptors on T-cells and chemokine levels in the blood was studied in 23 patients with SLE (ACR criteria), seven patients with rheumatoid arthritis (RA) and in 15 healthy controls using flow cytometry, RT-PCR and ELISA. The cell surface expression of the chemokine receptors CXCR5 and CCR6 was decreased in SLE patients compared with controls (P = 0.051 and P = 0.002, respectively). The decrease of CXCR5 was confined to SLE patients with inactive disease (SLEDAI < 6) compared with active disease (SLEDAI &GE; 6) and controls. CXCR2 and CCR1 were increased in patients with active SLE compared with patients with inactive disease (P = 0.001 and P = 0.01, respectively) and with controls ( P = 0.02 and P = 0.053, respectively). The levels of the chemokines MIP-1β MCP-1, SDF-1α, IP-10 and RANTES were significantly elevated in SLE patients compared with controls. Patients with renal involvement had increased surface expression of CXCR3 and CCR3 (P = 0.04 in both) and a lower level of soluble IP-10 compared with patients without renal disease (P = 0.025) and compared with controls (P = 0.001). The ratio between CCR5 and CCR3 was significantly increased in RA patients compared with SLE patients and controls supporting a Th1 overweight in RA. In conclusion, patients with SLE showed abnormal T-cell expression of several chemokine receptors and levels of soluble chemokines in their plasma/ serum.
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| 7. |
- Golovliov, Igor, et al.
(författare)
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An In Vitro Co-culture Mouse Model Demonstrates Efficient Vaccine-Mediated Control of Francisella tularensis SCHU S4 and Identifies Nitric Oxide as a Predictor of Efficacy
- 2016
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Ingår i: Frontiers in Cellular and Infection Microbiology. - : Frontiers Media SA. - 2235-2988. ; 6
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Tidskriftsartikel (refereegranskat)abstract
- Francisella tularensis is a highly virulent intracellular bacterium and cell-mediated immunity is critical for protection, but mechanisms of protection against highly virulent variants, such as the prototypic strain F. tularensis strain SCHU S4, are poorly understood. To this end, we established a co-culture system, based on splenocytes from naive, or immunized mice and in vitro infected bone marrow-derived macrophages that allowed assessment of mechanisms controlling infection with F. tularensis. We utilized the system to understand why the clpB gene deletion mutant, Delta clpB, of SCHU S4 shows superior efficacy as a vaccine in the mouse model as compared to the existing human vaccine, the live vaccine strain (LVS). Compared to naive splenocytes, Delta clpB-, or LVS-immune splenocytes conferred very significant control of a SCHU S4 infection and the Delta clpB-immune splenocytes were superior to the LVS-immune splenocytes. Cultures with the Delta clpB-immune splenocytes also contained higher levels of IFN-gamma, IL-17, and GM-CSF and nitric oxide, and T cells expressing combinations of IFN-gamma, TNF-alpha, and IL-17, than did cultures with LVS-immune splenocytes. There was strong inverse correlation between bacterial replication and levels of nitrite, an end product of nitric oxide, and essentially no control was observed when BMDM from iNOS(-/-) mice were infected. Collectively, the co-culture model identified a critical role of nitric oxide for protection against a highly virulent strain of F. tularensis.
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| 8. |
- Ihalin, R, et al.
(författare)
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Characterization of immunoaffinity purified peptidoglycan-associated lipoprotein of Actinobacillus actinomycetemcomitans.
- 2006
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Ingår i: Journal of chromatography. B. - : Elsevier BV. - 1570-0232 .- 1873-376X. ; 831:1-2, s. 116-125
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Tidskriftsartikel (refereegranskat)abstract
- Peptidoglycan-associated lipoprotein (PAL) is a highly conserved structural outer membrane protein among Gram-negative bacteria. In some species, it is proinflammatory and released extracellularly. We purified a newly identified PAL (AaPAL) of a periodontal pathogen Actinobacillus actinomycetemcomitans by using AaPAL antipeptide antibodies coupled to immunoaffinity chromatography column. No protein impurities originating in A. actinomycetemcomitans were found in the final product. Sera from patients infected by A. actinomycetemcomitans recognized the purified AaPAL. The present purification method seems to be suitable for isolation of AaPAL and probably PALs of other bacterial species, and applicable in studies investigating proinflammatory mechanisms of A. actinomycetemcomitans.
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| 9. |
- Karched, Maribasappa, et al.
(författare)
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Vesicle-independent extracellular release of a proinflammatory outer membrane lipoprotein in free-soluble form
- 2008
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Ingår i: BMC Microbiology. - : Springer Science and Business Media LLC. - 1471-2180. ; 28:8:18
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Tidskriftsartikel (refereegranskat)abstract
- Aggregatibacter actinomycetemcomitans is an oral bacterium associated with aggressively progressing periodontitis. Extracellular release of bacterial outer membrane proteins has been suggested to mainly occur via outer membrane vesicles. This study investigated the presence and conservation of peptidoglycan-associated lipoprotein (AaPAL) among A. actinomycetemcomitans strains, the immunostimulatory effect of AaPAL, and whether live cells release this structural outer membrane lipoprotein in free-soluble form independent of vesicles. RESULTS: The pal locus and its gene product were confirmed in clinical A. actinomycetemcomitans strains by PCR-restriction fragment length polymorphism and immunoblotting. Culturing under different growth conditions revealed no apparent requirement for the AaPAL expression. Inactivation of pal in a wild-type strain (D7S) and in its spontaneous laboratory variant (D7SS) resulted in pleiotropic cellular effects. In a cell culture insert model (filter pore size 0.02 um), AaPAL was detected from filtrates when strains D7S and D7SS were incubated in serum or broth in the inserts. Electron microscopy showed that A. actinomycetemcomitans vesicles (0.05-0.2 um) were larger than the filter pores and that there were no vesicles in the filtrates. The filtrates were immunoblot negative for a cytoplasmic marker, cyclic AMP (cAMP) receptor protein. An ex vivo model indicated cytokine production from human whole blood stimulated by AaPAL. CONCLUSIONS: Free-soluble AaPAL can be extracellularly released in a process independent of vesicles.
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| 10. |
- Lindgren, Helena, 1969-, et al.
(författare)
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Analyses of human immune responses to Francisella tularensis identify correlates of protection
- 2023
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Ingår i: Frontiers in Immunology. - : Frontiers Media S.A.. - 1664-3224. ; 14
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Tidskriftsartikel (refereegranskat)abstract
- Francisella tularensis is the etiological agent of the potentially severe infection tularemia. An existing F: tularensis vaccine, the live vaccine strain (LVS), has been used to protect at-risk personnel, but it is not licensed in any country and it has limited efficacy. Therefore, there is a need of a new, efficacious vaccine. The aim of the study was to perform a detailed analysis of the characteristics of the human immune response to F. tularensis, since this will generate crucial knowledge required to develop new vaccine candidates. Nine individuals were administered the LVS vaccine and peripheral blood mononuclear cells (PBMC) were collected before and at four time points up to one year after vaccination. The properties of the PBMC were characterized by flow cytometry analysis of surface markers and intracellular cytokine staining. In addition, the cytokine content of supernatants from F. tularensis-infected PBMC cultures was determined and the protective properties of the supernatants investigated by adding them to cultures with infected monocyte-derived macrophages (MDM). Unlike before vaccination, PBMC collected at all four time points after vaccination demonstrated F. tularensis-specific cell proliferation, cytokine secretion and cytokine-expressing memory cells. A majority of 17 cytokines were secreted at higher levels by PBMC collected at all time points after vaccination than before vaccination. A discriminative analysis based on IFN-γ and IL-13 secretion correctly classified samples obtained before and after vaccination. Increased expression of IFN-γ, IL-2, and MIP-1β were observed at all time points after vaccination vs. before vaccination and the most significant changes occurred among the CD4 transient memory, CD8 effector memory, and CD8 transient memory T-cell populations. Growth restriction of the highly virulent F. tularensis strain SCHU S4 in MDM was conferred by supernatants and protection correlated to levels of IFN-γ, IL-2, TNF, and IL-17. The findings demonstrate that F. tularensis vaccination induces long-term T-cell reactivity, including TEM and TTM cell populations. Individual cytokine levels correlated with the degree of protection conferred by the supernatants. Identification of such memory T cells and effector mechanisms provide an improved understanding of the protective mechanisms against F. tularensis. mechanisms against F. tularensis.
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