| 3561. |
- Strömberg, Erika, 1974
(författare)
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Mucosal T-cell and cytokine responses in Helicobacter pylori-infected duodenal ulcer patients
- 2003
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Helicobacter pylori colonizes the human stomach and areas of gastric metaplasia in the duodenum. The bacterium is the major cause of chronic active gastritis and peptic ulcer disease and is a risk factor for the development of gastric adenocarcinoma and lymphoma. However, the majority of those infected remain asymptomatic (AS) carriers of the bacteria, and only 10-15% develop duodenal ulcers (DU). It is still unknown which factors determine whether an individual will develop duodenal ulcer disease or remain an AS carrier, but bacterial factors as well as host immune responses are believed to be important for the outcome of infection. To evaluate the role of the immune response in the development of duodenal ulcers, we compared the mucosal T-cell and cytokine responses in DU patients, AS carriers, and uninfected individuals. Immunohistochemical analysis of the duodenal cytokine responses showed similar cytokine staining in normal and metaplastic duodenal mucosa of H. pylori-infected individuals. However, decreased levels of several cytokines, i.e. IL-8, IL-6, IL-1b, IFN-g and TGF-b were observed in the epithelium of duodenal biopsies from DU patients, as compared to from AS carriers and uninfected subjects. Analysis of freshly isolated duodenal epithelial cells further confirmed this finding, i.e. significantly lower levels of IL-8 were produced by cells from DU patients than from AS carriers. This was found to be due to properties of the epithelial cells rather than apoptosis, down-regulation by other immune cells or differences in bacterial strains. In the lamina propria of the duodenum, the number of cytokine positive mononuclear cells (MNCs) was found to be up-regulated in H. pylori-infected, as compared to uninfected individuals, but with similar levels in DU patients and AS carriers. Analysis of the T-cell responses in the duodenum and the antrum of the stomach showed increased infiltration of primarily CD4+ T cells in the antrum, whereas no differences in the number of T cells were found in the duodenum of H. pylori-infected and uninfected individuals. The expression of the activation markers CD69 and CD25 was found to be significantly higher in the antrum, and slightly increased in the duodenum of both H. pylori-infected AS carriers and DU patients. Flow cytometric analysis of isolated mucosal T cells revealed increased numbers of CD4+CD25high cells, i.e. regulatory T cells (Treg) in the antrum and duodenum of H. pylori-infected individuals, as compared to uninfected subjects. CTLA-4, a marker of Treg, was found to be highly expressed in the majority of these cells. Interestingly, when comparing the numbers of down-regulating CTLA-4+ cells in the duodenum of H. pylori-infected DU patients and AS carriers by immunohistochemistry, we observed significantly increased frequencies of these cells in the duodenal mucosa of DU patients. We speculate that these cells, at least in part, are regulatory T cells that may down-regulate the specific T-cell responses in the duodenal mucosa of DU patients. In conclusion, our results show that the immune responses in the duodenum against H. pylori may be down-regulated or suppressed in DU patients and may hence not be efficient enough to clear the infection, which consequently becomes chronic and may lead to the development of duodenal ulcers.
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| 3562. |
- Akhtar, M., et al.
(författare)
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Kinetics of antibody-secreting cell and fecal IgA responses after oral cholera vaccination in different age groups in a cholera endemic country
- 2017
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Ingår i: Vaccine. - : Elsevier BV. - 0264-410X. ; 35:2, s. 321-328
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Tidskriftsartikel (refereegranskat)abstract
- Immune responses to oral enteric vaccines in children and infants may be influenced by factors such as age, previous priming with related microorganisms and breast feeding. In this study, we aimed to determine optimal time points to assess immune responses to oral enteric vaccines in different clinical specimens. This was done by investigating antibody secreting cell (ASC) and fecal antibody responses on different days after vaccination using the licensed oral cholera vaccine Dukoral, containing cholera toxin B-subunit (rCTB) and inactivated Vibrio cholerae bacteria, as a model vaccine. Two vaccine doses were given 2 weeks apart to infants (6-11 months), young children (12-18 months), toddlers (19 months-5 years) and adults in a cholera endemic country (Bangladesh). IgA ASC responses, as determined by the antibodies in lymphocyte supernatant (ALS) assay, plasma IgA and IgG responses and secretory IgA (SIgA) responses in extracts of fecal samples were evaluated 4/5 and 7 days after each vaccination. After the first vaccine dose, anti-CTB ALS IgA responses in adults and toddlers were high and comparable on day 5 and 7, while responses were low and infrequent in young children. After the second dose, highest ALS responses were detected on day 5 among the time points studied in all age groups and the responses declined until day 7. In contrast, plasma IgA and IgG anti-CTB responses were high both on day 5 and 7 after the second dose. Fecal SIgA responses in young children and infants were highest on day 7 after the second dose. Our results suggest that ASC/ALS responses to two doses of the oral cholera vaccine Dukoral and related oral vaccines should be analyzed earlier than previously recommended (day 7) at all ages. Fecal antibody responses should preferably be analyzed later than ASC/ALS responses to detect the highest antibody responses. (C) 2016 Elsevier Ltd. All rights reserved.
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| 3563. |
- Antberg, Linn, et al.
(författare)
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Critical Comparison of Multidimensional Separation Methods for Increasing Protein Expression Coverage
- 2012
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Ingår i: Journal of Proteome Research. - : American Chemical Society (ACS). - 1535-3893 .- 1535-3907. ; 11:5, s. 2644-2652
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Tidskriftsartikel (refereegranskat)abstract
- We present a comparison of two-dimensional separation methods and how they affect the degree of coverage of protein expression in complex mixtures. We investigated the relative merits of various protein and peptide separations prior to acidic reversed-phase chromatography directly coupled to an ion trap mass spectrometer. The first dimensions investigated were density gradient organelle fractionation of cell extracts, 1D SDS-PAGE protein separation followed by digestion by trypsin or GluC proteases, strong cation exchange chromatography, and off-gel isoelectric focusing of tryptic peptides. The number of fractions from each first dimension and the total data accumulation RP-HPLC-MS/MS time was kept constant and the experiments were run in triplicate. We find that the most critical parameters are the data accumulation time, which defines the level of under-sampling and the avoidance of peptides from high expression level proteins eluting over the entire gradient.
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| 3564. |
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| 3565. |
- Codemo, Mario, et al.
(författare)
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Immunomodulatory Effects of Pneumococcal Extracellular Vesicles on Cellular and Humoral Host Defenses
- 2018
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Ingår i: mBio. - : American Society for Microbiology. - 2161-2129 .- 2150-7511. ; 9:2
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Tidskriftsartikel (refereegranskat)abstract
- Gram-positive bacteria, including the major respiratory pathogen Streptococcus pneumoniae, were recently shown to produce extracellular vesicles (EVs) that likely originate from the plasma membrane and are released into the extracellular environment. EVs may function as cargo for many bacterial proteins, however, their involvement in cellular processes and their interactions with the innate immune system are poorly understood. Here, EVs from pneumococci were characterized and their immunomodulatory effects investigated. Pneumococcal EVs were protruding from the bacterial surface and released into the medium as 25 to 250 nm lipid stained vesicles containing a large number of cytosolic, membrane, and surface-associated proteins. The cytosolic pore-forming toxin pneumolysin was significantly enriched in EVs compared to a total bacterial lysate but was not required for EV formation. Pneumococcal EVs were internalized into A549 lung epithelial cells and human monocyte-derived dendritic cells and induced proinflammatory cytokine responses irrespective of pneumolysin content. EVs from encapsulated pneumococci were recognized by serum proteins, resulting in C3b deposition and formation of C5b-9 membrane attack complexes as well as factor H recruitment, depending on the presence of the choline binding protein PspC. Addition of EVs to human serum decreased opsonophagocytic killing of encapsulated pneumococci. Our data suggest that EVs may act in an immunomodulatory manner by allowing delivery of vesicle-associated proteins and other macromolecules into host cells. In addition, EVs expose targets for complement factors in serum, promoting pneumococcal evasion of humoral host defense.Importance: Streptococcus pneumoniae is a major contributor to morbidity and mortality worldwide, being the major cause of milder respiratory tract infections such as otitis and sinusitis and of severe infections such as community-acquired pneumonia, with or without septicemia, and meningitis. More knowledge is needed on how pneumococci interact with the host, deliver virulence factors, and activate immune defenses. Here we show that pneumococci form extracellular vesicles that emanate from the plasma membrane and contain virulence properties, including enrichment of pneumolysin. We found that pneumococcal vesicles can be internalized into epithelial and dendritic cells and bind complement proteins, thereby promoting pneumococcal evasion of complement-mediated opsonophagocytosis. They also induce pneumolysin-independent proinflammatory responses. We suggest that these vesicles can function as a mechanism for delivery of pneumococcal proteins and other immunomodulatory components into host cells and help pneumococci to avoid complement deposition and phagocytosis-mediated killing, thereby possibly contributing to the symptoms found in pneumococcal infections.
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| 3566. |
- Luo, Zhengkang, et al.
(författare)
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Interleukin-35 Prevents the Elevation of the M1/M2 Ratio of Macrophages in Experimental Type 1 Diabetes
- 2022
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Ingår i: International Journal of Molecular Sciences. - : MDPI AG. - 1661-6596 .- 1422-0067. ; 23:14
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Tidskriftsartikel (refereegranskat)abstract
- Macrophages play an important role in the early development of type 1 diabetes (T1D). Based on the phenotype, macrophages can be classified into pro-inflammatory (M1) and anti-inflammatory (M2) macrophages. Despite intensive research in the field of macrophages and T1D, the kinetic response of M1/M2 ratio has not been studied in T1D. Thus, herein, we studied the M1 and M2 macrophages in the early development of T1D using the multiple low dose streptozotocin (MLDSTZ) mouse model. We determined the proportions of M1 and M2 macrophages in thymic glands, pancreatic lymph nodes and spleens on days 3, 7 and 10 after the first injection of STZ. In addition, we investigated the effect of IL-35 in vivo on the M1/M2 ratio and IL-35(+) plasmacytoid dendritic cells in diabetic mice and in vitro on the sorted macrophages. Our results revealed that the M1/M2 ratio is higher in STZ-treated mice but this was lowered upon the treatment with IL-35. Furthermore, IL-35 treated mice had lower blood glucose levels and a higher proportion of IL-35(+) cells among pDCs. Macrophages treated with IL-35 in vitro also had a higher proportion of M2 macrophages. Together, our data indicate that, under diabetic conditions, pro-inflammatory macrophages increased, but IL-35 treatment decreased the pro-inflammatory macrophages and increased anti-inflammatory macrophages, further suggesting that IL-35 prevents hyperglycemia by maintaining the anti-inflammatory phenotype of macrophages and other immune cells. Thus, IL-35 should be further investigated for the treatment of T1D and other autoimmune disorders.
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| 3567. |
- Lycke, Nils Y, 1954, et al.
(författare)
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Mucosal B Cell Differentiation and Regulation
- 2015
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Ingår i: Mucosal Immunology: Fourth Edition. Volume 1. - : Elsevier. - 9780124158474 ; 1-2, s. 701-719
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Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract
- A prime function of the mucosal immune system is the production of secretory immunoglobulin (Ig) A antibodies. To initiate this, the organized lymphoid system is strategically located at sites where mucosal antigens are encountered. The follicle-associated epithelium (FAE) hosts specialized cells called M cells that effectively take up antigen. After transport of antigen via the FAE, the mucosal-associated lymphoid tissues (MALT) support the priming, propagation, and differentiation of naïve B and T cells. Activated B cells undergo class-switch recombination from IgM to IgA in MALT. As a consequence of extensive cell division in germinal centers, formed with the help of CD4 T cells, these cells acquire mutations in their V(D)J Ig genes. Somatic mutations diversify the specificities of the receptors, and this contributes to an enhanced antigen binding ability after selection of high-affinity variants. IgA B cells develop into memory cells and long-lived plasma cells, and through an intricate system of ligands and receptors most of the IgA cells home to the effector sites in the lamina propria of the nonorganized mucosal membranes. Long-lived plasma cells also reside in the bone marrow from where most of the serum IgA emanates. Despite many years of intense interest in the regulation of mucosal IgA B cell responses, several questions still remain unanswered. This chapter describes how IgA B cells are activated, distributed, and maintained as either long-lived plasma cells or memory B cells, and it reviews recent developments in the field. Knowledge about IgA B cell development is critical not only for mucosal vaccine development but also for our understanding of how homeostasis can be maintained between the host and the microbiota. © 2015 Elsevier Inc. All rights reserved.
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| 3568. |
- Maouia, Amal, et al.
(författare)
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The Immune Nature of Platelets Revisited
- 2020
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Ingår i: Transfusion Medicine Reviews. - : Elsevier BV. - 0887-7963. ; 34:4, s. 209-220
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Forskningsöversikt (refereegranskat)abstract
- Platelets are the primary cellular mediators of hemostasis and this function firmly acquaints them with a variety of inflammatory processes. For example, platelets can act as circulating sentinels by expressing Toll-like receptors (TLR) that bind pathogens and this allows platelets to effectively kill them or present them to cells of the immune system. Furthermore, activated platelets secrete and express many pro- and anti-inflammatory molecules that attract and capture circulating leukocytes and direct them to inflamed tissues. In addition, platelets can directly influence adaptive immune responses via secretion of, for example, CD40 and CD40L molecules. Platelets are also the source of most of the microvesicles in the circulation and these miniscule elements further enhance the platelet's ability to communicate with the immune system. More recently, it has been demonstrated that platelets and their parent cells, the megakaryocytes (MK), can also uptake, process and present both foreign and self-antigens to CD8+ T-cells conferring on them the ability to directly alter adaptive immune responses. This review will highlight several of the non-hemostatic attributes of platelets that clearly and rightfully place them as integral players in immune reactions.
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| 3569. |
- Melin Fürst, Camilla
(författare)
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Interactions between extracellular matrix proteins and the complement system - In the perspective of cartilage degradation in inflammatory joint diseases
- 2016
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Abstract: The joint diseases osteoarthritis and rheumatoid arthritis are characterized by destructive inflammatory processes that result in pathological changes of the joint tissues, including proteolytic degradation of cartilage and release of extracellular matrix proteins or fragments to the synovial fluid. The complement system, which is a part of the innate immune system, plays a central role in promoting the joint inflammation in these diseases. Potential activators of complement are certain extracellular matrix proteins that become exposed during cartilage degradation. Previous studies have revealed that several proteins from cartilage can activate or inhibit the complement system in vitro. In the present work, we describe the interactions between the complement system and additional extracellular matrix proteins, with the aim to better understand the role of endogenous ligands in the inflammatory process in joint diseases. We also describe the interactions between complement proteins and cartilage explants that have been subjected to inflammation-induced degradation. In paper I, we found that the G3 domain of aggrecan activates the classical pathway of complement. However, the activation of the terminal pathway is limited due to the simultaneous binding of factor H. Whether it activates complement when maintained in cartilage or when released into the synovial fluid remains to be elucidated. In paper II and III, we found that both proline/arginine-rich end leucine-rich repeat protein (PRELP) and the domain NC4 of collagen type IX, inhibit complement by preventing the assembly of the membrane attack complex. Further, PRELP also inhibits the assembly of the alternative pathway C3 convertase, while NC4 enhances the cofactor activities of C4b-binding protein and factor H, in the factor I-mediated cleavage of C4b and C3b. NC4 and fragments of PRELP can be detected in the synovial fluid of rheumatoid arthritis patients. Located in the synovial fluid or exposed on the cartilage surface, they might be important for limiting the complement activation, induced by other extracellular matrix proteins or other potential triggers. In Paper IV, we found that both the classical and the alternative pathways are activated on the surface of degraded cartilage explants, while components released from cartilage might have a weak, somewhat delayed, opposing role by inhibiting complement. The main activation seems to occur after the major loss of aggrecan from cartilage. In sum, several proteins of the extracellular matrix, as well as degraded cartilage have the potential to interact with the complement system, and may regulate the inflammatory processes in joint diseases.
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| 3570. |
- Prohaszka, Zoltan, et al.
(författare)
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Complement analysis 2016 : Clinical indications, laboratory diagnostics and quality control
- 2016
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Ingår i: Immunobiology. - : Elsevier BV. - 0171-2985 .- 1878-3279. ; 211:11, s. 1247-1258
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Tidskriftsartikel (refereegranskat)abstract
- In recent years, complement analysis of body fluids and biopsies, going far beyond C3 and C4, has significantly enhanced our understanding of the disease process. Such expanded complement analysis allows for a more precise differential diagnosis and for critical monitoring of complement-targeted therapy. These changes are a result of the growing understanding of the involvement of complement in a diverse set of disorders. To appreciate the importance of proper complement analysis, it is important to understand the role it plays in disease. Historically, it was the absence of complement as manifested in severe infection that was noted. Since then complement has been connected to a variety of inflammatory disorders, such as autoimmune diseases and hereditary angioedema. While the role of complement in the rejection of renal grafts has been known longer, the significant impact of complement. In certain nephropathies has now led to the reclassification of some rare kidney diseases and an increased role for complement analysis in diagnosis. Even more unexpected is that complement has also been implicated in neural, ophtalmological and dermatological disorders. With this level of involvement in some varied and impactful health issues proper complement testing is clearly important; however, analysis of the complement system varies widely among laboratories. Except for a few proteins, such as C3 and C4, there are neither well-characterized standard preparations nor calibrated assays available. This is especially true for the inter-laboratory variation of tests which assess classical, alternative, or lectin pathway function. In addition, there is a need for the standardization of the measurement of complement activation products that are so critical in determining whether clinically relevant complement activation has occurred in vivo. Finally, autoantibodies to complement proteins (e.g. anti-C1q), C3 and C4 convertases (C3 and C4 nephritic factor) or to regulatory proteins (e.g. anti-Clinhibitor, anti-factor H) are important in defining autoimmune processes and diseases based on complement dysregulation. To improve the quality of complement laboratory analysis a standardization commmittee of the International Complement Society (ICS) and the International Union of Immunological Societies (IUIS) was formed to provide guidelines for modern complement analysis and standards for the development of international testing programs.
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