Browsing by Subject " immunology"
Now showing items 1-10 of 10
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(2020)Cutaneous lupus erythematosus (CLE) in humans encompasses multiple subtypes that exhibit a wide array of skin lesions and, in some cases, are associated with the development of systemic lupus erythematosus (SLE). We investigated dogs with exfoliative cutaneous lupus erythematosus (ECLE), a dog-specific form of chronic CLE that is inherited as a monogenic autosomal recessive trait. A genome-wide association study (GWAS) with 14 cases and 29 controls confirmed a previously published result that the causative variant maps to chromosome 18. Autozygosity mapping refined the ECLE locus to a 493 kb critical interval. Filtering of whole genome sequence data from two cases against 654 controls revealed a single private protein-changing variant in this critical interval, UNC93B1:c.1438C>A or p.Pro480Thr. The homozygous mutant genotype was exclusively observed in 23 ECLE affected German Shorthaired Pointers and an ECLE affected Vizsla, but absent from 845 controls. UNC93B1 is a transmembrane protein located in the endoplasmic reticulum and endolysosomes, which is required for correct trafficking of several Toll-like receptors (TLRs). The p.Pro480Thr variant is predicted to affect the C-terminal tail of the UNC93B1 that has recently been shown to restrict TLR7 mediated autoimmunity via an interaction with syndecan binding protein (SDCBP). The functional knowledge on UNC93B1 strongly suggests that p.Pro480Thr is causing ECLE in dogs. These dogs therefore represent an interesting spontaneous model for human lupus erythematosus. Our results warrant further investigations of whether genetic variants affecting the C-terminus of UNC93B1 might be involved in specific subsets of CLE or SLE cases in humans and other species.
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(2020)Elevated serum ferritin levels occur due to iron overload or during inflammation and macrophage activation. A correlation of high serum ferritin levels with increased mortality after alloSCT has been suggested by several retrospective analyses as well as by two smaller prospective studies. This prospective multicentric study aimed to study the association of ferritin serum levels before start of conditioning with alloSCT outcome. Patients with acute leukemia, lymphoma or MDS receiving a matched sibling alloSCT for the first time were considered for inclusion, regardless of conditioning. A comparison of outcomes between patients with high and low ferritin level was performed using univariate analysis and multivariate analysis using cause-specific Cox model. Twenty centers reported data on 298 alloSCT recipients. The ferritin cut off point was determined at 1500 mu g/l (median of measured ferritin levels). In alloSCT recipients with ferritin levels above cut off measured before the start of conditioning, overall survival (HR = 2.5, CI = 1.5-4.1, p = 0.0005) and progression-free survival (HR = 2.4, CI = 1.6-3.8, p <0.0001) were inferior. Excess mortality in the high ferritin group was due to both higher relapse incidence (HR = 2.2, CI = 1.2-3.8, p = 0.007) and increased non-relapse mortality (NRM) (HR = 3.1, CI = 1.5-6.4, p = 0.002). NRM was driven by significantly higher infection-related mortality in the high ferritin group (HR = 3.9, CI = 1.6-9.7, p = 0.003). Acute and chronic GVHD incidence or severity were not associated to serum ferritin levels. We conclude that ferritin levels can serve as routine laboratory biomarker for mortality risk assessment before alloSCT.
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(2020)Cells succumbing to stress via regulated cell death (RCD) can initiate an adaptive immune response associated with immunological memory, provided they display sufficient antigenicity and adjuvanticity. Moreover, multiple intracellular and microenvironmental features determine the propensity of RCD to drive adaptive immunity. Here, we provide an updated operational definition of immunogenic cell death (ICD), discuss the key factors that dictate the ability of dying cells to drive an adaptive immune response, summarize experimental assays that are currently available for the assessment of ICD in vitro and in vivo, and formulate guidelines for their interpretation.
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(Helsingin yliopisto, 2016)Extracellular vesicles (EVs) are small, membranous entities secreted from most eukaryotic cells at both homeostatic and stress conditions. Carrying active biological molecules nucleic acids, lipids and proteins EVs serve as important means of intercellular communication. In the immune system, EVs circulting in body fluids play important modulatory roles in coordination of responses. EVs are integral part of secretome all proteins secreted by cells. EVs provide means for secretion of proteins that are not trafficked through conventional, ER/Golgi-mediated mechanisms. Analysis of EV proteome provides basis for fundamental discoveries in understanding the biogenesis, secretion and delivery of these nanosized messengers to target cells. Macrophages are principal tissue-resident effector cells of innate immune system, performing surveillance of their neighborhood in search for danger. Macrophages express pattern recognition receptors (PRRs) which recognize conserved pathogen-associated molecular patterns (PAMPs) conserved range of molecules expressed by pathogens. PRRs also recognize endogeneous ligands that appear in the human body in other dangerous conditions and diseases. These are collectively called danger-associated molecular patterns (DAMPs). Recognition of PAMPs and DAMPs by PRRs triggers intracellular signaling, leading to activation of macrophage defense mechanisms. These begin with inflammation and secretion of pro-inflammatory cytokines, but many other proteins are also actively secreted by activated macrophages. Although inflammatory cytokine secretion is a well-studied process, very few studies investigating overall and EV-mediated protein secretion from human macrophages were performed. This thesis aims at broadening our understanding of EV-mediated protein secretion from human macrophages activated in response to selected innate immune activators, namely extracellular adenosine triphosphate (ATP), a potent DAMP released during cell damage; (1,3)-β-glucan, a polysaccharide component of fungal cell wall, activating dectin-1-mediated signaling and influenza A virus (IAV) - common seasonal pathogenic virus targeting lung epithelia and macrophages. Total secretome and purified EVs were analyzed using different high-throughput mass spectrometry-based methods and further explored using bioinformatic and biochemical studies. The presented results provide evidence that EV-mediated protein secretion is an integral part of responses of human macrophages to studied stimuli. Its activation is demonstrated with quantitative and comparative proteomic approaches. The secreted vesicles are characterized by a broad size range consistent with both exosomes and microvesicles, demonstrating that both types of vesicular structures are involved in protein secretion. The EVs carry distinct set of immunologically important proteins, and bioinformatic analysis suggests that the secreted EVs may exert immunomodulatory effects on recipient cells. It is shown that during IAV infection, EVs are mediators of pro-inflammatory and antiviral cytokine release, thus they may serve as protective capsules of targeted cytokine delivery. Proteomic analysis identified also a broad set of DAMPs unconventionally secreted in association with EVs, further extrapolating their function towards danger signaling in cellular immune responses. The study on ATP-mediated responses further investigates the intracellular signaling involving calpains, abundant cytosolic proteases, identifying their crucial roles downstream P2X7 receptor: in EV release, as well as inflammasome activation and IL-1β secretion. The data presented here indicate that EVs serve as unconventional means for secretion of a broad range of proteins secreted in PRR-mediated responses in human macrophages. Bioinformatic and functional analysis identifies potential processes involved in their generation as well as their roles in intercellular communication. Together, the presented thesis contributes to our understanding of unconventional, EV-mediated protein secretion in macrophage responses towards common, physiologically releveant threats. The studies presented here will serve as basis for further detailed functional analysis of the roles of EVs in communication between macrophages and other immune system cells. It will also lay the grounds for future studies involving EV-mediated macrophage responses in patients with fungal and viral infections.
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(2018)Purpose: The SQ tree sublingual immunotherapy (SLIT)-tablet containing allergen extracts with the major allergen Bet v 1 from birch pollen is currently being developed for the treatment of tree pollen induced allergic rhinitis/conjunctivitis with or without asthma. The aim of this Phase II trial was to investigate the dose-related efficacy and safety of the SQ tree SLIT-tablet. Methods: This study was a randomized, parallel group, double-blind, placebo-controlled, multi-national trial conducted in Europe. A total of 637 participants were randomized equally to receive placebo or treatment with the SQ tree SLIT-tablet in doses of 0.5, 1, 2, 4, 7, or 12 development units (DU). Treatment was initiated 16 weeks before onset of the 2013 birch pollen season (BPS) and was continued throughout the BPS with a total duration of at least 6 months. During the BPS and tree pollen season (TPS), subjects assessed rhinoconjunctivitis symptoms and medication use on a daily basis in an electronic diary; weekly assessments of rhinoconjunctivitis quality of life were also made. Findings: Analysis of the average daily symptom score during the BPS and the TPS showed that the difference between active treatment and placebo was statistically significant for the 7 DU group (BPS, P = 0.02; TPS, P = 0.03), with no clear dose response relationship. All doses of the SQ tree SLIT-tablet induced changes from baseline in birch-specific IgE and IgG(4) that were statistically significant compared with placebo at all time points assessed (P <0.0001) with a clear dose-response relationship for birch specific IgG(4). In general, the SQ tree SLIT-tablet was well tolerated, with the majority of treatment-related adverse events (>= 95%) being mild or moderate in severity. The most frequently reported treatment related adverse events were generally related to the sublingual administration of the tablet (ie, they occurred in the oral cavity). (C) 2018 Elsevier HS Journals, Inc. All rights reserved.
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(2016)Sensitive screening methods have revealed that many patients have donor-specific human leucocyte antigen antibodies (DSAs) prior to transplantation, regardless of negative crossmatch results. The clinical significance of pre-transplant (pre-Tx) DSAs for early graft function has remained unclear. Our aim was to examine the association of DSAs with delayed graft function (DGF). Pre-Tx sera of 771 patients who received kidney transplants in our single-centre study were retrospectively screened. All transplantations were performed after negative complement-dependent cytotoxicity (CDC) crossmatch. DSAs were detected in 13% of the patients. The overall DGF rate in our study was 29%. Patients with DSAs had a higher incidence of DGF when compared with non-sensitized patients (48 and 26%, respectively; P <0.0001). Third-party antibodies had no effect for DGF incidence (28%; P = 0.6098). The relative risk (RR) of DGF for patients with DSAs in the multivariate analysis was 2.039 (95% CI 1.246-3.335; P = 0.0046). Analyses of the cumulative mean fluorescent intensity (MFI) value of the DSAs revealed a rate of DGF more than two times higher in patients with a cumulative value of 3000-5000 MFI compared with a cumulative value of 1000-3000 (65 versus 31%; P = 0.0351). DSAs against any loci showed an elevated DGF incidence of 44-69% when compared with patients without DSA (27%). The risk of DGF is twice as high in patients having pre-formed DSAs. Pre-Tx DSAs is a modifiable risk factor that can be obviated with careful organ allocation relying on careful pre-Tx analysis of non-accepted mismatches determined with sensitive solid phase methods.
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(Helsingin yliopisto, 2020)Puumala hantavirus (PUUV) is the zoonotic pathogen of nephropathia epidemica (NE) known as myyräkuume in Finnish. PUUV hasn’t been reported to spread from human-to-human but the risk for human infection is directly correlating with the prevalence of PUUV in its natural host bank vole. Until now research has mainly focused on a one-host-one-pathogen framework, even though in natural systems individuals are usually coinfected with multiple species of parasites. An antagonist relationship between the immune pathways T-helper-1 (Th-1) and T-helper-2 (Th-2) is well studied in laboratory experiments. Th-1 directs immune responses against intracellular organisms such as viruses and Th-2 extracellular organisms such as helminths. These two pathways can’t fully function at the same time, leading usually to Th-1 or Th-2 biased immune response depending on the pathogen. A large field survey was conducted to analyze how concurrent helminth infections influence the prevalence and viral loads of PUUV in individual bank voles, and thereby influence human exposure to this virus. My hypothesis was that helminths induce a Th-2 biased immune response, leading to higher PUUV prevalence and viral loads in helminth infected voles than in uninfected voles. In contrary to my original hypothesis, intestinal helminths seemed to have a protective effect on voles acquiring PUUV infection and the disease burden. These findings were consistently shown through serology and PCR results from kidney and lungs. An explanation to this finding could be that helminths cause tissue damage in the intestinal wall, thus predisposing voles to secondary intracellular infections and enhanced Th-1 immune response. This enhanced Th-1 immune response could then protect the vole from new intracellular infections such as PUUV-infection. Coinfections are occurring everywhere in the wildlife systems and shouldn’t be neglected in the future disease management, especially when talking about zoonoses that pose a risk to humans. There can be surprising outcomes when multiple parasites share the same host, such as was found in this study, and these can lead to unintentional consequences of disease control procedures. More research and larger sample pools are needed to reinforce these results and deepen our knowledge in the immunology of coinfections. Puumala hantavirus (PUUV) on zoonoottinen virus, joka leviää metsämyyrien ulosteen saastuttaman pölyn välityksellä ja aiheuttaa ihmisessä myyräkuumetta. Koska se ei leviä ihmisestä ihmiseen, on tärkeää ymmärtää sen leviämisen dynamiikkaa myyräpopulaatioissa, jotta voidaan kontrolloida myös ihmisten altistumista virukselle. Luonnossa metsämyyrät altistuvat valtavalle määrälle erilaisia taudinaiheuttajia, ja yhteistartunnat useamman eri taudinaiheuttajan kanssa samanaikaisesti ovat hyvin yleisiä. Eri taudinaiheuttajien yhteistartunnat ovat jääneet etenkin villieläimissä vähälle huomiolle, vaikka ne voivat vaikuttaa ratkaisevasti ymmärrykseemme zoonoottisten tartuntojen leviämisestä. Laboratoriokokeissa paljon tutkittu antagonistinen suhde auttaja-T-solujen (Th-solu) indusoimien Th-1 ja Th-2 -soluvasteiden välillä vaikuttaa yhteistartuntojen immunologian taustalla. Th-1 -soluvaste ohjaa immuunireaktioita intrasellulaarisia taudinaiheuttajia, kuten viruksia vastaan, kun taas Th-2-soluvaste ekstrasellulaarisia taudinaiheuttajia, kuten suolistoloisia vastaan. Nämä kaksi soluvastetta tasapainottelevat keskenään niin, että toisen soluvasteen voimistuessa toinen heikkenee. Analysoin noin 130 metsämyyrän suolistoloisten sekä PUUV:n välisiä yhteistartuntoja selvittääkseni, miten samanaikaiset suolistoloistartunnat vaikuttavat PUUV:n esiintyvyyteen ja tartunnan voimakkuuteen yksittäisissä metsämyyrissä. Hypoteesini oli, että suolistoloistartunta voimistaa Th-2-soluvastetta heikentäen samalla Th-1-soluvastetta, ja täten lisää myyrän herkkyyttä PUUV-tartunnalle sekä lisää tartunnan voimakkuutta. Hypoteesin vastaisesti suolistoloistartunnalla tuntui olevan suojaava vaikutus myyrien PUUV-tartuntoja vastaan. Tämä ilmeni johdonmukaisesti sekä serologian että elinnäytteiden PCR-tulosten kautta. Mahdollinen selitys löydökselle on suolistoloisten aiheuttama kudosvaurio suoliston seinämässä, joka altistaa myyrän toissijaisille bakteeri- ja virustartunnoille voimistaen näin Th-1-soluvastetta. Tämä voimistunut Th-1-soluvaste voisi sitten suojella metsämyyrää uusilta PUUV-tartunnoilta. Yhteistartuntoja esiintyy kaikkialla luonnossa, eikä niiden vaikutuksia pidä laiminlyödä luonnonvaraisten eläinten tarttuvia tauteja tutkittaessa. Yhteistartuntojen seuraukset voivat olla hyvinkin yllättäviä ja johtaa tahattomiin lopputulemiin esimerkiksi zoonoosien hallinnan yhteydessä. Lisää tutkimusta ja suurempia näytöskokoja tarvitaan tulosten vahvistamiseksi ja yhteistartuntojen immunologian ymmärtämisen syventämiseksi.
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(Helsingin yliopisto, 2015)To live a healthy life, humans need to co-exist with foreign organisms. These consist of the thousands of different types of microbes that colonize the human body. But also, in the case of a pregnant woman, the fetus can be viewed as a foreign organism. To avoid disease, the barriers of the human body, e.g. the mucosal surfaces, must be maintained. Here the innate immune defense system plays an important role. The salivary scavenger and agglutinin (SALSA), also known as gp340, DMBT1 and SAG, is a molecule found at most mucosal surfaces. SALSA is associated with the epithelium or secreted into the lining fluids, such as tears, saliva and mucus in the respiratory tract. SALSA is known to bind and agglutinate a broad spectrum of bacteria, as well as viruses, and thus play a role in the innate immune defense against invading microbes. The effect of SALSA is mediated in concert with several other defense molecules such as IgA, surfactant proteins A and D, and the complement component C1q. These have all been shown to be ligands of SALSA. Alongside the role of SALSA in innate immunity, evidence for a function in epithelial and stem cell differentiation has emerged. This thesis work has addressed the function of SALSA in innate immunity, especially in early life. SALSA was found in the amniotic fluid and in meconium and feces of newborns. In fact, SALSA was among the most abundant proteins in the intestines of newborn children. By comparing the SALSA protein in the different samples we found size polymorphisms, varying from one individual to another, but also from compartment to compartment within the same individual. These differences were found to alter the ability of SALSA to bind known endogenous and bacterial ligands. SALSA was also found to be expressed in the human placental and decidual tissues. In the 1st trimester of pregnancy, SALSA was detected sporadically in maternal decidual capillaries. Closer to term SALSA was found to be expressed by the syncytiotrophoblast layer of the placental villous trees. In certain sites, e.g. at disrupted and damaged areas of the syncytium, SALSA was found deposited into fibrinoid formations. It partially co-localized with the fibrinoid component fibronectin. Complement activation has been observed at the feto-maternal interface of both healthy and complicated pregnancies. SALSA had previously been found to bind C1q. Thus, it was of interest to investigate the ability of SALSA to interact directly with the complement system. We found that SALSA bound to both mannan-binding lectin and to some extent to all three ficolins (H, L and M). SALSA activated complement, when it was bound to a surface. In contrast, fluid-phase SALSA was able to inhibit the deposition of complement on SALSA non-binding microbial surfaces. It thus acted in dual fashion to target complement attack. In the human placenta we observed C1q-targeting of the SALSA-positive fibrinoid formations. C1q and complement are known to function in the clearance of apoptotic cells and debris. Thereby SALSA and complement probably have a cooperative function in the containment and clearance of the injured structures, thus linking its innate immune activity with the maintenance of tissue homeostasis.
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(Helsingin yliopisto, 2020)Krooninen myelooinen leukemia (KML) on pahanlaatuinen veritauti, jonka ennuste on parantunut merkittävästi tyrosiinikinaasiestäjien (TKE) käyttöönoton jälkeen. Viimeaikaiset hoitokokeilut ovat osoittaneet, että 30–40 % KML-potilaista pystyy lopettamaan TKE-hoidon ilman taudin uudelleen ilmenemistä, mutta tutkimukset eivät ole pystyneet tuottamaan kliiniseen käyttöön tarvittavia parametreja hoitovasteen ennustamiseksi. Elimistön puolustusjärjestelmän aktivoituminen on osoittautunut tärkeäksi tavaksi kasvainsolukon tuhoamiseksi monissa syövissä, joten erot immuunijärjestelmän aktiivisuudessa voisi selittää eroja potilasryhmien välillä myös KML:ssa. Tutkimme tätä hypoteesia hyödyntämällä yksisolutekniikoita ja koneoppimista, joiden avulla voimme tarkastella erikseen syöpää tunnistavia ja syöpää tunnistamattomia immuunisoluja. Kokoamamme tutkimusaineisto käsittää lähes 150 KML-potilaan veri- tai luuydinnäytettä, joista on sekvensoitu yksittäisen immuunisolun tarkkuudella geenien aktiivisuusprofiili (n=25, scRNA+TCRab-seq) tai T-solureseptoriprofiili (n=137, TCRb-seq). Näytteemme käsittävät diagnoosivaiheen lisäksi myös näytteitä ennen TKE-hoidon lopettamista ja sen jälkeen potilailla, joilla tauti ei ole uusinut ja joilla on uusinut. Tutkimuksemme tulokset tarkentavat toimivan immuunijärjestelmän merkitystä TKE-hoidon onnistuneessa lopettamisessa. Vertailumme muihin kiinteisiin ja hematologisiin syöpiin osoittavat etenkin luonnollisten tappajasolujen (NK-solujen) tärkeän roolin KML:ssa ja selvittävät miten NK-solut vuorovaikuttavat KML-syöpäsolukon kanssa. Kouluttamamme koneoppimismalli erottelee tarkasti KML:aa tunnistavat T-solut muita kohteita tunnistavista, ja sen avulla pystymme osoittamaan miten syöpää tunnistavat T-solut liittyvät onnistuneen hoidon lopetukseen. Tutkimuksemme tarjoaa uuden tekoälypohjaisen työkalun lisäksi potentiaalisia mekanismeja, joiden avulla puolustusjärjestelmän soluja voitaisiin aktivoida esimerkiksi uusilla immuunivasteenaktivaationvapauttajilla, jotta yhä useampi potilas voitaisiin lopullisesti parantaa KML:sta.
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(Helsingin yliopisto, 2019)Co-infection, a state in which the host is infected with more than one micro- or macroparasite at a time, is the norm in the wild because of a wide range of interacting organisms and parasites. Bank vole is a reservoir host of Puumala hantavirus (PUUV), a pathogen causing Nephropathia Endemica, an endemic disease in Finland. The helper T cell (Th)1/Th2 polarization theory, which is established in the laboratory, but less-studied in the wild, suggests that there is a trade-off between Th1 response against microparasites and Th2 response against macroparasites. I studied whether helminth or hantavirus infection, individually and synergistically, have effect on the immune responses of wild bank voles and whether there is a trade-off between Th1 and Th2 responses. My hypothesis was that helminth infection would reduce the bank voles’ ability to mount an effective immune response against viral infections and make them more susceptible to chronic Puumala virus infection. I measured mRNA levels of transcription factors Tbet (Th1 response) and Gata3 (Th2 response) in the splenocytes of wild-caught bank voles after stimulating the cells with different immune stimulants. I also measured the constitutive levels of Tbet and Gata3 in bank voles’ spleens. The splenocytes of PUUV-infected bank voles were less responsive to stimulations than those of PUUV-negative ones. The reduced ability of splenocytes from PUUV-infected voles to respond to stimulation can be because of the virus itself affecting the T cell function or alternatively due to an inherent defect in immune cells making them more susceptible to PUUV infection. The constitutive expression of Gata3 in spleen correlated positively with gastrointestinal nematode load in PUUV-infected voles but not in PUUV-negative voles. This can be because of mounting an immune response against helminths reduces the bank voles’ ability to resist the viral infection in accordance with the trade-off between Th1 and Th2 responses or as previous studies have shown, Gata3 can act as a marker of infection tolerance in bank voles. Because of a small sample size and a heterologous group of studied bank voles, more research is needed on co-infection immunology in bank voles and other wild animals.
