| 1. |
- Abelius, Martina, 1980-
(författare)
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Immunological interactions between mother and child during pregnancy in relation to the development of allergic diseases in the offspring
- 2014
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Background: Pregnancy and allergic disease have both been postulated as T-helper 2 (Th2) phenomena. Thus, the increased propensity of allergic mothers to mount Th2-responses might generate favourable effects on the maintenance of pregnancy, but might also be unfavorable, as fetal exposure to a strong Th2 environment could influence the immune development in the offspring to a Th2-like phenotype, favouring IgE production and possibly allergy development later in life. The influence of the intrauterine environment on the immunity and allergy development in the offspring needs to be further investigated.Aim: The aim of this thesis was to explore the Th1/Th2 balance in allergic and non-allergic women during pregnancy and its influence on the shaping of the Th1/Th2 profile in the neonate and the development of allergic diseases in the offspring.Material and methods: The study group included 20 women with and 36 women without allergic symptoms followed during pregnancy (gestational week 10-12, 15-16, 25, 35, 39) and 2 and 12 months postpartum, and their children followed from birth to 6 years of age. The circulating Th1-like chemokines CXCL9, CXCL10, CXCL11, Th2-like chemokines CCL17, CCL18 and CCL22, and the allergen-induced secretion of interleukin-4 (IL-4), IL-5, IL-10, IL-13, Interferon-γ (IFN-γ), CXCL10 and CCL17 were measured by Luminex and ELISA. The allergen-specific and total IgE levels were quantified using ImmunoCAP Technology. mRNA expression of Th1-, Th2-, Treg- and Th17-associated genes were measured by PCR arrays and real-time PCR.Results: We found that sensitised women with allergic symptoms had increased total IgE levels and birch- and cat-induced IL-5, IL-13 and CCL17 responses during pregnancy as compared with postpartum. The non-sensitised women without allergic symptoms had elevated cat-induced IL-5 and IL-13 responses and lower birch- and cat-induced IFN-γ during pregnancy, but similar IgE levels as compared with postpartum.Maternal total IgE levels during and after pregnancy correlated with cord blood (CB) IgE and CCL22 levels (regardless of maternal allergy status). Circulating CXCL11, CCL18 and CCL22 levels during pregnancy and postpartum correlated with the corresponding chemokine levels in the offspring at various time points during childhood. Maternal IL-5 expression in peripheral blood mononuclear cells (PBMC) was associated with neonatal Galectin-1, and placental p35 expression was negatively associated with neonatal Tbx21 expression. Increased mRNA expression of CCL22 in cord blood mononuclear cells (CBMC), and increased CCL17 and CCL22 levels in CB were observed in children later developing allergic symptoms and sensitisation as compared with children who did not. Development of allergic symptoms and sensitisation were associated with increased total IgE, CCL17, CCL18 and CCL22 levels during childhood.Conclusions: Maternal allergy was associated with a pronounced Th2 deviation during pregnancy, shown as increased total IgE levels and birch- and cat-induced IL-5, IL-13 and CCL17 responses during pregnancy, possibly exposing their fetuses to a particular strong Th2 environment during gestation.Correlations were shown between the maternal immunity during pregnancy and the offspring’s immunity at birth and later during childhood, indicating an interplay between the maternal and fetal immunity.Allergy development during the first 6 years of life was associated with a marked Th2 deviation at birth and a delayed down-regulation of this Th2-skewed immunity during childhood.
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| 2. |
- Bujila, Ioana, 1983-
(författare)
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Plasmodium falciparum-mediated modulation of innate immune cells: responses and regulation
- 2016
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Plasmodium falciparum (P. falciparum) infection modulates the response of innate immune cells. The aim of this work was to study the impact of P. falciparum infection and P. falciparum-derived molecules on the response of dendritic cells (DC) and monocytes.In paper I we investigated the effects of natural hemozoin (nHZ), a P. falciparum-derived molecule, on the phenotype and functionality of DC. We found that exposure to nHZ impaired the capacity of DC to mature. Paper II is a follow-up on paper I, where the underlying transcriptional events preceding the nHZ-induced impairment of DC maturation were investigated. More specifically, we examined the involvement of certain transcription factors, subunits of chromatin remodeling complexes and histone modifications in the regulation of DC maturation. Our findings suggest that nHZ-exposure of DC does not lead to recruitment or enrichment of molecules needed for transcriptional activation. In paper III we investigated P. falciparum effects in vivo in sympatric ethnic groups with differential susceptibility towards P. falciparum infection living in Burkina Faso. The aim of this study was to establish the transcriptional networks underlying the relatively better protection against P. falciparum infection observed in the Fulani ethnic group compared to other sympatric ethnic groups. Our findings reveal differential gene expression in monocytes of infected Fulani compared to uninfected Fulani and the difference concerned multiple classes of genes including signal transduction, immunological responses and chromatin remodelers. The results provide new aspects on molecules and regulatory mechanisms that are involved in the relatively more protective response against P. falciparum infection.Taken together, the work presented in this thesis leads to a deeper understanding of the P. falciparum-induced modulation of responses of innate immune cells and the underlying mechanisms possibly regulating those responses.
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| 3. |
- Iriemenam, Nnaemeka C., 1973-
(författare)
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Antibody responses and Fc gamma receptor IIa polymorphism in relation to Plasmodium falciparum malaria
- 2009
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Immunity to asexual blood-stage of Plasmodium falciparum malaria is believed to be associated with protective antibodies of certain immunoglobulin classes and subclasses. This thesis addressed the importance of antibodies in relation to malaria infection and their effective interactions with Fc gamma receptor IIa (FcyRIIa) polymorphisms. Our data indicate that the frequency of FcyRIIa-R/R131 genotype was statistically significantly higher in Sudanese patients with severe malaria, while the FcyRIIa-H/H131 genotype showed a significant association with mild malaria. The levels of IgG1 and IgG3 subclass antibodies were statistically higher in the mild malaria patients. The Fulani ethnic group in West Africa has been shown to be relatively resistant to malaria. We investigated the possible impact of FcyRIIa polymorphisms in the Fulani and non-Fulani in Mali and Sudan, and analysed their malaria-reactive IgG subclass profiles. The FcyRIIa-H/H131 genotype and H131-allele were found to be prevalent in the Fulani while R131-allele was prevalent in non-Fulani. The Fulani had higher serum levels of IgG1-3, with higher proportion of IgG2 than the non-Fulani. Most clinico-epidemiology studies have been in areas with holo- and hyper-malaria endemicity. We have analysed antibody responses to a panel of six blood-stage antigens in relation to clinical malaria outcome in mesoendemic Sudan. Our results revealed a linear association with anti-AMA-1 IgG1 antibodies and reduced risk of severe malaria while a non-linear relationship with IgG3 antibodies was observed for MSP-2, MSP-3 and GLURP. In the combined final model, the highest levels of IgG1 subclass antibodies to AMA-1, GLURP-R0, and the highest levels of IgG3 subclass antibodies reactive to 3D7 MSP-2 were independently associated with a reduced risk of clinical malaria. Taken together, these data suggest a possible association between FcyRIIa-R/H131 and anti-malarial antibody responses in the clinical outcome of malaria.
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| 4. |
- Nasr, Amre, 1975-
(författare)
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Single nucleotide polymorphisms related to immune responses in Plasmodium falciparum malaria
- 2008
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The current research is directed towards dissection of host genetic factors involved in host immune response and the malaria disease outcome. A possible association between FcγRIIa polymorphism and anti-malarial antibody (A.M.A) responses were investigated in Sudanese patients in relation to clinical outcome of falciparum malaria. The frequency of the R/R131 genotype was significantly higher in patients with severe malaria as compared with mild malaria. A.M.A IgG3 was shown to be associated with reduced risk of clinical malaria in individuals carrying the H/H131 genotype. Low levels of IgG2 reactive with the Pf332-C231 antigen were associated with lower risk of severe malaria in individuals carrying the H131 allele. Fulani and Masaleit, two sympatric ethnic groups in Sudan, are characterized by marked differences in susceptibility to falciparum malaria. We investigated whether the two populations differ in the frequency of GM/KM allotypes. The distribution of GM/KM phenotypes differed significantly among the two groups, with Gm 6 being significantly lower among the Fulani, and the combined frequency of Km 1,3 and Gm 1,17 5,6,13,14 phenotypes was found to be higher among Masaleit. In interethnic study we investigated whether the two groups differ in the frequency of FcγRIIa and HbAS genotypes. The frequency of the H/H131, R/R13 and HbAS genotypes differed significantly among the two groups. Moreover, the Fulani showed higher levels of A.M.A IgG2 and lower IgG1 and IgG3 when compared to their sympatric non-Fulani neighbours.A tri-allelic SNP (C/T/A) in the CRP gene was investigated for possible ethnic associations. The A allele, which is associated with higher basal CRP levels, was found to be less frequent in the Fulani compared with non-Fulani ethnic groups both in Sudan and Mali. In conclusion, our results suggest possible associations between FcγRIIa, CRP genotypes, GM/KM allotypes, and anti-malarial antibody responses and the clinical outcome of falciparum malaria.
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| 5. |
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| 6. |
- Boström, Stéphanie, 1985-
(författare)
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Malaria during pregnancy and childhood : A focus on soluble mediators and neutrophils
- 2014
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- In areas where malaria is endemic, pregnant women and children bear the main burden of severe and life-threatening malarial disease. The aim of this work was to study the impact of Plasmodium falciparum infection on inflammatory responses in pregnant women and children residing in African countries. In paper I we investigated peripheral blood samples from pregnant women, living in Tanzania, for potential biomarkers of P. falciparum infection during pregnancy. We found that IL-10 and IP-10 were potential candidates, which increased upon infection, irrespective of gestational age. In addition, increased IL-10 and IP-10 and decreased RANTES levels were predictive of an infection. In paper II we investigated frequencies of peripheral blood-cell types and biomarkers upon infection, in pregnant women living in Benin, and assessed the predictive values of variables measured at inclusion for pregnancy outcomes at delivery. Higher IL-10 levels distinguished quantitative PCR-detectable, sub-microscopic infections, at inclusion, but not at delivery. Maternal anaemia at delivery was associated with increased numbers of circulating monocytes, Treg cells and IL-10 levels measured at inclusion. In paper III we investigated neutrophil functions in the context of pregnancy malaria in vivo and in vitro. Numbers of circulating neutrophils and IL-8 levels were reduced in the infected women, whilst increased levels of IL-8 were found in placental blood of those infected. In vitro assays suggested migration of neutrophils to infected placentas, which also was supported by histological examinations showing the presence of neutrophils containing hemozoin (Hz), in the infected placenta. Stimulation of neutrophils with various Hz preparations revealed distinct patterns of neutrophil activation. In paper IV we investigated cytokines and malaria-specific antibody titres in children belonging to two African ethnic groups, living in Mali, with known different susceptibility to malaria. The Fulani showed increased cytokines (IL-6, IL-8, IL-12, IFN-α, IFN-γ) and higher titres of malaria-specific antibody subclasses (IgG, IgM and IgG1-IgG3), compared to the Dogon. Taken together, this thesis shows that host biomarkers in peripheral blood may represent useful diagnostic markers for malaria during pregnancy. The neutrophil population was shown to be highly affected by the presence of P. falciparum parasites, suggesting a role for neutrophils during malaria infections. The Fulani, showed increased pro-inflammatory and antibody responses against P. falciparum parasites, as compared to Dogon, and these differences are established already at an early age.
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| 7. |
- Calla-Magariños, Jacqueline, 1963-
(författare)
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Bioactive leishmanicidal alkaloid molecules from Galipea longiflora Krause with immunomodulatory activity
- 2012
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- According to WHO, leishmaniasis is endemic in 98 countries, and has been placed ninth in a global analysis of infectious diseases. Treatment of leishmaniasis is based on pentavalent antimonials but toxicity and developing resistance have been reported. Traditional medicine and scientific studies have shown that the extract of Galipea longiflora Krause (Evanta) exhibits antileishmanial activity. We hypothesized that the healing observed when using this plant might not only be due to the direct action on the parasite, but possibly to a parallel effect on the host immune response. We found that an alkaloid extract of Evanta (AEE) inhibited the growth of Leishmania braziliensis promastigotes while viability of eukaryotic cells was practically not affected. We also found that AEE interfered with polyclonal activation or Leishmania-specific re-stimulation of lymphocytes, as revealed by a reduction of in vitro cellular proliferation and IFN-g production. More important, AEE treatment of mice hosting L. braziliensis showed that AEE is able to control both inflammation and parasite load. Additionally, the healing process was improved when AEE and meglumine antimoniate were administered simultaneously. Dendritic cells (DCs) play a pivotal role in T-cell stimulation and polarization of naïve T cells. Therefore, we investigated if AEE could alter the activation of DCs and if allostimulatory DCs properties were altered if activated in the presence of AEE. DCs activated in the presence of AEE reduced the production of IL-12p40 and IL-23. When we analyzed the allostimulatory capacity of AEE-treated DCs, we found that allogeneic CD4+ T-cells secreted lower levels of IFN-γ.In conclusion, this thesis provides valuable insight into the effects of Evanta derived extract. The dual effect found for AEE, on Leishmania parasite and on the immune response, suggests that AEE may be useful in controlling the parasite burden and preventing over-production of inflammatory mediators and subsequently avoiding tissue damage.
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| 8. |
- Lundberg, Anna, 1977-
(författare)
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Immune responses to lipopolysaccharide in relation to allergic disease : a TLR4 gene polymorphism and endotoxin exposure
- 2009
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Background: Allergic diseases have increased during the last decades, particularly in affluent countries, possibly due to a reduced and/or altered microbial exposure during infancy. Activation of the immune system by microbes early in life is probably required for accurate maturation of the immune system and tolerance development. It is not fully understood how microbial exposure is associated with the development of allergic diseases, however. Genetic factors may influence microbial induced immune responses. A certain polymorphism, in the gene coding for the Toll-like receptor 4, i.e. (TLR4 Asp299Gly), has been suggested to alter the immunological responsiveness to bacterial lipopolysaccharide (LPS).Aim: The aim of this thesis was to study the interplay between LPS induced immune responses, LPS signalling related genetic polymorphisms, allergic disease and endotoxin exposure.Subjects: The thesis is based on the results obtained from individuals in three different study groups, i.e. Estonian and Swedish children followed prospectively from birth up to five years of age, Swedish school-children eight and 14 years of age and young adults.Methods: The study subjects were clinically evaluated regarding allergic diseases with skin prick tests, circulating IgE levels, validated questionnaires and clinical examinations by paediatricians or research nurses. The gene polymorphisms TLR4 Asp299Gly and CD14/-159 were analysed. Peripheral blood mononuclear cells were isolated from blood and cultured with LPS from two Gram negative bacterial strains, i.e. Salmonella enterica serotype Typhimurium (Serotype Typhimurium) and Escherichia coli (E. coli). Cytokine and chemokine secretions were analysed with Luminex or ELISA technique. Receptor expression of circulating peripheral blood monocytes was analysed with flow cytometry. The phosphorylation of intracellular proteins involved in LPS signalling pathways was analysed with Luminex technique. mRNA expression of proteins involved in LPS signalling pathways and of markers for T regulatory cells were analysed with realtime-PCR.Results: In school-children and young adults, the TLR4 Asp299Gly gene polymorphism was associated with reduced LPS induced IκBα phosphorylation, IL-10 and IL-12 cytokine secretion. Interestingly, these findings were observed only when the cells were cultured with LPS from Serotype Typhimurium but not with LPS from E. coli. The polymorphism was positively associated with asthma, especially atopic asthma.Several differences in immunological responses to LPS were observed between allergic and non-allergic individuals. Asthma in school-children was associated with reduced LPS induced cytokine production of IL-10 and IL-12. The phosphorylation of IκBα was lower in adult allergic compared to non-allergic individuals. Swedish children who had developed allergic disease at five years of age had lower TLR2 mRNA expression at birth compared to children who remained healthy.Estonian children displayed generally lower LPS induced cytokine and chemokine production as compared to Swedish children both at birth and at 3 and 6 months of age. The mRNA expression of the T regulatory associated markers Foxp3 and Ebi3 were higher in the Estonian compared to the Swedish children at birth.Conclusion: Polymorphisms in genes coding for pattern recognition receptors can alter the immune responsiveness of the host to microbial components and may be of importance for the development of asthma. Lower LPS induced cytokine response and higher expression of T regulatory associated markers were seen in children from Estonia as compared to Sweden, suggesting an increased capacity for early immune regulation among infants from a country with a low prevalence of allergic disease.
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| 9. |
- Minang, Jacob, 1975-
(författare)
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Cytokine responses in metal-induced allergic contact dermatitis : Relationship to in vivo responses and implication for in vitro diagnosis
- 2005
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Transition metals such as nickel (Ni), cobalt (Co), palladium (Pd), chromium (Cr) and gold (Au) are widely used as alloys in jewelry and biomaterials such as orthodontic and orthopaedic appliances. These metals also cause cell-mediated allergic contact dermatitis (ACD) reactions in a significant proportion of the population upon prolonged direct exposure. The immune mechanisms underlying the response to these metals are not yet well defined. In the studies described in this thesis we therefore investigated the profile of cytokine responses to various metal ions in vitro and the relationship with the ACD reaction in vivo. In the first study, we investigated the relationship between the profile and magnitude of Ni2+-induced cytokine responses in vitro and the degree of in vivo reactivity to Ni2+. PBMC from Ni2+-reactive (ACD) and non-reactive control subjects were cultured with or without NiCl2. The numbers of IL-4-, IL-5- and IL-13-producing cells and the concentrations of IFN-γ, IL-10 and IL-13 produced were analysed by ELISpot and ELISA respectively. Ni2+ elicited a mixed Th1- and Th2-type cytokine profile in PBMC from ACD subjects with a positive correlation observed between the levels of the elicited cytokines and the degree of patch test reactivity. Hence, suggesting an involvement of both Th1- and Th2-type cytokines in ACD to Ni2+ and a direct association between the magnitude of the Ni2+-induced cytokine response overall and the in vivo reactivity to Ni2+. The impact of the regulatory cytokine IL-10 on Ni2+-induced Th1- and Th2-type cytokine responses in human PBMC was investigated in the next study. PBMC from blood donors with a history of Ni2+ reactivity and non-reactive control donors were stimulated with Ni2+ ex vivo with or without addition of human recombinant IL-10 (rIL-10) or neutralising mAb to IL-10. Depletion/enrichment experiments were performed to phenotype the Ni2+-specific cytokine producing cells. Exogenous rIL-10 significantly down-regulated the production of all cytokines but with a more pronounced effect on IFN-γ. IL-10 neutralisation, on the other hand, enhanced the levels of Ni2+-induced IFN-γ only. Ni2+-specific cytokine-producing cells in PBMC were found to be predominantly CD4+ T cells. Thus, IL-10 may play a regulatory role in vivo by counteracting the ACD reactions mediated by CD4+ T cells producing Th1-type cytokines. In the third study, we investigated the relationship between in vivo patch test reactivity to a number of metals (Ni, Co, Pd, Cr and Au) included in the standard and/or dental patch test series and in vitro responses to the metals in question. PBMC from metal patch test positive and negative control subjects were stimulated with a panel of eight metal salts and cytokine responses analysed by ELISpot and/or ELISA. A mixed Th1- (IL-2 and/or IFN-γ) and Th2-type (IL-4 and/or IL-13) cytokine profile was observed in PBMC from most metal allergic subjects upon in vitro stimulation with the metal(s) to which the subject was patch test positive. Our data suggest that other metals included in the standard and dental patch test series, just like Ni2+, induce a mixed Th1- and Th2-type cytokine profile in PBMC from ACD subjects in vitro. We further developed a simplified ELISpot protocol utilising plates precoated with capture monoclonal antibodies (mAb) and subsequent detection in one step using enzyme-labelled mAb, for enumerating the frequency of allergen (Ni2+)-specific cytokine producing cells. This was compared with a regular ELISpot protocol, with an overnight incubation for capture mAb adsorbtion and detection with biotinylated mAb followed by enzyme-labelled streptavidin. PBMC from Ni2+-reactive and non-reactive subjects were incubated with or without NiCl2 and the enumeration of cells producing IFN-γ, IL-4 or IL-13 by the two protocols were compared. PBMC from Ni2+-reactive subjects showed significantly higher Ni2+-induced IL-4 and IL-13 responses and the number of antigen-specific cytokine-producing cells determined by the two ELISpot protocols correlated well. In a nutshell, our data point to the potential use of in vitro cytokine assays as diagnostic tools in distinguishing ACD subjects sensitised to different metals and non-sensitised subjects.
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| 10. |
- Sundström, Yvonne, 1973-
(författare)
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Phenotypic and functional studies of NK cells in neonates and during early childhood
- 2008
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- During infancy, before adaptive immunity has matured, innate immunity is thought to be relatively more important. Human natural killer (NK) cells are innate immune cells involved in the control of virus-infected cells and can influence adaptive immunity mainly through cytokine production. This thesis aimed at investigating function and phenotype of NK cells in children from birth and during early childhood and to see if these features are altered in children that develop early allergy, in children latently infected by herpes viruses or born by preeclamptic mothers.Our results suggest that NK-cell populations are dynamic during the first years of life and start to resemble the phenotype of adults after five years of age. Early alterations in the NK-cell populations could lead to insufficient Th1 priming, with an increased risk to develop allergic disease. Early infection by common herpes viruses can influence NK-cell function and might be one important factor involved in early maturation processes of adaptive immunity. The altered NK-cell function and cytokine levels, noticed in CB from pathological pregnancies, suggest that NK cells could be influenced already in utero. These early alterations of innate immunity may affect the development of the child’s immune system, sometimes with beneficial outcome but could in some cases promote pathology.
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