Thesis (Ph.D)--Virginia Commonwealth University, 2009. / Prepared for: Dept. of Microbiology & Immunology. Title from title-page of electronic thesis. Bibliography: leaves 191-222.

Thesis (Ph.D.)--Indiana University, 2009. / Title from screen (viewed on August 26, 2009). Department of Microbiology and Immunology, Indiana University-Purdue University Indianapolis (IUPUI). Advisor(s): Mark Kaplan. Includes vita. Includes bibliographical references (leaves 107-125).

Submitted by Fabio Sobreira Campos da Costa (fabio.sobreira@ufpe.br) on 2016-04-12T15:33:27Z No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) Dissertacao_Final_Digital.pdf: 1044188 bytes, checksum: 49fcb98340d75c059b4fc044e603cce8 (MD5) / Made available in DSpace on 2016-04-12T15:33:27Z (GMT). No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) Dissertacao_Final_Digital.pdf: 1044188 bytes, checksum: 49fcb98340d75c059b4fc044e603cce8 (MD5) Previous issue date: 2015-02-27 / CAPEs / A prevalência de doenças alérgicas, como rinite e asma, é menor em países subdesenvolvidos, onde há uma maior exposição a agentes infecciosos, como os helmintos. A relação entre infecções com T. trichiura e a prevalência das doenças alérgicas e reatividade cutânea ainda não está estabelecida. Os estudos divergem quanto à alteração (potencializar ou reduzir) do quadro clínico e/ou testes cutâneos, bem como, a carga parasitária da população estudada. O estudo teve como objetivo verificar se existe diferença entre a ocorrência de asma alérgica, prick test, níveis séricos das citocinas IL-4, IL-6, IL-10, TNF-α e anticorpos IgE anti-ascaris em crianças com infecção ativa por T. trichiura. Para isto, crianças com ou sem asma foram definidas pelo questionário ISAAC, foram realizados o prick-test, parasitológico (Hoffman/Kato Katz) e coleta de sangue, que foi submetido a cultura (estimulada com PHA) e o sobrenadante coletado para a dosagens das citocinas (CBA). A prevalência de crianças com parasitológico positivo foi de 16,9 % (61/361 crianças), entre essas 27,9 % (17/61) foram positivas para infecção por Trichuris trichiura (12/17) ou co-infectadas por Trichuris trichiura/ Ascaris lumbricoides (5/17). O grupo de pacientes infectados, com ou sem asma, produziram níveis significantemente elevados para todas as citocinas em relação ao grupo controle. Além disso, o grupo dos pacientes infectados sem asma apresentou um tendência maior de produção de IL-6, TNF-alfa e IL-10 que os com asma; os pacientes infectados e asmáticos apresentaram uma menor reatividade no Prick Test quando comprado aos asmáticos não infectados. Então, a infecção por T. trichiura parece modular positivamente os níveis das citocinas TNF-α, IL-10 e IL-6, mas em pacientes asmáticos estes níveis tendem a ser controlados. As reações de hipersensibilidade cutânea imediata parece ser menos frequente em asmáticos quando infectados. Os dados levantam a possibilidade de uma modulação mútua entre asma e tricuríase, favorecendo um estado de maior cronicidade de ambas entidades de doença. / The prevalence of allergic diseases such as rhinitis and asthma is smaller in developing countries, where there is a greater exposure to infectious agents, such as helminths. The relationship between infection with T. trichiura and the prevalence of allergic diseases and skin reactivity is not yet established. Studies differ as to the nature of the change (increase or reduce) in the clinical condition and/or skin tests, as well as the parasite load of the studied population. The study aimed to determine whether there are differences between the occurrence of allergic asthma, prick test, serum levels of IL-4, IL-6, IL-10, TNF-α and anti-Ascaris IgE antibodies in children with active infection by T. trichiura. For this purpose, children with and without asthma were defined by the ISAAC questionnaire, prick-test and parasitological (Hoffman/Kato Katz) were performed and blood samples were collected, which were then subjected to culture (stimulated with PHA) and the collected supernatant for cytokines measurements (CBA). The prevalence of children with positive parasitological was 16.9% (61/361 children), and among these 27.9% (17/61) were positive for Trichuris trichiura infection (12/17) or co-infected with Trichuris trichiura/Ascaris lumbricoides (5/17). The group of infected patients, with or without asthma, produced significantly high levels for all cytokines in the control group. Furthermore, the group of patients infected without asthma showed a greater tendency of IL-6,TNF-α and IL-10 production than those with asthma; infected and asthmatic patients had a lower reactivity in Prick Test when compared to those with asthma who were uninfected. Thus, the infection with T. trichiura positively modulates the levels of TNF-α, IL-10 and IL-6 cytokines, but these levels in asthmatic patients tend to be controlled. The immediate hypersensitivity skin reactions appears to be less common in asthmatics when infected. The data raise the possibility of a mutual modulation between asthma and trichuriasis, favoring a state of chronic course on both disease entities.

Indiana University-Purdue University Indianapolis (IUPUI) / Adaptive and innate immune responses play a critical role in the protection against extracellular or intracellular pathogens. The function of these two types of immune responses is coordinated by CD4+ T-helper (Th) cells. Depending on the cytokine environment, Th progenitor (Thp) cells differentiate into three functionally different effector subsets. T-helper-1 (Th1) cells which mediate cell-mediated immunity, T-helper-2 (Th2) which orchestrates humoral immunity and T-helper-17 (Th17) cells key players in autoimmunity response. Cytokine induced transcription factors that are differentially expressed in Th cells are required for the development and commitment to a specific Th lineage. The population of Th2 cells can be subdivided in subpopulations depending on the level of a cytokine and the subsets of cytokines they produce. Very limited information is available about the regulation of cytokine production in this array of Th2 cells. We have recently identified the ETS family transcription factor PU.1 as regulating heterogeneity in Th2 populations. To define additional factors that might contribute to Th2 heterogeneity, we examined the PU.1 interacting protein IFN-regulatory factor (IRF)-4, a transcription factor expressed in lymphocytes and macrophages. When Th2 cells are separated based on levels of IL-10 secretion, IRF4 expression segregates into the subset of Th2 cells expressing high levels of IL-10. To investigate the role of IRF4 in cytokine heterogeneity, Th2 cells were infected with retrovirus expressing IRF4. The cells overexpressing IRF4 secreted significantly higher levels of IL-10 and IL-4 compared to cells infected with a control vector at the same time the level of IL-9 decreases. To understand the mechanism by which IRF4 regulates IL-10 expression in various Th2 cell subpopulations we used co-immunoprecipitation assays to determine transcription factors that interact with IRF4. Our data shows that PU.1, IRF4 and NFATc2 form a complex in Th2 nuclear extract. We also demonstrated by ChIP assay that IRF4 directly binds the Il10 and Il4 loci in a time dependent manner. The role of these protein-protein and protein-DNA complexes and their contribution towards Th2 heterogeneity will be further defined. Understanding the regulation of the anti-inflammatory cytokine IL-10 in Th2 cells may give us a tool to control inflammation.

Indiana University-Purdue University Indianapolis (IUPUI) / T helper cells play a crucial role in providing protection against a wide variety of pathogens. The differentiation and effector function of T helper cell subsets is dependent on cytokine activation of Signal Transducer and Activator of Transcription (STAT) family members. The development of Th17 cells, which are important for immunity to fungi and extracellular bacteria, relies on STAT3. We show that IL-23 in combination with IL-1β promotes maintenance of the Th17 phenotype following multiple rounds of stimulation. However, IL-23 does not promote commitment of Th17 cells, and when Th17 cells are cultured with IL-12 or IL-4 they switch to a Th1 and Th2 phenotype, respectively. The maintenance of the Th17 phenotype by IL-23 also requires STAT4. STAT4-deficient memory cells cultured with IL-23 have reduced IL-17 production following stimulation with either anti-CD3 or IL-18+IL-23 stimulation compared to wild type memory cells. Furthermore, STAT4-deficient mice have impaired in vivo Th17 development following immunization with ovalbumin. This challenges a one-STAT/one-subset paradigm and suggests that multiple STAT proteins can contribute to a single phenotype. To test this further we examined whether STAT3 is required for the development of Th2 cells, a subset known to depend upon the IL-4-induced activation of STAT6 for immunity to parasites and promoting allergic inflammation. We demonstrate that in the absence of STAT3, the expression of Th2-associated cytokines and transcription factors is dramatically reduced. STAT3 is also required for in vivo development of Th2 cells. Moreover, allergic inflammation is diminished in mice that have T cells lacking expression of STAT3. STAT3 does not affect STAT6 activation, but does impact how STAT6 functions in binding target genes. Thus, multiple STAT proteins can cooperate in promoting the development of specific T helper subsets.

Acute allograft rejection remains a major problem in solid organ transplantation, because rejection may lead to acute or chronic loss of graft function. The failure of certain anti-rejection prophylactic treatments suggests that several unexpected pathways might be involved in the rejection process. The aim of our experiments was to investigate the effector mechanisms responsible for skin graft rejection in mice. To adress this question, we took advantage of the possibility to restrict the alloimmune response to isolated allogeneic MHC class II molecules or to isolated minor transplantation antigens, combined with the possibility to study separately the response of CD4+ or CD8+ T cells in mice deficient for Th1 or Th2 cytokines or cytotoxic molecules. We used the bm12 skin graft combination (C57BL/6 H2Kbm12 grafted on C57BL/6 H2Kb) as a model of single MHC class II disparity and the b2microglobulin skin graft model (C57BL/6 b2m+/+ grafted on C57BL/6 b2m-/-) as a model of minor transplantation antigen disparity. Our goal was to engage a limited number of effectors, trying in a second time to block each rejection pathway selectively. We showed that Fas/FasL-mediated CD4+ T cells cytotoxicity, eosinophil recruitment, activation and degranulation induced by Th2 derived cytokines, and CD4-derived IFN-g production are involved in the rejection of grafts bearing either a single MHC class II disparity or b2m-derived minor histocompatibilty antigens. In addition, rejection of MHC class II disparate skin grafts also includes the participation of neutrophils, in particular conditions where the occurrence of the Th2/eosinophil pathway was prevented. Altogether, our data show a multiplicity and a redundancy of the effector pathways participating in allograft rejection. Among the different effectors pathways identified, including effectors from both innate and adaptive immune systems, some act synergistically, whereas others act as alternative pathways, depending of the degree of donor-recipient mismatch.

Thesis (Ph. D.)--University of Chicago, Committee on Immunology, August 2003. / Includes bibliographical references. Also available on the Internet.

No description available.

No description available.

T cell immunoglobulin and mucin (Tim) family molecules are cell membrane proteins with four functional Tim family members in mouse, and three in human. They are preferentially expressed on immune cells with Tim1 on Th2 cells, Tim3 on Th1 cells and Tim4 on antigen-presenting cells (APCs). They have several roles, including regulating immune responses and mediating phagocytosis of dead cells. However, little is known about them beyond these two species, and nothing outside mammals. To investigate the Tim family in the chicken, the genes were identified and cDNAs cloned. Differently to mammals, the chicken genome only contains genes for Tim1 and Tim4. Chicken Tim1 (chTim1) has similar mRNA expression patterns to those of mammalian Tim1 in lymphoid tissues and immune cells. Interestingly, chTim4 has at least four splice variants – an extra short isoform (chTimeS) lacking exons 5, 6, 7 and 8, a short isoform (chTim4S) without exons 3, 4 and 5, a long isoform (chTim4L) with all exons and an extra long isoform (chTim4eL), which is similar to chTim4L but with a longer exon 3. The chTim4S is a homologue of mammalian Tim4 with constitutive expression in lymphoid tissues and immune cells; other chTim4 variants showed inducible or cell-specific expression patterns. Like mammalian Tim4, chTim4S is expressed by APCs; but differently to mammals, chTim4S is also expressed by γδ T cells, suggesting a unique role for chTim4 in this population of T cells. The biological activities of the chicken Tim family molecules were also investigated using chTim-Ig fusion proteins. Like mammals, chTim1 and chTim4S fusion proteins can specifically recognise phosphatidylserine (PS), an indicator of apoptotic cells, suggesting they are PS receptors. Pre-incubation with PS blocked binding of the chTim4S fusion protein to PS-exposing apoptotic cells. Physiologically, recognition of PS by the chTim proteins mediates apoptotic cell clearance, which was demonstrated using chTim-transfected fibroblast cells (3T3), which significantly increased their uptake of apoptotic cells compared with untransfected cells. The chTim4-Ig fusion protein also had costimulatory activity on chicken T cells. Monoclonal antibodies against the chTim proteins were generated. They specifically recognise their own antigen tested intensively by different immunological assays. ChTim4L is expressed intracellularly in freshly-isolated splenocytes rather than on the surface, whereas PMA-stimulated splenocytes express chTim4S and chTim4L on the cell surface. Like mammals, chicken splenic macrophages also express chTim4S and chTim4L. Both of them are also expressed by bone marrow-derived macrophages but not bone marrow-derived DCs. The chTim1 protein was detected at high levels in bursal cells and splenocytes by western blot analysis using polyclonal anti-chTim1 serum, which is consistent with its mRNA expression pattern through qRT-PCR analysis, suggesting B and T cells may express chTim1, consistent with its expression in mammals. Mammalian Tim1 is expressed on Th2 cells, its ligand, Tim4, on APCs; the interaction between them drives Th2 cell proliferation. The knowledge from this study will help to further dissect how the chicken’s Th2 responses are regulated through cell surface molecules.