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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
31

Human Cellular Immune Responses to Dengue Virus Infection: Potential Roles in Immunopathology

Gagnon, Susan J. 01 May 1998 (has links)
The encompassing aim of this project was to gain a better understanding of the role of the cellular immune response to dengue virus (DV) infection. Dengue virus occurs as four distinct serotypes, called D1-D4. Symptomatic DV infection occurs as two forms of illness. The more severe form of DV infection, dengue hemorrhagic fever (DHF), is characterized by increased capillary permeability resulting in decreased plasma volume, which may be accompanied by hemorrhagic manifestations. At its most severe, DHF can result in circulatory shock and death. Epidemiological studies indicate that DHF is more likely to occur following a secondary infection with a serotype of DV other than that which caused the primary infection, and there is evidence of increased T cell activation in more severe disease. These data and others indicate that DHF may be of an immunopathological nature. The memory CD4+ T cell response of a D4-immune donor was analyzed. Bulk culture proliferative responses of peripheral blood mononuclear cells (PBMC) to noninfectious DV antigens showed the highest proliferation to D4V antigen, with lesser, crossreactive proliferation to D2V antigen. CD4+ cytotoxic T lymphocyte (CTL) clones were established by stimulation with D4 antigen using a limiting dilution method. Seven out of 15 clones recognized the D4V capsid protein. The clones showed heterogeneity in their usage of T cell receptor Vα and Vβ genes. Six of these CTL clones were crossreactive between 02 and 04, and one clone was specific for D4. Using synthetic peptides, the D4V-specific clone was found to recognize an epitope between amino acids (aa) 47-55 of the capsid protein, while the crossreactive CTL clones each recognized epitopes in a separate location, between aa 83 and 92, which is conserved between D2 and D4. These results showed that the DV capsid protein can be a target of the cellular immune response following DV infection. The bulk culture response of the donor's PBMC to the epitope peptide spanning aa 84-92 was also examined. Peptides containing this epitope induced proliferation of the donor's PBMC in bulk culture, but peptides not containing the entire epitope did not induce proliferation. Also, PBMC stimulated in bulk culture with noninfectious D4V antigen lysed autologous target cells pulsed with peptides containing aa 84-92. These results indicate that this donor exhibits memory CD4+ T cell responses directed against the DV capsid protein and suggest that the response to the capsid protein is dominant not only in vitro at the clonal level, but in bulk culture responses as well. Experiments were performed demonstrating that the CD4+ CTL clones were capable of mediating bystander lysis of non-antigen presenting target cells. Following activation on plate-bound anti-CD3 antibody or in the presence of unlabeled antigen-presenting target cells, these clones could lyse both Jurkat cells and HepG2 cells as bystander targets. Bystander lysis of neighboring, non-infected cells by activated CD4+ CTL clones might contribute to the pathology of DHF. The mechanisms of lysis employed by the T cell clones against both cognate and bystander target cells were assessed using chemical inhibitors of either the perforin- or Fas/FasL-mediated pathways. Three CD4+ CTL clones were demonstrated to lyse cognate, antigen-presenting target cells by a mechanism that primarily involves perforin, while bystander lysis occurred through Fas/FasL interactions. In contrast, one clone used a Fas/FasL mechanism to lyse both cognate and bystander targets. These experiments indicated that the perforin- and FasL-mediated mechanisms of target cell lysis are not mutually exclusive, in that a single clone can kill target cells using either mechanism. Additionally, the ability of CD4+ CTL clones to lyse target cells by the perforin pathway indicates that, like CD8+ CTL, these clones might play a role in viral clearance and recovery from infection through lysis of virus-infected cells. Cytokine production by the capsid-specific CTL clones was also examined. Six of six clones studied produced high quantities of IFN-γ in response to either D2V antigen or the epitope peptide. IFN-γ was also produced by PBMC in a bulk culture from this donor stimulated with D4V antigen. All of the clones produced both TNF-α and TNF-β following stimulation. Four of six clones produced low amounts of IL-2, and only three of six clones produced detectable amounts of IL-4. Production of cytokines by activated CD4+ T cell clones in vivo could contribute to both viral clearance and immunopathology. To better understand the role that cytokine production might play in vivo in response to DV infection, cytokine mRNA levels were examined by PCR in DV-infected Thai children. mRNA for the cytokines IFN-γ, TNF-β, TNF-α, IL-1β, and IL-6 were detectable in the PBMC of DV-infected children. Semi-quantitative PCR analysis indicated that TNF-α mRNA levels were elevated in Thai children with DHF compared to children with classical dengue fever, the less severe form of illness (p=.013). All other cytokines showed no statistically significant difference between children with DHF and those with DF, although IFN-γ showed a trend toward elevation in more severe disease (p=.l). Increased production of TNF-α and/or IFN-γ in vivo could potentially contribute to the immunopathology of severe dengue illness. Taken as a whole, the data presented in this thesis provide a better understanding of the role of the cellular immune response to dengue virus infection and its potential contribution to the immunopathology of dengue hemorrhagic fever.
32

Leishmaniose cutânea não ulcerada ou atípica causada pela Leishmania infantum chagasi no município de Amapala, Valle, Honduras: caracterização imuno-histopatológica das lesões de pele / Non-ulcerated or atypical cutaneous leishmaniasis caused by Leishmania (L.) infantum chagasi in the municipality of Amapala, Valle, Honduras: immunohistotopathological characterization of skin lesions

Sandoval Pacheco, Carmen Maria 01 September 2017 (has links)
Nas Américas, em especial na América do Sul, a infecção por Leishmania (L.) infantum chagasi causa manifestações subclínicas e leishmaniose visceral (LV), a qual quando não tratada é potencialmente fatal. Na América Central, especialmente em Honduras, a leishmaniose cutânea não ulcerada ou atípica e a leishmaniose visceral são causadas pelo mesmo agente etiológico Leishmania (L.) infantum chagasi e ocorrem na mesma região geográfica. Pouco se conhece sobre o perfil da infecção humana por Leishmania (L.) infantum chagasi em Honduras, especialmente sobre a forma não ulcerada ou atípica, sendo assim, no sentido de compreender melhor a patogênese da infecção causada por esta espécie de parasito no município de Amapala (Valle) e Orocuina (Choluteca), Honduras, o presente estudo visou a caracterização histopatológica e da resposta imune celular in situ em lesões de pacientes com leishmaniose cutânea não ulcerada ou atípica. Foram utilizadas 20 biópsias de pele de pacientes com diagnóstico parasitológico confirmado por raspado de lesão corado por Giemsa e observado em microscópio ótico. A histopatologia foi avaliada em cortes histológicos corados por hematoxilina-eosina (HE) e a resposta imune por meio da reação de imunoistoquímica utilizando anticorpos primários para macrófagos (CD68), linfócitos T (CD4, CD8), células natural killer - NK (CD56), linfócitos B (CD20), óxido nítrico sintetase (NOS2) e interferon-gama (IFN-y. Microscopicamente as alterações histopatológicas mais significativas foram observadas na derme superficial e profunda caracterizando-se por um infiltrado inflamatório predominantemente linfohistiocitário de intensidades variável com arranjo difuso e, por vezes, associado à formação de granulomas epitelioides. A observação de formas sugestivas do parasito ocorreu em apenas 55 % dos casos. A análise imunoistoquímica das lesões confirmou a presença de células mononucleares no infiltrado inflamatório caracterizada principalmente pela presença de linfócitos TCD8+, seguido por TCD4+, macrófagos, linfócitos B e células NK. A grande densidade de células INF-y+ e a presença da enzima iNOS, responsável pela produção de óxido nítrico, molécula com atividade leishmanicida, em quase a totalidade dos macrófagos do infiltrado inflamatório, sugere uma resposta imune local bastante efetiva, que colabora para o controle do número de parasitos e consequentemente a evolução do tamanho da lesão / In America, especially in South America, infection by Leishmania (L.) infantum chagasi causes subclinical manifestations and visceral leishmaniasis (VL), which when untreated is potentially fatal. In Central America, especially in Honduras, non-ulcerated or atypical cutaneous leishmaniasis and visceral leishmaniasis are caused by the same etiologic agent Leishmania (L.) infantum chagasi and occur in the same geographic region. Little is known about the profile of human infection by Leishmania (L.) infantum chagasi in Honduras, especially on the non-ulcerated or atypical form. In order to better understand the pathogenesis of the infection caused by this species of parasite in the municipality of Amapala (Valle) and Orocuina (Choluteca), Honduras, the present study aim the characterization of histopathological changes and cellular immune response in situ in lesions of patients with non-ulcerated or atypical cutaneous leishmaniasis. Twenty skin biopsies from patients with parasitological diagnosis confirmed by scraping of Giemsa-stained lesion and observed using an optical microscope. Histopathology, was evaluated by hematoxylin-eosin (HE) and the immunohistochemistry using the primary antibodies to macrophages (CD68), T lymphocytes (CD4, CD8), natural killer cells - NK (CD56), B lymphocytes CD20), nitric oxide synthase (NOS2) and interferon-gamma (IFN-y). Microscopically, the most significant histopathological changes were observed in the superficial and deep dermis, characterized by a predominantly lymphohistiocytic inflammatory infiltrate of variable intensities with diffuse arrangement and sometimes associated with the formation of epithelioid granulomas; the observation of suggestive forms of the parasite occurred in only 55 % of the cases. The immunohistochemical analysis of the lesions confirmed the presence of mononuclear cells in the inflammatory infiltrate characterized mainly by the presence of T-CD8+ lymphocytes, followed by T-CD4+, macrophages, B lymphocytes and NK cells. The high density of INF-y+ cells and the presence of iNOS, enzyme responsible for the production of nitric oxide, molecule with activity leishmanicide, in almost all of the macrophages in the inflammatory infiltrate, suggest an effective local immune response that collaborate to the control in the number of parasites and consequently the evolution of the lesion
33

Análise de imunogenicidade e proteção gerada pelos imunógenos de terceira geração pVAX1-FSD e pVAX1-SP contra a leishmaniose tegumentar americana experimental / Analysis of Immunogenicity and protection generated by third generation immunogens pVAX1-FSD and pVAX1-SP against experimental cutaneous leishmaniasis

Campos, Bruno Luiz Soares 17 April 2015 (has links)
A leishmaniose tegumentar é uma doença infecciosa, amplamente disseminada, sendo L. (V.) braziliensis e L. (L.) amazonensis, no Brasil, as espécies de maior importância médico-epidemiológica. Devido ao impacto epidemiológico da leishmaniose, medidas profiláticas devem ser desenvolvidas para o controle da doença, tal como vacinas. Portanto, o presente trabalho objetivou avaliar a imunogenicidade e potencial protetor de dois imunógenos denominados como ferro superóxido dismutase (FSD) e serino peptidase (SP). Os genes codificadores dos antígenos foram sintetizados e clonados no plasmídeo pVAX1 (pVAX1-FSD e pVAX1-SP). Camundongos BALB/c foram imunizados com ambos os alvos na concentração de 1,0 ug/uL, por três vezes, a intervalos regulares de 15 dias, e desafiados ou não com formas promastigotas de L. (L.) amazonensis. Os animais foram avaliados clínica, parasitológica e imunologicamente nos estudos de imunogenicidade e proteção. Os resultados obtidos demonstraram que ambas os imunógenos foram pouco imunogênicos, não apresentando alterações em linfócito T CD4; por outro lado, detectaram-se frequências diminuídas de linfócito TCD8 produtores de IFN-y e TNF-alfa. Entretanto, nos experimentos de desafio, verificou-se que os animais imunizados com pVAX1-FSD apresentaram uma resposta mista Th1 e Th2, devido ao aumento de linfócitos T produtores de IFN-y e IL-4, o que se associou a níveis altos de IgG1 e IgG2a, levando a uma diminuição da carga parasitária. O alvo pVAX1-SP também induziu resposta imunológica mista nos animais, todavia foi detectado frequências elevadas de linfócitos T CD8 produtores IL-10, e esta resposta foi associada a ausência de proteção nesses animais / American tegumentar leishmaniasis is an infectious disease, widespread, and in Brazil the species L. (V.) braziliensis and L. (L.) amazonensis are the most relevant in medical-epidemiological studies. Due to the epidemiological impact of leishmaniasis, prophylactic measures should be developed to control this disease, such as vaccines. Therefore, the present study aimed to evaluate the immunogenicity and the protective potential of two vaccine candidates known as iron superoxide dismutase (FSD) and serine peptidase (SP). FSD- and SP-coding genes were synthesized and cloned into plasmid pVAX1 (pVAX1-FSD and pVAX1-SP). BALB/c mice were immunized with both candidates at a concentration of 1.0 ug/uL, three times at intervals of 15 days and challenged or not with L. (L.) amazonensis promastigotes. Animals were evaluated clinically, immunologically and parasitologically in the studies of immunogenicity and protection. The results showed that both vaccines presented low immunogenicity, and after immunization BALB/c mice did not show significant changes in CD4 T lymphocytes, by the other side, the frequency of IFN-y and TNF-alfa producing cells were low. However, after challenge pVAX1-FSD-immunized mice presented a mixed Th1 and Th2 immune response, due to the high frequencies of IFN-ye IL-4-producing T lymphocytes, with association to high levels of IgG1 and IgG2a isotypes, leading to parasite burden decreasing. pVAX1-SP vaccine candidate also induced mixed immune response in animals, however high frequencies of IL-10-producing CD8 T lymphocytes was found, justifying the absence of protection in these animals
34

Studies of specific immunity against viral infections after stem cell transplantation /

Avetisyan, Gayane, January 2007 (has links)
Diss. (sammanfattning) Stockholm : Karolinska institutet, 2007. / Härtill 4 uppsatser.
35

Phenotypic changes in dendritic cells when challenged with cowpox virus

DeBernardis, Justin R., January 2004 (has links)
Thesis (M.S.)--University of Florida, 2004. / Typescript. Title from title page of source document. Document formatted into pages; contains 49 pages. Includes Vita. Includes bibliographical references.
36

Análise de imunogenicidade e proteção gerada pelos imunógenos de terceira geração pVAX1-FSD e pVAX1-SP contra a leishmaniose tegumentar americana experimental / Analysis of Immunogenicity and protection generated by third generation immunogens pVAX1-FSD and pVAX1-SP against experimental cutaneous leishmaniasis

Bruno Luiz Soares Campos 17 April 2015 (has links)
A leishmaniose tegumentar é uma doença infecciosa, amplamente disseminada, sendo L. (V.) braziliensis e L. (L.) amazonensis, no Brasil, as espécies de maior importância médico-epidemiológica. Devido ao impacto epidemiológico da leishmaniose, medidas profiláticas devem ser desenvolvidas para o controle da doença, tal como vacinas. Portanto, o presente trabalho objetivou avaliar a imunogenicidade e potencial protetor de dois imunógenos denominados como ferro superóxido dismutase (FSD) e serino peptidase (SP). Os genes codificadores dos antígenos foram sintetizados e clonados no plasmídeo pVAX1 (pVAX1-FSD e pVAX1-SP). Camundongos BALB/c foram imunizados com ambos os alvos na concentração de 1,0 ug/uL, por três vezes, a intervalos regulares de 15 dias, e desafiados ou não com formas promastigotas de L. (L.) amazonensis. Os animais foram avaliados clínica, parasitológica e imunologicamente nos estudos de imunogenicidade e proteção. Os resultados obtidos demonstraram que ambas os imunógenos foram pouco imunogênicos, não apresentando alterações em linfócito T CD4; por outro lado, detectaram-se frequências diminuídas de linfócito TCD8 produtores de IFN-y e TNF-alfa. Entretanto, nos experimentos de desafio, verificou-se que os animais imunizados com pVAX1-FSD apresentaram uma resposta mista Th1 e Th2, devido ao aumento de linfócitos T produtores de IFN-y e IL-4, o que se associou a níveis altos de IgG1 e IgG2a, levando a uma diminuição da carga parasitária. O alvo pVAX1-SP também induziu resposta imunológica mista nos animais, todavia foi detectado frequências elevadas de linfócitos T CD8 produtores IL-10, e esta resposta foi associada a ausência de proteção nesses animais / American tegumentar leishmaniasis is an infectious disease, widespread, and in Brazil the species L. (V.) braziliensis and L. (L.) amazonensis are the most relevant in medical-epidemiological studies. Due to the epidemiological impact of leishmaniasis, prophylactic measures should be developed to control this disease, such as vaccines. Therefore, the present study aimed to evaluate the immunogenicity and the protective potential of two vaccine candidates known as iron superoxide dismutase (FSD) and serine peptidase (SP). FSD- and SP-coding genes were synthesized and cloned into plasmid pVAX1 (pVAX1-FSD and pVAX1-SP). BALB/c mice were immunized with both candidates at a concentration of 1.0 ug/uL, three times at intervals of 15 days and challenged or not with L. (L.) amazonensis promastigotes. Animals were evaluated clinically, immunologically and parasitologically in the studies of immunogenicity and protection. The results showed that both vaccines presented low immunogenicity, and after immunization BALB/c mice did not show significant changes in CD4 T lymphocytes, by the other side, the frequency of IFN-y and TNF-alfa producing cells were low. However, after challenge pVAX1-FSD-immunized mice presented a mixed Th1 and Th2 immune response, due to the high frequencies of IFN-ye IL-4-producing T lymphocytes, with association to high levels of IgG1 and IgG2a isotypes, leading to parasite burden decreasing. pVAX1-SP vaccine candidate also induced mixed immune response in animals, however high frequencies of IL-10-producing CD8 T lymphocytes was found, justifying the absence of protection in these animals
37

Leishmaniose cutânea não ulcerada ou atípica causada pela Leishmania infantum chagasi no município de Amapala, Valle, Honduras: caracterização imuno-histopatológica das lesões de pele / Non-ulcerated or atypical cutaneous leishmaniasis caused by Leishmania (L.) infantum chagasi in the municipality of Amapala, Valle, Honduras: immunohistotopathological characterization of skin lesions

Carmen Maria Sandoval Pacheco 01 September 2017 (has links)
Nas Américas, em especial na América do Sul, a infecção por Leishmania (L.) infantum chagasi causa manifestações subclínicas e leishmaniose visceral (LV), a qual quando não tratada é potencialmente fatal. Na América Central, especialmente em Honduras, a leishmaniose cutânea não ulcerada ou atípica e a leishmaniose visceral são causadas pelo mesmo agente etiológico Leishmania (L.) infantum chagasi e ocorrem na mesma região geográfica. Pouco se conhece sobre o perfil da infecção humana por Leishmania (L.) infantum chagasi em Honduras, especialmente sobre a forma não ulcerada ou atípica, sendo assim, no sentido de compreender melhor a patogênese da infecção causada por esta espécie de parasito no município de Amapala (Valle) e Orocuina (Choluteca), Honduras, o presente estudo visou a caracterização histopatológica e da resposta imune celular in situ em lesões de pacientes com leishmaniose cutânea não ulcerada ou atípica. Foram utilizadas 20 biópsias de pele de pacientes com diagnóstico parasitológico confirmado por raspado de lesão corado por Giemsa e observado em microscópio ótico. A histopatologia foi avaliada em cortes histológicos corados por hematoxilina-eosina (HE) e a resposta imune por meio da reação de imunoistoquímica utilizando anticorpos primários para macrófagos (CD68), linfócitos T (CD4, CD8), células natural killer - NK (CD56), linfócitos B (CD20), óxido nítrico sintetase (NOS2) e interferon-gama (IFN-y. Microscopicamente as alterações histopatológicas mais significativas foram observadas na derme superficial e profunda caracterizando-se por um infiltrado inflamatório predominantemente linfohistiocitário de intensidades variável com arranjo difuso e, por vezes, associado à formação de granulomas epitelioides. A observação de formas sugestivas do parasito ocorreu em apenas 55 % dos casos. A análise imunoistoquímica das lesões confirmou a presença de células mononucleares no infiltrado inflamatório caracterizada principalmente pela presença de linfócitos TCD8+, seguido por TCD4+, macrófagos, linfócitos B e células NK. A grande densidade de células INF-y+ e a presença da enzima iNOS, responsável pela produção de óxido nítrico, molécula com atividade leishmanicida, em quase a totalidade dos macrófagos do infiltrado inflamatório, sugere uma resposta imune local bastante efetiva, que colabora para o controle do número de parasitos e consequentemente a evolução do tamanho da lesão / In America, especially in South America, infection by Leishmania (L.) infantum chagasi causes subclinical manifestations and visceral leishmaniasis (VL), which when untreated is potentially fatal. In Central America, especially in Honduras, non-ulcerated or atypical cutaneous leishmaniasis and visceral leishmaniasis are caused by the same etiologic agent Leishmania (L.) infantum chagasi and occur in the same geographic region. Little is known about the profile of human infection by Leishmania (L.) infantum chagasi in Honduras, especially on the non-ulcerated or atypical form. In order to better understand the pathogenesis of the infection caused by this species of parasite in the municipality of Amapala (Valle) and Orocuina (Choluteca), Honduras, the present study aim the characterization of histopathological changes and cellular immune response in situ in lesions of patients with non-ulcerated or atypical cutaneous leishmaniasis. Twenty skin biopsies from patients with parasitological diagnosis confirmed by scraping of Giemsa-stained lesion and observed using an optical microscope. Histopathology, was evaluated by hematoxylin-eosin (HE) and the immunohistochemistry using the primary antibodies to macrophages (CD68), T lymphocytes (CD4, CD8), natural killer cells - NK (CD56), B lymphocytes CD20), nitric oxide synthase (NOS2) and interferon-gamma (IFN-y). Microscopically, the most significant histopathological changes were observed in the superficial and deep dermis, characterized by a predominantly lymphohistiocytic inflammatory infiltrate of variable intensities with diffuse arrangement and sometimes associated with the formation of epithelioid granulomas; the observation of suggestive forms of the parasite occurred in only 55 % of the cases. The immunohistochemical analysis of the lesions confirmed the presence of mononuclear cells in the inflammatory infiltrate characterized mainly by the presence of T-CD8+ lymphocytes, followed by T-CD4+, macrophages, B lymphocytes and NK cells. The high density of INF-y+ cells and the presence of iNOS, enzyme responsible for the production of nitric oxide, molecule with activity leishmanicide, in almost all of the macrophages in the inflammatory infiltrate, suggest an effective local immune response that collaborate to the control in the number of parasites and consequently the evolution of the lesion
38

Tolerance Induction to a Foreign Protein Antigen: Analysing the Role of B Cells in Establishing Peripheral Tolerance

Yuschenkoff, Victoria Nicole 14 September 1995 (has links)
Tolerance to self proteins is largely dependent upon the deletion of immature, self-specific T and B cells in the thymus and bone marrow. Although highly efficient, the elimination of these self-reactive lymphocytes is dependent on the expression of their target antigen in these primary lymphoid organs. Many proteins, however, such as hormones, are developmentally regulated and expressed at different stages of life, while other proteins are expressed outside the thymus and marrow. To ensure self-tolerance, other mechanisms must exist to inactivate or prevent the activation of mature, potentially self-reactive lymphocytes and maintain peripheral tolerance. T cell activation requires direct recognition of a specific protein fragment, presented on the surface of an antigen presenting cell (APC), as well as the interaction between various T cell and APC surface molecules. In the absence of the costimulatory signals provided by these ligand-pair interactions and lymphokines, antigen recognition leads to T cell inactivation and tolerance to the protein. Since many autoimmune disorders appear to be based upon the aberrant activation of mature T lymphocytes, it is important to identify and understand the mechanisms of peripheral tolerance. The obvious importance of the APC in initiating the T cell immune response has led our lab to examine one of the many antigen-processing cells, the B lymphocyte. Our studies have shown that B cells are highly efficient APC and can present antigen at very low doses to cultured T cell lines. In addition, we have found that we can induce tolerance, as measured by a reduced antibody response to an immunogenic form of the protein, in naive, normal mice by targeting a foreign protein to their B cells for antigen processing and presentation. Tolerance in the treated mice can be traced to a lesion in the T cell compartment of the animals, thus suggesting that B cells can act as tolerizing APC for peripherally expressed antigens. To further explore this idea and find more direct evidence for the role of B cells in establishing peripheral tolerance, we developed a model system that would more closely resemble in vivo conditions. This thesis tests and provides additional evidence for the hypothesis that B cells are tolerizing antigen presenting cells for peripherally expressed protein antigens. Tolerance to the foreign protein human μ chain, is induced in normal recipient mice by the transfusion of splenocytes from transgenic mice that express the membrane-bound form of μ on their B cells. Tolerance is antigen-specific since the transfused recipients' antibody production to the irrelevant protein chicken IgG is not compromised. Only viable transgenic spleen cells are tolerogenic and even when human μ chain is accessible to other APCs for presentation, tolerance can be induced by the transfusion of live μ transgenic splenoctyes. These data suggested that the transfused μ chain-expressing B cells are the tolerizing APCs which was confirmed by experiments that compared the tolerizing abilities of purified B and T cells from the transgenic mice. Adoptive transfer experiments showed that the recipients' T cell response to human μ was impaired but an analysis of the isotypes produced by tolerized mice did not indicate that either helper T cell subset was specifically compromised. Splenocytes from human μ chain-secreting transgenic B cells also induce tolerance to human μ in nontransgenic mice. Although human μ chain-expressing B cells were not detected in transfused mice, the presence of measurable levels of human IgM in the sera of mice transfused with μ chain-secreting spleen cells suggests that the transfused transgenic B cells persist in their new host. In addition, the tolerizing ability of both resting and activated membrane-bound μ chain B cells was compared. Lipopolysaccharide (LPS)-activated transgenic spleen cells do not tolerize, nor do they prime for antibody to human μ, thus suggesting that the induction of costimulatory molecules on the transgenic B cells inhibits tolerance induction. To more specifically address this, human μ chain-expressing mice were bred to transgenic mice that express the costimulatory molecule, B7-1 (CD80), on their B cells. Double transgenic splenocytes, in which the B cells bear both human μ and B7-1, did not induce tolerance to human μ chain, a result that supports the idea that activated B cells are not tolerogenic. Together the data in this thesis show that resting B cells can process and present a foreign endogenous antigen in a tolerogenic manner to the immune system and suggest a role for the B cell in the maintenance of peripheral tolerance.
39

Avaliação da imunidade celular em pacientes com carcinoma epidermóide de cabeça e pescoço e sua correlação com nutrição, tamanho tumoral e recidiva / Avaliation of the cellular imunity in patients with squamous cell carcinoma of the head and neck and its correlation with nutrition, tumor size and recurrence

Sodré, Maria Teresa Assumpção Machado 14 March 2007 (has links)
INTRODUÇÃO: a imunidade celular de pacientes com carcinoma epidermóide de cabeça e pescoço tem sido foco de muitos estudos nas últimas décadas. As alterações do sistema imune parecem estar relacionadas com a progressão da doença. A avaliação da imunidade celular desses casos é necessária para programar estratégias de imunoterapia. A deficiência nutricional, o tamanho tumoral e a recidiva são fatores que também podem estar relacionados com a piora imunitária e clínica. O objetivo deste trabalho foi verificar se portadores de carcinoma epidermóide de cabeça e pescoço têm imunidade celular e estado nutricional diferente de controles e sua correlação com tamanho tumoral e recidiva. MÉTODOS: foram avaliados 155 pacientes admitidos nos serviços de cirurgia de cabeça e pescoço e cirurgia geral do Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo, entre 16 de agosto de 2005 a 31 de julho de 2006. Houve 52 controles e 103 casos com diagnóstico de carcinoma epidermóide de trato aerodigestivo alto, subdivididos em 29 casos pré-tratamento, 47 pós-tratamento sem doença e 27 pós-tratamento com doença. Foi realizada entrevista clínica, contendo dados demográficos, presença de tabagismo, etilismo e co-morbidades, e avaliado o índice de Karnofsky. Dados do tumor e tratamento foram anotados. Foi realizada avaliação nutricional antropométrica, através da medida do peso, estatura e índice de massa corpórea (IMC). A avaliação da composição corpórea foi feita através de bioimpedância elétrica, utilizando-se a porcentagem de massa magra em homens e mulheres. Os critérios bioquímicos usados foram concentração plasmática de albumina e contagem total de linfócitos (CTL). A avaliação da imunidade celular foi feita através de testes cutâneos com 3 antígenos (PPD, tricofitina e candidina). O tamanho tumoral também foi medido. A análise estatística foi feita através de média, desvio padrão, ANOVA e Bonferroni para variáveis numéricas e teste qui-quadrado de Pearson para as categóricas. RESULTADOS: As médias de IMC, albumina e CTL foram diferentes entre os grupos (p<0,0001), sendo que os recidivados diferiram nos 3 critérios nutricionais dos outros grupos, com média menor. Quanto à resposta aos testes cutâneos, comparando-se todos os grupos, não houve diferença (p=0,08). Quando comparados os grupos 2 a 2, no entanto, houve diferença entre controles e recidivados (p=0,02) e casos pré-tratamento e recidivados (p<0,002). A idade não alterou a positividade ao teste cutâneo nos casos, porém ela foi diferente nos controles, com idosos apresentando mais anergia em relação a adultos (p=0,04). A resposta aos testes cutâneos não foi diferente de acordo com o estado nutricional e com o tipo de procedimento realizado. Porém, nos casos pós-tratamento sem doença, a média de IMC e CTL diferiu entre grupos tratados por cirurgia e os que incluíram, além de cirurgia, radioterapia (p<0,05). O estádio clínico não apresentou relação com a nutrição e imunidade. A resposta ao teste cutâneo também não foi diferente de acordo com o tamanho tumoral. CONCLUSÕES: Pacientes com carcinoma epidermóide de cabeça e pescoço têm estado nutricional diferente de controles, sendo pior nos casos recidivados. Houve diferença de porcentagem de anergia entre os recidivados, quando comparados com controles e casos pré-tratamento, sendo maior nos primeiros. Não houve relação da imunidade celular com o estado nutricional e com o tamanho tumoral. / INTRODUCTION: the cellular immunity of patients with head and neck cancer has been studied for many authors at the last decades. The alterations of the immune system seems to be related with the progress of the disease. The avaliation of the cellular immunity at these patients is necessary in order to program strategies of immunotherapy. Malnutrition, tumor size and recurrence are related to a worse immunity and clinical outcome. This study was intended to verify if patients with squamous cell carcinoma of the head and neck have different cellular immunity and nutrition from others that do not have cancer, and their correlation with tumor size and recurrence. METHODS: there were 155 patients admitted at Hospital das Clínicas of the University of São Paulo Medical School, from August, 2005 to July, 2006. There were 52 controls and 103 cases with squamous cell carcinoma of the head and neck, which were divided in cases pretreatment (n=29), posttreatment without evidence of disease (n=47) and with recurrence (n=27). All patients were interviewed. Questions about age, sex, smoking, drinking and comorbidities were asked. The Karnofsky status performance was evaluated. Tumor\'s site, stage and treatment were noted. Nutritional assessment with anthropometric measures as weight, height and body mass coefficient (BMC) was done. Electrical bioimpedance was used to get men and women thin mass percentage. The level of albumin and total lymphocyte count (TLC) were used as biochemical criterias of nutrition. The cellular immunity was checked by the pattern of response to skin tests with 3 antigens (PPD, tricophitin and candidin). Tumor size was measured. Statistics were performed with median, ANOVA and Bonferroni for numeric variables and with Pearson\'s chi-square test for the string ones. RESULTS: The medians of BMC, albumin anc TLC were different between cases and controls (p<0,0001), and patients with recurrence had all nutritional criterias lower than the others. Skin tests were different , and cases with recurrence were more anergic thatn controls. Age does not alter the skin test response in cases, but in controls, patients with age above 65 years had more anergy than the others (p=0,04). Skin tests response was not different in relation of nutritional status and with the treatment used in cases that were treated. But, in cases treated and without evidence of recurrence, the nutritional status was different for all criterias. Stage of the tumour does not reveal any relation with nutrition and cellular immunity. So do the cellular immunity for tumor size. CONCLUSIONS: patients with squamous cell carcinoma of the head and neck have nutritional status different from controls, and worse at the patients with recurrence. There was no difference at the cellular immunity relationated with tumor size and nutritional status.
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Concepts in DNA immunization : overcoming viral diversity and enhancing plasmid immunogenicity /

Rollman, Erik, January 2004 (has links)
Diss. (sammanfattning) Stockholm : Karol. inst., 2004. / Härtill 6 uppsatser.

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