In these studies we sought to determine the role of Fyn kinase and ADAM10 in B cell biology. A disintegrin and metalloproteinase 10 (ADAM10) is a zinc dependent proteinase related to matrix metalloproteinases. ADAM10 has emerged as a key regulator of cellular processes by cleaving and shedding extracellular domains of multiple transmembrane receptors and ligands. In particular, ADAM10 has been identified as a key regulator of lymphocyte development. Here we report that ADAM10 is dispensable for early B cell development within the bone marrow. However, deletion of ADAM10 from all peripheral B cells or in post-switch cells leads to severe impairments in humoral responses. When ADAM10 was deleted from all peripheral B cells a decrease in antigen specific IgG production was seen both with respect to serum levels and IgG ASCs, indicating that plasma cell (PC) differentiation is influenced. Cells producing high affinity antigen specific antibodies were particularly affected, consistent with defects in germinal center (GC) reactions. Moreover, changes in lymphoid architecture were also observed. Consistent with these findings, follicular dendritic cell (FDC)-reticula was undetectable following immunization. On the other hand, when ADAM10 was deleted in post-switch B cells, GC formation and lymphoid architecture were not impaired. Despite normal architecture, however, antibody production was still affected, likely due to abnormal gene expression in ADAM10-deficient PCs. Consistent with this hypothesis, PCs isolated from ADAM10Δ/ΔIgG1-cre+/- showed decreased expression of genes that facilitate plasma cell differentiation and function and increased expression of Bcl6, an inhibitor of PC differentiation. Fyn kinase is a member of the Src protein tyrosine kinase. Fyn is widely expressed in many cell types, including lymphocytes. Fyn has been shown to interact with both the B cell and T cell receptor (BCR and TCR, respectively). While Fyn-deletion did not impair the development of immature T cells and B cells, TCR signaling was altered in mature T cells. Our results demonstrate that Fyn-KO mice have significantly low basal levels of IgG1 and IgG2a. Additionally, these mice displayed delayed kinetics in the production of NP-specific IgG1 and IgG2b, and significantly low NP-specific IgG2a after a T-dependent immunization protocol. Defects in antibody production correlated with significantly reduced numbers of GC B cells, TFH cells and splenic PCs. Moreover, Fyn-KO B cells showed decreased production antibody following in vitro activation. Our results thus demonstrate that Fyn-mediated signaling and B cell ADAM10 expression are necessary for optimal humoral responses.

MSc (Med), Faculty of Health Sciences, University of the Witwatersrand, 2009 / Background: RTS,S candidate malaria vaccine has been shown to be highly immunogenic in children and infants, but the protective immune mechanisms still remain to be clearly elucidated. It is believed that RTS,S elicits a strong neutralizing humoral immune response directed against surface-exposed sporozoite proteins and cell mediated immune (CMI) responses characterized by predominantly CD4+ Th1 cells. The objective of this study was to investigate humoral and cell-mediated immune responses to the RTS,S/AS02D malaria vaccine and its association with protection against infection and disease by P. falciparum. Methodology and Principal Findings: This secondary data analysis from data of a phase I/IIb randomized, double-blind, controlled trial, included 154 healthy infants living in rural Mozambique, previously immunized with RTS,S/AS02D candidate malaria vaccine or the control Engerix-B™ vaccine. Antibodies against circumsporozoite protein (CSP) and hepatitis-B surface antigen (HBsAg) were measured with a standard ELISA. Fresh blood intracellular staining assay was performed to evaluate the expression of IL-2 and IFN-γ by CD4+ and CD8+ cells in response to in vitro stimulation of specific peptides. Data was evaluated for association with the risk of malaria detected by both active and passive case detection of infection over a period of 6 months post dose 3. Anti-HBs antibody geometric mean titers declined from 10,082 mIU/mL one month post Dose 3 to 2,751 mIU/mL at 12 months post Dose 3 in the RTS,S/AS02D group; anti-HBs v geometric mean titers were 392.4 mIU/mL and 263.9 mIU/mL, respectively in the Engerix- BTM group. Anti-CSP antibody geometric mean titers declined from 199.9 EU/mL one month post Dose 3 to 7.3 EU/mL at 12 months post Dose 3 in the RTS,S/AS02D group. Median stimulation indices of HBs-specific IL-2 and IFN-γ producing CD8+ T cells was higher in the RTS,S/AS02D group than in control group (Wilcoxon rank sum p-values for IFN-γ = 0.015, for IL-2 = 0.030) at 10.5 weeks post immunization. Median stimulation indices of anti-CSP specific IFN-γ producing CD8+ T cells at the same time point was 1.13 (IQR: 0.79 - 1.67; p=0.029). For specific IL-2-producing CD4+ T cells, the median SI was 1.14 (IQR: 0.74 – 1.60, p=0.043) at 10.5 weeks post dose three. The reduction in hazards of malaria infection were 18.3 % (95% CI: -267.9 – 81.8, p=0.793) and -12.0 % (95% CI: -295 – 68.2, p=0.86) for specific IL-2 CD4+ stimulation indices; For specific CD8+ IFN-γ stimulation indices the hazards were -103.6% (95% CI: -690.9 – 47.6; p=0.305) and 48.8% (95% CI: -97.0 – 86.7; p=0.33) at four and 10.5 weeks post immunization respectively. Conclusion: The RTS,S/AS02D vaccine was immunogenic and has elicited detectable levels of CSP specific cell mediated responses. No evidence of association was found between the antibodies anti-CSP and specific cell mediated responses and the risk of malaria.

Hepatitis C virus (HCV) infection has become a global public health concern with over 130 million people chronically infected and over 350,000 deaths every year from HCV-related liver diseases. GB virus-B (GBV-B) infection in tamarins is a surrogate model for acute HCV infection. Whilst HCV infection commonly leads to chronicity, GBV-B is naturally cleared. To better understand this natural clearance, this project aimed to study the associated humoral immune response to GBV-B. Additionally, GBV-B-specific antibodies were produced with the aim of characterising the pathology of the virus. Previously, there was no available GBV-B neutralisation assay to identify antibodies in this animal model. Therefore, a GBV-B neutralisation assay, based on a method that is known to be successful for the closely-related HCV, was developed. This method involved producing pseudotyped retroviral particles (PV) expressing the GBV-B envelope that could infect a human hepatocarcinoma cell line. GBV-B PV production was confirmed by western blotting. Future studies can now test archived tamarin sera in this assay for the presence of neutralising antibodies. Neutralising antibodies found through this model could be epitope mapped, and incorporated into HCV vaccine design strategies. To study the pathology of GBV-B infection, GBV-B-specific antibodies were also produced using two techniques in parallel- classical hybridoma technology and ribosome display. Antibodies targeting the nucleocapsid core protein of GBV-B have been previously detected in tamarins and served as the target for production of GBV-B antibodies using both aforementioned technologies. GBV-B core-specific antibodies were successfully isolated using both technologies and can now be used in downstream techniques, such as immunohistochemistry, to characterise the pathology of GBV-B infection thereby further validating the use of the animal model.

Submitted by Marília Salgado Caxito null (mariliasalgado@ymail.com) on 2017-02-24T00:12:23Z No. of bitstreams: 1 DISSERTAÇÃO (MARÍLIA SALGADO CAXITO) - Defesa em 17-02-2017.pdf: 1916563 bytes, checksum: ad7825421c4deb080f61ac2ac7c94a42 (MD5) / Approved for entry into archive by Juliano Benedito Ferreira (julianoferreira@reitoria.unesp.br) on 2017-03-06T13:44:02Z (GMT) No. of bitstreams: 1 caxito_ms_me_bot.pdf: 1916563 bytes, checksum: ad7825421c4deb080f61ac2ac7c94a42 (MD5) / Made available in DSpace on 2017-03-06T13:44:02Z (GMT). No. of bitstreams: 1 caxito_ms_me_bot.pdf: 1916563 bytes, checksum: ad7825421c4deb080f61ac2ac7c94a42 (MD5) Previous issue date: 2017-02-17 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / A Ehrlichiose Monocítica Canina (EMC), causada por Ehrlichia canis, destaca-se dentre as hemoparasitoses de cães. A EMC causa doença multissistêmica e pode ser classificada em fase aguda, subclínica ou crônica. A fase crônica caracteriza-se por hipoplasia/aplasia medular e muitos cães vêm a óbito por falência medular, embora as causas da supressão medular ainda sejam indefinidas. Neste estudo, foi investigado se a fase crônica resulta de alterações medulares iniciadas na fase aguda. Em particular, verificar se, durante a fase aguda, células precursoras podem ser parasitadas por E. canis e se processos imunomediados podem ser responsáveis por alterações hematológicas durante o curso da doença. Dezoito cães com EMC na fase aguda foram submetidos a exames hematológicos (hemograma, bioquímica sérica e mielograma) e sorológicos. A presença de E. canis foi confirmada mediante PCR e cultivo celular. A citologia de medula óssea revelou alterações principalmente na série eritróide que comumente estão associadas a doenças imunomediadas, inclusive em animais não anêmicos. Também confirmou-se a presença de E. canis na medula óssea de 11/18 cães e certa tendência entre a positividade das amostras medulares e a série eritróide, embora sem significância estatística. Os títulos sorológicos de 2560 em 9/18 e 10240 nos demais confirmou a resposta humoral exacerbada descrita pela literatura, contudo também sem relação significativa com a presença de E. canis na medula e algumas variáveis medulares. Este estudo evidenciou a importância do mielograma na EMC, inclusive para predizer alterações hematológicas em cães com hemograma normal. / The Canine Monocytic Ehrlichiosis (CME), caused by Ehrlichia canis, one of the most frequent hemoparasites dogs. CME causes multisystemic disease and includes a acute, subclinical or chronic phase. The chronic phase is characterized by medullary hypoplasia/aplasia and many dogs die from bone marrow failure. However, the causes of medullary suppression remain unknow. In this study, we investigated whether the chronic phase can result from marrow changes initiated during the acute phase. In particular, we evaluated if precursor cells can be parasitized by E. canis during the acute phase and whether immune-mediated processes are responsible for hematological changes during the course of the disease. Eighteen dogs with CME in the acute phase were submitted to hematological (hemogram, serum biochemistry and myelogram) and serological tests. The presence of E. canis was confirmed by PCR and cell culture. Bone marrow cytology analyses mainly revealed changes in the erythroid series that are usually associated with immune-mediated diseases, including in non-anemic animals. This study confirmed the presence of E. canis in the bone marrow of the 11/18 dogs and a potential positive relation between the positivity of the marrow samples and the erythroid series was observed, although whithout statistical significance. The serological titers of 2560 in 9/18 and 10240 in the others confirmed an exacerbated humoral response to CME described in the literature, but they were not associated with the presence of E. canis in the bone marrow and medullary alterations. This study evidenced the importance of the myelogram, as well predicting hematological alterations in dogs with normal hemogram.

<p>The humoral immune response is dependent on the formation of antibodies. Antibodies are produced by terminally differentiated B cells, plasma cells. Plasma cells are generated either directly from antigen challenged B cells, memory cells or from cells that have undergone the germinal center (GC) reaction. The GC is the main site for class switch, somatic hypermutation and generation of memory cells.</p><p>Different factors, both internal and external, shape the outcome of the immune response. In this thesis, we have studied a few factors that influence the maturation of the humoral response. We have studied how age affects the response, and we show that responses against thymus dependent antigens (TD) are more affected than responses to thymus independent (TI) antigens, in concordance with the view that the T cell compartment is more affected by age than the B cell compartment. Furthermore, we demonstrate that priming early in life have a big influence on the immune response in the aged individual. Priming with a TI form of the carbohydrate dextran B512 (Dx) induces a reduction of IgG levels in later TD responses against Dx. We have evaluated possible mechanisms for this reduction. The reduction does not seem to be caused by clonal exhaustion or antibody mediated mechanisms. We also showed that the reduced TD response after TI priming can be induced against another molecule than Dx. With the hypothesis that TI antigens induce a plasma cell biased maturation of the responding B cells, we examined the presence of Blimp-1, a master regulator of plasma cell differentiation, in GCs induced by TD and TI antigen. Blimp-1 was found earlier in GCs induced by TI antigen and the staining intensity in these GCs was stronger than in TD antigen induced GCs, indicating that plasma cells might be continuously recruited from these GCs.</p><p>B cells undergoing the GC reaction are thought to be under a strict selection pressure that removes cells with low affinity for the antigen and also cells that have acquired self-reactivity. We investigated the effect of apoptotic deficiencies on the accumulation of somatic mutations in GC B cells. In mice lacking the death receptor Fas, <i>lpr</i> mice, the frequency of mutations was increased but the pattern of the mutations did not differ from wild type mice. In contrast, mice over-expressing the anti-apoptotic protein Bcl-2, had a lowered frequency of mutations and the mutations introduced had other characteristics.</p>

The humoral immune response is dependent on the formation of antibodies. Antibodies are produced by terminally differentiated B cells, plasma cells. Plasma cells are generated either directly from antigen challenged B cells, memory cells or from cells that have undergone the germinal center (GC) reaction. The GC is the main site for class switch, somatic hypermutation and generation of memory cells. Different factors, both internal and external, shape the outcome of the immune response. In this thesis, we have studied a few factors that influence the maturation of the humoral response. We have studied how age affects the response, and we show that responses against thymus dependent antigens (TD) are more affected than responses to thymus independent (TI) antigens, in concordance with the view that the T cell compartment is more affected by age than the B cell compartment. Furthermore, we demonstrate that priming early in life have a big influence on the immune response in the aged individual. Priming with a TI form of the carbohydrate dextran B512 (Dx) induces a reduction of IgG levels in later TD responses against Dx. We have evaluated possible mechanisms for this reduction. The reduction does not seem to be caused by clonal exhaustion or antibody mediated mechanisms. We also showed that the reduced TD response after TI priming can be induced against another molecule than Dx. With the hypothesis that TI antigens induce a plasma cell biased maturation of the responding B cells, we examined the presence of Blimp-1, a master regulator of plasma cell differentiation, in GCs induced by TD and TI antigen. Blimp-1 was found earlier in GCs induced by TI antigen and the staining intensity in these GCs was stronger than in TD antigen induced GCs, indicating that plasma cells might be continuously recruited from these GCs. B cells undergoing the GC reaction are thought to be under a strict selection pressure that removes cells with low affinity for the antigen and also cells that have acquired self-reactivity. We investigated the effect of apoptotic deficiencies on the accumulation of somatic mutations in GC B cells. In mice lacking the death receptor Fas, lpr mice, the frequency of mutations was increased but the pattern of the mutations did not differ from wild type mice. In contrast, mice over-expressing the anti-apoptotic protein Bcl-2, had a lowered frequency of mutations and the mutations introduced had other characteristics.

Abstract -1 The immune response occurred in the mice infected with Angiostrongylus cantonensis was mainly humoral immune response. This study was designed to compare the systemic and localized humoral immune responses occurred after primary and secondary infections in C57BL/6J mice. Eight weeks after the primary infection with 20 third-stage larvae, each mouse received a second inoculation of the same dosage. Specific serum IgM, IgG and IgE were found in the second week after primary infection. However, the titers of IgG1 and IgG2b increased at the fourth week after primary infection. Antibodies of these mentioned increased continuously as the progress of infection. On the other hand, the IgM and IgG1 titers increased in brain tissue infusion since the forth week after primary infection, while the titer of IgG start to elevate at the sixth week. Nevertheless, the increase of IgG2B was only noticed at the sixth week and no significant change was observed for IgG2a and IgE. After the secondary infection, serum IgM titers increased while the titer of IgG1 in the brain tissue infusion decreased. Results of Western blot showed that IgG1and IgE in the brain tissue infusion lost the ability to recognize a 42 kDa molecule of the somatic and excreting-secreting antigens of fifth-stage larvae. These variations could be used in the diagnosis of the early stage of mice that re-infected with Angiostrongylus cantonensis. Abstract -2 The radiographic lateral views of the skulls of the mice infected with Angiostrongylus cantonensis were taken. Thus, the parietofrontal index ( PI ) was obtained by measuring and calculating the distances among specific positions on their skulls. Compared with the controls, a significant elevation over the top of the crania of the cases was observed sixty days post-infection. In addition, the phenomenon emerged apparently during the second to the fourth week post-infection. These findings are able to be applied as the external diagnostic references for the infection course of mice infected with Angiostrongylus cantonensis.

Submitted by Hiolanda Rêgo (hiolandarego@gmail.com) on 2016-08-22T15:42:47Z No. of bitstreams: 1 Tese_ICS_ José Vasconcelos Lima Oliveira.pdf: 540159 bytes, checksum: 47dbc8499e63f844012184f4cc1bfab4 (MD5) / Approved for entry into archive by Delba Rosa (delba@ufba.br) on 2016-08-31T11:46:18Z (GMT) No. of bitstreams: 1 Tese_ICS_ José Vasconcelos Lima Oliveira.pdf: 540159 bytes, checksum: 47dbc8499e63f844012184f4cc1bfab4 (MD5) / Made available in DSpace on 2016-08-31T11:46:18Z (GMT). No. of bitstreams: 1 Tese_ICS_ José Vasconcelos Lima Oliveira.pdf: 540159 bytes, checksum: 47dbc8499e63f844012184f4cc1bfab4 (MD5) / Considerando a grande dificuldade em identificar e excluir animais com infecções subclínicas de Corynebacterium pseudotuberculosis nos programas de biotecnologia da reprodução, foram analisados aspectos das respostas imune celular e humoral de caprinos infectados experimentalmente com uma cepa selvagem de C. pseudotuberculosis. Foram determinados os valores séricos de IgG e IgM total e específico anti- C. pseudotuberculosis, contagem total e diferencial dos leucócitos de sangue periférico e os níveis da produção de interferon-γ por células de sangue total. Utilizaram-se seis grupos experimentais assim distribuídos: G I – ovariectomizados + C. pseudotuberculosis; G II – estrógeno + C. pseudotuberculosis; G III – ciclo estral + C. pseudotuberculosis; G IV – Progesterona + C. pseudotuberculosis; G V – Animais machos + C. pseudotuberculosis; G VI – Controle. Os resultados obtidos na utilização do antígeno secretado como revelador da ativação dos componentes humoral e celular na resposta imune do hospedeiro caprino, na comparação das médias dos índices de produção do IFN- لا entre as coletas dos diversos grupos experimentais, não apresentaram diferenças (p > 0,05), como também entre as respostas dos índices do antígeno com mitógeno PWM e com PBS. Observou-se nas fêmeas redução do número total de leucócitos, ficando abaixo da média normal da espécie, e no grupo dos animais masculinos houve um aumento do número total dos leucócitos, comparado com o grupo controle e as médias leucocitárias descritas na literatura. Concluiu-se que as alterações fisiológicas nas fêmeas e nos machos podem ser causadas pelos hormônios utilizados nos respectivos grupos experimentais. Não foi observada influência (p>0,05) sobre os níveis séricos de imunoglobulinas (IgG e IgM) entre os grupos experimentais tratados. Porém, os anticorpos IgG específicos foram bem caracterizados com diferença (p < 0,05) entre os grupos infectados experimentalmente e o grupo não infectado (controle).

Made available in DSpace on 2015-11-18T13:20:34Z (GMT). No. of bitstreams: 2 debora_mattos_ioc_mest_2014.pdf: 25027935 bytes, checksum: 36794f8df745a06c2879690ef1660179 (MD5) license.txt: 1748 bytes, checksum: 8a4605be74aa9ea9d79846c1fba20a33 (MD5) Previous issue date: 2015-04-14 / Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Rio de Janeiro, RJ, Brasil / A susceptibilidade de Rhodnius prolixus ao T. rangeli depende da cepa do parasita e das interações moleculares no intestino e na hemocele do vetor. T. rangeli pode modular a resposta imune do vetor, preparando o hospedeiro à invasão e a sobrevivência dos parasitas na hemocele, superando assim as adversidades encontradas nos diferentes órgãos do inseto. Neste trabalho, são discutidos os mecanismos destas interações, destacando também o papel da microbiota intestinal e outros mecanismos importantes para o desenvolvimento do parasita. Inicialmente nossas investigações foram realizadas para comparar aspectos da imunidade celular e humoral de ninfas de 4º e 5º estádio de R. prolixus em resposta a uma infecção oral com a cepa Macias de T. rangeli. Na infecção oral em 4º estádio (acompanhamento em longo prazo), não foi observada diferença na mortalidade e muda ao comparar com os insetos controle não infectados. Constatou-se um número aumentado de flagelados no intestino das ninfas de 5º estádio durante o curso da infecção. Também, não houve alteração significativa na contagem de microagregados hemocitários (nódulos) em infecções de 4º estádio, enquanto em ninfas infectadas em 5º estádio houve um aumento no número de nódulos. Por outro lado, não houve diferença no número de hemócitos em ambas as infecções Demonstramos nos dois tipos de infecção oral com T. rangeli em R. prolixus, em comparação com os insetos controle não infectados, que o intestino médio atenuou a atividade de fenoloxidase, aumentou as atividades antibacterianas testadas in vitro contra Serratia marcescens, e alterou a expressão relativa de genes que codificam para defensinas (DefA, DefB, DefC), prolixicina e lisozimas (LisAe LisB). Isto sugere a influência destas atividades sobre a contagem de unidades formadoras de colônias, encontradas diminuídas no trato digestivo do inseto. Em uma segunda etapa do estudo, foram comparadas as respostas de defesa em ninfas de 5º estádio de R. prolixus inoculadas com T. rangeli, cepas Macias e H14. A cepa Macias de T. rangeli não aumentou a mortalidade desses insetos, apresentou capacidade de sobreviver e se multiplicar na hemolinfa, aumentou o número de hemócitos, e induziu alta atividade de fenoloxidase. Em contraste, estes mesmos parâmetros medidos em insetos inoculados com a cepa H14 de T. rangeli foram diferentes daqueles encontrados com inoculação de insetos usando a cepa Macias. Conclui-se que R. prolixus responde de forma distinta frente a vias de infecção oral ou por inoculação com T. rangeli, sugerindo que a capacidade infectiva deste protozoário, pode ser alterada por modulação do sistema imune do vetor

Made available in DSpace on 2014-06-11T19:31:12Z (GMT). No. of bitstreams: 0 Previous issue date: 2004Bitstream added on 2014-06-13T21:02:24Z : No. of bitstreams: 1 giometti_j_dr_botfmvz.pdf: 479475 bytes, checksum: 5a083a25e321335dd33e91917eeffa20 (MD5) / Universidade Estadual Paulista (UNESP) / With the objective of to evaluate the effect of the addition of orgainc chromium in the humoral immune response against rabies, five Neloreþs bovine breed groups with 15 animals each, were supplementeds with chromium yeast being the group GC (control), GV (vaccinated and without chromium), GV+8,5 (vaccinated + 8,5 ppm of chromium), GV+17 (vaccinated + 17 ppm of chromium) and GV+34 (vaccinated +34 ppm of chromium). Serum samples of this animals were analyseds with serum neutralization test (SN) in albines mices in the days 30,60 and 90 pos -vaccination. Simultaneously, serum concentrations of the chromium were determinated for analysis with spectrophotometer of atomic absorption in graphite oven and analysis of the cortisol was achieved through of the radioimmunoassay.These results allows to conclude that the animals of the group GV+34 have persistence of the protector's antibody titulation anti rabies until 90 days pos- vaccination. This response does not dependt of the cortisol levels, since the chromium donþt show to be effective to decrease its levels.