Severe Plasmodium vivax malaria exhibits marked inflammatory imbalance

<p>Abstract</p> <p>Background</p> <p>Despite clinical descriptions of severe vivax malaria cases having been reported, data regarding immunological and inflammatory patterns are scarce. In this report, the inflammatory and immunological status of both mild and severe vivax malaria cases are compared in order to explore immunopathological events in this disease.</p> <p>Methods and Results</p> <p>Active and passive malaria case detections were performed during 2007 in Buritis, Rondônia, in the Brazilian Amazon. A total of 219 participants enrolled the study. Study individuals were classified according to the presence of <it>Plasmodium vivax </it>infection within four groups: non-infected (n = 90), asymptomatic (n = 60), mild (n = 50) and severe vivax infection (n = 19). A diagnosis of malaria was made by microscopy and molecular assays. Since at present no clear criteria define severe vivax malaria, this study adapted the consensual criteria from falciparum malaria. Patients with severe <it>P. vivax </it>infection were younger, had lived for shorter time in the endemic area, and recalled having experienced less previous malaria episodes than individuals with no malaria infection and with mild or asymptomatic infection. Strong linear trends were identified regarding increasing plasma levels of C reactive protein (CRP), serum creatinine, bilirubins and the graduation of disease severity. Plasma levels of tumour necrosis factor (TNF), interferon-gamma(IFN-gamma) and also IFN-gamma/interleukin-10 ratios were increased and exhibited a linear trend with gradual augmentation of disease severity. Both laboratory parameters of organ dysfunction and inflammatory cytokines were reduced during anti-parasite therapy in those patients with severe disease.</p> <p>Conclusion</p> <p>Different clinical presentations of vivax malaria infection present strong association with activation of pro-inflammatory responses and cytokine imbalance. These findings are of utmost importance to improve current knowledge about physiopathological concepts of this serious widespread disease.</p

Lutzomyia longipalpis Saliva Triggers Lipid Body Formation and Prostaglandin E2 Production in Murine Macrophages

After the injection of saliva into the host's skin by sand flies, a transient erythematous reaction is observed, which is related to an influx of inflammatory cells and the release of various molecules that actively facilitate the blood meal. It is important to understand the specific mechanisms by which sand fly saliva manipulates the host's inflammatory responses. Herein, we report that saliva from Lutzomyia (L.) longipalpis, a widespread Leishmania vector, induces early production of eicosanoids. Intense formation of intracellular organelles called lipid bodies (LBs) was noted within those cells that migrated to the site of saliva injection. In vitro and ex vivo, sand fly saliva was able to induce LB formation and PGE2 release by macrophages. Interestingly, PGE2 production induced by L. longipalpis saliva was dependent on intracellular mechanisms involving phosphorylation of signaling proteins such as PKC-α and ERK-1/2 and subsequent activation of cyclooxygenase-2. Thus, this study provides new insights into the pharmacological properties of sand fly saliva and opens new opportunities for intervening with the induction of the host's inflammatory pathways by L. longipalpis bites

Enhanced Leishmania braziliensis Infection Following Pre-Exposure to Sandfly Saliva

Parasites of the genus Leishmania cause a variety of diseases known as leishmaniasis, that are transmitted by bites of female sand flies that, during blood-feeding, inject humans with parasites and saliva. It was shown that, in mice, immunity to sand-fly saliva is able to protect against the development of leishmaniasis. We have investigated, in the present study, whether this finding extends the sand fly species Lutzomyia intermedia, which is responsible for transmission of Leishmania braziliensis, a parasite species able to cause destructive skin lesions that can be fatal if left untreated. We observed that mice injected with sand fly saliva develop a specific immune response against salivary proteins. Most importantly, however, this immune response was unable to protect mice against a challenge infection with L. braziliensis, indicating that exposure to this sand fly saliva is harmful to the host. Indeed, subjects with cutaneous leishmaniasis have a higher immune response against L. intermedia saliva. These findings indicate that the anti-saliva immune response to sand fly saliva plays an important role in the outcome of leishmaniasis caused by L. braziliensis, in both mice and humans, and emphasize possible hurdles in the development of vaccines based on sand fly saliva

Avaliação da resposta imune celular nas leishmanioses cutânea e visceral humanas

Submitted by Repositório Arca ([email protected]) on 2019-09-04T17:23:29Z No. of bitstreams: 1 license.txt: 1748 bytes, checksum: 8a4605be74aa9ea9d79846c1fba20a33 (MD5)Approved for entry into archive by Ana Maria Fiscina Sampaio ([email protected]) on 2019-09-11T11:46:12Z (GMT) No. of bitstreams: 2 Jorge Clarencio Souza Andrade Avaliação...2005.pdf: 90493673 bytes, checksum: 010719bf62c91eb2c7ee7f185af3261b (MD5) license.txt: 1748 bytes, checksum: 8a4605be74aa9ea9d79846c1fba20a33 (MD5)Made available in DSpace on 2019-09-11T11:46:12Z (GMT). No. of bitstreams: 2 Jorge Clarencio Souza Andrade Avaliação...2005.pdf: 90493673 bytes, checksum: 010719bf62c91eb2c7ee7f185af3261b (MD5) license.txt: 1748 bytes, checksum: 8a4605be74aa9ea9d79846c1fba20a33 (MD5) Previous issue date: 2005CPqGM/FIOCRUZ-LIMI-LIP, CNPq, TRMC.Universidade Federal da Bahia. Faculdade de Medicina. Salvador, BA, Brasil / Fundação Oswaldo Cruz. Centro de Pesquisas Gonçalo Moniz. Salvador, BA, Brasil.Na LCL existe urna elevada resposta imune celular, e isto pode estar associado à presença de clones bastante reativos, sendo sua identificação muito relevante. Uma das abordagens para avaliar o papel de agentes infecciosos sobre o sistema imune é a análise do padrão dos receptores antigénicos expressos pelos linfócitos que participam ativamente das respostas específicas contra estes agentes. Técnicas imunológicas como a citometria de fluxo, tomam exeqüível examinar a expressão de genes variáveis a e p dos receptores antigénicos de células T. Na LV existe urna ausência de resposta imune celular que pode ser atribuida a deleção de determinados clones de células T, como pela diminuição na expressão de ligantes e moléculas de adesão ou apoptose ñas células responsivas. Neste trabalho tivemos como objetivo avaliar os mecanismos imunológicos relacionados a hiperativação celular que é observada na leishmaniose cutânea localizada e a anergia que é observada na leishmaniose visceral. Nossos dados indicaram que em LCL: i) existe expressão diferencial no repertorio T VP porém não apresentou nenhuma deleção nem hiper reatividade clonal frente a L. amazonensis, ex vivo e in vitro; ii) apresentou resposta compartimentalizada no linfonodo drenante somente em células T CDS"^; iii) uma ativação oligoclonal das células T após 60 dias de imunização com vacina anti-leishmaniose nas células T CD4^ e CD8^; iv) uma expressão diferencial do TCR Vpi2 como sendo o clone mais relacionado à infecção causada pela Leishmania amazonensis e v) correlação positiva entre a expansão de células T CD4'^ e CD8^ TCR Vpi2 e a produção rápida de IFN-y na resposta imune in vivo em indivíduos vacinados e in vitro em indivíduos sadios. Na LV os dados indicaram; i) em pacientes antes do tratamento imia diminuição da expressão de a IL-2R em células T CD4^ e CDS"^ não estimulados e não proliferação in vitro pelo ensaio da blastogênese; ii) houve imi aumento da expressão de a IL-2R em células T CD4^ e CDS"^ de pacientes pré-tratamento em células estimuladas com antígeno; iii) a expressão de repertório T Vp em células 004"^ e CDS"^ e expressão de CD28 e CTLA-4 não sofi-eram alteração quando comprados pré e pós-tratamento; iv) houve uma diminuição na expressão de CD 18 em células T CD8"^ e uma diminuição na expressão de CD45Ro tanto em células T CD4'^ quanto em células T CDS"^, ex vivo, nos pacientes pré-tratamento; v) houve aumento na incorporação de anexina V ex vivo e diminuição in vitro em células T CD4"*^ e CD8'^ como também aumento ex vivo na expressão de Fas (CD95) em células T CD4’*’ e CD8"^. Podemos concluir que infecção por L. amazonensis no hospedeiro humano induz modulação na expressão de genes codificadores para a cadeia Vp do TCR das células T CD4^ e CD8"^, com expansão marcante de células do tipo Vpi2 e que a anergia observada na LV humana parece estar relacionada ao desenvolvimento de múltiplos fatores, como modulação negativa em moléculas de ativação, moléculas de adesão e indução de apoptose em células T responsivas. Estes fatores podem estar levando a uma ineficiência nas atividades protetoras desenvolvidas pelas células T, facilitando assim a produção dos mecanismos de sobrevivência do parasito dentro dos macrófagos de indivíduos com leishmaniose visceral.CL is characterized by an elevated cellular immune response that may be associated with highly reactive cell clones, making their identification important. One of the approaches to evaluate the role of infectious agents on the immune system is the analysis of the antigenic receptors expressed by lymphocytes that participate in the response against these agents. Immuological techniques such as flow cytometry allow us to examine the expression of variable a and (3 genes, present in the antigenic receptors of T cells. In VL, there is a lack of cellular immune response that may be attributed to the deletion of certain T cell clones, or to a decrease in ligand expression and adhesion molecules or even to the apoptosis of responder cells. In this work, we aimed at evaluating the immune mechanisms related to the hyper-activation of the cellular immune response, observed in CL and the anergy observed in VL. Our data indicate that, in CL, there is a differential expression of the Vp T repertoire. However, we did not see any clonal deletion or hyper activation of the response against L. amazonensis, ex vivo and in vitro. We also observed: i) a response localized to the draining lymph node only for CD8+ T cells, ii) oligoclonal activation of T cells 60 days post immunization with a leishmaniasis vaccine for both CD4+ and CD8+ T cells, iii) a differential expression of the TCR Vpl2, iv) a positive correlation between the expansion of T CD4"^ and CDS"^ TCR Vpi2 and rapid IFN-y in the in vivo immune response of vaccinated individuals and in the in vitro immune response of healthy individuals. In VL, our data show: i) a decrease in a IL-2R expression in both CD4^ e CD8^ T cells in patients prior to treatment, ii) a lack of in vitro proliferation, iii) an increase in a IL-2R expression in both €04"^ e CDB"^ T cells antigen stimulated, from patients prior to treatment, iv) no difference pre- and post treatment in the Vp T repertoire from both CD4^ and CDS^ T cells or in the expression of CD28 and CTLA4, v) a decrease in the expression of CD 18 in CDS'^ T cells, vi) a decrease in the expression of CD45Ro in both CD4+ and CD8"^ T cells, ex vivo, vii) in patients prior to treatment, there was an increase in the uptake of Annexin V, ex vivo, and a decrease in both 004“^ and CD8^ T cells, viii) an increase in the ex vivo expression of Fas (CD95) in both CD4'^ and CDS"^ T cells. We can conclude that the presence of L amazonensis in the vertebrate host, in CL, modulates the expression of genes that code for the TCR V|3 chain of both €04"^ and CDS"^ T cells paralleled by the marked expansion of Vpi2 cells. The presence of L. chagasi, in VL, seems to be related to the negative modulation of activation markers, adhesion molecules and induction of apoptosis in reactive T cells. These factors may lead to a deficiency in the responder T cells and their protective role. Together, this facilitates the parasite's survival mechanisms within macrophages of individuals with VL

Avaliação Ex vivo e In vitro da diversidade do repertório VB em linfócitos T de pacientes com leishmaniose cutânea localizada

Submitted by Repositório Arca ([email protected]) on 2019-07-08T18:54:10Z No. of bitstreams: 1 license.txt: 1748 bytes, checksum: 8a4605be74aa9ea9d79846c1fba20a33 (MD5)Approved for entry into archive by Ana Maria Fiscina Sampaio ([email protected]) on 2019-07-10T16:11:24Z (GMT) No. of bitstreams: 2 Jorge Clarencio Souza Andrade Avaliação...2001 (1).pdf: 3225513 bytes, checksum: de78c5b1ebaca6d7e93ffcaaf8619db4 (MD5) license.txt: 1748 bytes, checksum: 8a4605be74aa9ea9d79846c1fba20a33 (MD5)Made available in DSpace on 2019-07-10T16:11:24Z (GMT). No. of bitstreams: 2 Jorge Clarencio Souza Andrade Avaliação...2001 (1).pdf: 3225513 bytes, checksum: de78c5b1ebaca6d7e93ffcaaf8619db4 (MD5) license.txt: 1748 bytes, checksum: 8a4605be74aa9ea9d79846c1fba20a33 (MD5) Previous issue date: 2001Universidade Federal da Bahia. Faculdade de Medicina. Salvador, BA, Brasil / Fundação Oswaldo Cruz. Centro de Pesquisas Gonçalo Moniz. Salvador, BA, Brasil.Muitos trabalhos recentes na literatura em doenças infecciosas, como toxoplasmose, malária, doença de Chagas e filariose avaliaram a relação da diversidade do repertório dos linfócitos TVβ com as respectivas patologias visando identificar deleção ou hiper reatividade clonal implica da na patologia da doença. Nosso objetivo neste trabalho é avaliar o repertório TVβ através de: 1) Caracterizar o repertório TVβ em células do sangue periférico, comparando pacientes com LCL com indivíduos normais; 2) Comparar células do linfonodo com sangue periférico de pacientes com LCL; 3) Avaliar o efeito do estímulo com antígeno de Leishmania braziliensis na expressão de Vβs; 4) Comparar células de voluntários normais antes e após imunização com vacina antileismaniose. Utilizando a técnica de Citometria de Fluxo e usando anticorpos monoclonais anti TCR Vβ, anti CD4 e anti CD8, mostram uma expansão diferencial, oligoclonal, tanto para CD4+ quanto CD8+ e peptídica preferencial. Nesta análise verificamos que o gene Vβ12 foi o mais relacionado com a infecção por Leishmania braziliensis, (dados na tabela abaixo), e que os indivíduos vacinados apresentam uma grande ativação policlonal após 60 dias de imunização, mais evidenciada em CD4+. Expressão do gene V beta 12 de linfócitos T CD4+ e CD8+ na leishmaniose.Several recent studies found ine infectious disease literature (in toxoplasmosis, malaria, filariasis and Chagas’ disease, e.g.) have addressed the relationship of diversity in Vp T cell repertoire looking for deletion or hyper responsive clonal activity at different stages of infection or disease progression. Most have found a policlonal activation. We report here the observation of the T cell Vp repertoire in human cutaneous leishmaniasis (CL), using the following approaches: a) the comparasion of compare VP repertoire of peripheral blood mononuclear cells (PBMC) of CL patients to normal volunteers (NV); b) exploration of compartmentalization, by comparing cells from regional lymph nodes draining the lesion area to PBMC in CL patients; c) the evaluation of in vitro stimulation by Leishmania, by comparing lymph node cells before and after culture with Leishmania braziliensis antigen; d) the evaluation in vivo stimulation, by comparing pre- to post-vaccination responses of NV submitted to anti-leishmania vacciantion (BIOBRÁS, MG-Br). All evaluations were performed by cytofluorimetric analysis (FACSort- BD) using an extended panel of anti-TCR Vp monoclonal antibodies (Immunotech), as well as anti-CD4 and anti-CD8 monoclonal antibodies (BD). Our results indicate an oligoclonal differential and peptide preferential expansion in CD4 and oligoclonal in CD8 populations

Leishmania amazonensis infection impairs differentiation and function of human dendritic cells

Agradecimentos a C. Indiani de Oliveira pelos comentários e críticas.Submitted by Éder Freyre ([email protected]) on 2011-08-10T18:10:29Z No. of bitstreams: 1 Favali_Tavares_Clarencio_etal.pdf: 244383 bytes, checksum: eb3ffd645d94f2ecd1ac4152f0c4c1c0 (MD5)Made available in DSpace on 2011-08-10T18:10:29Z (GMT). No. of bitstreams: 1 Favali_Tavares_Clarencio_etal.pdf: 244383 bytes, checksum: eb3ffd645d94f2ecd1ac4152f0c4c1c0 (MD5) Previous issue date: 2007Este trabalho foi financiado pelo CNPq-PRONEX.Fundação Oswaldo Cruz. Centro de Pesquisas Gonçalo Moniz. Salvador, BA, BrasilFundação Oswaldo Cruz. Centro de Pesquisas Gonçalo Moniz. Salvador, BA, BrasilFundação Oswaldo Cruz. Centro de Pesquisas Gonçalo Moniz. Salvador, BA, BrasilFundação Oswaldo Cruz. Centro de Pesquisas Gonçalo Moniz. Salvador, BA, BrasilFundação Oswaldo Cruz. Centro de Pesquisas Gonçalo Moniz. Salvador, BA, Brasil / Universidade Federal da Bahia. Instituto de Ciências da Saúde. PPGIm. Salvador, BA, Brasil / Instituto de Investigação em Imunologia. São Paulo, SP, BrasilFundação Oswaldo Cruz. Centro de Pesquisas Gonçalo Moniz. Salvador, BA, Brasil / Universidade Federal da Bahia. Instituto de Ciências da Saúde. PPGIm. Salvador, BA, BrasilDendritic cells (DCs) are of utmost importance in initiating an immune response and may also function as targets for pathogens. The presence of pathogens inside DCs is likely to impair their functions and thus, influence immune responses. In the present report, we evaluated the impact of the presence of Leishmania amazonensis during differentiation and maturation of human monocyte-derived DCs. The presence of live L. amazonensis parasites during DC differentiation led to a significant decrease in CD80 (92%) and CD1a (56%) expression and an increase in CD86 (56%) cell surface expression. Phenotypic changes were accompanied by a lower secretion of IL-6, observed after 6 days of DC differentiation in the presence of L. amazonensis. DCs differentiated in the presence of L. amazonensis were used as APC in an autologous coculture, and lower amounts of IFN- were obtained compared with control DCs differentiated in the absence of parasites. The effect of heat-killed parasites, but not of Leishmania antigen, during DC differentiation and maturation was similar to that observed with viable parasites. During maturation, the presence of live L. amazonensis parasites, but not of soluble Leishmania antigen, led to a decrease in IL-6 and IL-10 production. In this way, we observed that the parasite is able to abrogate full DC differentiation, causing a delay in the immune response and likely, favoring its establishment in human hosts

Peripheral Blood Mononuclear Cells from Individuals Infected with Human T-Cell Lymphotropic Virus Type 1 Have a Reduced Capacity To Respond to Recall Antigens

Evidence indicates that human T-cell lymphotropic virus type 1 (HTLV-1) infection leads to chronic immunosuppression and a greater susceptibility to infectious diseases. Spontaneous in vitro proliferation of peripheral blood mononuclear cells (PBMC) is an important immunological feature of HTLV-1-infected individuals. However, the association between spontaneous proliferation and immunosuppression is not clear. In this study, we evaluated the cellular immune responses of PBMC from 58 asymptomatic HTLV-1-infected individuals with PBMC showing or not showing spontaneous proliferation. Individuals with PBMC that spontaneously proliferated had increased proportions of CD4 T cells expressing CD45RO and dramatically reduced responses to recall antigens. In addition, frequencies of positive responses to recall antigens were also decreased in HTLV-infected individuals without spontaneous proliferation of PBMC. There was a polyclonal expansion of multiple T-cell receptor Vβ families of CD4(+) T lymphocytes in patients with spontaneous proliferation. We observed that HTLV-1 induced an immunosuppression characterized by a decrease in the stimulation index to a recall antigen, even in individuals who did not present spontaneous proliferation. On the other hand, only patients with PBMC presenting spontaneous proliferation showed polyclonal activation and increased proportion of CD4 T cells expressing CD45RO

Toward a Novel Experimental Model of Infection To Study American Cutaneous Leishmaniasis Caused by Leishmania braziliensis

Leishmania spp. cause a broad spectrum of diseases collectively known as leishmaniasis. Leishmania braziliensis is the main etiological agent of American cutaneous leishmaniasis (ACL) and mucocutaneous leishmaniasis. In the present study, we have developed an experimental model of infection that closely resembles ACL caused by L. braziliensis. In order to do so, BALB/c mice were infected in the ear dermis with 10(5) parasites and distinct aspects of the infection were evaluated. Following inoculation, parasite expansion in the ear dermis was accompanied by the development of an ulcerated dermal lesion which healed spontaneously, as seen by the presence of a scar. Histological analysis of infected ears showed the presence of a mixed inflammatory infiltrate consisting of both mononuclear and polymorphonuclear cells. In draining lymph nodes, parasite replication was detected throughout the infection. In vitro restimulation of draining lymph node cells followed by intracellular staining showed an up-regulation in the production of gamma interferon (IFN-γ) and in the frequency of IFN-γ-secreting CD4(+) and CD8(+) T cells. Reverse transcription-PCR of ears and draining lymph node cells showed the expression of CC chemokines. The dermal model of infection with L. braziliensis herein is able to reproduce aspects of the natural infection, such as the presence of an ulcerated lesion, parasite dissemination to lymphoid areas, and the development of a Th1-type immune response. These results indicate that this model shall be useful to address questions related to the concomitant immunity to reinfection and parasite persistence leading to mucocutaneous leishmaniasis

Cellular analysis of cutaneous leishmaniasis lymphadenopathy: insights into the early phases of human disease.

Submitted by Ana Maria Fiscina Sampaio ([email protected]) on 2014-03-17T17:07:05Z No. of bitstreams: 1 Bomfim G Cellular analysis....pdf: 160243 bytes, checksum: 7473c415ca2c57947a0d2f0c249d9e2d (MD5)Made available in DSpace on 2014-03-17T17:07:05Z (GMT). No. of bitstreams: 1 Bomfim G Cellular analysis....pdf: 160243 bytes, checksum: 7473c415ca2c57947a0d2f0c249d9e2d (MD5) Previous issue date: 2007Hospital Universitário Professor Edgard Santos. Serviço de Imunologia. Salvador, BA, BrasilHospital Universitário Professor Edgard Santos. Serviço de Imunologia. Salvador, BA, BrasilFundação Oswaldo Cruz. Centro de Pesquisa Gonçalo Moniz. Salvador, BA, BrasilFundação Oswaldo Cruz. Centro de Pesquisa Gonçalo Moniz. Salvador, BA, BrasilFundação Oswaldo Cruz. Centro de Pesquisa Gonçalo Moniz. Salvador, BA, Brasil / Instituto de Investigação em Imunologia. Instituto do Milênio. Salvador, BA, BrasilFundação Oswaldo Cruz. Centro de Pesquisa Gonçalo Moniz. Salvador, BA, Brasil / Instituto de Investigação em Imunologia. Instituto do Milênio. Salvador, BA, BrasilLymphadenopathy is an early clinical sign in cutaneous leishmaniasis (CL), caused by Viannia parasites, and may help to understand the initial host response to these species of Leishmania. We report on characteristics of cells obtained from lymph nodes from cutaneous leishmaniasis patients with lymphadenopathy without ulceration (early phase, N = 21) or lymphadenopathy and ulceration (late phase, N = 29). Early-phase patients exhibited a higher proportion of neutrophils, eosinophils, and CD8+ T cells. Conversely, CD19+ B lymphocytes and plasma cells were more frequently observed in late-phase patients. The signal for IL-10 was significantly higher in late-phase patients; signals for IFN-gamma or IL-4 were similar in both groups. These data reinforce observations of an initial mixed Th1-Th2 profile as well as the early role of the CD8 T cell in cutaneous leishmaniasis. Additionally, there is a chronologic relationship between ulcer development and B-cell increase. IL-10 also increases at a late stage and may be important in limiting tissue damage