In silico predicted epitopes from the COOH-terminal extension of cysteine proteinase B inducing distinct immune responses during Leishmania (Leishmania) amazonensis experimental murine infection

<p>Abstract</p> <p>Background</p> <p><it>Leishmania </it>parasites have been reported to interfere and even subvert their host immune responses to enhance their chances of survival and proliferation. Experimental <it>Leishmania </it>infection in mice has been widely used in the identification of specific parasite virulence factors involved in the interaction with the host immune system. Cysteine-proteinase B (CPB) is an important virulence factor in parasites from the <it>Leishmania (Leishmania) mexicana </it>complex: it inhibits lymphocytes Th1 and/or promotes Th2 responses either through proteolytic activity or through epitopes derived from its COOH-terminal extension. In the present study we analyzed the effects of <it>Leishmania (Leishmania) amazonensis </it>CPB COOH-terminal extension-derived peptides on cell cultures from murine strains with distinct levels of susceptibility to infection: BALB/c, highly susceptible, and CBA, mildly resistant.</p> <p>Results</p> <p>Predicted epitopes, obtained by <it>in silico </it>mapping, displayed the ability to induce cell proliferation and expression of cytokines related to Th1 and Th2 responses. Furthermore, we applied <it>in silico </it>simulations to investigate how the MHC/epitopes interactions could be related to the immunomodulatory effects on cytokines, finding evidence that specific interaction patterns can be related to <it>in vitro </it>activities.</p> <p>Conclusions</p> <p>Based on our results, we consider that some peptides from the CPB COOH-terminal extension may influence host immune responses in the murine infection, thus helping <it>Leishmania </it>survival.</p

A dysflagellar mutant of Leishmania (Viannia) braziliensis isolated from a cutaneous leishmaniasis patient

<p>Abstract</p> <p>Background</p> <p>Parasites of the <it>Leishmania </it>genus alternate between the flagellated extracellular promastigote stage and intracellular amastigotes. Here we report the characterization of a <it>Leishmania </it>isolate, obtained from a cutaneous leishmaniasis patient, which presents peculiar morphological features.</p> <p>Methods</p> <p>The parasite was cultured <it>in vitro </it>and characterized morphologically using optical and electron microscopy. Identification was performed based on monoclonal antibodies and internal ribosomal spacer typing. <it>In vitro </it>macrophage cultures, murine experimental models and sand fly infections were used to evaluate infectivity <it>in vitro </it>and <it>in vivo</it>.</p> <p>Results</p> <p>The isolate was identified as <it>Leishmania </it>(<it>Viannia</it>) <it>braziliensis</it>. In the atypical promastigotes grown in culture, a short flagellum surrounded or interrupted by a protuberance of disorganized material was observed. A normal axoneme was present close to the basal body but without elongation much further outside the flagellar pocket. A disorganized swelling at the precocious end of the axoneme coincided with the lack of a paraflagellar rod structure. The isolate was able to infect macrophages <it>in vitro</it>, induce lesions in BALB/c mice and infect <it>Lutzomyia longipalpis</it>.</p> <p>Conclusions</p> <p>Notwithstanding the lack of an extracellular flagellum, this isolate infects macrophages <it>in vitro </it>and produces lesions when inoculated into mice. Moreover, it is able to colonize phlebotomine sand flies. Considering the importance attributed to the flagellum in the successful infection and survival of <it>Leishmania </it>in the insect midgut and in the invasion of macrophages, these findings may bring new light into the infectious mechanisms of <it>L</it>. (<it>V</it>.) <it>braziliensis</it>.</p

Complete In Vitro Life Cycle of Trypanosoma congolense: Development of Genetic Tools

Trypanosoma congolense is a parasite responsible for severe disease of African livestock. Its life cycle is complex and divided into two phases, one in the tsetse fly vector and one in the bloodstream of the mammalian host. Molecular tools for gene function analyses in parasitic organisms are essential. Previous studies described the possibility of completing the entire T. congolense life cycle in vitro. However, the model showed major flaws including the absence of stable long-term culture of the infectious bloodstream forms, a laborious time-consuming period to perform the cycle and a lack of genetic tools. We therefore aimed to develop a standardized model convenient for genetic engineering. We succeeded in producing long-term cultures of all the developmental stages on long-term, to define all the differentiation steps and to finally complete the whole cycle in vitro. This improved model offers the opportunity to conduct phenotype analyses of genetically modified strains throughout the in vitro cycle and also during experimental infections

Characterization of tubulin genes in Trypanosoma rangeli

Submitted by sandra infurna ([email protected]) on 2016-06-30T15:48:44Z No. of bitstreams: 1 carlos32_morel_etal_IOC_1989.pdf: 699991 bytes, checksum: d4eff0ec6aa35110ad45c05a579558ce (MD5)Approved for entry into archive by sandra infurna ([email protected]) on 2016-06-30T15:55:36Z (GMT) No. of bitstreams: 1 carlos32_morel_etal_IOC_1989.pdf: 699991 bytes, checksum: d4eff0ec6aa35110ad45c05a579558ce (MD5)Made available in DSpace on 2016-06-30T15:55:36Z (GMT). No. of bitstreams: 1 carlos32_morel_etal_IOC_1989.pdf: 699991 bytes, checksum: d4eff0ec6aa35110ad45c05a579558ce (MD5) Previous issue date: 1989Submitted by Angelo Silva ([email protected]) on 2016-07-07T11:16:55Z No. of bitstreams: 3 carlos32_morel_etal_IOC_1989.pdf.txt: 22830 bytes, checksum: bf953707e0572a542c9fed4c98b27e0a (MD5) carlos32_morel_etal_IOC_1989.pdf: 699991 bytes, checksum: d4eff0ec6aa35110ad45c05a579558ce (MD5) license.txt: 2991 bytes, checksum: 5a560609d32a3863062d77ff32785d58 (MD5)Approved for entry into archive by sandra infurna ([email protected]) on 2016-07-07T12:24:07Z (GMT) No. of bitstreams: 3 license.txt: 2991 bytes, checksum: 5a560609d32a3863062d77ff32785d58 (MD5) carlos32_morel_etal_IOC_1989.pdf: 699991 bytes, checksum: d4eff0ec6aa35110ad45c05a579558ce (MD5) carlos32_morel_etal_IOC_1989.pdf.txt: 22830 bytes, checksum: bf953707e0572a542c9fed4c98b27e0a (MD5)Made available in DSpace on 2016-07-07T12:24:07Z (GMT). No. of bitstreams: 3 license.txt: 2991 bytes, checksum: 5a560609d32a3863062d77ff32785d58 (MD5) carlos32_morel_etal_IOC_1989.pdf: 699991 bytes, checksum: d4eff0ec6aa35110ad45c05a579558ce (MD5) carlos32_morel_etal_IOC_1989.pdf.txt: 22830 bytes, checksum: bf953707e0572a542c9fed4c98b27e0a (MD5) Previous issue date: 1989Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Departamento de Bioquímica e Biologia Molecular. Rio de Janeiro, RJ, Brasil.Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Departamento de Bioquímica e Biologia Molecular. Rio de Janeiro, RJ, Brasil.Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Departamento de Bioquímica e Biologia Molecular. Rio de Janeiro, RJ, Brasil.Tubulin genes in Trypanosoma rangeli, the only trypanosome besides 7'. cruzi to infect humans in America, are organized in homogeneous, alternate c~ and 13 gene tandem repeats of 3.8 kb. The basic repeat was cloned, mapped and partially sequenced. In contrast to most other eukaryotes, where tubulin genes are scattered throughout the genome, trypanosomatids so far studied are characterized by tandem arrangements of these genes with the genus Trypanosoma displaying an alternating a- and 13-tubulin tandem repeat

Considerações sobre o efeito de anticorpos antiflebótomos sobre parâmetros biológicos de Lutzomyia longipalpis (Lutz e Neiva, 1912) (Diptera: Psychodidae: Phlebotominae)

Submitted by Sandra Infurna ([email protected]) on 2020-02-06T12:23:08Z No. of bitstreams: 1 MLVilela_EFRangel_etal_IOC_2006.pdf: 672096 bytes, checksum: 875eb168eb1692acab74e1f88968a838 (MD5)Approved for entry into archive by Sandra Infurna ([email protected]) on 2020-02-06T12:33:42Z (GMT) No. of bitstreams: 1 MLVilela_EFRangel_etal_IOC_2006.pdf: 672096 bytes, checksum: 875eb168eb1692acab74e1f88968a838 (MD5)Made available in DSpace on 2020-02-06T12:33:42Z (GMT). No. of bitstreams: 1 MLVilela_EFRangel_etal_IOC_2006.pdf: 672096 bytes, checksum: 875eb168eb1692acab74e1f88968a838 (MD5) Previous issue date: 2006Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Departamento de Entomologia. Laboratório de Transmissores de Leishmaniose,. Rio de Janeiro, RJ, Brasil.Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Departamento de Entomologia. Laboratório de Transmissores de Leishmaniose,. Rio de Janeiro, RJ, Brasil.Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Departamento de Entomologia. Laboratório de Transmissores de Leishmaniose,. Rio de Janeiro, RJ, Brasil.Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Departamento de Bioquímica e Biologia Molecular. Laboratório de Biologia Molecular de Tripanosomatídeos e Flebotomíneos. Rio de Janeiro, RJ, Brasil.Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Departamento de Genética. Laboratório de Genética Humana. Rio de Janeiro, RJ, Brasil.Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Departamento de Entomologia. Laboratório de Transmissores de Leishmaniose,. Rio de Janeiro, RJ, Brasil.Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Departamento de Bioquímica e Biologia Molecular. Laboratório de Biologia Molecular de Tripanosomatídeos e Flebotomíneos. Rio de Janeiro, RJ, Brasil.A imunização de hospedeiros vertebrados com componentes derivados de vetores pode se constituir numa estratégia alternativa para o controle de doenças transmitidas por insetos. No presente estudo avaliamos o efeito de anticorpos antiflebótomos sobre alguns parâmetros biológicos de fêmeas de Lutzomyia longipalpis, vetor de leishmaniose visceral. Coelhos foram imunizados com extratos de tubos digestivos de fêmeas alimentadas com açúcar (GS), fêmeas alimentadas com sangue (GB), carcaças de fêmeas alimentadas com açúcar (CS) ou carcaças de fêmeas alimentadas com sangue (CB), e coelho imunizado por repetidas picadas de fêmeas de flebótomos (BITE). Os soros imunes de coelhos apresentaram títulos aumentados quando comparados com os soros pré-imunes, e bandas específicas foram detectadas por meio de Western Blot. A análise dos parâmetros biológicos revelou um decréscimo na fecundidade no grupo de fêmeas alimentadas em coelho imunizado com GB e BITE. A longevidade e a mortalidade foram estudadas em fêmeas com postura (paridas) e fêmeas sem postura (nulíparas). Fêmeas nulíparas que se alimentaram em coelho imunizado por repetidas picadas morreram em maior percentual. A análise da mortalidade, após a postura dos ovos, revelou um pico no quinto dia em todos os grupos, mas em fêmeas que se alimentaram em coelho submetido a repetidas picadas, foi antecipada para o terceiro dia.The immunization of vertebrate hosts with vector components may be an alternative for the control of diseases transmitted by insects. In the present study we evaluated the effects of anti-sandfly antibodies on some of the biological parameters of female Lutzomyia longipalpis, a vector of visceral leishmaniasis. Rabbits were immunized with extracts of gut from blood-fed (GB) or sugar-fed (GS) females, carcass of sugar-fed (CS) or blood-fed (CB) females, and with repeated sandfly bites (BITE). Immune sera showed increased antibody titers compared to pre-immunized animals, and specific bands were detected by Western Blot. An analysis of biological parameters revealed a decline in fecundity in the group of females fed on rabbits immunized with GB and BITE. Longevity and mortality were studied in females with oviposition (parous) and without oviposition (nulliparous). Nulliparous females that fed on rabbits immunized with bites died in the highest percentage. A mortality analysis after egg laying revealed a peak on the fifth day in all the groups, but females fed on rabbit subjected to repeated bites showed a shift towards the third day

Long-Term Protective Immune Response Elicited by Vaccination with an Expression Genomic Library of Toxoplasma gondii

Immunization of BALB/c mice with an expression genomic library of Toxoplasma gondii induces a Th1-type immune response, with recognition of several T. gondii proteins (21 to 117 kDa) and long-term protective immunity against a lethal challenge. These results support further investigations to achieve a multicomponent anti-T. gondii DNA vaccine