LUIZ FELIPE DOMINGUES PASSERO
Projetos de Pesquisa
Unidades Organizacionais
LIM/50 - Laboratório de Patologia das Moléstias Infecciosas, Hospital das Clínicas, Faculdade de Medicina
4 resultados
Resultados de Busca
Agora exibindo 1 - 4 de 4
- Salivary gland homogenates from wild-caught sand flies Lutzomyia flaviscutellata and Lutzomyia (Psychodopygus) complexus showed inhibitory effects on Leishmania (Leishmania) amazonensis and Leishmania (Viannia) braziliensis infection in BALB/c mice(2014) FRANCESQUINI, Fernanda C.; SILVEIRA, Fernando T.; PASSERO, Luiz Felipe D.; TOMOKANE, Thaise Y.; CARVALHO, Ana Kely; CORBETT, Carlos Eduardo P.; LAURENTI, Marcia D.During the natural transmission of Leishmania parasites, the infected sand fly female regurgitates promastigotes into the host's skin together with its saliva. It has been reported that vector saliva contains immunomodulatory molecules that facilitate the establishment of infection. Thus, the main objective of this study was to evaluate the specificity of Lutzomyia (Lu.) flaviscutellata and Lu.(Psychodopygus) complexus salivas on the infectivity of Leishmania (L.) (Leishmania) amazonensis and L.(Viannia) braziliensis, respectively. BALB/c mice were inoculated into the skin of hind footpad with L.(L.) amazonensis and L.(V.) braziliensis promastigotes in the absence or presence of Lu.flaviscutellata and Lu.(P.) complexus salivary gland homogenates (SGHs). The evolution of the infection was evaluated by lesion size, histopathological analysis and determination of the parasite load in the skin biopsies collected from the site of infection at 4 and 8weeks PI. The lesion size and the parasite load of both groups of mice infected in the presence of SGHs were smaller than the control groups. The histopathological features showed that the inflammatory reaction was less prominent in the groups of mice infected in the presence of both SGHs when compared to the control group. The results showed that the presence of SGHs of Lu.flaviscutellata and Lu.(P.) complexus led to induction of processes that were disadvantageous to parasite establishment during infection by L.(L.) amazonensis and L.(V.) braziliensis. An inhibitory effect on Leishmania infection could be observed in both groups inoculated with SGHs, especially when the SGH from Lu.(P.) complexus was used.
- Leishmania (V.) braziliensis and L. (L.) amazonensis promote differential expression of dendritic cells and cellular immune response in murine model(2012) CARVALHO, A. K.; SILVEIRA, F. T.; PASSERO, L. F. D.; GOMES, C. M. C.; CORBETT, C. E. P.; LAURENTI, M. D.The expression of Langerhans cell (LC) and dermal dendritic cell (dDC) as well as T CD4+ and CD8+ immune responses was evaluated in the skin of BALB/c mice experimentally infected by L. (L.) amazonensis (La) and L. (V.) braziliensis (Lb). At 4th and 8th weeks post infection (PI), skin biopsies were collected to determine the parasite load and CD207+, CD11c+, CD4+, CD8+, iNOS+ cellular densities. Cytokine (IFN-?, IL-4 and IL-10) profiles were also analysed in draining lymph node. At 4th week, the densities of CD207+ and CD11c+ were higher in the La infection, while in the Lb infection, these markers revealed a significant increase at 8th week. At 4th week, CD4+ and CD8+ were higher in the La infection, but at 8th week, there was a substantial increase in both markers in the Lb infection. iNOS+ was higher in the Lb infection at 4th and 8th weeks. In contrast, the parasite load was higher in the La infection at 4th and 8th weeks. The concentration of IFN-? was higher in the Lb infection, but IL-4 and IL-10 were higher in the La infection at 4th and 8th weeks. These results confirm the role of the Leishmania species in the BALB/c mice disease characterized by differences in the expression of dendritic cells and cellular immune response.
- Leishmania (Viannia) shawi purified antigens confer protection against murine cutaneous leishmaniasis(2012) PASSERO, Luiz Felipe Domingues; CARVALHO, Ana Kely; BORDON, Maria Luiza A. C.; BONFIM-MELO, Alexis; TOYAMA, Marcos Hikari; CORBETT, Carlos Eduardo Pereira; LAURENTI, Marcia DalastraLeishmania (Viannia) shawi was characterized only recently, and few studies concerning the immunogenic and protective properties of its antigens have been performed. The present study aimed to evaluate the protective potential of the five antigenic fractions isolated from L. (V.) shawi promastigotes in experimental cutaneous leishmaniasis. Soluble antigen from L. (V.) shawi promastigotes was submitted to reverse phase HPLC to purify F1, F2, F3, F4 and F5 antigens. BALB/c mice were immunized once a week for two consecutive weeks by subcutaneous routes in the rump, using 25 mu g protein. After 1 week, groups were challenged in the footpad with L. (V.) shawi promastigotes. After 8 weeks, those same mice were sacrificed and parasite burden as well as the cellular and humoral immune responses were evaluated. F1 and F5-immunized mice restrained lesion progression and parasite load in the skin. However, only the F1 group was able to control the parasitism in lymph nodes, which was associated with low IL-4 and high IFN-gamma production; IgG2a isotype was increased in this group. Immunizations with F2, F3 and F4 antigens did not protect mice. The capability of antigens to restrain IL-4 levels and increase IFN-gamma was associated with protection, such as in immunization using F1 antigen.
- Proteins of Leishmania (Viannia) shawi confer protection associated with Th1 immune response and memory generation(2012) PASSERO, Luiz Felipe D.; CARVALHO, Ana Kely; BORDON, Maria L. A. C.; BONFIM-MELO, Alexis; CARVALHO, Karina; KALLAS, Esper G.; SANTOS, Bianca B. A.; TOYAMA, Marcos H.; PAES-LEME, Adriana; CORBETT, Carlos E. P.; LAURENTI, Marcia D.Background: Leishmania (Viannia) shawi parasite was first characterized in 1989. Recently the protective effects of soluble leishmanial antigen (SLA) from L. (V.) shawi promastigotes were demonstrated using BALB/c mice, the susceptibility model for this parasite. In order to identify protective fractions, SLA was fractionated by reverse phase HPLC and five antigenic fractions were obtained. Methods: F1 fraction was purified from L. (V.) shawi parasite extract by reverse phase HPLC. BALB/c mice were immunized once a week for two consecutive weeks by subcutaneous routes in the rump, using 25 mu g of F1. After 1 and 16 weeks of last immunization, groups were challenged in the footpad with L. (V.) shawi promastigotes. After 2 months, those same mice were sacrificed and parasite burden, cellular and humoral immune responses were evaluated. Results: The F1 fraction induced a high degree of protection associated with an increase in IFN-gamma, a decrease in IL-4, increased cell proliferation and activation of CD8(+)T lymphocytes. Long-term protection was acquired in F1-immunized mice, associated with increased CD4(+) central memory T lymphocytes and activation of both CD4+ and CD8(+) T cells. In addition, F1-immunized groups showed an increase in IgG2a levels. Conclusions: The inductor capability of antigens to generate memory lymphocytes that can proliferate and secrete beneficial cytokines upon infection could be an important factor in the development of vaccine candidates against American Tegumentary Leishmaniasis.