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
- Differential Recruitment of Dendritic Cells Subsets to Lymph Nodes Correlates with a Protective or Permissive T-Cell Response during Leishmania (Viannia) Braziliensis or Leishmania (Leishmania) Amazonensis Infection(2016) CARVALHO, A. K.; CARVALHO, K.; PASSERO, L. F. D.; SOUSA, M. G. T.; MATTA, V. L. R. da; GOMES, C. M. C.; CORBETT, C. E. P.; KALLAS, G. E.; SILVEIRA, F. T.; LAURENTI, M. D.Leishmania (L.) amazonensis (La) and L. (V.) braziliensis (Lb) are responsible for a large clinical and immunopathological spectrum in human disease; while La may be responsible for anergic disease, Lb infection leads to cellular hypersensitivity. To better understand the dichotomy in the immune response caused by these Leishmania species, we evaluated subsets of dendritic cells (DCs) and T lymphocyte in draining lymph nodes during the course of La and Lb infection in BALB/c mice. Our results demonstrated a high involvement of DCs in La infection, which was characterized by the greater accumulation of Langerhans cells (LCs); conversely, Lb infection led to an increase in dermal DCs (dDCs) throughout the infection. Considering the T lymphocyte response, an increase of effector, activated, and memory CD4(+) T-cells was observed in Lb infection. Interleukin- (IL-) 4- and IL-10- producing CD4(+) and CD8(+) T-cells were present in both La and Lb infection; however, interferon-(IFN-) gamma-producing CD4(+) and CD8(+) T-cells were detected only in Lb infection. The results suggest that during Lb infection, the dDCs were the predominant subset of DCs that in turn was associated with the development of Th1 immune response; in contrast La infection was associated with a preferential accumulation of LCs and total blockage of the development of Th1 immune response.
- The Effect of Ursolic Acid on Leishmania (Leishmania) amazonensis Is Related to Programed Cell Death and Presents Therapeutic Potential in Experimental Cutaneous Leishmaniasis(2015) YAMAMOTO, Eduardo S.; CAMPOS, Bruno L. S.; JESUS, Jessica A.; LAURENTI, Marcia D.; RIBEIRO, Susan P.; KALLAS, Esper G.; RAFAEL-FERNANDES, Mariana; SANTOS-GOMES, Gabriela; SILVA, Marcelo S.; SESSA, Deborah P.; LAGO, Joao H. G.; LEVY, Debora; PASSERO, Luiz F. D.Among neglected tropical diseases, leishmaniasis is one of the most important ones, affecting more than 12 million people worldwide. The available treatments are not well tolerated, and present diverse side effects, justifying the search for new therapeutic compounds. In the present study, the activity of ursolic acid (UA) and oleanolic acid (OA) were assayed in experimental cutaneous leishmaniasis (in vitro and in vivo). Promastigote forms of L. amazonensis were incubated with OA and UA for 24h, and effective concentration 50% (EC50) was estimated. Ultraestructural alterations in Leishmania amazonensis promastigotes after UA treatment were evaluated by transmission electron microscopy, and the possible mode of action was assayed through Annexin V and propidium iodide staining, caspase 3/7 activity, DNA fragmentation and transmembrane mitochondrial potential. The UA potential was evaluated in intracellular amastigotes, and its therapeutic potential was evaluated in L. amazonensis infected BALB/c mice. UA eliminated L. amazonensis promastigotes with an EC50 of 6.4 mu g/mL, comparable with miltefosine, while OA presented only a marginal effect on promastigote forms at 100 mu g/mL. The possible mechanism by which promastigotes were eliminated by UA was programmed cell death, independent of caspase 3/7, but it was highly dependent on mitochondria activity. UA was not toxic for peritoneal macrophages from BALB/c mice, and it was able to eliminate intracellular amastigotes, associated with nitric oxide (NO) production. OA did not eliminate amastigotes nor trigger NO. L. amazonensis infected BALB/c mice submitted to UA treatment presented lesser lesion size and parasitism compared to control. This study showed, for the first time, that UA eliminate promastigote forms through a mechanism associated with programed cell death, and importantly, was effective in vivo. Therefore, UA can be considered an interesting candidate for future tests as a prototype drug for the treatment of cutaneous leishmaniasis.
- Analysis of iron superoxide dismutase-encoding DNA vaccine on the evolution of the Leishmania amazonensis experimental infection(2015) CAMPOS, B. L. S.; SILVA, T. N.; RIBEIRO, S. P.; CARVALHO, K. I. L.; KALLAS, E. G.; LAURENTI, M. D.; PASSERO, L. F. D.The present work aimed to evaluate the immunogenicity of Leishmania amazonensis iron superoxide dismutase (SOD) -encoding DNA experimental vaccine and the protective properties of this DNA vaccine during infection. The SOD gene was subcloned into the pVAX1 plasmid, and it was used to immunize BALB/c mice. Twenty-one days after the last immunization, mice were sacrificed (immunogenicity studies) or subcutaneously challenged with L. amazonensis (studies of protection), and alterations in cellular and humoral immune responses were evaluated, as well as the course of infection. Mice only immunized with pVAX1-SOD presented increased frequencies of CD4(+) IFN-gamma(+), CD8(+) IFN- gamma(+) and CD8(+) IL-4(+) lymphocytes; moreover, high levels of IgG2a were detected. After challenge, mice that were immunized with pVAX1-SOD had increased frequencies of the CD4(+) IL- 4(+), CD8(+) IFN-gamma(+) and CD8(+) IL-4(+) T lymphocytes. In addition, the lymph node cells produced high amounts of IFN-gamma and IL-4 cytokines. Increased IgG2a was also detected. The pattern of immunity induced by pVAX1-SOD partially protected the BALB/c mice from a challenge with L. amazonensis, as the animals presented reduced parasitism and lesion size when compared to controls. Taken together, these results indicate that leishmanial SOD modulates the lymphocyte response, and that the elevation in IFN-gamma possibly accounted for the decreased skin parasitism observed in immunized animals.
- 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.