Navegando por Autor "Ottino, Jennifer"
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Item Nanoformulations with Leishmania braziliensis antigens triggered controlled parasite burden in vaccinated golden hamster (Mesocricetus auratus) against visceral leishmaniasis.(2022) Ottino, Jennifer; Leite, Jaqueline Costa; Melo Júnior, Otoni Alves de Oliveira; Cabrera González, Marco Antonio; Carvalho, Tatiane Furtado de; Garcia, Giani Martins; Batista, Maurício Azevedo; Silveira, Patrícia; Cardoso, Mariana Santos; Bueno, Lilian Lacerda; Fujiwara, Ricardo Toshio; Santos, Renato Lima; Paes, Paulo Ricardo de Oliveira; Lemos, Denise da Silveira; Martins Filho, Olindo Assis; Galdino, Alexsandro Sobreira; Chávez Fumagalli, Miguel Angel; Dutra, Walderez Ornelas; Mosqueira, Vanessa Carla Furtado; Giunchetti, Rodolfo CordeiroLeishmaniasis is a widespread vector-borne disease in Brazil, with Leishmania (Leishmania) infantum as the primary etiological agent of visceral leishmaniasis (VL). Dogs are considered the main reservoir of this parasite, whose treatment in Brazil is restricted to the use of veterinary medicines, which do not promote a parasitological cure. Therefore, efficient vaccine development is the best approach to Canine Visceral Leishmaniasis (CVL) control. With this in mind, this study used hamsters (Mesocricetus auratus) as an experimental model in an anti-Leishmania preclinical vaccine trial to evaluate the safety, antigenicity, humoral response, and effects on tissue parasite load. Two novel formulations of nanoparticles made from poly(D, L-lactic) acid (PLA) polymer loading Leishmania braziliensis crude antigen (LB) exhibiting two different particle sizes were utilized: LBPSmG (570 nm) and LBPSmP (388 nm). The results showed that the nanoparticles were safe and harmless to hamsters and were antigenic with the induction in LBSap, LBPSmG, and LBPSmG groups of total anti-Leishmania IgG antibodies 30 days after challenge, which persists 200 days in LBSap and LBPSmP. At the same time, a less pronounced hepatosplenomegaly in LBSap, LBPSmG, and LBPSmP was found when compared to control groups, as well as a less pronounced inflammatory infiltrate and granuloma formation in the spleen. Furthermore, significant reductions of 84%, 81%, and 90% were observed in spleen parasite burden accessed by qPCR in the LBSap, LBPSmG, and LBPSmP groups, respectively. In this way, LBSap, LBPSmG, and LBPSmP formulations showed better results in vaccinated and L. infantum-challenged animals in further reducing parasitic load in the spleen and attenuating lesions in liver and splenic tissues. This results in safe, harmless nanoformulation vaccines with significant immunogenic and infection control potential. In addition, animals vaccinated with LBPSmP had an overall reduction in parasite burden in the spleen, indicating that a smaller nanoparticle could be more efficient in targeting antigen-presenting cells.Item Replacement of Leishmania (Leishmania) infantum populations in an endemic focus of visceral leishmaniasis in Brazil.(2022) Valdivia Rodríguez, Hugo Oswaldo; Roatt, Bruno Mendes; Baptista, Rodrigo de Paula; Ottino, Jennifer; Santos, Anderson Coqueiro dos; Sanders, Mandy J.; Reis, Alexandre Barbosa; Cotton, James A.; Bartholomeu, Daniella CastanheiraVisceral leishmaniasis is an important global health problem with an estimated of 50,000 to 90,000 new cases per year. VL is the most serious form of leishmaniasis as it can be fatal in 95% of the cases if it remains untreated. VL is a particularly acute problem in Brazil which contributed with 97% of all cases reported in 2020 in the Americas. In this country, VL affects mainly the poorest people in both urban and rural areas and continues to have a high mortality rate estimated around 8.15%. Here, we performed a temporal parasite population study using whole genome sequence data from a set of 34 canine isolates sampled in 2008, 2012 and 2015 from a re-emergent focus in Southeastern Brazil. Our study found the presence of two distinct sexual subpopulations that corresponded to two isolation periods. These subpopulations diverged hundreds of years ago with no apparent gene flow between them suggesting a process of rapid replacement during a two-year period. Sequence comparisons and analysis of nucleotide diversity also showed evidence of balancing selection acting on transport-related genes and antigenic families. To our knowledge this is the first population genomic study showing a turn-over of parasite populations in an endemic region for leishmaniasis. The complexity and rapid adaptability of these parasites pose new challenges to control activities and demand more integrated approaches to understand this disease in New World foci.Item Vaccination with formulation of nanoparticles loaded with Leishmania amazonensis antigens confers protection against experimental visceral leishmaniasis in hamster.(2023) Cabrera González, Marco Antonio; Gonçalves, Ana Alice Maia; Ottino, Jennifer; Leite, Jaqueline Costa; Resende, Lucilene Aparecida; Melo Júnior, Otoni Alves de Oliveira; Silveira, Patricia; Cardoso, Mariana Santos; Fujiwara, Ricardo Toshio; Bueno, Lilian Lacerda; Santos, Renato Lima; Carvalho, Tatiane Furtado de; Garcia, Giani Martins; Paes, Paulo Ricardo de Oliveira; Galdino, Alexsandro Sobreira; Chávez Fumagalli, Miguel Angel; Melo, Marilia Martins; Lemos, Denise da Silveira; Martins Filho, Olindo Assis; Dutra, Walderez Ornelas; Mosqueira, Vanessa Carla Furtado; Giunchetti, Rodolfo CordeiroVisceral leishmaniasis (VL) is a fatal disease caused by the protozoa Leishmania infantum for which dogs are the main reservoirs. A vaccine against canine visceral leishmaniasis (CVL) could be an important tool in the control of human and CVL by reducing the infection pressure of L. infantum. Despite the CVL vaccine available on the market, the Brazilian Ministry of Health did not implement the use of it in their control programs. In this sense, there is an urgent need to develop more efficient vaccines. In this study, the association between two polymeric nanoformulations, (poly (D, L-lactic) acid (PLA) polymer) loading Leishmania amazonensis antigens, was evaluated as a potential immunobiological agent against VL using golden hamsters as an experimental model. The results indicated that no significant adverse reactions were observed in animals vaccinated with LAPSmP. LAPSmP presented similar levels of total anti-Leishmania IgG as compared to LAPSmG. The LAPSmP and LAPSmG groups showed an intense reduction in liver and spleen parasitic load by qPCR. The LAPSmP and LAPSmG vaccines showed exceptional results, indicating that they may be promising candidates as a VL vaccine.