Navegando por Autor "Grimaldi Junior, Gabriel"
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Item Antibody responses induced by Leish-Tec®, an A2-basedvaccine for visceral leishmaniasis, in a heterogeneous caninepopulation.(2014) Testasicca, Miriam Conceição de Souza; Santos, Mariana Silva dos; Machado, Leopoldo Marques; Serufo, Ângela Vieira; Doro, Daniel; Avelar, Daniel Moreira de; Tibúrcio, Ana Maria Leonardi; Abrantes, Christiane de Freitas; Coelho, George Luiz Lins Machado; Grimaldi Junior, Gabriel; Gazzinelli, Ricardo Tostes; Fernandes, Ana Paula Salles MouraZoonotic visceral leishmaniasis (VL) is a widespread disease, and dogs are the main reser-voirs for human parasite transmission. Hence, development of an effective vaccine thatprevents disease and reduces the transmission of VL is required. As euthanasia of seropos-itive dogs is recommended in Brazil for VL epidemiological control, to include anti-VLcanine vaccines as a mass control measure it is necessary to characterize the humoralresponses induced by vaccination and if they interfere with the reactivity of vaccinateddogs in serological diagnostic tests. Leish-Tec®is an amastigote-specific A2 recombinantprotein vaccine against canine visceral leishmaniasis (CVL) that is commercially availablein Brazil. Here, we tested the immunogenicity of Leish-Tec®in a heterogeneous dog popula-tion by measuring A2-specific antibody responses. Healthy dogs (n = 140) of various breedswere allocated to two groups: one group received Leish-Tec®(n = 70), and the other groupreceived a placebo (n = 70). Anti-A2 or anti-Leishmania promastigote antigen (LPA) antibodylevels were measured by ELISA in serum samples collected before and after vaccination.An immunochromatographic test (DPP) based on the recombinant K28 antigen was alsoused for serodiagnosis of CVL. Vaccinated animals, except one, remained seronegative foranti-LPA total IgG and anti-K28 antibodies. Conversely, seropositivity for anti-A2 total IgGantibodies was found in 98% of animals after vaccination. This value decreased to 81.13% at6 months before rising again (98%), after the vaccination boost. Anti-A2 IgG2 and IgG1 titers.Item Making an anti-amastigote vaccine for visceral leishmaniasis : rational, update and perspectives.(2012) Fernandes, Ana Paula Salles Moura; Coelho, Eduardo Antônio Ferraz; Coelho, George Luiz Lins Machado; Grimaldi Junior, Gabriel; Gazzinelli, Ricardo TostesVisceral leishmaniasis is a major health problem in Latina America, as well as the Mediterranean region of Europe and Asia. We aimed to develop a vaccine against visceral leishmaniasis targeting the intracellular amastigotes, which is the parasite stage that persists throughout infections with Leishmania parasites. With this in mind, we identified an amastigote specific antigen (A2) that contains an immunogenic epitope for CD4+ T helper (Th) cells and multiple repetitive units encoding CD8+ cytotoxic T lymphocyte (CTL) epitopes. Vaccine formulations containing the recombinant A2 associated with saponin, alum and IL-12 or expressed by attenuated adenovirus were shown to be protective in mice, dogs and nonhuman-primates. We are currently identifying novel amastigote specific immunogenic proteins that could be aggregated to A2 to further improve the level of vaccineinduced cell-mediated immunity and protection against visceral leishmaniasis.Item Multi-antigen print immunoassay (MAPIA)-based evaluation of novel recombinant Leishmania infantum antigens for the serodiagnosis of canine visceral leishmaniasis.(2015) Oliveira, Isaac Queiroz de; Silva, Rodrigo Araujo; Sucupira, Michel Vergne; Silva, Edmilson Domingos da; Reis, Alexandre Barbosa; Grimaldi Junior, Gabriel; Fraga, Deborah Bittencourt Mothé; Veras, Patrícia Sampaio TavaresBackground: Domestic dogs are the principal reservoir hosts of Leishmania infantum in regions where visceral leishmaniasis (VL) is endemic. Although serologic methods are frequently used for the screening of infected dogs, antibody-based tests require further assessment, due to lack of sensitivity and specificity. In this study, we employed a multi-antigen printing immunoassay (MAPIA) to compare the antibody responses to novel recombinant proteins of L. infantum with the potential for the detection of canine VL. Findings: MAPIA strips were prepared employing 12 recombinant proteins. Antibody reactivity to these antigens was compared using a panel of sera collected from clinically asymptomatic (n = 16) and symptomatic (n = 41) culture-positive animals. Our findings showed that the canine immune response to antigen differs between dogs and depends on infection status. Using this screening assay, when five out of the 12 antigens were combined, an overall 81% detection rate of L. infantum-infected dogs was achieved. Conclusions: We conclude that MAPIA is an effective screening tool to rapidly select multiple antigens of diagnostic utility to be used in a more sensitive point of care diagnostic test such as the Dual-Path Platform (DPP) multiplex test for the rapid detection of infected dogs.