HEITOR FRANCO DE ANDRADE JUNIOR
Projetos de Pesquisa
Unidades Organizacionais
Departamento de Patologia, Faculdade de Medicina - Docente
LIM/49 - Laboratório de Protozoologia, Hospital das Clínicas, Faculdade de Medicina - Líder
LIM/49 - Laboratório de Protozoologia, Hospital das Clínicas, Faculdade de Medicina - Líder
14 resultados
Resultados de Busca
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- Understanding hypergammaglobulinemia in experimental or natural visceral leishmaniasis(2024) CARVALHO, Camila Aparecida de; HIRAMOTO, Roberto Mitsuyoshi; MEIRELES, Luciana Regina; ANDRADE, Heitor Franco deNonspecific hypergammaglobulinemia (HGG) occurs in symptomatic human visceral leishmaniasis (VL) caused by L. L. infantum. This study assessed this finding in experimental infection in hamsters and natural infection in dogs. The serum concentration of proteins, albumin and globulins was determined through the biuret and bromocresol green reaction, where the HGG was better expressed through the albumin/globulin (A/G) ratio. HGG was associated with a higher concentration of specific anti-glycan antibodies (BSA-G)/promastigote soluble extract (PSE) and the presence of circulating immune complexes (IC) by dissociative enzyme-linked immunoassay (ELISA). The study found monovalent IC in 37.9% (PSE) and 50% (BSA-G) of sera from infected hamsters, with increased frequency as the disease progressed. HGG was found in >60% of the samples in dogs with VL, associated with higher levels of specific immunoglobulin (Ig)A and IgM, but not IgG, determined using the PSE and BSA-G ELISA. HGG was associated with the presence of monovalent IC in 58.9% (PSE) and 63.4% (BSA-G) positive dog samples. HGG may result not only from the nonspecific activation of B cells, with greater production of specific and nonspecific antibodies, but also due to lower IgG excretion due to the presence of soluble monovalent IC. HGG correlates to the progression of VL and may be a marker for manifested disease.
- The oral transmission of chagas disease in Brazil: New food supplies and travel experience(2019) FUJITA, Dennis Minoru; NASCIMENTO, Marilda Savoia; ANDRADE JUNIOR, Heitor Franco de
- Early high avidity specific IgG production in experimental hamster visceral leishmaniasis(2020) CARVALHO, Camila Aparecida de; FERRAO, Thiago Fidelis; CAVALCANTE, Fernanda Siqueira; FREITAS, Flavia Regina Novais de; MEIRELES, Luciana Regina; ANDRADE JUNIOR, Heitor Franco deVisceral leishmaniasis (VL) byLeishmania (Leishmania) infantumis epidemic in Brazil. Hypergammaglobulinemia appears early in patients with VL and is ineffective. Usually, high-affinity IgG B cells are selected during most infections, a critical step for an effective humoral response. The avidity of IgG antibodies in VL is unexplored due to the absence of temporal parameters in most patients, associated to low clinical significance. Experimental infection models overcome this fact, allowing the monitoring of the disease temporal evolution. In this study, the avidity of IgG antibodies was evaluated in experimental models, in infection in hamsters, and in immunization in rabbits. Specific IgG antibodies were detected by ELISA, using chaotropic solution to determine avidity, as reported for viral infections. The levels of IgG antibodies correlated with the progression of experimental infection in hamsters or antigenic stimulation in immunized rabbits. However, IgG avidity was high early in infected animals, even in early periods (> 80%), while in immunized rabbits, they had early antibodies of low avidity with progressive maturation, similar as other infections. These data suggest that the affinity maturation of the avidity of anti-LeishmaniaIgG antibodies promoted at an early stage, influencing the appropriate interaction between antigens and affecting the disease progression. This fact could be associated to monovalent immune complexes, as reported in human and experimental VL. This scenario may be related to an independent process of immune cell activation by the parasite but absent in antigen preparation used as immunogens.
- In vitro efficacy of Coriandrum sativum, Lippia sidoides and Copaifera reticulata against Leishmania chagasi(2012) RONDON, Fernanda Cristina Macedo; BEVILAQUA, Claudia Maria Leal; ACCIOLY, Marina Parissi; MORAIS, Selene Maia de; ANDRADE-JUNIOR, Heitor Franco de; CARVALHO, Camila Aparecida de; LIMA, Josemar Coelho; MAGALHAES, Hilton Cesar RodriguesThe increased incidence of visceral leishmaniasis (VL) in Brazil is due to a lack of effective disease control measures. In addition to that, no effective treatment exists for canine VL in response to synthetic drugs. Thus, the objective of this study was to evaluate the effect of the essential oils of Coriandrum sativum and Lippia sidoides, and oleoresin from Copaifera reticulata, on Leishmania chagasi promastigotes and amastigotes. We also examined the toxicity of these treatments on the murine monocyte cell line RAW 264.7. To determine the IC50 a MTT test (3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) was performed on promastigotes, and an in situ ELISA assay was conducted on amastigotes. Here, we demonstrate that oleoresin from C. reticulata was effective against both promastigotes (IC50 of 7.88 mu g.mL(-1)) and amastigotes (IC50 of 0.52 mu g.mL(-1)), and neither of the two treatments differed significantly (p > 0.05) from pentamidine (IC50 of 2.149 mu g.mL(-1)) and amphotericin B (IC50 of 9.754 mu g.mL(-1)). Of the three plant oils tested, only oleoresin showed no toxicity toward monocyte, with 78.45% viability after treatment. Inhibition of promastigote and amastigote growth and the lack of cytotoxicity by C. reticulata demonstrate that oleoresin may be a viable option for analyzing the in vivo therapeutic effects of leishmanicidal plants
- Effect of chaotropes in Chagas disease and leishmaniasis cross-reacting serology assays for epidemiological surveys(2018) SANTOS, Anderson Pacheco dos; CARVALHO, Maria Esther de; MEIRELLES, Luciana Regina; ANDRADE JUNIOR, Heitor Franco deIntroduction: Serological cross-reactivity between leishmaniasis and Chagas disease, especially at low titers, leads to difficulties of the seroepidemiological interpretation. Methods: We have studied the ability of urea as a chaotrope to select high-avidity antibodies in IgG ELISA, thus reducing low-avidity IgG cross-reactivity in serologically positive samples in both assays. Results: Using 0.5M urea for diluting the sample efficiently defined leishmaniasis or double infections in high-avidity IgG ELISA and eliminated false-positive results. Conclusions: The use of a chaotropic diluting agent is useful for improving the specificity of Chagas disease and leishmaniasis immunoassays.
- Isolation and characterization of Toxoplasma gondii isolates from human congenital toxoplasmosis cases reveal a new virulent genotype in Sao Paulo, Brazil(2022) MEIRELES, Luciana Regina; BEZERRA, Elizama Carneiro Machado; ANDRADE, Joelma Queiroz; CASSIANO, Larissa Aparecida; PENA, Hilda Fatima Jesus; ALVES, Bruna Farias; FRANCISCO, Rossana Pulcineli Vieira; JR, Heitor Franco de AndradeToxoplasma gondii causes severe disease in congenitally infected fetuses. The severity of fetal infection is related to the gestational stage at the time of maternal infection, parasite burden, and genotypic characteristics. South America has a high incidence of congenital toxoplasmosis and has the highest genotypic diversity of the parasite. In Brazil, clinical toxoplasmosis in children is notorious, however there are very limited data regarding the strains recovered from congenital infections. In this study, T. gondii strains from two cases of severe congenital toxoplasmosis from the Sao Paulo metropolitan area were isolated (TgHumIMTBr2 and TgHumIMTBr3) and biologically and molecularly characterized using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) and microsatellite analysis, revealing a new non-archetypal virulent genotype designated as #318. The other isolate, genotype #175, has already been described in domestic and wild animals in Brazil, but is now associated with acute toxoplasmosis in humans. These data reinforce the role of non-archetypal T. gondii genotypes in the severity of human congenital toxoplasmosis, highlighting the importance of studies focused on parasite isolation and genotyping for a better understanding of the virulence of isolates from human toxoplasmosis and contributing to the knowledge of the diversity of T. gondii in Brazil.
- Leishmanicidal activity in vitro of Musa paradisiaca L. and Spondias mombin L. fractions(2012) ACCIOLY, Marina Parissi; BEVILAQUA, Claudia Maria Leal; RONDON, Fernanda C. M.; MORAIS, Selene Maia de; MACHADO, Lyeghyna K. A.; ALMEIDA, Camila A.; ANDRADE JR., Heitor Franco de; CARDOSO, Roselaine P. A.Visceral leishmaniasis (VL) is a zoonotic disease characterized by infection of mononuclear phagocytes by Leishmania chagasi. The primary vector is Lutzomyia longipalpis and the dog is the main domestic reservoir. The control and current treatment of dogs using synthetic drugs have not shown effectiveness in reducing the incidence of disease in man. In attempt to find new compounds with leishmanicidal action, plant secondary metabolites have been studied in search of treatments of VL. This study aimed to evaluate the leishmanicidal activity of Musa paradisiaca (banana tree) and Spondias mombin (cajazeira) chemical constituents on promastigotes and amastigotes of L. chagasi. Phytochemical analysis by column chromatography was performed on ethanol extracts of two plants and fractions were isolated. Thin layer chromatography was used to compare the fractions and for isolation the substances to be used in vitro tests. The in vitro tests on promastigotes of L chagasi used the MTT colorimetric method and the method of ELISA in situ was used against amastigotes besides the cytotoxicity in RAW 264.7 cells. Of the eight fractions tested, Sm1 and Sm2 from S. mombin had no action against promastigotes, but had good activity against amastigotes. The fractions Mp1 e Mp4 of M. paradisiaca were very cytotoxic to RAW 264.7 cells. The best result was obtained with the fraction Sm3 from S. mombin with IC50 of 11.26 mu g/ml against promastigotes and amastigotes of 0.27 mu g/ml. The fraction Sm3 characterized as tannic acid showed the best results against both forms of Leishmania being a good candidate for evaluation in in vivo tests. (C) 2012 Published by Elsevier B.V.
- Biodistribution of meglumine antimoniate in healthy and Leishmania (Leishmania) infantum chagasi-infected BALB/c mice(2013) BORBOREMA, Samanta Etel Treiger; OSSO JUNIOR, Joao Alberto; ANDRADE JUNIOR, Heitor Franco de; NASCIMENTO, Nanci doPentavalent antimonials such as meglumine antimoniate (MA) are the primary treatments for leishmaniasis, a complex disease caused by protozoan parasites of the genus Leishmania. Despite over 70 years of clinical use, their mechanisms of action, toxicity and pharmacokinetics have not been fully elucidated. Radiotracer studies performed on animals have the potential to play a major role in pharmaceutical development. The aims of this study were to prepare an antimony radiotracer by neutron irradiation of MA and to determine the biodistribution of MA in healthy and Leishmania (Leishmania) infantum chagasi-infected mice. MA (Glucantime (R)) was neutron irradiated inside the IEA-R1 nuclear reactor, producing two radioisotopes, Sb-122 and Sb-124, with high radionuclidic purity and good specific activity. This irradiated compound presented anti-leishmanial activity similar to that of non-irradiated MA in both in vitro and in vivo evaluations. In the biodistribution studies, healthy mice showed higher uptake of antimony in the liver than infected mice and elimination occurred primarily through biliary excretion, with a small proportion of the drug excreted by the kidneys. The serum kinetic curve was bi-exponential, with two compartments: the central compartment and another compartment associated with drug excretion. Radiotracers, which can be easily produced by neutron irradiation, were demonstrated to be an interesting tool for answering several questions regarding antimonial pharmacokinetics and chemotherapy.
- Serum antibodies blocked by glycan antigens in canine visceral leishmaniasis serology are mostly IgA immune complexes(2021) CARVALHO, Camila Aparecida de; HIRAMOTO, Roberto Mitsuyoshi; MEIRELES, Luciana Regina; ANDRADE JUNIOR, Heitor Franco deImmune complexes (ICs) are found in canine visceral leishmaniasis (CVL) and interfere with the serum detection of antibodies. Dissociation of these monovalent complexes by dissociative enzyme-linked immunosorbent assay (ELISA) removes false-negative results and allows some characterization of antibodies and antigens. We studied the serology of dogs with suspected CVL in an endemic area, testing two Leishmania (Leishmania) [L. (L.)] infantum antigens. We analysed the presence of immunoglobulin G (IgG), immunoglobulin A (IgA) and immunoglobulin M (IgM) antibodies specific to promastigote soluble extract (PSE) and low-molecular weight glycans (glycan-bovine serum albumin (BSA) complex - GBC) by conventional and dissociative ELISA. Our results showed a significant fraction of IgA ICs (46.5% for PSE and 47.6% for GBC), followed by IgG ICs (10% for PSE and 23.5% for GBC). IgM ICs were more frequent for PSE (22.7%). Hypergammaglobulinaemia in CVL would be related to the presence of IgA and IgG ICs, resulting in deficient elimination of these antibodies. Our data confirmed the presence of ICs that can generate false-negative results in conventional serology. The production of IgA antibodies and the high frequency of blockade by glycan antigens suggest the active participation of this immunoglobulin and its ICs in the immunopathology of CVL, indicating a new path for further research.
- A simple immune complex dissociation ELISA for leishmaniasis: Standardization of the assay in experimental models and preliminary results in canine and human samples(2013) CARVALHO, Camila Aparecida de; PARTATA, Anette Kelsei; HIRAMOTO, Roberto Mitsuyoshi; BORBOREMA, Samanta Etel Treiger; MEIRELES, Luciana Regina; NASCIMENTO, Nanci do; ANDRADE JR., Heitor Franco deVisceral leishmaniasis, caused by Leishmania (Leishmania) chagasi, is a chronic parasitic disease of humans and dogs. Confirmation of the protozoal agent in bone marrow, lymph node or spleen aspirate is diagnostic, while specific-IgG serology is used mainly for epidemiology despite the general presence of high levels of serum immunoglobulin. Anecdotal reports of false-negative serology in active disease cases are known and are ascribed to the formation of immune complexes. Because dissociation of immune complexes can be accomplished by acid treatment, we devised a simple, routine enzyme immunoassay (ELISA) for the dissociation of immune complexes in serum samples using acid treatment in wells adsorbed with Leishmania antigen (dELISA). Confirmatory acid dot-blot was also developed for antigen detection by anti-Leishmania rabbit antiserum. In experimental L. chagasi hamster models, immune complexes interfered with ELISA mostly in the 30 and 60 days postinfection, according to both dELISA and antigen dot-blot results. In larger samples from endemic areas, dELISA was positive in 10% of seronegative dog samples (7/70) and 3.5% in negative human samples (3/88), showing that dELISA could be used in the serodiagnosis of visceral leishmaniasis. Moreover, dELISA could be used as an alternative approach to screening asymptomatic visceral leishmaniasis patients, instead of invasive confirmatory testing.