CAMILA APARECIDA DE CARVALHO
Projetos de Pesquisa
Unidades Organizacionais
LIM/49 - Laboratório de Protozoologia, Hospital das Clínicas, Faculdade de Medicina
4 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.
- 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.
- Natural versus Recombinant Viral Antigens in SARS-CoV-2 Serology: Challenges in Optimizing Laboratory Diagnosis of COVID-19(2020) MEIRELES, Luciana Regina; SILVA, Angelica Moura Freixeira da; CARVALHO, Camila Aparecida; KESPER, Norival; GALISTEO JR., Andres Jimenez; SOARES, Camila Pereira; ARAUJO, Danielle Bastos; DURIGON, Edison Luiz; OLIVEIRA, Danielle Bruna Leal; MORGANTI, Ligia; CHURA-CHAMBI, Rosa Maria; ANDRADE JR., Heitor Franco deOBJECTIVES: COVID-19 is a public health emergency of international concern whose detection in recovered asymptomatic patients is dependent on accurate diagnosis as it enables the estimation of the susceptibility of the population to the infection. This demand has resulted in the development of several commercial assays employing recombinant proteins, but the results of these assays are not reliable as they do not involve comparison with natural viral antigens. We independently used the SARS-CoV-2 whole viral antigen (WVA) and recombinant nucleocapsid protein (rNP) to develop in-house ELISAs for IgG detection; the results of these ELISAs were then compared to obtain reliable results. METHODS: WVA and rNP ELISAs were performed on COVID-19 negative sera from patients before the pandemic in Brazil, and on RT-qPCR-positive or SARS-CoV-2-IgG against rNP and IgG against WVA-positive samples from recently infected patients in Sao Paulo, Brazil. RESULTS: Both ELISAs detected a large fraction of infected patients but exhibited certain drawbacks. Higher signals and lower numbers of false-negatives were observed in rNP ELISA; however, a higher fraction of false-ositives was observed in control groups. A high number of false-negatives was observed with WVA ELISA. Correlating the results of rNP and WVA ELISAs resulted in improved performance for COVID-19 diagnosis. CONCLUSION: The choice of antigen is an important aspect in optimizing the laboratory diagnosis of COVID-19. The use of rNP ELISA for the detection of anti-SARS-CoV-2 IgG antibodies seems promising, but comparison of the results with those of WVA ELISA is crucial for accurate test development prior to commercialization. IgG serology using several assays, and with the spectral patterns of SARS-CoV-2, resulted in confusing information that must be clarified before the establishment of diagnostic serology criteria.
- 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.