ABSTRACT
A neurocisticercose (NC) é uma doença provocada por larvas de Taenia solium (Tso) no sistema nervoso central. Seu diagnóstico fundamenta-se em critérios clínicos, epidemiológicos e laboratoriais. A utilização de antígenos parasitários no imunodiagnóstico apresenta desvantagens como: necessidade de animais, ausência de homogeneidade entre lotes, baixo rendimento, e contaminação com proteínas suínas. Assim, os antígenos recombinantes podem otimizar o imunodiagnóstico da NC, pois são reagentes simples e reprodutíveis, sem requerer animais. Este estudo teve como objetivo a obtenção, caracterização e análise da reatividade de proteína recombinante baseada em antígenos de líquido vesicular de Taenia crassiceps (Tcra). Assim, o cDNA foi obtido por amplificação a partir de RNAm de cisticercos de Tcra. A proteína recombinante Tc14 foi produzida em Escherichia coli (DE3) BL21 utilizando-se o vetor de expressão pET-22b e purificada por cromatografia de afinidade. A caracterização antigênica deu-se por Imunoblot (IB) utilizando anticorpos monoclonais (AcMo). Houve reatividade com todos os AcMo utilizados (AcMo anti-antígeno de excreção/secreção de Tcra, AcMo anti-líquido vesicular de Tcra, AcMo antilíquido vesicular de Tso e AcMo anti-antígeno total de Tso), exceto com o AcMo anti-antígeno de escólex de Tso. Utilizando-se 22 amostras de soro e 19 de líquor (LCR) de pacientes com NC, 48 soros e 28 LCR do grupo controle negativo (GCN) e 17 soros de hidatidose do grupo outras parasitoses (OP) em Imunoblot foi observada reatividade na região de 14kDa, correspondente a Tc14, em todas as amostras NC, mas não nos GCN e OP. Em ELISA com Tc14 obteve-se sensibilidade (S) e especificidade (E) de 100% com LCR (29 amostras de NC e 35 do GCN) e S de 95,1% e E de 100% com soro (41 amostras de NC, 52 do GCN). Dentre 51 soros de OP, mostraram-se reagentes um de hidatidose e outro de estrongiloidíase. A análise comparativa entre diferentes antígenos e testes sorológicos apresentou índice...
The neurocisticercosis (NC) disease is caused by the presence of Taenia solium (Tso) larvae in the central nervous system. Its diagnosis is based on clinical criteria, epidemiological studies and laboratorial exams. Nevertheless, the use of parasite antigenic extracts into the immunodiagnosis presents some disadvantages: it requires animals, lacks of homogeneity between lots, low yield and may become contaminated with swine proteins. Consequently, the utilization of recombinant antigens could optimize the immunodiagnostic of NC, as they are simple and reproducible reagents that do not require animals. This study aimed the capture, characterization and reactivity analysis of the recombinant protein based on antigens of the vesicular fluid of Taenia crassiceps (Tcra). In order to do so, the cDNA was obtained through the amplification deriving from RNAm of cysticerci of Tcra. The recombinant protein Tc14 was produced in Escherichia coli (DE3) BL21 using the expression vector pET-22b and purified by affinity chromatography (nickel resin). The antigenic characterization was performed by immunoblotting (IB) using monoclonal antibodies (MoAb). The recombinant protein presented reactivity with all the MoAb used (Anti-secretion/excretion antigens from Tcra MoAb, anti-vesicular fluid from Tcra MoAb, anti-vesicular fluid from Tso MoAb and anti- total antigen from Tso MoAb), except with the anti-antigen from Tso scolex MoAb. The immunoblot was performed using 22 serum samples and 19 cerebrospinal fluid (CSF) from patients with NC, 48 serum and 28 CSF from the negative control group (GCN) and 17 hydatidosis serum from other parasitosis' group (OP). It showed reactivity in the 14kDa region, correlated to Tc14, in all NC samples, but not presented on GCN and OP. In ELISA with Tc14, the sensibility (S) and specificity (E) of 100% was obtained with CSF (29 NC samples and 35 GCN samples) and 95.1% of S and 100% of E with serum (41 NC samples, 52 GCN samples)...
Subject(s)
Humans , Female , Mice , Cestoda/chemistry , In Vitro Techniques , Neurocysticercosis , Recombinant Proteins/analysis , Immunologic Tests/statistics & numerical data , Proliferating Cell Nuclear Antigen/analysis , Enzyme-Linked Immunosorbent Assay , Data Interpretation, StatisticalABSTRACT
Seven swine were experimentally infected with Taenia solium eggs and blood samples from each animal were periodically collected. At the end of the experiment (t140) the animals did not show clinical aspects of cysticercosis or parasites in tongue inspection. All animals were slaughtered and cut into thin slices in searching for cysts. The number of cysts found in each animal varied from 1 to 85. Enzyme-linked immunosorbent assay (ELISA) tests for antibody (Ab) detection and for antigen (Ag) detection were performed, which presented respectively 71 and 57 percent of positivity. By immunoblot (IB), using 18/14(T. crassiceps Ag) or lentil-lectin-purified glycoproteins from T. solium Ag (LLGP) as Ag, five (71 percent) and six (86 percent) animals were positive, respectively. The association between Ag-ELISA with any IB (18/14 or LLGP) allowed the detection of all animals at 140 days post-experimental infection (days p.e.i.). The use of IB 18/14 combined to the Ag-ELISA allowed the detection of all animals since 70 days p.e.i., and the association between IB LLGP and Ag-ELISA allowed the detection of all animals since 112 days p.e.i. While all animals could be considered healthy by conventional screening tests, the use of immunoassays for detecting Ab and Ag showed better accuracy; therefore it would be more useful than usual clinical examination for screening cysticercosis in slightly infected pigs.