Taenia saginata metacestode antigenic fractions without affinity to concanavalin A are an important source of specific antigens for the diagnosis of human neurocysticercosis.

Taenia saginata metacestode antigens have been constituted a useful alternative antigen for neurocysticercosis (NC) serodiagnosis, particularly due to an increasing difficulty to obtain Taenia solium homologous antigen. Cross-reactivity with Echinococcus granulosus infection occurs in homologous and heterologous antigens and could be avoided by using different purified methods. The present study evaluated antigen fractions obtained from saline extracts of T. saginata metacestodes purified by affinity chromatography with jacalin or concanavalin A (ConA) lectins to detect IgG antibodies by enzyme-linked immunosorbent assay (ELISA) and immunoblot analysis to diagnose human NC. Serum samples were collected from 142 individuals: 40 of them were diagnosed with NC, 62 presented Taenia sp. and other parasites, and 40 were apparently healthy individuals. The jacalin- and ConA-unbound fractions demonstrated sensitivity and specificity higher than those of bound fractions. Among unbound fractions, ConA demonstrated statistically higher sensitivity and specificity by ELISA (90% and 93.1%, respectively). By immunoblot assay, the 64- to 68-kDa component from the ConA-unbound fraction showed 100% sensitivity and specificity, making this component suitable for use as a specific antigen for diagnosis of NC. To our knowledge, this is the first report showing the relevance of using the unbound ConA fraction of T. saginata metacestodes to diagnose NC. In conclusion, the results obtained herein clearly demonstrate that antigenic fractions without affinity to ConA, obtained from T. saginata metacestodes, are an important source of specific peptides and are efficient in the diagnosis of NC when tested by immunoblot assay.

Saline extract of Taenia saginata metacestodes as an alternative antigen for the immunodiagnosis of neurocysticercosis in human cerebrospinal fluid.

The aim of the present research was to test the application of Taenia saginata metacestodes as an alternative antigen for use in enzyme-linked immunosorbent assay (ELISA) and Western Blotting (WB) tests compared with the use of metacestodes antigen of Taenia solium in cerebrospinal fluid (CSF) samples. The samples were obtained from 35 patients with definitive neurocysticercosis (NCC)-group 1-and 44 patients with other neurological disorders (control)-group 2. The sensitivity and specificity of ELISA, using antigen obtained from T. solium, applied to the patients of group 1 yielded results of 100%. When the tests were conducted using T. saginata metacestodes, results were 100% and 93.2%, respectively. The 47-52-, 64-68-, and 70-kDa antigens showed high frequencies in CSF samples from patients with NCC when WB was conducted with both antigens. The results indicate that T. saginata metacestodes can be used as an alternative antigen for the diagnosis of human NCC in CSF samples.

Application of Taenia saginata metacestodes as an alternative antigen for the serological diagnosis of human neurocysticercosis.

Serological tests are an important tool for the diagnosis of neurocysticercosis (NCC), the disease caused by Taenia solium metacestodes. The aim of the present research was to test the application of Taenia saginata metacestodes as an alternative antigen for use in the immunofluorescence antibody test (IFAT), enzyme-linked immunosorbent assay (ELISA), and Western blotting (WB) tests compared with the metacestodes antigen of T. solium in serum samples. The samples were obtained from 130 individuals: 20 from patients with definitive NCC, Group 1; 18 from individuals infected by Taenia sp., Group 2; 40 from individuals infected by various parasites, Group 3; and 40 from healthy individuals, Group 4. The sensitivity of IFAT, ELISA, and WB using antigen obtained from T. solium applied to the patients of Group 1 yielded results of 85, 95, and 95%, respectively, for the three tests. When the tests were conducted using T. saginata metacestodes, results were 75, 80, and 85%, respectively. The specificity of IFAT, ELISA, and WB using antigen obtained from T. solium yielded results of 94.9, 88.8, and 93.9%. When the tests were conducted using T. saginata metacestodes, results were 95.9, 88.8, and 93.6%, respectively. No statistical differences for sensitivity or specificity among the antigens were found. In conclusion, the results indicated that T. saginata metacestodes can be used as an alternative antigen for NCC diagnosis.

Anti-Taenia solium metacestode IgG antibodies in serum samples from inhabitants of a central-western region of Brazil.

A total of 354 serum samples from inhabitants who frequent the Clinical Laboratory in Catalão, Goiás, in the central-western region of Brazil, were collected from June to August, 2002. The samples were evaluated by indirect immunofluorescence antibody tests and an enzyme linked immunosorbent assay in order to detect anti-Taenia solium metacestode IgG antibodies. Reactive and inconclusive samples were tested by Western blotting (WB). Considering WB as a confirmation, the frequency of antibodies in the serum samples of the above population was 11.3% (CI 5.09-17.51). The immunodominant bands most frequently recognized in WB were 64-68 kDa (97.5%) and 47-52 kDa (80%). The percentage of seropositivity to cysticercosis was significantly higher for individuals residing in areas without sewage systems (p < 0.0001). In conclusion, the results indicate a probable endemic situation of cysticercosis in this population. These results reinforce the urgent need for control and prevention measures to be taken by the local public health services.

Anti-Taenia solium metacestode IgG antibodies in serum samples from inhabitants of a central-western region of Brazil

Um total de 354 amostras de soro de habitantes que freqüentaram o Laboratório Clínico em Catalão, Goiás, na região centro-oeste do Brasil, foram colhidas no período de junho a agosto de 2002. As amostras foram avaliadas pelo teste de imunofluorescência indireta e enzyme-linked immunosorbent assay (ELISA) com o objetivo de detectar anticorpos IgG anti-metacestódeo de Taenia solium. As amostras reativas e inconclusivas foram testadas pelo Western blotting (WB). Considerando WB como reação confirmatória, a freqüência de anticorpos nas amostras de soro da população estudada foi 11,3% (IC: 5,09 - 17,51). As bandas imunodominantes mais frequentemente reconhecidas no WB foram 64-68 kDa (97,5%) e 47-52 kDa (80%). A porcentagem de soropositividade para cisticercose foi significativamente maior nos indivíduos que residiam em áreas sem sistema de esgoto (p < 0,0001). Concluiu-se que os resultados indicam uma provável situação de endemicidade para cisticercose nesta população, reforçando a urgente necessidade de medidas de controle e prevenção que devem ser implantadas pelo serviço de saúde pública local.