Immunodiagnosis of human neurocysticercosis by using semi- purified scolex antigens from Taenia solium cysticerci Imunodiagnóstico da neurocisticercose humana usando antígenos semipurificados de escolex de cisticercos de Taenia solium

Crude antigen and semi-purified proteins from scolices of Taenia solium cysticerci were evaluated for the immunodiagnosis of human neurocysticercosis neurocysticercosis. Semi-purified proteins obtained by electrophoresis on polyacrylamide gel and by electroelution were tested by means of the immunoenzymatic reaction against sera from normal individuals and from patients with neurocysticercosis or other parasitic diseases. The 100kDa protein provided 100% sensitivity and specificity in the immunodiagnosis. When 95 or 26kDa proteins were used, 95 and 100% sensitivity and specificity were obtained, respectively. The assays involving crude antigen and sera from normal individuals or from patients with neurocysticercosis, diluted to 1:256, gave excellent agreement with those in which 100, 95 or 26kDa proteins were tested against the same serum samples diluted to 1:64. (Kappa: 0.95 to 1.00). Crude scolex antigen may be useful for serological screening, while 100, 95 or 26kDa protein can be used in confirmatory tests on neurocysticercosis-positive cases. Key-words: Taenia solium. Human neurocysticercosis. Semi-purified proteins. Immunodiagnosis. RESUMO Antígeno bruto e proteínas semipurificadas de escóleces de cisticercos de Taenia solium foram avaliados para o imunodiagnóstico da neurocisticercose humana neurocisticercose. As proteínas semipurificadas, obtidas por eletroforese em gel de poliacrilamida e eletroeluição, foram testadas na reação imunoenzimática contra soros de indivíduos normais e de pacientes com neurocisticercose ou outras parasitoses. A proteína de 100kDa proporcionou 100% de sensibilidade e especificidade no imunodiagnóstico. Quando a proteína de 95 ou 26kDa foi empregada, foram obtidos 95 e 100% de sensibilidade e especificidade, respectivamente. Os ensaios envolvendo antígeno bruto e soros de indivíduos normais ou de pacientes com neurocisticercose, diluídos a 1:256, tiveram ótima concordância com aqueles onde a proteína de 100, 95 ou 25kDa foi testada contra os mesmas amostras de soro diluídas a 1:64 (Kappa: 0,95 a 1,00). O antígeno bruto de escolex poderá ser empregado na triagem sorológica enquanto a proteína de 100, 95 ou 26kDa nos testes confirmatórios dos casos positivos de NC. Palavras-chaves: Taenia solium. Neurocisticercose humana. Proteínas semipurificadas. Imunodiagnóstico. 1. Departamento de Parasitologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, MG. 2. Departamento de Neurologia, Faculdade de Medicina, Universidade Federal de Minas Gerais, Belo Horizonte, MG. 3. Divisão de Epidemiologia e Controle de Doenças, Instituto Octávio Magalhães, Fundação Ezequiel Dias, Belo Horizonte, MG. Supported by Coordenação de Aperfeiçoamento de Pessoal de Nível Superior and Fundação de Amparo a Pesquisa de Minas Gerais. Address to: Prof. Evaldo Nascimento. Depto de Parasitologia//ICB/UFMG. Av. Presidente Antonio Carlos 6627, Pampulha, 31270-901 Belo Horizonte, MG, Brasil. Fax: 55 31-3499-2859 e-mail: [email protected] Recebido para publicação em 23/9/2005 Aceito em 8/2/2007 Cerebral cysticercosis, also known as neurocysticercosis (NC), is the most frequent parasitic infection of the human central nervous system (CNS) and is the main cause of epilepsy in underdeveloped countries.Degenerating larvae may cause severe damage to nerve tissue because of inflammatory reactions surrounding the infected area, with subsequent collagen deposition. Complex hydrocephalic syndrome, edema and further complications because of larvae calcification are also important clinical manifestations, and these lead to neurological disorders . Neurocysticercosis is difficult to diagnose because of the dimensions, quantities and localization of cysticerci in the CNS. The diagnostic methods include neuroimaging and immunological and histological techniques. Computed tomography and magnetic resonance are formally indicated for diagnosing NC, but the costs relating to these procedures make it difficult for most of the population with high infection rates in developing countries to have access to these services. Moreover, doubts concerning images may occur and auxiliary diagnostic methods are required . Immunoenzymatic tests