Cláudio Lúcio Rossi; Emília Emiko Hieda Takahashi; Angela Lauand Sampaio Teixeira; Sílvia de Barros-Mazon; Rose Clélia Grion Trevisan
RESUMO
Preparações antigênicas de Strongyloides stercoralis para o imunodiagnóstico da estrongiloidíase têm sido tradicionalmente obtidas pela extração de antígenos do parasita com solução salina. No presente trabalho, após obtenção da preparação antigênica de S. stercoralis com extração salina, a fração residual foi solubilizada com uréia, e as duas preparações foram avaliadas para o imunodiagnóstico da estrongiloidíase, através de uma técnica imunoenzimática. Não foram encontradas diferenças significativas entre as duas preparações, em termos de atividade antigência específica e reatividade cruzada. A dificuldade de obtenção de larvas de S. stercoralis tem sido um fator limitante para o desenvolvimento de reações mais sensíveis e específicas que possam ser empregadas no imunodiagnóstico da estrongiloidíase. A possibilidade de um maior rendimento, em termos de material antigênico ativo, abre perspectivas de fracionamento do extrato bruto do parasita, na tentativa de se encontrar frações com maior atividade antigênica específica e menor reatividade cruzada.
Palavras-chave: Strongyloides stercoralis. Estrongiloidíase. Imunodiagnóstico. Antígenos.
ABSTRACT
Aqueous-soluble (AS) antigens from larvae of Strongyloides stercoralis, extracted with phosphate- buffered saline, are traditionally used for serodiagnosis of strongyloidiasis. To identify sources of antigens for use in serodiagnosis, residual particulates from parasite larvae after aqueous extraction were solubilized with Tris-buffered 8M urea, yielding a urea-soluble (US) antigen fraction. Both AS and US antigens from S. stercoralis were evaluated by an enzyme-linked immunosorbent assay. No significalive differences were observed between AS and US antigens from the parasite regarding specific antigenic activity and cross-reactivity. lmmunoassays are highly dependent on the antigen for sensitivity and specificity. Crude extracts from S. stercoralis should be further studied, mainly in relation to antigenic fractions which could provide even more sensitive and specific results. Studies of fractionation of S. stercoralis must take into account the antigen yield of both the crude extract and fractions, since larvae of parasite are normally difficult to obtain. Considering this aspect, the results from this study are very useful, since the extraction with urea subslantialty increased the amounts of antigenic materiais normally obtained with the classical aqueous extraction.
Keywords: Strongyloides stercoralis. Strongyloidiasis. Immunodiagnosis. Antigens.
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Endereço para correspondência:
Dr. Cláudio Lúcio Rossi.
Depto. de Patologia Clínica/FCM/UNICAMP.
CP: 6111
13081-970
Campinas, SP.
Recebido para publicação em 30/12/92.
Trabalho realizado no Departamento de Patologia Clínica da Faculdade de Ciências Médicas da Universidade Estadual de Campinas, Campinas, SP.
