Potential immunological markers for diagnosis of human strongyloidiasis using heterologous antigens

Abstract

Strongyloides venezuelensis is a parasitic nematode of rodents that is frequently used to obtain heterologous antigens for immunological diagnosis of human strongyloidiasis. The aim of this study was to identify antigens from filariform larvae of S. venezuelensis for immunodiagnosis of human strongyloidiasis. Soluble and membrane fractions from filariform larvae of S. venezuelensis were obtained in phosphate saline (SS and SM) and in Tris-HCl buffer (TS and TM), and were analysed by Western blotting. Different antigenic components were recognized by IgG antibodies from the sera of strongyloidiasis patients. Highest recognition was observed for a 30-40 kDa mass range present in all antigenic fractions. The band encompassing this mass range was then excised and subjected to mass spectrometry for protein identification. Immunoreactive proteins identified in the soluble fractions corresponded to metabolic enzymes, whereas cytoskeletal proteins and galectins were more abundant in the membrane fractions. These results represent the first approach towards identification of S. venezuelensis antigens for use in immunodiagnostic assays for human strongyloidiasis.

Diagnosis of strongyloides stercoralis infection in immunocompromised patients: problems and perspectives / Diagnóstico da infecção por strongyloides stercoralis em pacientes imunocomprometidos: problemas e perspectivas

“…In contrast, several immunological tests, with increased sensitivity and specificity, have been proposed for the diagnosis of Strongyloides stercoralis human infection. The ELISA test has been highlighted mainly by the practicality of the analysis of several samples together, while Western blotting is indicated by the recognition of antigenic protein fractions of the parasite (12)(13)(14) . However, the use of these methods has some limitations, such as cross-reactivity with other helminthic infections, serological positivity resulting from previous Strongyloides stercoralis infections or, even, low sensitivity in immunocompromised patients.…”

“…On the other hand, the development and implementation of new studies involving proteomic techniques will be of fundamental importance for the accurate serological diagnosis of Strongyloides stercoralis infection in the future (13)(14)(19)(20) . In this context, using the Strongyloides venezuelensis heterologous species as an alternative source for antigen production, proteins recognized by antibodies present in the sera of patients with strongyloidiasis has been evaluated (14) .…”

Immunoreactivity of proteins within 30-40 kDa range during the acute and the recovery phases in rats experimentally infected with Strongyloides venezuelensis

“…Electrophoresis and Western blotting were performed as previously described 6 . Briefly, approximately 140 µg (2 µg/mm of gel) of the antigenic fractions (SAg and MAg) underwent electrophoresis in 12% polyacrylamide gel (SDS-PAGE) for 2 h (20 mA).…”

Análise proteômica dos estágios evolutivos de larva filarioide e fêmea parasita de Strongyloides venezuelensis

“…83,84 Os recentes estudos têm demonstrado a possiblidade de utilização das galectinas no imunodiagnóstico da estrongilodiíase humana e experimental 118 . A galectina foi destacada em estudos proteômicos como um alvo promissor para o diagnóstico da infecção por S. stercoralis 75,122 . Além disso, foi recentemente demonstrada a expressão diferencial das galectinas nos produtos de secreção/excreção de diferentes estágios de S. ratti 77,118…”

“…Goulart de Carvalho et al 152 demonstraram bandas imunorreativas de 17, 38 e 50kDa usando extratos alcalinos de larvas de S. venezuelensis na estrongiloidiase experimental.Pode-se destacar que no presente estudo ocorreu o reconhecimento da banda de 30-40kDa nas fases aguda e de recuperação da infecção. Essa faixa de massa tem sido citada por vários autores75,122,155 como sendo de grande importância para o diagnóstico de estrongiloidíase humana. O nosso grupo 122 identificou as proteínas presentes na faixa de 30-40kDa utilizando a proteômica, e dentre os constituintes proteicos tem-se destaque para as galectinas.…”