Caracterização de moléculas imunodominantes de Strongyloides stercoralis e de Strongyloides venezuelensis para o diagnóstico imunológico da estrongiloidíase.

Abstract

Strongyloidiasis is a neglected parasitic disease which prevalence might be underestimated in many countries, it has a particular importance among immunosuppressed patients due to the risk of hyperinfection, which might be fatal. Early diagnosis is essential to prevent the serious forms of the disease, but the methods used nowadays involve looking larvae in the feces, technique which only raises its sensitivity through repetitions using fecal samples collected on alternate days. Immunological methods, especially the Enzyme-Linked Immunosorbent Assay (ELISA), are practical and able to test several samples at once, but still lack of standardization with an antigen easy to obtain and reproduct. The aim of this study is to evaluate the efficiency of the crude antigen extracts of S. stercoralis and S. venezuelensis and their fractions higher and lower than 100 kDa for the immunodiagnosis of human strongyloidiasis, and to identify their immunodominant molecules through Western Blotting technique. Serum samples obtained from patients with strongyloidiasis, or other helminthiasis, and healthy adults were analyzed by enzyme-linked immunosorbent assay (ELISA). The crude antigenic extract of S. stercoralis and fractions with molecular weight higher and lower than 100 kDa showed 90%, 90% and 84% sensitivity, and 95%, 98% and 95% specificity, respectively. The crude antigenic extract of S. venezuelensis and fractions with molecular weight higher and lower than 100 kDa showed 76%, 82% and 75% sensitivity, and 43%, 93% and 64% specificity, respectively. The results reached suggest that the fraction higher than 100 kDa concentrates immunodiminant molecules and its presentation as lower than 100 kDa on Western Blotting suggests that they’re organized in protein complexes dismantled by the desnaturation process realized before the eletroforesis