Immunoblotting utilizando extratos alcalinos de larvas L3, fêmeas partenogenéticas ou ovos de Strongyloides venezuelensis na estrongiloidíase experimental associada à imunossupressão

Abstract

The nematode Strongyloides stercoralis responsible for strongyloidiasis diagnosed by detection of larvae in feces. However, the elimination of low larvae hampers the detection of disease particularly in cases of immunosuppression. Immunodiagnostic tests have been developed, but the difficulty of obtaining larvae of S. stercoralis for the production of homologous antigenic extract, thereby Strongyloides venezuelensis and their different evolutionary forms for the production of antigen extracts. The aim of this study was to evaluate the detection of antibodies anti S. venezuelensis against alkaline extracts of L3 larvae, parthenogenetic females or eggs in experimental strongyloidiasis associated with immunosuppression. Male rats were divided into two groups: non-immunosuppressed and immunosuppressed experimentally infected and serum from all animals were obtained at 0, 5th, 8th, 13th and 21th days post infection (d.p.i.). The test enzyme-linked immunosorbent assay (ELISA) was performed to compare the reactive potential of alkaline extracts of L3 larvae, parthenogenetic females and eggs of S. venezuelensis in rats non-immunosuppressed and immunosuppressed. Immunoblotting was also evaluated for detection of IgG anti S. venezuelensis in both groups front to alkaline of the three developmental forms of the parasite extracts. In all comparative ELISA extracts were skilled in detecting IgG S. venezuelensis. The extract of larvae showed reactivity from the 5th dpi ceasing at 21th d.p.i in the non-immunosuppressed group while the group immunosuppressed this reactivity remained at 21th d.p.i. immunoblotting showed the reactivity profile with immunoreactive fractions in immunosuppressed group from the 5th d.p.i. while the non-immunosuppressed group reactivity from 8th d.p.i. The alkali extracts of parthenogenetic females and eggs showed a similar profile of reactivity in both ELISA and immunoblotting. Immunoreactive protein fractions of 26 and 17 kDa present in the alkaline extract of larvae presented as important markers of infection in immunosuppressed animals. It is concluded that all alkali extracts have diagnostic potential in experimental strongyloidiasis especially the larval extract in cases of immunosuppression, and immunoblotting an important complementary diagnostic tool.