Beneficial effects of Strongyloides venezuelensis antigen extract in acute experimental toxoplasmosis.

BACKGROUND: Toxoplasma gondii is a protozoan with worldwide distribution and triggers a strong Th1 immune response in infected susceptible hosts. On the contrary, most helminth infections are characterized by Th2 immune response and the use of helminth-derived antigens to regulate immune response in inflammatory disorders has been broadly investigated. OBJECTIVES: The aim of this study was to investigate whether treatment with Strongyloides venezuelensis antigen extract (SvAg) would alter immune response against T gondii. METHODS: C57BL/6 mice were orally infected with T gondii and treated with SvAg, and parasitological, histological and immunological parameters were investigated. RESULTS: It was observed that SvAg treatment improved survival rates of T gondii-infected mice. At day 7 post-infection, the parasite load was lower in the lung and small intestine of infected SvAg-treated mice than untreated infected mice. Remarkably, SvAg-treated mice infected with T gondii presented reduced inflammatory lesions in the small intestine than infected untreated mice and decreased intestinal and systemic levels of IFN-γ, TNF-α and IL-6. In contrast, SvAg treatment increased T gondii-specific IgA serum levels in infected mice. CONCLUSIONS: S venezuelensis antigen extract has anti-parasitic and anti-inflammatory properties during T gondii infection suggesting as a possible alternative to parasite and inflammation control.

Immunoblotting using Strongyloides venezuelensis larvae, parthenogenetic females or eggs extracts for the diagnosis of experimentally infected immunosuppressed rats.

The nematode Strongyloides stercoralis is responsible for strongyloidiasis in humans. Diagnosis of infection occurs through detection of larvae in feces, but low elimination of larvae often hampers the detection of disease, particularly in cases of patient immunosuppression. Immunodiagnostic tests have been developed; however obtaining S. stercoralis larvae for the production of homologous antigen extract is technically difficult. Thus, the use different developmental forms of Strongyloides venezuelensis has become an alternative method for the production of antigen extracts. The aim of this study was to evaluate immunoblotting using alkaline extracts from S. venezuelensis L3 larvae, parthenogenetic females or eggs to test detection of experimental strongyloidiasis associated with immunosuppression. Immunocompetent and immunosuppressed male rats were experimentally infected, and serum sample from all animals were obtained at 0, 5, 8 13, and 21 days post infection (d.p.i.). Immunoblotting was evaluated for use in detection of anti-S. venezuelensis IgG in both experimental rat groups. The larval extract immunoblotting profile had the most immunoreactive fractions in the immunosuppressed group beginning at 5 d.p.i., while the immunocompetent group reactivity began on 8 d.p.i. Immunoreactive protein fractions of 17 kDa present in larval alkaline extract presented as possible markers of infection in immunosuppressed rats. It is concluded that all extracts using immunoblotting have diagnostic potential in experimental strongyloidiasis, particularly larval extract in immunosuppressed individuals.