Evaluation of the immune response against Strongyloides venezuelensis in antigen‐immunized or previously infected mice

Abstract

The present study was carried out to investigate the immune response against Strongyloides venezuelensis infection in Balb/c mice previously immunized with larva-antigens or primed with live-larvae. Our results indicate that all primed mice developed a strong protection against challenge infection that remained active for 45 days. In mice primed with live-larvae the challenge infection resulted in great reduction of migrating larvae and the worms were completely eliminated from the small intestine before maturation. The protection pattern did not alter when the primary infection was aborted by drug treatment. In these experimental groups, the challenge infection was accompanied by a type-2 predominant immune response, intense IgE and reactive IgG1 production, and granulocyte infiltration in skin, lungs and intestine. The challenge infection in antigen-immunized mice also resulted in great reduction of migrating larvae. However, the worms that reached the host intestine matured, produced eggs and were eliminated similarly to the ones from nonimmunized mice. Protective mechanisms after immunization with larva antigen were migrating larva-specific and associated with a strong and mixed Th1 and Th2 response, without tissue granulocyte infiltration. In conclusion, protective immunity induced by a previous infection or antigen-immunization are stage-specific and operate through different effector mechanisms.

Differences in the Importance of Mast Cells, Basophils, IgE, and IgG versus That of CD4+T Cells and ILC2 Cells in Primary and Secondary Immunity to Strongyloides venezuelensis

“…The more rapidly effective expulsion of S. venezuelensis observed in wild-type mice in the secondary infection is consistent with prior work indicating that adaptive immunity enhances host resistance to this nematode (39,40,45). To investigate the importance of various potential effector mechanisms in orchestrating immune responses to S. venezuelensis, we examined primary and secondary infections in mice deficient in different components of innate or adaptive immunity.…”

“…We also examined whether MCs and/or basophils contribute to cessation of S. venezuelensis egg excretion during secondary infections. Several studies indicated that, in secondary nematode infections of wild-type mice, the larvae can be trapped in the skin and lungs before reaching the intestines, as reported for S. venezuelensis (39)(40)(41), Strongyloides ratti (41), and Nippostrongylus brasiliensis (42)(43)(44). In this study, we assessed fecal egg numbers as an indicator of whether larvae could reach the intestines and then produce eggs.…”

Lower production of IL-17A and increased susceptibility to Mycobacterium bovis in mice coinfected with Strongyloides venezuelensis

“…Strongyloides venezuelensis, a murine intestinal parasite, has been used as a model for understanding the host-parasite relationship in strongyloidiasis (Fernandes et al 2008). The aim of this study was to evaluate whether S. venezuelensis coinfection can modulate M. bovis infection, affecting IL-17A production and granuloma formation in BALB/c mice.…”

Comparative study of cultivation of feces in vermiculite or charcoal to obtain larvae of Strongyloides venezuelensis

“…Vermiculite is a compound formed by hydration of basaltic mineral; it has been used as a substrate for fecal culture, particularly in veterinary parasitology, as it has the advantages of being similar to soil and costing less [3][4][5][6][7] . It has also been used for growing insect 8 or nematodes larvae in order to evaluate the larvicidal effects of fungi [9][10][11][12] .…”