Attempts to induce resistance in mice to Schistosoma japonicum and Schistosoma mansoni by exposure to crude schistosome antigens plus cloned glutathione‐S‐transferases

Abstract

Summary Several attempts have been made to induce resistance in mice to Schistosoma japonicum (Philippines) or Schistosoma mansoni by exposure to living male and/or female adult worms, their antigens or irradiated cercariae. No resistance was demonstrated in the following cases: re-exposure of mice to cercariae following praziquantel (PZQ) treatment of existing infection; re-exposure of mice following cyclosporin A (CsA) treatment at the time of first cerearial exposure; subcutaneous or intraperitoneal deposition of living male or female worms; repeated intranasal administration of crude worm homogenates plus Bordetella pertussis vaccine (BPV) as adjuvant. Homologous ^^Co-irradiated cercariae were very effective at inducing resistance to infection with 5. mansoni but not to infection with S. japonicum (Philippines) in a limited series of experiments. A regime of infection, immunization with homologous Escherichia co//-derived glutathione-S-transferases (GST), then PZQ treatment followed by homologous re-exposure did not result in significant resistance in either the 5. mansoni or the S. japonicum (Philippines) systems. Mice given irradiated cercariae plus GST were not more resistant to subsequent 5. mansoni infection than mice given irradiated cercariae alone. The results generally confirm and extend those reported by others with the conclusion that resistance to schistosomes in mice is difficult to achieve by exposure to adult worm antigens alone. Moreover, additional immunization with the GST available to date as cloned gene products, and injected in Freund's complete adjuvant, does not influence the outcome of exposure to crude worm antigens including any additive effects of protective irradiated cercariae.

Gene expression patterns during adaptation of a helminth parasite to different environmental niches

“…These include Sm23 [39-45], integral membrane protein 25 [46], Sm14 [47,48], and 26 and 28 glutathione S-transferases [49-52]. …”

IL-10 Blocks the Development of Resistance to Re-Infection with Schistosoma mansoni

“…However, despite exhibiting significantly elevated anti-worm responses, the mice remained fully susceptible to a secondary challenge infection. Mitchell and colleagues also investigated this phenomenon and found that immunizing mice with adult worm antigens in combination with PZQ treatment was still incapable of conferring protection from re-infection [39]. A large proportion of drug treated patients also remain highly susceptible to reinfection [30].…”

Identification of the Schistosoma japonicum 22.6–kDa Antigen as a Major Target of the Human IgE Response: Similarity of IgE–Binding Epitopes to Allergen Peptides

“…For many years, vaccine development approaches against human S. japonicum infection relied on testing S. japonicum homologues of S. mansoni vaccine candidates in the mouse model [16, 27, 28]. This approach has the advantage of rapid testing of antigens, however (1) some candidate vaccine antigens may be species–specific [17, 29]and (2) the concordance between the murine and human immune response against candidate schistosome vaccines is still unclear [30, 31].…”