Immunization with adultSchistosoma mansonitegument, treated with sub-curative praziquantel, partially protects mice against the infection

Abstract

The tegument of schistosomes is a source of many potential anti-Schistosoma vaccine molecules. This work aimed to assess the protective effects of the adult Schistosoma mansoni tegument treated (TT) with sub-curative praziquantel (PZQ), whether in vivo (in vivo TT) or in vitro (in vitro TT), in murine schistosomiasis. In vitro TT and in vivo TT showed great similarity, and they differed from untreated tegument antigen (Teg) in terms of quantity and quality of protein bands on SDS–PAGE. Two immunization trials were performed, each with 50 mice, divided randomly into five groups of 10 mice each: (1) uninfected control mice (UC), (2) infected mice given phosphate buffer saline + adjuvant (PBS + adjuvant), (3) infected, Teg vaccinated, (4) infected, in vivo TT vaccinated, and (5) infected, in vitro TT vaccinated. All the immunizations with antigens induced mixed Th1/Th2 immune responses, as indicated by significantly high (P < 0.001) specific IgG2a and IgG1 levels, with Th1 predominating, as shown by a diminished IgG1/IgG2a ratio, as well as a high serum concentration of IFN-γ, an absence of IL-4 and increased IL-10. In vitro TT gave the most pronounced response. With respect to reduction of total worm burden, relative to PBS + adjuvant mice, in vitro TT achieved the highest significant (P < 0.001) results, followed by in vivo TT and Teg (51.8–57.04%, 44.6–50.2% and 35.2–39.3%, respectively). In scanning electron microscopy studies, all the tested antigens caused tegumental changes in adult worms, with the worst occurring with in vitro TT, such as retracted ventral sucker, an effect on the gynaecophoric canal, and changes to tubercles. In conclusion, in vitro TT, which is cheap to prepare, could be a potential vaccine against S. mansoni.

Evaluation of the Eucalyptus Camaldulensis-Killed Cercariae as a Candidate Vaccine for Experimental Schistosomiasis Mansoni

“…Soliman et al (2008) found that worm reduction with CAP was 53.8% due to eggs reduction post immunization. Etewa et al (2014) tested the CAP with 2 types of adjuvants, BCG and was 56.02% & 51.85%, respectively with reduction of eggs.…”

“…Each mouse of GIII was immunized subcutaneously with 500 killed cercariae at the right flank (Hsu et al, 1981). A booster dose of 500killed cercaria was subcutaneously injected at right flank after 2 weeks of the 1 st immunization (Etewa et al, 2014).…”

Blocking prostanoid receptors switches on multiple immune responses and cascades of inflammatory signaling against larval stages in snail fever

“…The poor ability of the RA larvae to induce PGE2 and IL10 has been proposed to be responsible for differential capacity for infection compared to normal larvae (Ramaswamy et al 2000 ; Winkel et al 2018 ). IL-10 is released early after exposure to normal larvae (El-Aswad et al 2020 ). Likewise, the level of dermal inflammation and the provoked protective immunity are governed by IL-10/IL-12 balance (Hogg et al 2003 ).…”

Evaluation of Protective Effects of Soluble Egg Antigen Conjugated With Trehalose Dimycolate Adjuvant in Experimental Schistosomiasis Mansoni

“…ELISA for detection of specific IgG, IgG1, IgG2a, IFN--10: Serum levels of specific IgG, IgG1 and IgG2a were measured in serum samples by homemade ELISA technique (El-Aswad et al, 2019). Serum levels of IFN--10 were measured at the 2 times intervals before infection using a solid-phase sandwich ELISA which were purchased from Life Technologies Corporation for IFN--10.…”