Immunization with rP22 induces protective immunity against Schistosoma mansoni: Effects on granuloma down-modulation and cytokine production

Abstract

Schistosomiasis remains a significant public health problem in tropical countries and it is recognized as the most important human helminth infection in terms of morbidity and mortality. Although the existing antischistosomal drugs are highly effective, they do not prevent against reinfection or granuloma formation. Therefore, vaccine strategies are essential for the control of schistosomiasis. Our group recently identified the recombinant (r) P22 protein, a component of the adult worm protein fraction PIII that has been shown to engender protective and immunomodulatory effects on murine schistosomiasis. A cDNA clone encoding rP22 was isolated from a Schistosoma mansoni adult worm cDNA library using anti-PIII rabbit serum; it exhibited complete identity with S. mansoni Sm21.7 EF-hand antigen. Confocal microscopy revealed that rP22 is a tegument protein localized on the surface of S. mansoni miracidia and adult worms. Mice immunized with rP22 exhibited a 51% and 22.5% decrease in adult worm burden and in hepatic eggs, respectively. Additionally, rP22 vaccine produced a reduction in 60% of liver granuloma size and 71% of fibrosis in mice, suggesting that rP22 might contribute to down-modulate granulomatous hypersensitivity to S. mansoni eggs. Protective immunity in mice was associated with high titers of rP22-specific IgG antibodies; elevated production of IFN-γ, TNF-α and IL-10; and a reduced level of IL-4. In conclusion, these findings indicate that rP22-based vaccines could be useful to elicit protection and reduce pathology associated to schistosomiasis.

Extracellular vesicles induce protective immunity against Trichuris muris

“…Martin‐Jaular and co‐workers also reported a protective role for reticulocyte‐derived EVs containing Plasmodium yoelii material, showing that vaccination with these EVs stimulated IgG antibodies capable of binding infected red blood cells, with 83% of mice surviving an otherwise lethal P. yoelii infection. Previously described S. mansoni vaccine candidates have also been identified in EV samples, supporting the data presented here, which suggest that helminth EVs may be an important source of protective material.…”

Modelling approaches to predict and evaluate schistosomiasis immunization utilizing SEA loaded on chitosan nanoparticles via liver tissue differentiation and angiogenesis

“…The significant decrease of hepatic egg load in the same group (G7) vaccinated with both SEA-FCA+SEA-ChNPs, correlates with the previously reported significant percentage reduction of 89.5% using different antigens preparations composed of combined SWAP+SEA+FCA [51] . A lower record was attained by El-Ahwany et al [52] who used SEA without FCA and by Rezende et al [53] in a SWAP vaccinated model. They reported a percentage reduction in liver tissue egg load of 42.8% and 8.4%, respectively, which substantiates the higher protective effect of both SEA-FCA+SEA-ChNPs together with the augmenting role of the used adjuvants (FCA and ChNPs).…”

DNA Vaccine Encoding the Chimeric Form of Schistosoma mansoni Sm-TSP2 and Sm29 Confers Partial Protection against Challenge Infection

“…mansoni , such as Sm-p80, Sm29, stomatin-like protein-2 and rp22, which achieved higher levels of protection. Additionally, these results were associated with increases in the production of IFN-γ and TNF-α [ 15 , 19 , 37 – 39 ]. The involvement of IFN-γ in protective immunity against S .…”