Fig 1.
Transmission electron microscopic structure of the Schistosoma mansoni-egg derived extracellular vesicles (EVs) showing variable sized multiple EVs with regular rounded outline.
(A: X 10000, B: X 15000).
Fig 2.
Scatter plot of parasitological evaluation parameters of the studied groups.
A: Adult worm load in different studied groups obtained by perfusion technique 6 weeks post infection. B: Couple worm load in the studied groups C: Hepatic tissue egg count in the studied groups. D: Intestinal tissue egg count in the studied groups. E: Granuloma number in the livers of the studied groups. F: Granuloma size in micrometre measured in the livers of the studied groups. %: Represent the percent change. *: Statistically significant at p ≤ 0.05.
Fig 3.
Morphological features of S. mansoni eggs retrieved after tissue digestion using Pellegrino’s method.
(A-D) Eggs died immaturely. (A &B) Finely granular (Fg) eggs (X100). (C) Transparent (T) egg (X 100). (D) Darkened (D) egg (X 100). (E-F) Mature eggs. (E) Disintegrated (Di) egg (X 100). (F) Egg showing dense granules (Dg) (X 100).
Fig 4.
Scanning electron micrographs of adult S. mansoni worms recovered from infected control group (A-B), infected vaccinated group (C-E) and infected vaccinated adjuvanted group (F). (A) Adult couple worms obtained with normal configuration, muscle tone and normal male sucker (X 200). (B) Male dorsal tegument showing uniform size, distribution tubercles (T) and visible spines (S) (X 5000). (C) Dorsal tegument of adult male with white blood cell (W) attached to it (X 5000). (D) Distorted elongated couple with wide gynaecophoric canal (GYC) (X100). (E) Dorsal tegument with variably sized tubercles and complete loss of spines of male worm (X 5000). (F) Adult male worm with sloughing of the dorsal tegumental tubercles (ST) and lost spines (X 5000).
Fig 5.
TEM of adult male tegument in infected control group (A), infected vaccinated group (B) and infected vaccinated adjuvanted group (C). (A) Normal outer tegumental layer showing large triangular spines (S), circular muscles (CM), and longitudinal muscles (LM) (X3000). (B) Blebbing of the tegument with deeply sunken spines (Sp), the subtegumental tissue shows vacuolation (V) with disruption of the circular muscles (Cm) (X 2000). (C) Irregularity of the tegument with absence of the spine, the subsegmental tissue shows vacuolation (V) with disruption of the circular muscle (X 2000).
Fig 6.
Histopathological findings in liver sections of infected control group (A, B), infected adjuvanted control group (C, D), infected vaccinated group (E-G) and infected vaccinated adjuvanted group (H, I). (A) H &E-stained section shows three eggs (E) surrounded by diffuse infiltrate (X400), (B) Trichrome-stained section showing fibrosis in granuloma around the eggs (X400). (C) H &E-stained section shows egg surrounded by granulomatous infiltrate formed mainly of histiocytes (H) (X400), (D) Trichrome-stained section showing fibrosis around the eggs. (X100). (E) H & E-stained liver section shows few eggs (E) surrounded by granulomatous reaction (X100), (F) H & E-stained liver section shows minimal infiltrate around the central vein with neutrophils infiltration (N) (X 400), (G) Trichrome -stained section showing fibrosis around the eggs with minimal fibrosis around central vein. (H) H & E-stained S. mansoni granulomatous rection formed mainly of histocytes (H) (X400), (I) Trichrome -stained section showing fibrosis around the eggs with minimal fibrosis around central vein (X100).
Fig 7.
IgG profile in mice of different studied groups.
Sera of mice were collected at days 14, 28, 42, and 84 after the first immunization and assayed by ELISA. Results are presented as the mean absorbance measured at 450 nm for each group. (*) Statistically significant at p ≤ 0.05.
Fig 8.
IFN γ levels in mice of different studied groups.
Sera of mice were collected at days 14, 28, 42, and 84 after the first immunization and assayed by ELISA. (*) Statistically significant at p ≤ 0.05.
Fig 9.
Two immunogenic bands obtained by western blot analysis of EVs using vaccinated mice sera as a source of primary antibody.