Scores of millions of people around the world are infected by
Schistosoma mansoni
causing
considerable morbidity, mortality and loss of productivity. Safe chemotherapeutic agents have been
used though there are challenges of re-infection due to resistance. Both epidemiological and
experimental data suggest that acquired cell mediated immunity play significant roles in regulating
the intensity of
S. mansoni infection as well as its patho-physiologic sequelae. Improved control of this
trematode parasite may be obtained with immunization to enhance the resistance of individuals to
risk of infection. This study investigated the cellular responses of mice immunized with soluble
proteins from foot and digestive gland of the vector snail and challenged with
S. mansoni. The
proteins were used to immunize the experimental groups then challenged with the
S. mansoni. The
experimental groups were FT (immunized with foot protein) and DG (immunized with digestive
gland). The parameters, which were analyzed to demonstrate protection, included; the worm counts
and cellular (IFN-γ, IL-5 cytokines) responses. It was observed that, the experimental groups showed
significant protection in terms of worm reduction and immune responses. The group vaccinated with
foot protein showed higher protection (87.5%) as compared to the group vaccinated with the
digestive gland (50%) in terms of worm reduction. Cytokines (IFN-γ and IL-5) production was
present in different levels during the assay time points which showed an aspect of protection. The
Foot protein of the vector showed more immunizing power than the digestive gland. Research
towards utilizing the two proteins as feasible vaccine candidates is encouraged.
