Abstract :
The diagnosis of Schistosoma mansoni in prepatent phase of infection is necessary to prompt liver damage
and to prevent late morbidity. This study was designed to purify and characterize a glycoprotein antigen from mature
S. mansoni fluke using Con-A lectin. In this Study, crude adult worm antigen (AWA) and purified fraction were
separated by molecular weight using SDS-PAGE. Chemical structure of purified fraction determined using Mass
spectrometry technique. ELISA used to evaluate diagnostic efficacy of both crude and purified antigens. AWA was
electrophoresed by SDS-PAGE in to 10 bands with Mwt ranged from14.2 to 220 kDa while the purified Ag was
separated in to two bands with Mwt 74.6 and 20 kDa. The chemical structure of the purified antigen was found to be
(Al-Ser-Arg-Ser-Arg-GlucNac). The purified glycoprotein exhibited 100% positivity with both human sera and mice
sera collected at different intervals from infection. In addition, purified Ag detects the infection at early patent period
(24h post infection). Results of immune blotting confirmed the immune reactivity of the purified glycoprotein as the
human positive sera identified the band at 74.6kDa. Also, ELISA presented 100% sensitivity compared to 84.4% of
the available commercial IHA kits. When the purified antigen was tested with serum samples infected with other
parasites in ELISA, it showed 100% specificity compared to 96.6% of the commercial IHA kits.
The described antigen is a promising diagnostic antigen for prepatent S. mansoni infection, and its immune
prophylactic potency will be tested in further study.
Keyword :
Schistosoma mansoni, glycoprotein, Diagnosis, Mass spectrometry, ELISA.