We have previously confirmed the presence of common antigens
between
Schistosoma mansoni
and its vector,
Biomphalaria glabrata
. Cross-reactive antigens may be important as possible candidates for vaccine
and diagnosis of schistosomiasis. Sera from outbred mice immunized with
a soluble Biomphalaria glabrata antigen (
SBg
A) of non-infected
B. glabrata
snails recognized molecules of
SBg
A itself and
S. mansoni
AWA by Western blot. Recognition of several molecules of the
SBg
A were inhibited by pre-incubation with AWA (16, 30, 36, 60 and 155 kDa).
The only specific molecule of AWA, inhibited by
SBg
A, was a 120 kDa protein. In order to determine which epitopes of
SBg
A were glycoproteins, the antigen was treated with sodium metaperiodate
and compared with non-treated antigen. Molecules of 140, 60 and 24 kDa in
the
SBg
A appear to be glycoproteins. Possible protective effects of the
SBg
A were evaluated immunizing outbred mice in two different experiments using
Freund's Adjuvant. In the first one (12 mice/group), we obtained a
significant level of protection (46%) in the total worm load, with a high
variability in worm recovery. In the second experiment (22 mice/group),
no significant protection was observed, neither in worm load nor in egg
production per female. Our results suggest that
SBg
A constitutes a rich source of candidate antigens for diagnosis and prophylactic
studies.
