P. Margutti et al., Cloning and expression of a cDNA encoding an elongation factor 1 beta/delta protein from Echinococcus granulosus with immunogenic activity, PARASITE IM, 21(9), 1999, pp. 485-492
A cDNA clone (Eg EF-1 beta/delta) of Echinococcus granulosus has beer isola
ted by an expression library screened with immunoglobulin (Ig)E of sera fro
m patients with cystic echinococcosis (CE). The Eg EF-1 beta/delta was iden
tified on the basis of sequence homology to the subunits beta or delta of t
he elongation factor-1. The amino acid sequence deduced from this open read
ing frame is 244 residues long with a predicted molecular mass of 31 kDa. I
n Southern blot under high stringent condition, Eg EF-1 beta/delta hybridiz
ed to genomic DNA of E. granulosus at two bands of 4 and 2.5 Kb. In immunob
lotting analysis, the Eg EF-1 beta/delta protein shows immunological reacti
vity with sera from CE patients: 51.7% of sera contained IgE, 41.7% IgG and
18.3% IgG4 specific to the recombinant protein. We identify the Eg EF-1 be
ta/delta by immunoblotting with specific monoclonal antibody both in protos
coleces mid in sheep hydatid fluid. The higher percentage of humoral immune
response against Eg EF-1 beta/delta observed in CE patients with calcified
cysts than in patients with active cysts indicates the possible release of
the protein in the hydatid fluid after protoscoleces degeneration suggesti
ng the possible use of this antigen in the immunosurveillance of CE. Overal
l, these findings seem to assign to Eg EF-1 beta/delta a key role in the al
lergic disorders and in the complex host-parasite relationship in CE.