Evaluation of the integral membrane proteins of juvenile fasciola gigantica for control of ovine fascioliasis
Abstract
Phase separation of Fasciola gigantica metacercarial homogenate was
carried out using non-ionic detergent Triton X-114. The protein composition of the
homogenate (FgWh), detergent phase (FgTx) and the aqueous phase (FgAq) were
analyzed using Sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDSPAGE)
and gel were stained for proteins by coomassie blue. More than 21 proteins
were demonstrated in the homogenate distributed between 10-200 kDa molecular
weight range. Distributed within the same range, were more than 16 proteins in the
detergent phase. the aqueous phase contained more than 19 proteins. Two proteins
of about 58 and 75 kDa in the homogenate, separated strongly in the detergent
phase.
Sheep were immunized 3 times in 4 weeks with the homogenate (FgWh),
detergent phase (FgTx) and aqueous phase (FgAq). They were then challenged with
150 metacercariae of Fasciola gigantica. Immunization induced high antibody
responses to several antigens in the homogenate and the phase fractions in contrast
to the response observed in t~e. control animals after challenge. The control group
mounted antibodies to 12 protein in both FgWh and FgTx and 7 in FgAq 2 weeks
after infection.
Throughout the study, the progress of fluke infection was monitored by
measuring the extent of liver damage by ana lysing serum glutamate dehydrogenase
and gamma glutamyl transferase. Faecal egg counts and packed cell volume were
used to asses patency and development of anaemia respectively. Sheep immunized
with FgTx had low serum liver enzyme activity, delayed patency, lower mean faecal
egg counts and reduced tendency towards developing anaemia compared with
FgWh, FgAq and the control group. This was complementary to the lower fluke
burden in this group relative to the controls giving a reduction percentage of 87% as
compared to the controls. The result suggest that the detergent phase has one or
more protein components that significantly reduce the effects of Fasciola gigantica
infection in sheep.
Citation
MASTER OF SCIENCE IN VETERINARY MICROBIOLOGY.Publisher
University of Nairobi Department of veterinary pathology and microbiology,