Fasciola gigantica: Immunization of rabbits with proteins isolated from copropantigen

ABSTRACT

Two fractions were isolated from coproantigen by ion-exchange chromatography, in which DEAE cellulose was utilized. Both fractions and crude antigen were characterized by SDS-polyacrylamide gel electrophoresis, which revealed 13 bands of molecular weight ranged from 205-31 in crude coproantigen. While, fraction I was resolved into 6 bands of molecular weights of 198, 178, 148, 111, 101 and 45. Fraction II showed seven bands of 191 kDa, 178 kDa, 166 kDa, 118 kDa, 98.5 kDa, 72 kDa and 32 kDa. Fraction II showed higher immunoreactivity than fraction I by ELISA. Three immunoreactive bands of 191 kDa, 118 kDa and 98.5 kDa were identified in fraction II using immunoblot assay. Five bands of 178 kDa, 148 kDa, 111 kDa, 101 kDa and 45 kDa were detected in fraction I. Immunization of rabbits twice with fraction II in Freund's adjuvant with two-week interval, followed by challenge with F. gigantica metacercariae resulted in 66.6% protection from infection. The protection was assessed by the detection of hepatic damage, worm recoveries and antibody response. A high level of IgG response in vaccinated rabbits than control infected ones occurred and was found to be responsible for the recorded protection