The specificity of antibody responses in cattle naturally exposed to Fasciola hepatica

Fasciola hepatica causes significant morbidity and mortality in dairy cattl e in the Andean region of Cajamarca, Peru, where prevalence of infection of up to 78% has been reported. ELISA and Western blot analyses were used to characterise antibody responses in dairy cattle to adult F. hepatica to exc retory-secretory (E/S), somatic (SO) and surface (SU) antigens. Three group s of dairy cattle - calves, heifers and adult cows - naturally exposed to F . hepatica in this region, were monitored every 2 months over a 2-year peri od. Calves, heifers and adult cows all had antibodies which recognised a 28 kDa protein in the SO preparation, whereas only adult cows had antibodies that recognised a 28 kDa protein in E/S products, All three groups of cattl e responded to a 60-66 kDa group of proteins in E/S and SU preparations and a 17 kDa antigen in SO products was recognised by antibodies from cows and heifers but not calves. The total antibody response to E/S antigens measur ed by ELISA, increased over time in calves and remained constantly high ove r the 2-year period in all three groups of cattle. Slight fluctuations in t he antibody response occurred in the group of heifers and cows coinciding w ith seasonal changes in the level of challenge. (C) 2000 Elsevier Science B .V. All rights reserved.