Common antigenic determinants of Fasciola gigantica as defined by monoclonal antibodies to phosphocholine

Monoclonal antibodies:(MAbs) raised against the circulating filarial antigens (CA(101), CA(86)) and the excretory-secretory (ES) antigens (ES-1, ES-3) of Brugia malayi and subsequently shown to be directed against the phosphocholine (PC) epitope and carbohydrate-like epitope, respectively, were used to determine the: cross-reactive epitopes of Fasciola gigantica. While MAb to PC reacted strongly with F. gigantica, other ES antibodies did not show any reactivity. Western blot analysis using CA(101) and CA(86) showed multiple banding pattern in high molecular weight proteins (200-30 kD) that indicated the presence of PC determinants on many different antigenic molecules. A two-site enzyme immunoassay using affinity purified rabbit immunoglobulins to B. malayi antigen as capture antibodies and CA(101) and CA(86) as detection antibody was developed to detect the presence of PC containing Fasciola antigen. While serum from 80 to 90% of Fasciola infected goats (7 of 8) or cattle (8 to 10) contained PC containing antigens in their circulation, 1 of a normal goats sera also reacted in this assay. Despite some "false positivity"; detection of PC antigens may provide a valuable immunodiagnostic tool for detection of helminth infection in animals.