Identification of genes that encode Fasciola-specific arc 2 antigens.

Previous studies have shown that serum from humans with fascioliasis had precipitating antibodies that identified a line of precipitation as specific for Fasciola. This Fasciola-specific band was designated arc 2. The specificity of a Fasciola-specific anti-arc 2 antiserum, evaluated by Western blot analysis, reveals a mosaic of antigens with molecular weights in the range of 10-43 kD. In the current study, the antibodies reacting with a subset of antigens in the 10-21-kD range were eluted from nitrocellulose and used to probe an F. hepatica cDNA library. Four clones were purified and amplified by the polymerase chain reaction. The DNA hybridizations among these clones revealed different groups of clones derived from different mRNAs. The finding of multiple genes supports the observation that F. hepatica arc 2 is a mosaic of antigens. The studies show that molecular cloning technology can be used to identify potential genes, each of which encode distinct antigens that may be used for the specific immunodiagnosis of fascioliasis.