ABSTRACT
The liver fluke, Opisthorchis viverrini (OV), is an important human pathogen distributed in northeast Thailand. The linkage between the liver fluke and CCA is strongly supported by previous literature. The molecular mechanisms by which OV induces CCA in humans are unknown. Opisthorchis antigens are found in the bile ducts (in regions where parasites reside as well as those in smaller ducts where they do not) as well as damaged liver cells and various inflammatory cell infiltrates, further incriminating ES antigens in cholangiocarcinogenesis. Characterization of OV molecules associated with OV infection and cholangiocarcinoma using the immunoscreening method was performed. The adult cDNA library screening was done with cholangiocarcinoma associated opisthorchiasis serum. The results show that 6 protein encoding genes including asparaginyl endopeptidase, egg protein, actin, testis enhanced gene transcript and 2 unknown function genes were positive with strong reaction to human serum. Further investigation on OV asparaginyl endopeptidase show that the full length of the OV asparaginyl endopeptidase gene was 1,302 bp, encoded 408 amino acid residues predicted molecular weight at 47 kDa and predicted cleavage site between amino acid residure 17 and 18.