Expression and characterization of aspartic protease gene in eggs and larvae stage of Ancylostoma caninum.

Hookworm infection is still a public health problem in developing countries. Aspartic protease plays an important role in parasite invasion and migration in the host. Aspartic protease gene from Ancylostoma caninum has been reported (Biochem Biophys Res Commun 227:294-302, 1996), but the activity of Acasp in eggs and larvae stage has not been studied. This paper reported the cloning of Acasp, expression in Escherichia coli, and characterization in eggs and larval stage. The mRNA encoding Acasp was detected using reverse transcriptase polymerase chain reaction in L4 and adult worm. A polyclonal antiserum against E. coli expressed recombinant Acasp was produced and used to detect and localize the Acasp in various developmental stages of A. caninum. Results from Western blot and indirect fluorescent immunoassay showed that the Acasp was present in the embryo, larvae, as well as in the adult worms. The recombinant Acasp exhibited the protease activity by the gelatin gel digestion assay.