Leucine Aminopeptidase of Fasciola gigantica: Functional Characterization and Evaluation as a Vaccine in Animal Fasciolosis

Abstract

The infection of livestock animals with the parasite Fasciola gigantica causes
economic loss due to mortality, weight loss, reduced productivity and poor milk production.
An effective vaccine to overcome these problems would be a viable alternative to the
currently used drugs. Leucine aminopeptidase (LAP) plays an important role in the parasite's
biology, such as in processing, maturation, activation or degradation of substrates and is,
therefore, considered as a candidate for development of a vaccine. In the presented work the
protein coding fragment of a FgLAP cDNA was subcloned into the pThioHisB bacterial
expression vector. Recombinant FgLAP was expressed and purified from Escherichia coli
TOP10. The purified rFgLAP has and will be used in further studies such as proteolytic
activity assays, immunohistochemistry and vaccine development. FgLAP protein- and DNAbased
immunization trials have been performed in mice to test the antigen's vaccine potential.
In addition to the recombinant FgLAP, a complex of synthetic FgLAP peptides (spFgLAP)
was designed from the active site of FgLAP and has also been used for protein-based
immunization. DNA-based immunization has been performed with the pSecTag2A
mammalian expression vector containing the FgLAP coding DNA.