Development of expression constructs for production of human recombinant IFNγ in Leishmania tarentolae

The aim of the present study was to express recombinant human interferon-gamma in Leishmania tarentolae. The Leishmania expression system represents the combination of easy handling known from bacterial expression systems with the potential of a eukaryotic protein expression, folding and modification system. The trypanosomatid protozoan host Leishmania tarentolae was isolated from lizard and is not pathogenic to mammals. In this study, two constructs were developed for expression of recombinant human interferon-gamma (hrIFNg) in L. tarentolae. Each one of constructs carries an antibiotic resistant gene such as Hygromycin and Nourseothericin. For high level expression of the human interferon-gamma, developed DNA cassette that contains interferon-gamma (IFNg) cDNA was designed to integrate into a genomic small subunit rRNA locus of L. tarentolae by homologous recombination. The integration of the expression cassette into the ssu locus was confirmed by diagnostic PCR of the genomic DNA of transgenic strain. Although it has been shown that E. coli might be considered as a suitable host with a relatively high level of expression and lack of posttranslational modifications and the need for refolding stages are still big challenges. In contrast, L. tarentolae is eukaryotic gene expression machinery, which includes full glycosylation and disulfide bond formation, and thus represents a potential advantage over other expression systems. These facts confirm that the gene expression system using Leishmania parasites combines many of the advantages of both prokaryotic and eukaryotic expression systems.