en Related Fields Related Fields مقاله کامل Full Length/Original Article <strong>Background: </strong>The expression of bio-therapeutic proteins in mammalian cells, such as CHO, attains high homogeneity related to post-translational modifications. Although CHO remains the most popular cell line for bestselling biotherapeutic proteins on the market, there are still drawbacks such as expensive culture media, long time line, and high drug cost. Recently, researches on a novel <em>Leishmania</em> protozoan system have confirmed that this low level eukaryote could represent a competitive alternative to the mammalian cell lines. <strong>Methods: </strong>The full length of coding sequence of modified tPA TNKase tenecteplase) was synthesized and cloned into an inducible expression vector of <em>L. tarentolae</em> T7-TR cells. <strong>Results: </strong>The expression of the construct was driven by a Tet-inducible promoter. A <em>Leishmania</em> secretory signal sequence was also added to the expression cassette to facilitate the release of the recombinant protein into the medium. The secretory recombinant protein was analyzed and confirmed by SDS-PAGE and Western blot analyses. The expression level of TNKase in this novel system of <em>L. tarentolae</em> was 810 IU/mL after induction, which means that the percentage of expression increases two times compared to previous models in <em>L. tarentolae</em>. The TNKase activity was comparable with Activase. <strong>Conclusion: </strong>Our results suggested that expressed TNK (modified tPA) is functionally compatible with Activase regarding their effect on fibrinolysis. Given the post-translational modification similarities between mammalian and <em>L. tarentolae</em>, it is speculated that this system is capable of producing complex proteins such as tPA similar to mammalian system, with easier manipulation and non-expensive method. Leishmania tarentolae, Tenecteplase, Tissue plasminogen activator 272 279 http://ibj.pasteur.ac.ir/browse.php?a_code=A-10-1-751&slc_lang=en&sid=1 Mohammad Mehdi Attarpour Yazdi 0000-0002-0338-4092 No Department of Microbiology, Faculty of Medicine, Shahed University, Tehran, Iran Nikky Tofighi No Biotechnology Research Center, Pasteur Institute of Iran, Tehran, Iran Taraneh Rajaee No Biotechnology Research Center, Pasteur Institute of Iran, Tehran, Iran Marzieh Ghahremanlou 0000-0001-6495-5779 No Biotechnology Research Center, Pasteur Institute of Iran, Tehran, Iran Ahmad Adeli No Biotechnology Research Center, Pasteur Institute of Iran, Tehran, Iran Azam Bolhassani 0000-0001-7363-7406 No Department of Hepatitis and AIDS, Pasteur Institute of Iran, Tehran, Iran Mohammad Azizi 0000-0003-1326-1755 No Biotechnology Research Center, Pasteur Institute of Iran, Tehran, Iran Noushin Davoudi 0000-0001-6114-4188 Yes Biotechnology Research Center, Pasteur Institute of Iran, Tehran, Iran