Expression of Leishmania major LmSTI1 in Yeast Pichia Pastoris

Background: Leishmania major LmSTI1 is a conserved protein among different species of leishmania, and expressed in both amastigote and promastigote forms of L. major life cycle. It has previously been expressed in bacterial systems. M aterials and Methods: To express LmSTI1 in the methylotrophic yeast         Pichia pastoris ( P. pastoris ), the shuttle vector pPICZA containing gene lmsti1 was constructed under the control of the AOX1 promoter. The recombinant vector was electro-transformed into P. pastoris, and induced by 0.5% methanol in the buffered medium. The expression of the LmSTI1 protein was visualized in the total soluble protein of P. pastoris by 12% SDS-PAGE, and further confirmed by Western blotting with L.major -infected mouse sera and HRP-conjugated goat anti-mouse IgG as the first and secondary antibodies, respectively. Results : The expression level was 0.2% of total soluble proteins. Conclusion: It might be possible to use this formulation as a whole yeast candidate vaccine against cutaneous leishmanization.