Expression Of Recombinat Human Interleukin-11 In Pichia Pastoris And The Protective And Therapeutic Effects Of Cytokines On Acute Irradiation Injury In A Murine Model

~ Expression of recombinant human interleukin-11 in Pichiapastoris Myelosuppression is a serious complication of current chemotherapy and radiotherapy regimens, resulting in life-threatening neutropenia and thrombocytopenia and hampering full deployment of anticancer therapy. With the commercial availability of granulocyte-macrophage colony stimulating factor (GM-CSF), granulocyte colony stimulating factor (G-C SF) and erythropoietin (EPO), cytokine treatment has become established therapeutics for alleviating cytopenia, in particular the anemia and neutropenia resulting from intensive cytoreductive treatment. Although GM- CSF has advantages in that it also stimulates megakaryocytopoiesis to a certain extent, thrombocytopenia can not be ameliorated satisfactorily. So it is pressing to establish an effective agent to improve the function and count of platelet for the cancer patients who would accept chemotherapy and radiotherapy. It has been found that a single dose of TPO might be sufficient for a clinically significant response of treatment on thrombocyte recovery. VIII Ic? Expression of recombinant human interleukin-I I in Pichia pastoris and the protective and therapeutic effects of cytokines on acute irradiation injury in a murine model Abstract But the clinical application of rhTPO is limited by the clinical trial results that TPO might cause thrombus in circulation vessel. Interleukin- 11 (IL-li) is a hematopoietic growth factor, which is cloned from hematopoietic microenvironment stromal cell line PU-34 in 1990. In vitro as a single agent, IL-il can stimulate the proliferation of the human megakaryoblastic cell lines in serum-free semisolid (methylcellulose) culture in a dose dependent manner. 11-11 does synergize with IL-3 to enhance the growth of both murine and human megaaryocyte colonies. IL-li also increases the size and DNA content (ploidy) of constituent megakaryocyte. Preclinical and clinical trial have shown it is an effective therapeutic for IL- 11 to ameliorate chemotherapy and radiation induced thrombocytopenia in vivo. IL-il was also shown to be well tolerated and could reduce the need of engraft of platelet. As a unique clinical agent to increase the platelet count, the effective dose of IL-li is about 50 --?5 ii g/kg/d, far exceeding the dose of other clinical applied cytokine such as GM-CSF,G-CSF or EPO. So it is critical to choose a proper expression system to obtain high yield of recombinant protein with high biological activity. Expression of rhIL-11 in Pichia pastoris As an eukaryote, Pichia pastoris has many advantages of eukaryotic expression systems such as protein processing, protein folding and posttranslational modification, while being as easy to manipulate as F. coli or Saccharomyces cerevisiae. So Pichia pastoris was selected as expression system candidate to express human IL 11. In order to obtain a high level production of rhJL- 11, an artificial gene with the optimal codon usage of Pichia pastoris was synthesized. Twenty Ix 11 Expression of recombinant human interleukin-1 I in Pichia pastoris and the protective and therapeutic effects of...