Design of a recombinant immunotoxin against the human granulocyte-colony stimulating factor receptor.

Immunotoxin is a new strategy for protein therapy of cancer. This engineered protein contains two parts, the immune part which is an antibody or cytokine, directed against the cancer cell receptor, and the toxin part consisting of a plant or bacterial toxin leading to apoptosis by protein synthesis inhibition. The knowledge of cell-surface receptor overexpression in cancer cells can help scientists to construct new anti-cancer agents. The granulocyte colony stimulating factor (G-CSF) receptor is expressed on the cell surface of some blood cancers such as acute myeloid leukemia (AML). Therefore, this receptor can be used as an immunotoxin for treatment of some cancers. The aim of this work was to design and produce DT-GCSF immunotoxin using truncated DT fused to G-CSF. For fusion protein construction, DT389 and G-CSF fragments, were amplified by PCR using specific primers. A flexible linker SerGly4SerMet (SG4SM) was used to fuse the PCR products by SOEing PCR procedure to achieve an appropriate fusion protein, and the fused fragment was subcloned into pET21b. The new construction (pET-DT389GCSF) was transformed into E. coli strain BL21 (DE3) and the expression of the construction was confirmed by SDS-PAGE and Western blotting techniques. The data demonstrated the expression and purity rates of DT389GCSF about 25% and 90%, respectively. This chimeric protein construction can be used as a new anti-AML drug, but its in vitro and in vivo biological activity should be analyzed.

Kidney retransplantation in comparison with first kidney transplantation.

INTRODUCTION: The aim of this study was to depict the outcome of second and third kidney allografts in comparison with first kidney allografts. METHODS: Among 2150 kidney transplantations are 103 second and 5 third transplantations. Demographic characteristics and survivals of retransplanted patients were compared with a randomly selected group of first kidney recipients, consisting of two cases matched with each retransplanted patient for age, gender, and date of transplantation. RESULTS: Retransplanted patients consisted of 78 men and 30 women of mean age 32.63 +/- 11.92 years. They had received kidneys from 91 living-unrelated and 17 living-related donors. Median followup was 27 months. One-, 2-, 3-, and 5-year graft survivals were 81.4%, 78.9%, 78.9%, and 73.7% among retransplants, versus 92.9%, 91.5%, 89.8%, and 85.3% in the control group, respectively (P = .0037). Patient survival was 96%, 94.6%, 92.4%, and 87.8% in the retransplant group versus 93.1%, 92.4%, 90.9%, 87.4% in the control group, respectively (P = .63). Also, graft survivals were slightly lower in female compared to male retransplant patients (P = .09). No significant difference in survival rates was seen in different age groups. CONCLUSION: It seems that kidney retransplantation can yield desirable outcomes, albeit relatively lower graft survivals.