ABSTRACT
Objective:To prepare nanobody-based immunotoxin BI7D12-PE38KDEL targeting EGFR and to examine its cytotoxicity against EGFR positive tumor cells.Methods:By using molecular cloning strategy,prokaryotic expression construct of pET28a-BI7D12-PE38KDEL was generated which consisted of nanobody 7D12 targeting EGFR in the form of a divalent fused with PE38KDEL,a truncated form of pseudomonas exotoxin A via a flexible peptide(G4S)4,and then transformed into E.coli BL21(DE3).Protein expression was induced by adding IPTG,purified by Ni-affinity column chromatography,and verified by Western blot.The binding capacity of the resulted immunotoxin to EGFR-positive cells A549,HT29,MCF-7 and EGFR-negative cells CEM,Jurkat were determined by flow cytometry assay,and its cytotoxicity against the target cells was examined.Briefly,tumor cells were treated with different dosage of the immunotoxin,and the killing efficacy of BI7D12-PE38KDEL on these cells were assessed by WST-1 assay after 72 hours.Results:The SDS-PAGE and Western blot results showed the recombinant immunotoxin BI7D12-PE38KDEL was successfully prepared,and majority of them was expressed in soluble form.BI7D12-PE38KDEL could selectively bind to EGFR-positive cells of A549,HT29,and MCF-7.More importantly,the immunotoxin exhibited much more significant killing effect on these EGFR positive cells compared to the negative control group of CEM and Jurkat cells(P<0.01).Conclusion:In the current study,the nanobody-based immunotoxin BI7D12-PE38KDEL targeting EGFR was successfully prepared and exhibited a superior inhibition effect for the growth of EGFR-positive cells.
ABSTRACT
Objective:To prepare a new type of anti-leukemia immunotoxin with killing activity.Methods:The method of cytotoxicity was used to study the activity of the immunotoxin after the induction of IPTG. Results:The expressed fusion proteins were detected mostly as inclusion bodies at high level.The result showed IL3-PE38KDEL had liable activity of toxicity. Conclusion:The fusion protein IL3-PE38KDEL has good biological activity,which paves way for the further study on its treatment of leukemia.
ABSTRACT
Objective To prepare the immunotoxin protein (183B 2ScFvPE38) which might be useful in immuno guided therapy for ovarian carcinoma and study the activity of the protein. Methods The methods of ELISA and cytotoxicity were used to study the immunotoxin after induced with IPTG and the activity of the immunotoxin. Results The expressed fusion proteins were detected mostly as inclusion bodies at high level, and soluble immunotoxins were also observed. The results showed liable activity of antibody part and toxic part. Conclusion The recombinant fusion protein 183B 2ScFvPE38 keeps the activity of both components and might be of great use in the future to deal with ovarian carcinoma. [