Mutagenic Deimmunization of Diphtheria Toxin for Use in Biologic Drug Development

Toxins

Joerg U. Schmohl¹  Deborah Todhunter¹  Seung Oh¹  Daniel A. Vallera¹ 

[1] University of Minnesota Masonic Cancer Center, Section of Molecular Cancer Therapeutics, Therapeutic Radiology-Radiation Oncology, University of Minnesota, Minneapolis, MN 55423, USA; E-Mails:

关键词: deimmunization;    diphtheria;    toxin;    biologic drug;    cancer;    cancer treatment;   

DOI  :  10.3390/toxins7104067

来源: mdpi

【 摘 要 】

Background: Targeted toxins require multiple treatments and therefore must be deimmunized. We report a method of protein deimmunization based on the point mutation of highly hydrophilic R, K, D, E, and Q amino acids on the molecular surface of truncated diphtheria-toxin (DT390). Methods: Based on their surface position derived from an X-ray-crystallographic model, residues were chosen for point mutation that were located in prominent positions on the molecular surface and away from the catalytic site. Mice were immunized with a targeted toxin containing either a mutated DT390 containing seven critical point mutations or the non-mutated parental toxin form. Results: Serum analysis revealed a significant 90% reduction in anti-toxin antibodies in mice immunized with the mutant, but not the parental drug form despite multiple immunizations. The experiment was repeated in a second strain of mice with a different MHC-haplotype to address whether point mutation removed T or B cell epitopes. Findings were identical indicating that B cell epitopes were eliminated from DT. The mutant drug form lost only minimal activity in vitro as well as in vivo. Conclusion: These findings indicate that this method may be effective for deimmunizing of other proteins and that discovery of a deimmunized form of DT may lead to the development of more effective targeted toxin.

【 授权许可】

CC BY   
© 2015 by the authors; licensee MDPI, Basel, Switzerland.