Efficient killing of CD22+ tumor cells by a humanized diabody-RNase fusion protein |
| |
Authors: | Krauss Jürgen Arndt Michaela A E Vu Bang K Newton Dianne L Seeber Siegfried Rybak Susanna M |
| |
Affiliation: | Department of Medical Oncology and Cancer Research, University of Essen, D-45122 Essen, Germany. juergen.krauss@uni-essen.de |
| |
Abstract: | We report on the generation of a dimeric immunoenzyme capable of simultaneously delivering two ribonuclease (RNase) effector domains on one molecule to CD22(+) tumor cells. As targeting moiety a diabody derived from the previously humanized scFv SGIII with grafted specificity of the murine anti-CD22 mAb RFB4 was constructed. Further engineering the interface of this construct (V(L)36(Leu-->Tyr)) resulted in a highly robust bivalent molecule that retained the same high affinity as the murine mAb RFB4 (K(D)=0.2 nM). A dimeric immunoenzyme comprising this diabody and Rana pipiens liver ribonuclease I (rapLRI) was generated, expressed as soluble protein in bacteria, and purified to homogeneity. The dimeric fusion protein killed several CD22(+) tumor cell lines with high efficacy (IC(50)=3-20 nM) and exhibited 9- to 48-fold stronger cytotoxicity than a monovalent rapLRI-scFv counterpart. Our results demonstrate that engineering of dimeric antibody-ribonuclease fusion proteins can markedly enhance their biological efficacy. |
| |
Keywords: | CD22 Ribonuclease Fusion protein Cytotoxicity Humanized diabody |
本文献已被 ScienceDirect PubMed 等数据库收录! |