Humanization of an anti-p185HER2 antibody for human cancer therapy

  • Proc Natl Acad Sci U S A. 1992 May 15;89(10):4285-9. doi: 10.1073/pnas.89.10.4285.
P Carter  1 ,  L Presta ,  C M Gorman ,  J B Ridgway ,  D Henner ,  W L Wong ,  A M Rowland ,  C Kotts ,  M E Carver ,  H M Shepard
Affiliations
  • 1. Department of Protein Engineering, Genentech Inc., South San Francisco, CA 94080.
PMID: 1350088 DOI: 10.1073/pnas.89.10.4285
Abstract

The murine monoclonal antibody mumAb4D5, directed against human epidermal growth factor receptor 2 (p185HER2), specifically inhibits proliferation of human tumor cells overexpressing p185HER2. However, the efficacy of mumAb4D5 in human Cancer therapy is likely to be limited by a human anti-mouse antibody response and lack of effector functions. A "humanized" antibody, humAb4D5-1, containing only the antigen binding loops from mumAb4D5 and human variable region framework residues plus IgG1 constant domains was constructed. Light- and heavy-chain variable regions were simultaneously humanized in one step by "gene conversion mutagenesis" using 311-mer and 361-mer preassembled oligonucleotides, respectively. The humAb4D5-1 variant does not block the proliferation of human breast carcinoma SK-BR-3 cells, which overexpress p185HER2, despite tight antigen binding (Kd = 25 nM). One of seven additional humanized variants designed by molecular modeling (humAb4D5-8) binds the p185HER2 antigen 250-fold and 3-fold more tightly than humAb4D5-1 and mumAb4D5, respectively. In addition, humAb4D5-8 has potency comparable to the murine antibody in blocking SK-BR-3 cell proliferation. Furthermore, humAb4D5-8 is much more efficient in supporting antibody-dependent cellular cytotoxicity against SK-BR-3 cells than mumAb4D5, but it does not efficiently kill WI-38 cells, which express p185HER2 at lower levels.

Products