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Publication Abstract from PubMed

Antibodies are widely used as cancer therapeutics, but their current use is limited by the low number of antigens restricted to cancer cells. A receptor tyrosine kinase, receptor tyrosine kinase-like orphan receptor 2 (ROR2), is normally expressed only during embryogenesis and is tightly down-regulated in postnatal healthy tissues, but is up-regulated in a diverse set of hematologic and solid malignancies. Thus, ROR2 represents a candidate antigen for antibody-based cancer therapy. Here we describe the affinity maturation and humanization of a rabbit mAb that binds human and mouse ROR2 but not human ROR1 or other human cell-surface antigens. Co-crystallization of the parental rabbit mAb in complex with the human ROR2 kringle domain (hROR2-Kr) guided affinity maturation by heavy chain complementarity-determining region 3 (HCDR3)-focused mutagenesis and selection. The affinity-matured rabbit mAb was then humanized by complementarity-determining region (CDR) grafting and framework fine tuning, and again co-crystallized with hROR2-Kr. We show that the affinity matured and humanized mAb retains strong affinity and specificity to ROR2 and, following conversion to a T-cell engaging bispecific antibody, has potent cytotoxicity toward ROR2-expressing cells. We anticipate that this humanized affinity matured mAb will find application for antibody-based cancer therapy of ROR2-expressing neoplasms.

Affinity maturation, humanization, and co-crystallization of a rabbit anti-human ROR2 monoclonal antibody for therapeutic applications.,Goydel RS, Weber J, Peng H, Qi J, Soden J, Freeth J, Park H, Rader C J Biol Chem. 2020 Mar 19. pii: RA120.012791. doi: 10.1074/jbc.RA120.012791. PMID:32193207^[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.