Abstract
5C11, a murine monoclonal antibody with a high specificity for human CD40 molecule, is a promising candidate for cancer targeting therapy. We have therefore attempted to construct a humanized antibody of 5C11 to minimize its immunogenicity for potential clinical use. A chimeric version of 5C11 (ch-5C11) was generated by transferring these mouse variable regions onto a human framework. This chimeric antibody retained reactivity to human CD40. In vitro, ch-5C11 could effectively inhibit B lymphoma Daudi cell proliferation, suggesting that it might have the potential to be developed for future clinical use.