FCYRIIB-SPECIFIC FC REGION VARIANT

摘要

An objective of the present invention is to provide an Fc region variant with enhanced Fc³RIIb-binding activity, and/or enhanced binding selectivity to Fc³RIIb compared to Fc³RIIa (type R), as compared to those of a polypeptide containing an Fc region to which an amino acid alteration(s) has not been introduced; a polypeptide which includes the Fc region variant; a pharmaceutical composition containing the polypeptide; preventing therapeutic or preventive agent for immunological inflammatory diseases that includes the pharmaceutical composition; a production method thereof; and a method of enhancing Fc³RIIb-binding activity and also enhancing binding selectivity to Fc³RIIb compared to Fc³RIIa (type R). It was found that a polypeptide containing an antibody Fc region variant that contains an amino acid sequence in which an amino-acid alteration at position 238 (EU numbering) is combined with other specific amino-acid alterations enhances Fc³RIIb-binding activity, and/or enhances binding selectivity to Fc³RIIb compared to Fc³RIIa (type R).