Abstract: The present disclosure relates to a polypeptide containing an Fc domain in which a part of an amino acid sequence of a human antibody Fc domain is substituted with another amino acid sequence, or an aglycosylated antibody containing the same. The Fc domain of the present disclosure is optimized by substituting a part of an amino acid sequence of a wild-type Fc domain with another amino acid sequence. Therefore, it is useful in treatment of cancer due to superior selective binding ability to Fc?RIIIa among Fc receptors, and can be prepared as a homogeneous aglycosylated antibody through bacterial culture.