#$%^&*AU2019203917A120190801.pdf#####ABSTRACT Provided are antibody and antigen-binding fragment with modified CK and CHI domains that still enable pairing of the CK and CHI domains but have reduced pairing compared to wild type CHI and CK domains without the modification. Such modifications can particularly useful for preparing bispecific antibodies which two different pairs of CK and CHI domains. -69-