There is provided an isolated monoclonal antibody or antigen-binding fragment thereof that specifically binds to human IL-31 comprising a humanized heavy chain variable domain and a humanized light chain variable domain, wherein the humanized heavy chain variable domain comprises a CDR1, CDR2 and CDR3 consisting of the amino acid sequences of SEQ ID NOs: 1, 2 and 3, respectively, and framework regions FR1, FR2, FR3, and FR4 having an amino acid sequence that is at least 90% identical to the amino acid sequence of SEQ ID NO:12 (FR1), SEQ ID NO:13 (FR2), SEQ ID NO:14 (FR3) and SEQ ID NO:15 (FR4) respectively； and wherein the humanized light chain variable domain comprises a CDR1, CDR2 and CDR3 consisting of the amino acid sequences of SEQ ID NOs: 5, 6 and 7, respectively, and framework regions FR1, FR2, FR3, and FR4 having an amino acid sequence that is at least 90% identical to the amino acid sequence of SEQ ID NO:17 (FR5), SEQ ID NO:18 (FR6), SEQ ID NO:19 (FR7) and SEQ ID NO:20 (FR8) respectively.
