A nucleic acid construct that encodes a monoclonal antibody or antigen-binding fragment that specifically binds to stage-specific embryonic antigen 4. The monoclonal antibody or antigen-binding fragment includes a heavy-chain CDR1 having the sequence of SEQ ID NO: 33 or SEQ ID NO: 40, a heavy-chain CDR2 having the sequence of SEQ ID NO: 34 or SEQ ID NO: 39, a heavy-chain CDR3 having the sequence of SEQ ID NO: 35 or SEQ ID NO: 41, a light-chain CDR1 having the sequence of SEQ ID NO: 36 or SEQ ID NO: 42, a light-chain CDR2 having the sequence of SEQ ID NO: 37 or SEQ ID NO: 43, and a light-chain CDR3 having the sequence of SEQ ID NO: 38 or SEQ ID NO: 44. Also disclosed are recombinant cells containing the nucleic acid construct.