| abstract |
Disclosed is a LAG-3 binding protein, comprising a light chain variable region and/or a heavy chain variable region. The light chain variable region comprises a CDR1 having an amino acid sequence as shown in SEQ ID NO: 5, a CDR2 having an amino acid sequence as shown in SEQ ID NO: 6, and/or a CDR3 having an amino acid sequence as shown in SEQ ID NO: 7. The heavy chain variable region comprises a CDR1 having an amino acid sequence as shown in SEQ ID NO: 8, a CDR2 having an amino acid sequence as shown in SEQ ID NO: 9, and/or a CDR3 having an amino acid sequence as shown in SEQ ID NO: 10. Also disclosed are a bispecific antibody targeting LAG-3 and use thereof. The LAG-3 binding protein and bispecific antibody above can effectively block the binding of LAG-3 to MHC II and activate T cells. |