Provided is a novel antibody. According to the present invention, a monoclonal antibody or a binding fragment thereof binds to domain 3 of a human LAG-3, and has the properties described in (i) and (vi) and one or more of the properties described in (ii) to (v) below: (i) the antibody has in vitro ADCC activity； (ii) the antibody is a low-fucose antibody and reduces the number of LAG-3 positive cells in vivo； (iii) the antibody is a low-fucose antibody and suppresses experimental autoimmune encephalomyelitis in vivo； (iv) the human LAG-3 binds to a human activated T cell； (v) the human LAG-3 binds to a human major histocompatibility gene complex class II molecule in the presence of the antibody or a binding fragment thereof； and (vi) the human LAG-3 exhibits a human T cell suppression function in the presence of the antibody or a binding fragment thereof.
