An asymmetric heterodimeric antibody includes a knob structure formed in a CH3 domain of a first heavy chain； a hole structure formed in a CH3 domain of a second heavy chain, wherein the hole structure is configured to accommodate the knob structure so that a heterodimeric antibody is formed； and a T-cell targeting domain fused to the CH3 domain of the first heavy chain or the second heavy chain, wherein the T-cell targeting domain binds specifically to an antigen on the T-cell. The T-cell targeting domain is a ScFv or Fab derived from an anti-CD3 antibody. The asymmetric heterodimeric antibody may have L234A and L235A mutations or L235A and G237A such that its effector binding is compromised.
