Disclosed herein are isolated multi-specific heteromultimer constructs that bind to CD3 expressed on T-cells and to an antigen expressed on B-cells. The multi-specific heteromultimer constructs are capable of bridging T- and B-cells and mediating killing of B-cells. The multi-specific heteromultimer constructs are based on a heterodimeric Fc scaffold or on a segmented albumin scaffold. Also disclosed herein are multi-specific heteromultimer constructs that bind to HER2 and HER3.
