Abstract: A therapeutic molecule (single chain-based antibody or ligand-based) optimized for expression and secretion from engineered T cells, which may be gamma delta (gd) T cells. When expressed from engineered gdT cells, the STAR will be secreted and mediate engagement between gdT cells and antigen/receptor on target cells. Binding mediates the formation of a cytolytic synapse between the gdT cell and the target cell leading to activation the gdT cells to release proteolytic enzymes that kill target cells.