The Anti-BCMA-Anti-CD19-Anti-CD3-His Trispecific Antibody is engineered to bind to three different targets simultaneously: 1) BCMA, a B cell antigen that is highly expressed by mature B cells and malignant myeloma cells, 2) CD19, a B-cell marker that is a target for many leukemias and lymphomas, and 3) CD3, a T cell receptor activation signal that leads to cytokine secretion. The multi-functionality of this trispecific antibody allows it to bind to BCMA and CD19 on the tumor cell and CD3 on T cells simultaneously, thus bringing T lymphocytes closer to the cancer cells. The binding event targets the tumor while providing co-stimulatory signals that promote T cell expansion and cytotoxicity against BCMA+ and CD19+ cancer cells.