Generation and characterization of humanized anti-CD19 chimeric antigen receptor T (CAR-T) cells for the treatment of hematologic malignancies

Chimeric antigen receptor expressing T cells (CAR-T) represent a novel approach to cancer therapy. Recent studies have shown successful targeting and killing of CD19 expressing malignancies with CAR-T cells targeting the CD19 antigen. Dramatic responses have been observed with this approach in patients with relapsed and refractory acute and chronic lymphocytic leukemia and lymphomas. The CD19 CARs in current clinical trials contain scFv fragments derived from murine monoclonal antibodies. The development of antibodies against the murine antibody fragments not only contributes to lack of persistence of T cells expressing such CARs but could also lead to allergic reactions, including anaphylaxis. To overcome this limitation, we have generated a CD19 CAR containing scFv fragment derived from a humanized CD19 monoclonal antibody. We demonstrate that this CAR is expressed on the surface of T cells and induce selective killing of CD19 expressing lymphoma cells.