In line with the effort to enhance T cell activation and tumor targeting, an in vivo study of a tri-specific antibody targeting CD38, CD3 and CD28 has shown ability to suppress myeloma growth in a humanized mouse model and to stimulate memory/effector T cell proliferation and reduce regulatory T cells in non-human primates at well-tolerated doses [226]. This evidence concerns the gene CD38 and plasma cell myeloma.