CD69 and acute myeloid leukemia: Following incubation of 8F4 bi-specific antibodies with T cells and PR2/HLA_A2+ target cells, we found that T cells were quickly activated, evidenced by upregulation of activation marker, CD69, and released various inflammatory cytokines such as Il-6, IFN-gamma, and TNF-alpha that can potentially augment anti-tumor immunity through apoptosis of tumor cells (23) Next, the bi-specific antibody showed robust redirected T-cell engagement and cytotoxicity toward PR1/HLA-A2+ AML cell lines and primary AML blasts was achieved at picomolar concentrations of bi-specific antibody.