The monoclonal antibodies of this invention are antibodies that specifically recognize human Integrin Associated Protein, and the antigens that induce apoptosis of nucleated blood cells having human Integrin Associated Protein. Accordingly, they are useful as antibodies that recognize human Integrin Associated Protein for its distinction and identification, while also having an action of inducing apoptosis of nucleated blood cells; these properties can be utilized to prepare useful therapeutic agents in the field of treatment for myeloid leukemia and lymphoid leukemia.