According to the literature, this antibody recognizes the zeta-associated protein of 70 KDa (ZAP-70), a member of the Syk family of protein tyrosine kinases. ZAP-70 is expressed primarily in T cells and natural killer (NK) cells and is critical for signal transduction following T cell receptor engagement. More recently, ZAP-70 has been reported to be expressed in chronic lymphocytic leukemia (CLL) and to correlate with IgVH mutational status, disease progression, and survival. The IE7.2 antibody reportedly binds to both human and mouse ZAP-70 and is effective for flow cytometric analysis as well as Western blotting.