The clone 124-1D1, a mouse monoclonal antibody selectively recognizes ~40 kDa type I transmembrane glycorotein antigen known as CD7. It is a member of Ig superfamily and abundantly expressed on the cell surface of the human T cells and a subset of NK cells. The CD7 is expressed throughout the process of T lymphocyte differentiation and is present on 85% to 90% of peripheral blood T cells. It is also expressed on acute lymphocytic leukemia (ALL) and some type of acute myeloid leukemia (AML) cells.