A MONOCLONAL ANTIBODY IDENTIFYING A CELL-SURFACE ANTIGEN SHARED BY COMMON ACUTE LYMPHOBLASTIC LEUKEMIAS AND B-LINEAGE CELLS

Abstract

A monoclonal antibody [from humans], designated PI153/3, identifies a cell surface determinant shared by pre-B and mature B cells and their corresponding leukemias including chronic lymphocytic leukemia, non-Hodgkin''s lymphoma, B acute lymphoblastic leukemia [B-ALL] and hairy cell leukemia but not plasmacytoma. Almost all non-T, non-B acute lymphoid leukemias bind PI153/3. The latter includes 71 of 74 common ALL tested, most but not all unclassified or null ALL and cases of acute undifferentiated leukemia and Ph1 positive chronic myeloid leukemia in blast crisis with common ALL phenotypes. The antigen is absent or present at very low density on normal and leukemic T lymphocyte, myeloid and erythroid cells. The determinant appears to co-redistribute with cell surface Ig on B lymphocytes and segregates independently of other cell surface antigens associated with B cells and/or c[chronic]ALL including HLA-DR (Ia[immune response associated]-like antigens) and the cALL (gp 100) antigen.