Expression of a non-T, non-B ALL associated antigen on leukemic cells, lymphoblastoid cell lines and normal blood cells.

Two of our preparations of rabbit immune sera against Non-T, Non-B ALL cells were characterized. After a previously described absorption schedule used at present with some modifications, the sera were tested by indirect immunofluorescence and by a complement-dependent microcytotoxicity technique on a panel of cells: various types of ALL, lymphoblastoid cell lines of T, B and Non-T, Non-B surface characteristics, other leukemias (AML, CLL, Ph1 positive CML-BC), nonleukemic tissue of normal bone marrow, lymph-nodes and tonsils and also PBL. About 70% of Non-T, Non-B ALL, the Non-T, Non-B ALL line "REH" and CML cells in Ph1 positive "lymphoid" blast crisis were reactive in both test systems. Non-regenerating normal bone marrow, peripheral blood lymphocytes, and lymph node cells were non-reactive. CLL cells and tonsil cels, however, showed a positive fluorescence, yet gave a negative reaction in the complement-dependent microcytotoxicity test. This phenomenon might be explained by unspecific binding to Fc receptors. The antisera thus appear to detect a common Non-T, Non-B ALL antigen.