A Monoclonal Antibody GR2110 Reactive With a P24 Antigen Present in a Subgroup of Acute Lymphoid Leukemias

Abstract

A monoclonal antibody IgG_1K against a P24 antigen has been obtained. This antigen is present on a subgroup of non-T-ALL and platelets. GR2110 monoclonal antibody was produced by immunizing with a CALL (CALLA⁺, Ia⁺, IgS^-, E^-, T3^-) This P24 antigen is absent in normal T-lymphocytes, monocytes, mitogen-activated T-cells; weakly expressed on B-cells and granulocytes and negative with several cell lines, except with KM3. GR2110 monoclonal antibody was tested with chronic and acute human leukemias. It was positive only with some CALL, NULL ALL, B-ALL and negative with B-CLL, T-CLL, T-cell lymphoma, Hairy cell leukemia, AML, T-ALL. The immunoprecipitation of ¹²⁵I-labeled cell membrane with the monoclonal antibody and SDS-PAGE analysis revealed a 24 kD molecular weight polypeptide. The comparison of GR2110 and FMC 8 in capping experiments and cellular reaction patterns, showed that both antibodies react with the same molecule but probably with different epitopes.