Monoclonal and heteroantibody reacting with different antigens common to human blast cells and monocytes

A mouse monoclonal antibody CBL1 and a rabbit heteroantisera 157 raised to a lymphoblastoid T ALL cell line, CEM, appear to be specific for blast cells. Both CBL1 and 157 reacted with all PHA blasts and lymphoblastoid cell lines and the majority of leukemic blast cells tested. From serological reactivity and immunoprecipation experiments, CBL1 and 157 appeared to detect different blast cell antigens. There were leukemia blast cells from six patients that gave a different reaction pattern with CBL1 and 157. Antiserum 157 immunoprecipitated a 90,000 dalton antigen under reducing conditions which appeared as a 180,000 dalton disulfide-linked dimer under nonreducing conditions. Immunoprecipitation with CBL1 using the same 125I-labeled cell lysates gave no observable antigenic peaks.