Reactivity of monoclonal antibodies with human myeloid precursor cells

Five monoclonal antibodies have been tested for their ability to bind to myeloid precursor cells in normal human bone marrow. Indirect immunofluorescence and the fluorescence activated cell sorter was used to separate cells according to their reactivity for trial culture in vitro in order to grow granulocyte-macrophage colony forming cells (CFUc). Two antibodies (OKT3 and OKT11) which react strongly with bone marrow T lymphocytes were found to be unreactive with CFUc. YD1/23 reacts very strongly with both T and B lymphocytes but is only weakly reactive with CFUc. In contrast, OKT10 and YE2/36 did react with CFUc. The consequences of these findings and the potential clinical use of these antibodies in bone marrow transplantation are discussed.