Studies of human myeloid antigens using monoclonal antibodies and variant lines from the promyeloid cell line HL60.

Monoclonal antibodies were produced using mice immunized with the human promyeloid cell line HL60. Two antibodies are described which identify antigens selectively expressed by myeloid cells. Studies using normal bone marrow and myeloid leukaemia cells demonstrated that one of these antibodies (AGF4.48) identifies an antigen expressed throughout the promyeloid to neutrophil stages of maturation. In contrast, the second antibody (AGF4.36) identifies an antigen expressed at the promyeloid to metamyeloid stages and is absent from most blood neutrophils. The HL60 line can be induced to differentiate into neutrophils by 1 . 25% dimethylsulphoxide (DMSO) (Collins et al., 1978). Variant lines from HL60, unresponsive to 1 . 25% DMSO, lack the 'transient' myeloid antigen (AGF4.36) and show a reduced expression of the myeloid antigen (AGF4.48). The variant lines can be induced to mature using higher DMSO concentrations (1 . 5-1 . 75%) and do not express the 'transient' antigen (AGF4.36) during their maturation. The use of these lines in studies of myelopoiesis is discussed.