Human leukocyte markers defined by monoclonal antibodies. I. Expression of X-hapten structure on cells of myeloid lineage.

We report on the characterization of four monoclonal antibodies which were prepared against membrane markers of human myeloid lineage. Fusion, isolation of hybridoma cells and their cloning and testing of the monoclonal antibodies by indirect immunofluorescence and FACS 440 analysis were performed by means of standard procedures. The results indicate that the monoclonal antibodies have a specificity against membrane markers of human myeloid lineage (exactly promyelo-granulocytes). These monoclonal antibodies do not react with human T and B lymphocytes, monocytes, erythrocytes and thrombocytes of peripheral blood. In normal bone marrow reactivity to matured myeloid cells was found to occur in promyelocytes and expressed on all granulocytes. These monoclonal antibodies also react with cells of myeloid cell lines and with other precursor cell lines represented by NALM-1, NALM-16, HEL, K-562, REH no reactivity was detected. The produced antibodies react with some leukaemic cells from patients with more mature myeloid cells (AML with promyelocytes, myelocytes and CML) they do not react with pathological cells from patients with CLL, AML (with myeloblasts), ALL, hairy cell leukaemia, erythroleukaemia and several types lymphoma. All antibodies have a IgM class and express granulocytotoxic and granuloagglutination activity. Using flow cytometry comparative analysis with other monoclonal antibodies was performed to detect the membrane structure (X-haptene) included in standard International classification as CD 15 group.