BEHAVIOR IN-VITRO OF LONG-TERM CULTURED BONE-MARROW OR BLOOD-CELLS FROM CHRONIC MYELOID-LEUKEMIA - ADHESION MOLECULES AND DIFFERENTIATION ANTIGENS AS DETECTED BY IMMUNOCYTOCHEMISTRY

Long-term cultures (LTC) were established from chronic myeloid leukemi c bone marrow or blood. As detected by immunocytochemistry using 25 di fferent monoclonal antibodies, the in vitro cultured cells express a v ariety of adhesion molecules and differentiation antigens. beta 1 and beta 2 integrins are constantly present on long-term cultured cells. C D4, CB54, CD58, and CD71 markers become highly expressed oil the cells after about 10 days in vitro while CD56 is permanently lacking. Only 5 of the 17 patients studied had between 25 and 85 per cent CD33 and C D34 differentiation antigen-positive cells initially in the bone marro w or blood. There was a decrease to less than 10 per cent after six to eight weeks in culture. In later stages of long-term culture, monocyt es/macrophages become the dominating cell types. Blast cells are admir ed to these cells in varying numbers. In 4 of the 17 cases studled the long-term cultures converted to cell lines showing indefinite cell gr owth. The cells were identified as B cell blasts spontaneously transfo rmed by Epstein Barr virus (EBV). The permanent myeloid and monocytic leukemia cell lines K-562, HL-60, KG-1, RC-2a, CTV-1, THP-1, and U-937 were likewise tested for adhesion molecules and differentiation antig ens. A stable marker expression was found, the pattern of which is cha racteristic of each cell line. CD4 is frequently present on myeloid an d monocytic leukemia cell lines (HL-60, RC-2a, THP-1, and U-937). Exce ptionally, CD2 and CD34 were shown on KG-1. CD49e, CD49f, CD44, and CD 71 are expressed on all cell lines tested.