INTERFERON-ALPHA SELECTIVELY AFFECTS EXPRESSION OF THE HUMAN MYELOID CELL NUCLEAR DIFFERENTIATION ANTIGEN IN LATE-STAGE CELLS IN THE MONOCYTIC BUT NOT THE GRANULOCYTIC LINEAGE

The human myeloid cell nuclear differentiation antigen (MNDA) is expre ssed constitutively in cells of the myeloid lineage, appearing in myel oblast cells in some cases of acute myeloid leukemia and consistently being detected in promyelocyte stage cells as well as in all later sta ge cells including peripheral blood monocytes and granulocytes. The hu man myeloid leukemia cell lines, HL-60, U937, and THP-1, express simil ar levels of immunochemically detectable MNDA. Although, the level of MNDA mRNA in primary monocytes is very low it was up-regulated at 6 h following the addition of interferon alpha. The effect of interferon a lpha on the MNDA mRNA is also observed in the cell lines HL-60, U937, and THP-1. The MNDA mRNA level in primary granulocytes was unaffected by addition of interferon cr and other agents including interferon y, endotoxin, poly (I) poly (C), and FMLP. The MNDA mRNA level in the mye loid cell lines was also unaffected by the latter four agents. Inducti on of differentiation in the myeloid cell lines with phorbol ester ind uces monocyte differentiation which was accompanied by a decrease in M NDA mRNA level. This reduced level of mRNA could then be elevated with subsequent interferon alpha treatment. The effects of phorbol ester o n MNDA mRNA appeared to be associated with induced differentiation sin ce inhibiting cell proliferation did not alter the level of MNDA mRNA and cell cycle variation in MNDA mRNA levels were not observed. The ab ility of interferon alpha to up-regulate MNDA mRNA in phorbol ester tr eated myeloid cell lines is consistent with the observations made in p rimary monocytes. Granulocyte differentiation induced by retinoic acid treatment of HL-60 cells did not alter the MNDA mRNA level which was also unchanged following subsequent treatment with interferon alpha. T he lack of interferon alpha effects on retinoic acid treated HL-60 cel ls is consistent with its inability to influence MNDA mRNA level in pr imary granulocytes. (C) 1994 Wiley-Liss, Inc.