Interferon-alpha and dexamethasone effect on AF10 myeloma cell line sialytransferase activity

Interferon-alpha and the synthetic glucocorticoid dexamethasone are used in the treatment of multiple myeloma. The effect of 48 h exposure to recombinant interferon-alpha 2b (100 to 10,000 U/ml) and dexamethasone (1 microM to 1 mM) was studied in AF10, and IgE-secreting myeloma cell line. Interferon-alpha and dexamethasone at 10,000 U/ml and 1 mM respectively had a synergistic inhibitory effect on IgE concentration. Interferon-alpha and dexamethasone had an additive inhibitory effect on myeloma cell concentration. Interferon-alpha at 10,000 U/ml caused a twofold increase in sialyltransferase activity. Dexamethasone decreased sialytransferase activity and attenuated the stimulatory effect of interferon-alpha. These data suggest that combined interferon-alpha and dexamethasone therapy might have a synergistic effect on monoclonal protein production and a diverse effect on sialytransferase activity.