Differential mRNA accumulation of TNFalpha and IFNbeta. Only PMA differentiated cells, representatives of macrophages, exhibit distinct biphasic behavior of TNFalpha accumulation (2 and 22 hrs) and time dependent up regulation (10 hrs and 22 hrs) of IFNbeta. Error bars refer to technical variation. Relative expressions were represented as log RQ (base 2) in which RQ (relative quantification) = 2-ddCt. Different duration of LPS stimulation was indicated by white bar (2 hrs), black bar (10 hrs for IFNbeta, 12 hrs for TNFalpha) and gray bar (22 hrs) on the graph.