A subclonal cl.1-14 cell was established from a monocytic cell line U937 by a limiting dilution method. The anti-HIV-1 activity of some antiviral compounds was evaluated in HIV-1-infected cl.1-14 cells. The results demonstrated that although AZT was a potent inhibitor of HIV-1 replication in cl.1-14 cells, its 50% effective concentration (EC50) values was 80 times higher than that in HIV-1 infected MT-4 cells; the EC50 of AZT was 0.16 microM and 0.002 microM in cl.1-14 and MT-4 cells, respectively. In contrast, the anti-HIV-1 activity of ddA, ddI and ddC in cl.1-14 cells was comparable to that in MT-4 cells. The antiviral activity of nevirapine, dextran sulfate, curdlan sulfate and T22 did not differ significantly between the cl.1-14 and MT-4 cells. The antiviral activity of several compounds in the HIV-1-infected cl.1-14 cells was similar to that in the HIV-1JR-FL-infected human peripheral macrophages. Our results suggest that cl.1-14 cell cultures are very useful for estimating antiviral activity and more advantageous than the use of peripheral blood macrophages.