Modification of human immunodeficiency viral replication by pine cone extracts.

We have shown previously that two fractions (PC6 and PC7) extracted from cones of the Japanese white pine Pinus parvifloria Sieb. et Zucc have potent immunopotentiating effects. Here, we show that PC6 and PC7 inhibited HIV-1 replication (greater than 95%), in a dose-dependent manner, in chronically infected CR10/HIV-1 cells and in acute cytolytic HIV-1 infection of CEM cells. Treatment of CEM cells, prior to or after acute infection with HIV-1, reduced subsequent viral production, but the best inhibitory effect was obtained with treatment before and after infection: an 80% inhibition was achieved with as little as 3 micrograms/ml of PC6. Comparable results were also obtained when PC6 was used to inhibit HIV-1 replication in the U937 human histiocytic lymphoma cell line. Both PC6 and PC7 were relatively nontoxic to cells. The anti-HIV-1 effect of PC6 and PC7 we observed in this report, coupled with earlier reports of their immunopotentiating properties suggest their potential as ideal therapeutic agents for the treatment of AIDS.