Recombinant human interferon-beta suppresses the replication of HIV and acts synergistically with AZT.

The in vitro effects of recombinant human interferon-beta ser (rIFN-beta ser) and 3'-azido-3'-deoxythymidine (AZT) alone and in combination on human immunodeficiency virus (HIV) replication were examined. rIFN-beta ser inhibited HIV progeny virus synthesis in cell cultures chronically infected with HIV. When used in combination, suboptimally effective concentrations of rIFN-beta ser and AZT synergistically inhibited HIV-mediated syncytium formation in HeLa T4 cell cultures. Whereas AZT alone reduced HIV replication in human MT-2 cells, addition of low concentrations of rIFN-beta ser reduced by 4- to 1,000-fold the amount of AZT required to maximally block HIV p24 antigen synthesis and HIV-mediated cell lysis. No drug-related cytoxicity was observed when the two agents were used together at and above maximally effective concentrations. These results suggest that a safer, yet effective, therapy for HIV infections may be achieved with reduced doses of AZT in combination with rIFN-beta ser.