Human Alpha- and Beta-Interferon But Not Gamma- Suppress the In Vitro Replication of LAV, HTLV-III, and ARV-2

The effect of human interferons (IFNs) (alpha, beta, and gamma) on the in vitro replication of AIDS viruses (LAV, HTLV-III, and ARV-2) in human peripheral blood lymphocytes was investigated. At the time of peak virus production, IFN-α preparations (leukocyte, Namalwa, α₁, and α₂) at 100 U/ml, suppressed LAV, HTLV-III, and ARV-2 replication as measured by reverse transcriptase (RT) activity by greater than 50%. This suppression was dose dependent and high dosages (500 U/ml) of IFN-α resulted in almost complete suppression of RT activities (77–99%). A low dose (100 U/ml) of IFN-β suppressed all three AIDS viruses by 75%. In contrast, human IFN-α at a dose range from 100 U/ml to 500 U/ml had no significant effect on the production of infectious viruses. These results indicate that only IFN-α and -β are effective against LAV, HTLV-III, and ARV-2 replication. A continuous supply of IFN appeared to be essential for the constant suppression of RT activity. In fact, upon termination of single IFN treatment, enhanced virus production resulted.