In vitro determination of antiviral activity of MSS209, a new amphotericin B derivative, against primary isolates of HIV1

MS8209. an amphotericin B derivative, was previously reported to be an inhibitor of HIV1 replication in vitro. In the present study, we determined the 50 and 90% in vitro inhibitory concentrations of MS8209 for 9 HIV1 isolates including both zidovudine-sensitive and zidovudine-resistant isolates and the reference strain Lai, using the peripheral blood mononuclear cell (PBMC) assay. We also evaluated the sensitivity of HIV1 replication to MS8209 during primary isolation from PBMCs. An inhibitory effect of MS8209 in PBMC infection was observed either when the drug was only present during the adsorption step or when the drug was initially absent but maintained throughout the culture period; the combination of these two approaches provided the highest inhibition rate. These results indicate that MS8209 can inhibit the replication of HIV1 isolates in PBMCs and suggest that it mainly acts by blocking the virus entry into cells.