%0 Journal Article %A Konopka, Krystyna %A Stamatatos, Leonidas %A Larsen, Charles E. %A Davis, Brian R. %A Düzgüneş, Nejat %T Enhancement of human immunodeficiency virus type 1 infection by cationic liposomes: the role of CD4, serum and liposome-cell interactions %D 1991 %J Journal of General Virology, %V 72 %N 11 %P 2685-2696 %@ 1465-2099 %R https://doi.org/10.1099/0022-1317-72-11-2685 %I Microbiology Society, %X We have reported previously the enhancement of the infectivity of human immunodeficiency virus type 1 (HIV-1) by liposomes composed of the cationic lipid N-[2, 3-(dioleyloxy) propyl]-N, N, N-trimethylammonium chloride (DOTMA). To determine the mechanism by which this process occurs, we have investigated the role of CD4, serum concentration and liposome-cell interactions in the DOTMA-mediated stimulation of HIV-1 infection of A3.01 cells. Serum alone significantly inhibited the binding and infectivity of HIV-1, but DOTMA-mediated enhancement of infectivity was more pronounced in the presence of serum than in its absence. HIV-1 binding to cells was increased in the presence of DOTMA liposomes, DEAE-dextran and polybrene, all of which also enhanced infectivity to a similar extent at comparable concentrations. Fluorescence dequenching measurements indicated that DOTMA liposomes fused with HIV-1, but not with cell membranes, in the presence of serum. The enhancing effect of DOTMA liposomes on HIV-1 infectivity was CD4-dependent, and appeared to involve virus-liposome fusion and liposome binding to the cell surface. DOTMA liposomes did not mediate infection of the CD4− K562 and Raji cell lines. %U https://www.microbiologyresearch.org/content/journal/jgv/10.1099/0022-1317-72-11-2685