Inhibition of plating of human T cell leukemia virus type I and syncytium-inducing types of human immunodeficiency virus type 1 by polycations.

We examined the effects of polycations, namely, diethylaminoethyl-dextran (DEAE-dextran) and hexadimethrine bromide (Polybrene), on infection with the retroviruses human T cell leukemia virus types I and II (HTLV-I and HTLV-II) and human immunodeficiency virus type 1 (HIV-1). The plating of vesicular stomatitis virus (VSV) pseudotype bearing envelope antigens of HTLV-I [VSV(HTLV-I)] was inhibited about 2- and 10-fold by treatment with DEAE-dextran and Polybrene, respectively. The formation of HTLV-I viral DNA detected 1 day after infection was also inhibited by these polycations. In contrast, polycations enhanced the plating of the VSV (HTLV-II) pseudotype two- to threefold. The polycations did not affect the plating efficiency of HTLV-I or HTLV-II when added after virus adsorption. Infection of human T cell lines, peripheral blood lymphocytes (PBLs), or brain-derived cells with syncytium-inducing (SI) types of HIV-1 strains (GUN1 and IIIB) was inhibited 3- to 20-fold by polycations. However, infection of PBLs or monocyte-derived macrophages with the macrophage-tropic Ba-L or SF162 strain was enhanced 1.5- to twofold by polycations. On the other hand, syncytium formation in coculture induced by HTLV-I, HTLV-II, or HIV-1 was enhanced two- to threefold unanimously by DEAE-dextran or Polybrene. Although polycations have been used to potentiate human retrovirus adsorption, they inhibited infection of cell-free HTLV-I or SI-type HIV-1 strains.