Anti-HIV-1 Activity of an Ionically Modified Porous Polypropylene Membrane Determined by Filtration of a Viral Suspension

Abstract

We describe here a unique anti-HIV-1 membrane, derived from a chemically modified porous polypropylene (PP) membrane, which lowers viral infectivity upon the filtration of HIV-1 suspension. A cationic polymer, polyethyleneimine (PEI) was graft-polymerized onto the PP filter membrane (PP-PEI), and infectious HIV-1_HTLV-IIIB derived from MOLT-4/HIV-1_HTLV-IIIB cells (HIV-1_{HTLV-IIIB(MOLT-4)}) was applied. When a viral suspension of high titer (10^3.93 TCID₅₀ ml^-1) was filtered, efficient reduction (>99%) of gag p24 antigen levels and infectious titer resulted. In a viral suspension of medium titer (10^2.37 TCID₅₀ ml^-1), a significant decrease in the p24 antigen did not occur, although the titer was markedly reduced (>95%). Electron microscopic observation suggested that PEI induced viral aggregations under high titer conditions, and under medium titer conditions, PEI deprived HIV-1_HTLV-IIIB of its infectivity alone to avoid virus adsorption. In contrast, HIV-1 propagated in human peripheral blood mononuclear cells (PBMC) such as HIV-1_{HTLV- IIIB(PBMC)} was more efficiently trapped by PP-PEI at lower titers as compared with HIV-1_{HTLV-IIIB(MOLT-4)} from MOLT-4/HIV-1_HTLV-IIIB cells. These data suggest host cell modification in the interactions between PP-PEI and HIV-1 strains. Since HIV-1_{HTLV-IIIB(MOLT-4)} and HIV-1_{HTLV-IIIB(PBMC)} were almost electrically neutral and negative, respectively, we concluded that the divergent effect of PEI on each HIV-1_HTLV-IIIB resulted from their different electrical characteristics.