Anti-HIV-1 activity of an ionically modified porous polypropylene membranedetermined by filtration of a viral suspension

We describe here a unique anti-HIV-1 membrane, derived from a chemically mo dified porous polypropylene (PP) membrane, which lowers viral infectivity u pon the filtration of HIV-1 suspension. A cationic polymer, polyethyleneimi ne (PEI) was graft-polymerized onto the PP filter membrane (PP-PEI), and in fectious 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 a ntigen levels and infectious titer resulted, In a viral suspension of mediu m 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 mi croscopic observation suggested that PEI induced viral aggregations under h igh 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 t iters 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 betw een 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, w e concluded that the divergent effect of PEI on each HIV-1(HTLV-IIIB) resul ted from their different electrical characteristics.