Sulfated fibroin, a novel sulfated peptide derived from silk, inhibits human immunodeficiency virus replication in vitro

We prepared two kinds of sulfated silk fibroins, SclFib30 and SclFib31, whi ch contain different amounts of sulfate. These sulfated silk fibroins have anti-HIV-l activity in vitro, apparently due to interference with the adsor ption of virus particles to CD4(+) cells, and completely blocked virus bind ing to the cells at a concentration of 100 mu g/ml. Sulfated fibroins also abolished cell-to-cell infection-induced syncytium formation upon cocultiva tion of MOLT-4 and MOLT-4/HIV-1(IIIB) cells, suggesting that they would int erfere with gp120 and prevent the formation of gp120/CD4 complex. Silk is u sed in biomaterials such as surgical sutures and is believed to be a safe m aterial for humans. In accordance with low anticoagulant activity and high anti-HIV-1 activity against both X4 HIV-1 and R5 HIV-1 strains, sulfated si lk fibroins have potential as antiviral material such for a vaginal anti-HI V formulation.