Effect of topical microbicides on infectious human immunodeficiency virus type 1 binding to epithelial cells

Topical microbicides (cellulose acetate 1,2 benzene dicarboxylate [CAP], PRO 2000, SPL7013, and UC781) are being investigated to reduce the sexual transmission of human immunodeficiency virus type 1 (HIV-1). These products were shown to prevent the transfer of infectious HIV-1 from urogenital and colorectal epithelial cell lines to peripheral blood mononuclear cells. However, it was unclear if the topical microbicides rendered the virus noninfectious and/or reduced the binding to the epithelial cells. To test this, epithelial cells were cultured with HIV-1 in the presence or absence of topical microbicides or their placebos. The cells were washed, RNA lysates were made, and real-time PCR was performed for HIV-1. PRO 2000 and SPL7013 significantly (P < 0.0001) reduced the amount of bound HIV-1 to the colorectal epithelial cell line across clades A, B, C, and CRF01-AE. While none of the products reduced the binding of HIV-1 clades A and C to the urogenital cell line, CAP, PRO 2000, and SPL7013 significantly (P