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02421 MICROBICIDAL DETERGENTS INCREASE HSV SUSCEPTIBILITY IN MICE W/O CAUSING VISIBLE EPITHELIAL DEFECTS Cone, Richard A.*# Background: To block HSV infections, a detergent must be delivered at a concentration that rapidly disrupts epithelial cell membranes, and even at much lower concentrations, detergents still disturb cellular functions. In the mouse rectum, N9 (a nonionic detergent) delivered at a viricidal concentration rapidly injures columnar epithelium cells and later markedly increases rectal susceptibility to HSV (Phillips and Zacharopoulos, Contraception 1998). In the vagina of the mouse, when pre-treated with Depo-Provera to transform the entire epithelium to become columnar, a single application of N9 causes a long-lasting inflammatory response (Milligan et al, STDs, 29:597-605, 2002) and also causes a prolonged and marked increase in susceptibility to HSV (Abusuwwa et al, Microbicides 2002, Antwerp). Here we report tests of four major categories of detergents that are now used as spermicides and/or are being evaluated as microbicides: cationic (benzlkonium chloride), anionic (SDS sodium dodecyl (lauryl) sulfate), zwitterionic (cetyl betaine; myristyl dimethylamine oxide), and nonionic (nonoxynol-9). Methods: Mice pretreated with DepoProvera were exposed to a single application of the test detergent (2% in PBS). (This concentration was selected since it is the minimal concentration of N9 that provides detectable protection of mice against HSV infection.) Twelve hours after delivering the test detergent, mice were inoculated with a low-dose of virus (0.1 Vaginal Infectious Dose50 of HSV-2). One group of control mice (PBS w/o detergent) was inoculated with this same low-dose inoculum, and another control group with a high-dose inoculum (10 Vaginal Infectious Dose50). Infections were detected 3 days later by culturing vaginal lavage fluid on human foreskin fibroblasts. Results: Every detergent tested to date markedly increased the susceptibility of mice (range:10-30 fold) when challenged 12 hours after one exposure to the detergent. Also, this increased susceptibility occurred without inducing epithelial defects as visualized by colposcopy. Conclusions: A detergent applied only once to a columnar epithelium can cause a prolonged and marked increase in the susceptibility of the epithelium to HSV. Our results suggest that in clinical trials, this toxic effect on columnar epithelium would not be detected by colposcopy. Richard Cone |
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