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02593 DETECTION OF HIV-1 RNA LOADS IN THE PRESENCE OF MICROBICIDE FORMULATIONS INTENDED FOR HUMAN USE Evans-Strickfaden, Tammy The clinical evaluation of topical microbicide formulations should include an analysis of how daily applications of a product affect HIV-1 vaginal shedding in infected women. Therefore, accurate measurements of cell-free HIV-1 in vaginal secretions containing microbicide formulations are necessary. This study investigated the impact of microbicide and available placebo formulations of CarraguardTM, cellulose acetate phthalate (CAP), PRO-2000 (0.5%), UC781 (0.1 and 1.0%), and VenaGelTM on HIV-1 RNA virus load measurements using the Roche Amplicor HIV-1 Monitor® Assay (version 1.5). Microbicides were diluted in PBS to 10 and 50% of their original formulations and spiked with cell-free plasma virus (5,000 HIV-1 RNA copies/ml). HIV-1 RNA was extracted directly from the diluted formulations and from pelleted virus (1 hr at 105xg) using the NucliSens® 9-ml and 0.9-ml silica-based protocols, respectively. Virus-spiked 50% concentrations of CarraguardTM, its methylcellulose placebo, CAP, and VenaGelTM with direct RNA extractions had the same virus loads as those in the virus-spiked PBS only controls (< 0.5 log10 difference). In contrast, virus-spiked 10 and 50% concentrations of PRO-2000, UC781 (1.0%), and their placebos completely inhibited the virus load assay. However, a normal virus load (< 0.5 log10 difference versus the PBS control) was obtained from a 10% concentration of UC781 (0.1%), but not of PRO-2000, by pelleting virus before RNA extraction. These results indicate that the ability to accurately measure the effect of microbicide formulations on HIV-1 vaginal shedding will require a knowledge of the RNA extraction methodology and virus load protocols best suited for each product. Ms. Tammy Evans-Strickfaden |
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