The development and optimization of anti-viral screening methods are essential to develop newer more effective, treatments against HIV. The XTT method is a widely described method for antiviral screening. Both continuous HIVinfected cells and experimentally infected T-cells have been used in the XTT assay. We compared these methods to screen several plant-derived extracts for cytotoxicity. Several considerations were taken into account when performing these tests (effect of media, solvents and plant enymes). Experiments were performed to investigate these effects. In addition, p24 and viral load quantification were compared as antiviral screening methods. The study showed that several modifications were necessary when performing the XTT assay on plant extracts, due to the effect of media, solvents and plant enymes. The XTT assays and p24 assays performed using experimentally infected cells are far more specific than those using chronically infected cells. The use of viral loads as an antiviral screening method consistently demonstrated the expected efficacy of AZT.

Thesis(MMed.)-University of KwaZulu-Natal, 2009.