Figure 6
Lack of emergence of HIV-1 resistance during long-term virus passaging in the presence of Cistus incanus extract.
Virus was passaged with or without Ci extract for 48 passages (i.e. 24 weeks) and monitored for sensitivity to inhibition by Ci extract every week. For each passage with Ci extract, LC5-RIC target cells were exposed to HIV-1LAI virus in the presence of Ci extract for one day, followed by expansion of the escape virus for 2–3 days without Ci extract. Long-term virus passaging was performed with two concentrations of Ci extract, corresponding to EC50 (CiEC50 line graph) or EC90 (CiEC90 line graph) inhibitory concentrations against the initial virus inoculum. Passaging in the presence of the higher Ci extract concentration (CiEC90) was initiated with virus collected after 6 weeks of passaging with the lower Ci extract concentration. Virus was passaged in parallel without Ci extract as control (Virus only line graph). Virus collected from every second passage was evaluated for inhibition by Ci extract in infection assays with different concentrations of Ci extract (100 μg/ml to 3.125 μg/ml; two-fold serial dilutions) or without extract (=100% infection). Symbols represent the mean EC50 determined for each virus sample in three independent experiments and the error bars the standard deviation of the mean.
