Repeated low-dose SIVmac239 challenge of AAV-immunized and control animals.

<p>(<b>A</b>) Kaplan-Meier analysis of the three test groups. The percentage of animals remaining uninfected is plotted against the number of SIV exposures. SIV virus challenges were conducted in 3-week intervals. Four low-dose challenges with one half-maximal infectious dose (1x ID50) were followed by a two ID50 (2x) and a subsequent ten ID50 (10x) challenge. The survival curves are not significantly different (Mantel-Cox test). (<b>B</b>) Peak viral load comparison. The geometric mean (red line) is significantly different in the 5L7 IgG1 group compared to the control group (two-tailed, unpaired <i>t</i> test). (<b>C</b>) Set-point viral load analysis. All values within one group between weeks 8 and 25 were averaged, the resulting values were logarithmized (log10) and compared to each other. The geometric mean of the 5L7 IgG1 group differs significantly from the other two groups (two-tailed, unpaired <i>t</i> test). (<b>D</b>) Time of peak viremia. Most of the immunized animals show peak viremia at week 3, while 5 of 6 controls peak at week 2. (<b>E</b> and <b>F</b>) Viral loads <i>in vivo</i> after infectious exposure with SIVmac239. Viral loads in plasma of AAV animals (blue) and controls (red) measured as SIV RNA genome equivalent per ml are shown as a function of time since the infectious exposure. Control animal 139–08 was a rapid progressor and had to be sacrificed after 9 weeks due to AIDS-related symptoms. Test animal 84–05 remained uninfected after 6 SIV challenges.