Plasma viral loads after SIVmac239 challenge in unvaccinated macaques.

<p>Plasma viral loads (SIV <i>gag</i> RNA copies/ml plasma) were determined as described previously <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0054300#pone.0054300-Matano2" target="_blank">[35]</a>. The lower limit of detection is approximately 4×10² copies/ml. (A) Changes in plasma viral loads after challenge in unvaccinated macaques possessing MHC-I haplotype D. (B) Changes in geometric means of plasma viral loads after challenge in five unvaccinated D⁺ animals in the present study and twenty D⁻ animals in our previous cohorts <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0054300#pone.0054300-Nomura1" target="_blank">[21]</a>. Three of twenty D⁻ animals were euthanized because of AIDS before 12 months, and we compared viral loads between D⁺ and D⁻ animals until 12 months. (C) Comparison of plasma viral loads at 3 months (left panel), 6 months (middle panel), and 9 months (right panel) between the unvaccinated D⁺ and the D⁻ animals. Viral loads at 6 months and 9 months in D⁺ animals were significantly lower than those in the latter D⁻ animals (p = 0.0360 at 6 months and p = 0.0135 at 9 months by t-test).