Informed consent and human subjects protocols were approved by the Emory University Institutional Review Board, and the Figure 9 . Sequence variation occurs in similar regions of Env in 185F and 205F. A 3-dimensional representation of the sequence variation in gp120 over time in 185F and 205F is shown in panels (A and B) , respectively. The gp120 backbones were generated by homology modeling of the 0-month Env sequences of 185F and 205F onto the CD4-liganded HIV-1 YU-2 gp120 structure [54] , with modeled V1V2 and V3 loops as described previously [25] . Blue to green to red indicates degree of sequence conservation (high to low) within the alignment. doi:10.1371/journal.ppat.1000594.g009