Therapeutic vaccination reduces HIV sequence variability

With HIV persisting lifelong in infected persons, therapeutic vaccination is a novel alternative concept to control virus replication. Even though CD8 and CD4 cell responses to such immunizations have been demonstrated, their effects on virus replication are still unclear. In view of this fact, we studied the impact of a therapeutic vaccination with HIV nef delivered by a recombinant modified vaccinia Ankara vector on viral diversity. We investigated HIV sequences derived from chronically infected persons before and after therapeutic vaccination. Before immunization the mean ± SE pairwise variability of patient-derived Nef protein sequences was 0.1527 ± 0.0041. After vaccination the respective value was 0.1249 ± 0.0042, resulting in a significant (P