Replication kinetics and persistence of a conditionally live attenuated SIV (SIVrtTA) in vivo confers protection against homologous and heterologous wild-type challenge in macaques

Background Vaccination with live attenuated SIV confers potent protection against wild-type SIV challenge in the SIV/ macaque model of HIV. Although safety concerns preclude direct application of this vaccine approach in humans, a clearer understanding of the mechanistic processes at play may lead to better HIV vaccines. A novel live attenuated SIVmac239Δnef vaccine (SIVrtTA), dependent on doxycycline (dox) administration for replication, has been evaluated for its ability to protect in vivo against independent homologous and heterologous pathogenic wild-type (wt) SIV challenges, and the role of vaccine persistence assessed. We recently demonstrated immunophenotyping of SIVrtTA vaccinees prior to wt challenge drives global polarisation of a T cell memory phenotype, particularly in the CD4 population, toward an effector memory response.