Heterologous prime-boost approaches to CD8+ T cell induction

The ability to clear many intracellular infections is likely to require a consorted immune response that includes CD8+ T cells. Although a large number of approaches have been taken to generating such responses in humans, achieving the magnitude and functionality of natural viral infections has been difficult. The most promising approach published to date is to employ a heterologous prime-boost, usually using two replicating or non-replicating viral vectors. The Jenner Institute has extensively used a replication-deficient adenovirus followed by a replication-deficient pox virus, and achieve ELISPOT levels of balanced CD4+ and CD8+ T cells in the many thousands of spot forming units per million PBMCs. Vaccitech has in-licensed programs based on the use of this strategy to control chronic HBV and chronic HPV. The progress of these programs will be discussed.