Development of non-live vectors and procedures (liposomes, pseudo-viral particles, toxin, beads, adjuvants…) as tools for cancer vaccines

Abstract

Recombinant virus encoding tumor antigens are the most used vectors in human clinical trials of cancer vaccines because of their ability to target exogenous antigen in the endogenous MHC class I pathway and to elicit CTL. However, their use requires different constraining procedures to avoid their spreading. The immunosuppression of cancer patients may also increase their intrinsic toxicity. Therefore, the development of non-live vectors may avoid these drawbacks. Different groups now clearly demonstrated that particulate antigens when they are phagocytosed could be targeted in the MHC class I pathway. They also induce CTL in mice which when immunized with these particulate antigens were protected against a challenge with tumors expressing this antigen. Other strategies using toxins or antigens fused or incorporated into various oil or lipid based chemical adjuvants have also suceeded in the induction of CTL response and in some cases have been shown to be efficient as cancer vaccine.