Plant Production of Vaccine Against HPV: A New Perspectives

Infection by human papilloma virus (HPV) attracted attention in connection with cervical cancer in humans (zur Hausen, 1996). HPV type 16 alone accounts for approximately 50% of all cases of cervical cancer. The virus icosahedral capsid is composed of the L1 major and the L2 minor proteins. L1 alone has the capacity to self-assemble into virus-like particles (VLPs) without participation of L2 or other proteins. Because of similar immunogenicity compared to infectious virions, VLPs can be produced and used as a safe prophylactic vaccine against viral transmission of cervical cancer. During recent years two highly efficient VLP-based HPV vaccines (e.g. Gardasil, Merck MSD and Cervarix, GlaxoSmithKline) become available. For commercial production of vaccines and recombinant therapeutics, plants are often considered as a cost-effective alternative with several benefits. Firstly, production in plants can be easily scaled up in the case of acute demand for production and secondly, produced proteins are unlikely to be contaminated by human or animal pathogens, toxins and oncogenic sequences. Moreover, plants provide a convenient environment for protein expression and storage including the possibility of direct administration as edible vaccine if expressed in the appropriate plant tissue. In this article, we report recent promising advances in the production of prophylactic and therapeutic vaccines against HPV by expression of the relevant antigens in plants, and discuss future prospects for the use of such vaccines.