BACKGROUND: The expression of vaccine antigens in lactic acid bacteria (LAB) is a safe and cost-effective alternative to traditional expression systems. In this study, we investigated i) the expression of Human papillomavirus type 16 (HPV-16) L1 major capsid protein in the model LAB Lactococcus lactis and ii) the ability of the resulting recombinant strain to produce either capsomer-or virus-like particles (VLPs).

RESULTS AND CONCLUSION: HPV-16 L1 gene was cloned into two vectors, pCYT and pSEC, designed for controlled intra- or extracellular heterologous expression in L. lactis, respectively. The capacity of L. lactis harboring either pCYT:L1 or pSEC:L1 plasmid to accumulate L1 in the cytoplasm and supernatant samples was confirmed by Western blot assays. Electron microscopy analysis suggests that, L1 protein produced by recombinant lactococci can self-assemble into structures morphologically similar to VLPs intracellularly. The presence of conformational epitopes on the L. lactis-derived VLPs was confirmed by ELISA using an anti-HPV16 L1 capsid antigen antibody.

Our results support the feasibility of using recombinant food-grade LAB, such as L. lactis, for the production of L1-based VLPs and open the possibility for the development of a new safe mucosal vector for HPV-16 prophylactic vaccination.

About the Authors

Cortes-Perez NG, Kharrat P, Langella P, Berm�dez-Humar�n LG. (2009) Heterologous production of human papillomavirus type-16 L1 protein by a lactic acid bacterium. BMC Res Notes. 2009 Aug 24;2:167. Equipe Interactions des bact�ries commensales et probiotiques avec l'h�te, Unit� d'Ecologie et physiologie du Syst�me Digestif, Institut National de la Recherche Agronomique, 78352 Jouy-en-Josas, France.