Development of alternative vaccines against human papilloma virus 16 (HPV16) expressing the E7 oncoprotein in Nicotiana tabacum from a Potato virus X-based vector.

ZELADA A., CONTE F., STEINBERG T., GISSMANN L. AND MENTABERRY A.

Buenos Aires, Argentina

Simposio; VI Simposio Argentino de Biotecnología Vegetal (REDBIO/FAO), Encuentro trinacional Argentina- Chile-Uruguay; 2005

REDBIO-FAO

Two basic strategies can be used to obtain recombinant proteins in plants, use of plant virus vectors for transient expression or the generation of transgenic plants. In particular, small single-stranded RNA plant viruses, as TMV Tobacco mosaic virus, PVX Potato mosaic virus or CPMV Cowpea mosaic virus, have emerged as promising tools, because they can be engineered to rapidly express foreign genes in susceptible host plants, producing larger amounts of proteins compared with those obtained by stable transformation procedures. We have previously developed a vector based in PVX strain CP that allows the expression of the cDNA of the complete genome of PVX under the control of the 35S CaMV promoter. This vector was efficiently expressed in a transient system by agroinfiltration of Nicotiana tabacum leaves.  It was modified to obtain two different constructions that allow the expression of foreign proteins from the viral capsid (CP) subgenomic promotor either as a CP fusion protein (pGPVXCPf) or as a unfused protein (pGPVXCPd). In the present work we present different strategies to express E7 protein in Nicotiana tabacum. One strategy consists in expressing E7 as a citoplasmatic protein for use in diagnostics and vaccination, and the other consists in expressing E7 fused to the viral capsid (CP) to obtain recombinant chimaeric virions expressing E7 on the surface to be used as particulate antigen in vaccination.