USE OF Lactuca sativa l. (LETTUCE) FOR THE EXPRESSION OF the main surface antigen 1 (SAG1) of Toxoplasma gondii

SANCHEZ LOPEZ, E.; RADONIC, L.; CORIGLIANO, M.; RIVERA, M.; ALBARRACIN, R.; SANDER, V.; BENGOA LUONI, S.; LOPEZ BILBAO, M.; CLEMENTE, M.

Congreso; XXIV Congreso Latinoamericano de Parasitología Santiago de Chile; 2017

Sociedad Chilena de Parasitología

Advances in biotechnology have allowed plants to be conceived as bioreactors to produce proteins of immunological interest. In this way, proteins are expressed in plant tissues to be used as oral vaccines and to induce a protective immune response in the host. The production of proteins in lettuce showed some advantages making it a convenient system to produce edible vaccines, such as low cost of production, the possibility of achieving optimal expression levels and free-animal and free-human pathogens proteins. In this sense and due to its medical importance, toxoplasmosis is presented as a good model to study the antigenic properties of proteins expressed in this system. Therefore, we proposed the use of lettuce transformation system to produce T. gondii antigens to produce a plant-made vaccine. SAG1 is the main surface antigen of this parasite and a promising candidate to develop a vaccine. Therefore, we worked with the construction of the mature protein (SAG1) fused to the 90 kDa heat shock protein of Nicotiana benthamiana (NbHsp90.3) as an adjuvant. This construction was cloned into the binary vector pK7WGR. The genetic transformation of Grand Rapids variety of Lactuca sativa l. was carried out using the strain LBA4404 of Agrobacterium tumefaciens. The shoots that showed root development in the presence of the selective agent were taken to the greenhouse for acclimation, growth and subsequent analysis by PCR. The expression of the fusion protein (NbHsp90.3-SAG1) was evaluated by western blot in 11 transgenic lines, observing expression in 7 of them, but only 2 lines showed the highest levels of expression, around 30 μg/mg of lyophilized leaf. Finally, the antigenic properties were evaluated by western blot. We observed that the protein expressed in lettuce were recognized by IgG antibodies from seropositive human patients, indicating that SAG1 fused to NbHsp90.3 is recognized by antibodies generated during natural infections and would act as a promising candidate to develop a vaccine. Our results show that lettuce plants can be an attractive platform for the expression of antigens since they are able to maintain its antigenic properties.