PLASTID EXPRESSION OF TOXOPLASMA GONDII SAG1 VACCINE CANDIDATE FUSED TO LEISHMANIA INFANTUM HEAT SHOCK PROTEIN AS CARRIER

LAGUÍA BECHER, M.; SANDER, V.; FARRAN, I.; ALBARRACIN, R.; VERAMENDI, J.; CLEMENTE, M.

Mar del Plata

Encuentro; VIII Encuentro Latinoamericano y del Caribe de Biotecnologia; 2013

RedBio Argentina

The aim of our work is to analyze the expression of the main T. gondii vaccine antigen, SAG1, in tobacco chloroplasts. In order to improve the SAG1 antigen expression in transplastomic plants, we made a fusion protein between SAG1 and L. infantum 83-kDa heat shock protein (LiHsp83). LiHsp83:SAG1 transplastomic plants showed stunted growth during the in vitro as well as under greenhouse conditions. Also, the leaves from these plants were pale in color compared with wild-type tobacco plants. However, LiHsp83:SAG1 plants reached maturity and produced fertile seeds. A band of approximately 130-kDa was observed by coomasie blue staining in samples from LiHsp83:SAG1 plants and it was absent in wild-type plants. This band was clearly visualized in samples from plants 50 and 75 days old and its intensity decreased in older plants. The 130-kDa band was immunodetected by using anti-LiHsp83 or anti-SAG1 antibodies. The relative amount of LiHsp83:SAG1 fusion protein accumulated in transplastomic plants was up to approximately 100 µg per gram of fresh weight (around 2.5 % of the total proteins) and LiHsp83:SAG1 was mainly accumulated in inferior and medium leaves. These results show that fusion of SAG1 to LiHsp83 increase significantly the level of SAG1 accumulation in tobacco chloroplasts.