Estratégias de indução do antígeno 503 recombinante de Leishmania i. chagasi expresso em Escherichia coli M15

Abstract

With nearly 900,000 to 1.3 million new cases annually, Leishmaniosis is a complex of diseases that can be fatal if not given proper attention. Despite its relevance in the public health system, there is no vaccine capable of preventing disease in humans so far, and its treatment is expensive and aggressive to human health. Vaccination remains the most practical and realistic way of fight against the disease, thus, the production of recombinant antigens as a pathway towards a vaccine acquisition is necessary. In addition, the optimization of the strategy of the recombinant antigen’s production is of interest so it can make the process viable. Therefore, the present study aims to optimize the induction parameters of the 503 Leishmania i. chagasi antigen expressed in recombinant Escherichia coli. Hence, the induction at different cell densities (optical density at 600 nm of 0.5 and 1.0) was evaluated in order to analyse the influence of the induction time on the yield of the protein of interest. In this segment, lactose and isopropyl-β-Dthiogalactopyranoside (IPTG) were used as inducer molecules, using various concentrations: 0.1 g/L, 1.0 g/L and 10 g/L for lactose and 20 μM, 100 μM, 500 μM and 1000 μM for IPTG. The results presented that the concentration of IPTG that obtained the higher antigen levels was that of 100 μM (0.087 g/L), a 10-fold lower concentration than was being previously used in this type of system, and for lactose it was 1 g/L (0.016 g/L). Thus, the induction with 100 μM allowed to obtain the antigen with a concentration 5.6 times higher than the lactose induction maximum concentration.