P78: Evaluation of biomass growth and expression of 503 antigen from Leishmania infantum chagasi using Escherichia coli host strain

Leishmaniasis is an old disease occurring in several countries, including Brazil. Among the different types of leishmaniasis we highlight the visceral leishmaniasis showing the greatest potential for lethality. Despite the expressive advance of the studies about the molecular biology and immunology of the infections, there is not, actually, any prophylactic drug capable to prevent the visceral leishmaniasis. Therefore, there is a bona fide necessity for identifying specific antigens for the development of vaccines and diagnostic kits against this disease. The objective of this study was to evaluate the kinetic behavior and the ability to produce 503 antigen from Leishmania infantum chagasi using two different cultivation medium with complex compositions (2xTY, TB) supplemented with antibiotics. The assays were conducted in shaker with 200 rpm of stirring speed, temperature at 37 °C and pH 7.0. During cultivation induction procedure using IPTG was carried out in order to evaluate the expression of the target protein. Cell growth was monitored using DO_590nm as well as by dry weight (biomass), protein expression and total protein were assayed by electrophoresis and Lowry method, respectively. The results showed that there were both biomass growth and protein expression using the two medium. However it was observed that the TB medium promoted cell growth, while the 2xTY one favored the expression of recombinant protein. Observing the curves of total protein during the cultivation, it was observed that protein expression was associated to growth for both medium.