Monday, July 25, 2011
Grand Ballroom, 5th fl (Sheraton New Orleans)
Malaria is one of the most prevalent diseases worldwide and causes several million deaths, mainly in children under 5 years of age. Infection by Plasmodium falciparum is the predominant cause of malaria deaths. We describe the production of a recombinant malarial vaccine candidate, Pf MSP-119, which is known to induce production of antibodies against the surface proteins of the parasite. Such antibodies are expected to block attachment of the parasite to RBCs, thus preventing invasion. Pf MSP-119 is a membrane protein with six intramolecular disulphide bonds; therefore production and recovery is difficult in most conventional expression systems. In the present work, we discuss the ability of Bacillus subtilis to make functional Pf MSP-119. The desired antigen was successfully expressed in Bacillus subtilis and was found to be secreted into the culture supernatant. Purification was done using Ni-NTA affinity chromatography with a resultant yield of ~5 mg/L at a shake flask level. This study established the ability of Bacillus subtilis to express and secrete the Pf MSP-119. The expressed protein was shown to retain its antigenic epitopes as evident from Western blots. Bacillus subtilis seems to be an ideal host for the expression and secretion of malaria vaccine candidates owing to its high secretory production compared to the levels of the same protein expressed in the other bacterial and fungal hosts