Production of Mycobacterium bovis Antigens in Escherichia coli by Recombinant DNA technology and Subunit Vaccine Development

Tuberculosis is one of the most common infectious diseases that has not been prevented for many years. BCG vaccine is the only vaccine approved for use in humans to prevent spread of the disease. However, the searches continue to solve problems such as protection of BCG vaccine variations between individuals, and inability to prevent infection. In this context, evaluatation of the effects of AhpC and LprG proteins playing an important role in the virulence of M. tuberculosis and M. bovis, on the humoral and cellular immune responses, alone or as a booster vaccine antigen after BCG prime vaccination was aimed in this thesis study. In order to achieve this goal, the ahpC and the lprG genes encoding the AhpC and the LprG proteins, respectively were amplified from the M. bovis genome by polymerase chain reaction, cloned into the bacterial expression vector, and recombinantly produced in E.coli. The recombinant proteins were purified by affinity chromatography and characterized by electrophoresis and immunoblotting methods. Subsequently, recombinant AhpC and LprG proteins were formulated with Montanide ISA 61VG, an oil-based emulsion adjuvant. The humoral and cellular immune responses were investigated by using ELISA method. Evaluation of humoral response based on IgG measurement and cellular response based on IL-12 measurement in mice sera showed that both proteins are effective as vaccine antigens. It was concluded that AhpC vaccine can be a good booster vaccine candidate, and LprG vaccine may be more effective when administered alone.