Expression, purification and characterization of Mycobacterium tuberculosis RpfE protein☆

Resuscitation promoting factor E (RpfE) is one of the five Rpf-like proteins in Mycobacterium tuberculosis (M. tuberculosis). These Rpf-like proteins are secretory, which make them candidates for recognition by the host immune system. In this study, the RpfE gene was amplified from M. tuberculosis, cloned into the expression vectors pDE22 and pPRO EXHT, and were expressed in Mycobacterium vaccae (M. vaccae) and Escherichia coli DH5α, respectively. Both recombinant RpfE proteins were purified by Ni-Sepharose affinity chromatography, and were given to C57BL/6 mice. The RpfE proteins elicited T cell proliferation, and stimulated the production of gamma interferon (IFN-γ), interleukin-10 (IL-10) and IL-12. Our results indicated that the RpfE protein expressed in M. vaccae could more efficiently stimulate cellular immune response, making it a promising candidate as a subunit vaccine.