A recombinant Mycobacterium smegmatis induces potent bactericidal immunity against Mycobacterium tuberculosis

New vaccine candidates are urgently needed for the control and prevention of Mycobacterium tuberculosis (Mtb) infection. Kari Sweeney and her colleagues now report that an attenuated strain of Mycobacterium smegmatis expressing the esx-3 genes from Mtb induces effective CD4+ T cell dependent immunity against infection with Mtb in mice. The study offers a new avenue for the identification of protective immunogens in Mtb infection and a candidate vaccine platform warranting further study.