Protection Against M. leprae Infection By The ID83/GLA-SE And ID93/GLA-SE Vaccines Developed For Tuberculosis.

Despite the dramatic reduction in the number of leprosy cases worldwide in the 1990s, transmission of the causative agent Mycobacterium leprae is still occurring and new cases continue to appear. New strategies are required in the pursuit of leprosy elimination. The cross application of vaccines in development for tuberculosis may lead to tools applicable to leprosy elimination. In this report we demonstrate that the chimeric fusion proteins ID83 and ID93, developed as antigens for TB vaccine candidates, elicited IFNγ responses from both TB and PB leprosy patients, as well as and healthy household contacts of MB patients (HHC), but not from non-exposed healthy controls. Immunization of mice with either protein formulated with a TLR4L containing adjuvant (GLA-SE) stimulated antigen-specific IFNγ secretion from pluripotent Th1 cells. When immunized mice were experimentally infected with M. leprae both cellular infiltration into the local lymph node and bacterial growth at the site were reduced relative to unimmunized mice. Thus, the use of Mtb candidate vaccines ID83/GLA-SE and ID93/GLA-SE may confer cross-protection against M. leprae infection. Our data suggest these vaccines could potentially be used as an additional control measure for leprosy.