TB-018 is a phase IIb study designed to evaluate the protective efficacy of M72/AS01E (GSK 692342), a candidate TB vaccine being developed by GlaxoSmithKline, against pulmonary TB disease in adults. It is a multicenter, double-blind, randomized, placebo-controlled trial sponsored by GSK. The study will follow participants for approximately 3 years after vaccination for safety and the development of pulmonary TB. Samples collected at regular intervals in TB-018 could provide a valuable source of information on changes in the immune profiles of participants just prior to the onset of TB and, if the vaccine prevents TB, information that could potentially identify immune responses that correlate with protection from TB.