A Toll-like receptor-2-directed fusion protein vaccine against tuberculosis.

A fusion protein designated CSU-F36 was constructed that consisted of acylated Rv1411, a potent Toll-like receptor-2 agonist, fused to ESAT-6, a well-characterized immunogenic protein from Mycobacterium tuberculosis. The CSU-F36 fusion protein strongly induced interleukin 12 secretion from macrophages and induced the increased accumulation of CD4 T cells capable of secreting gamma interferon in the lungs of infected mice. These mice were significantly protected from low-dose aerosol challenge with M. tuberculosis, even with CSU-F36 delivered in a simple depot material. This "natural adjuvant"-containing system could potentially bypass the need for more expensive TH1-inducing adjuvants and could be applied to many mycobacterial proteins to provide effective and cheap new vaccines against tuberculosis.