Efficient Activation of Human T Cells of Both CD4 and CD8 Subsets by Urease-Deficient Recombinant Mycobacterium bovis BCG That Produced a Heat Shock Protein 70-M. tuberculosis-Derived Major Membrane Protein II Fusion Protein

Abstract

ABSTRACTFor the purpose of obtainingMycobacterium bovisbacillus Calmette-Guérin (BCG) capable of activating human naive T cells, urease-deficient BCG expressing a fusion protein composed ofMycobacterium tuberculosis-derived major membrane protein II (MMP-II) and heat shock protein 70 (HSP70) of BCG (BCG-DHTM) was produced. BCG-DHTM secreted the HSP70-MMP-II fusion protein and effectively activated human monocyte-derived dendritic cells (DCs) by inducing phenotypic changes and enhanced cytokine production. BCG-DHTM-infected DCs activated naive T cells of both CD4 and naive CD8 subsets, in an antigen (Ag)-dependent manner. The T cell activation induced by BCG-DHTM was inhibited by the pretreatment of DCs with chloroquine. The naive CD8+T cell activation was mediated by the transporter associated with antigen presentation (TAP) and the proteosome-dependent cytosolic cross-priming pathway. Memory CD8+T cells and perforin-producing effector CD8+T cells were efficiently produced from the naive T cell population by BCG-DHTM stimulation. Single primary infection with BCG-DHTM in C57BL/6 mice efficiently produced T cells responsive toin vitrosecondary stimulation with HSP70, MMP-II, andM. tuberculosis-derived cytosolic protein and inhibited the multiplication of subsequently aerosol-challengedM. tuberculosismore efficiently than did vector control BCG. These results indicate that the introduction of MMP-II and HSP70 into urease-deficient BCG may be useful for improving BCG for control of tuberculosis.