Non-Thermal Plasma Jet-Treated Medium Induces Selective Cytotoxicity against Mycobacterium tuberculosis-Infected Macrophages.

Plasma-treated media (PTM) serve as an adjuvant therapy to postoperatively remove residual cancerous lesions. We speculated that PTM could selectively kill cells infected with Mycobacterium tuberculosis (Mtb) and remove postoperative residual tuberculous lesions. We therefore investigated the effects of a medium exposed to a non-thermal plasma jet on the suppression of intracellular Mtb replication, cell death, signaling, and selectivity. We propose that PTM elevates the levels of the detoxifying enzymes, glutathione peroxidase, catalase, and ataxia-telangiectasia mutated serine/threonine kinase and increases intracellular reactive oxygen species production in Mtb-infected cells. The bacterial load was significantly decreased in spleen and lung tissues and single-cell suspensions from mice intraperitoneally injected with PTM compared with saline and untreated medium. Therefore, PTM has the potential as a novel treatment that can eliminate residual Mtb-infected cells after infected tissues are surgically resected.

A Dendritic Cell-Activating Rv1876 Protein Elicits Mycobacterium Bovis BCG-Prime Effect via Th1-Immune Response.

The widely administered tuberculosis (TB) vaccine, Bacillus Calmette-Guerin (BCG), is the only licensed vaccine, but has highly variable efficiency against childhood and pulmonary TB. Therefore, the BCG prime-boost strategy is a rational solution for the development of new TB vaccines. Studies have shown that Mycobacterium tuberculosis (Mtb) culture filtrates contain proteins that have promising vaccine potential. In this study, Rv1876 bacterioferritin was identified from the culture filtrate fraction with strong immunoreactivity. Its immunobiological potential has not been reported previously. We found that recombinant Rv1876 protein induced dendritic cells' (DCs) maturation by MAPK and NF-κB signaling activation, induced a T helper type 1 cell-immune response, and expanded the population of the effector/memory T cell. Boosting BCG with Rv1876 protein enhanced the BCG-primed Th1 immune response and reduced the bacterial load in the lung compared to those of BCG alone. Thus, Rv1876 is a good target for the prime-boost strategy.

Recombinant Rv1654 protein of Mycobacterium tuberculosis induces mitochondria-mediated apoptosis in macrophage.

Mycobacterium tuberculosis contains diverse immunologically active components. This study investigated the biological function of a newly identified component, Rv1654, with the potential to induce apoptosis in macrophages. Recombinant Rv1654 induced macrophage apoptosis in a caspase-9/3-dependent manner through the production of reactive oxygen species (ROS) and interaction with Toll-like receptor 4. In addition, Rv1654 induced the production of tumor necrosis factor-α, interleukin-6, and monocyte chemoattractant protein-1 through the mitogen-activated protein kinase pathway. Furthermore, Rv1654-induced c-Jun N-terminal kinase (JNK) activation was inhibited by the ROS scavenger and Rv1654-induced apoptosis was inhibited by the JNK inhibitor. Moreover, it was found that treatment of macrophages with Rv1654 led to the loss of mitochondrial membrane potential, release of cytochrome c into the cytosol, and translocation of Bax into the mitochondria. Finally, Rv1654-mediated apoptosis was inhibited in macrophages transfected with Bax siRNA. These results suggest that Rv1654 induces macrophage apoptosis through a mitochondrial-dependent pathway and ROS-mediated JNK activation.