Acta Academiae Medicinae Sinica

Abstract: ABSTRACT:Objective To explore the influences of Mycobacterium tuberculosis on the levels of human acute monocytic leukemia cell line THP-1 apoptosis and death. Methods Human acute monocytic leukemia cell line THP-1 were infected with Mycobacterium tuberculosis strains H37Ra, H37Rv, or Beijing genotype (BJTB), respectively, to construct the infection models. Cell apoptosis was detected using flow cytometry. The distribution of the apoptotic proteins was detected using immunofluorescent staining assays. The cells late apoptosis was detected using terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling staining assays. The change of cell death was determined by Tyrpan blue staining assays. Results THP-1apoptosis was induced by Mycobacterium tuberculosis strains H37Ra, H37Rv, and BJTB. H37Ra strongly induced THP-1 apoptosis, H37Rv weakly induced THP-1 apoptosis, and BJTB induced THP-1 apoptosis at the lowest level among these three Mycobacterium tuberculosis strains. On the contrary, BJTB strongly induced THP-1 death, H37Rv weakly induced THP-1 death, and H37Ra induced THP-1 death at the lowest level. Conclusions My-cobacterial strains with different virulence induce different levels of apoptosis and death of THP-1 cells. Compared with highly virulent strains, attenuated strains induce more apoptosis and less death.

Key words: mycobacterium tuberculosis, cell apoptosis/deatd, beijinc cenotype, virulence