Bactericidal activity of human granulysin expressed in macrophages against intracellular Mycobacterium tuberculosis / 中华传染病杂志

ABSTRACT

Objective To construct eukaryotic expression recombinant plasmid containing human granulysin(GLS) and investigate the effect of GLS expression in macrophage RAW264.7 cells on the bactericidal activity against intracellular Mycobacterium tuberculosis.Methods GLS gene was amplified by nested-polymerase chain reaction(PCR) from human cytotoxicity T lymphocyte(CTL) activated by allogenic antigen,and inserted into pBudCE4.1 vector to construct recombinant plasmid.Subsequently,the plasmid was transfccted into RAW264.7 cells which were infected with Mycobacterium tuberculosis H37Rv.The expression of GLS was detected by nested-PCR and immunocytochemistry method.The RAW264.7 cells were lysed after transfected for 96 h,then acidfast stained,cultivated and colony count were done to determine the intraeellular bactericidal activity of GLS.The data were analyzed by t or t' test.Results The pBudCE4.1/GLS eukaryotic expression recombinant plasmid was successfully constructed.The transcriptional and translational expressions of target gene GLS were detected in RAW264.7 cells which were infected with Mycobacterium tuberculosis H37Rv.The bacterial load in macrophages of phorbol myristate acetate(PMA)+pBudCE4.1/GLS group,PMA+pBudCEA.1 group and non-activated group were 1.44±1.25,3.16±0.20 and 3.59±0.21,respectively.The differences between groups were all significant (t=2.403,t=2.854,both P＜0.05).Conclusion Eukaryotic expression recombinant plasmid carrying human GLS gene expressed in macrophages has strong bactericidal activity against intracellular mycobacteria,which provide information for the further study on therapeutic vaccine against Mycobacterium tuberculosis.