title: [ESX-1 secreted protein ESAT-6 of Mycobacterium tuberculosis enhances the phagocytosis of RAW264.7 macrophages].
abstract: OBJECTIVE
  To investigate the effects of Mycobacterium tuberculosis ESX-1 protein early secreted antigenic target of 6 kDa (ESAT-6) in modulating phagocytosis of RAW264.7 cells.
  
  
  METHODS
  RAW264.7 cells were transfected with recombinant plasmids pFLAG-ESAT-6 and pFLAG-EGFP by liposome. After screening with a high level of G418, the macrophage cell lines stably expressing flag-ESAT-6 or flag-EGFP proteins were obtained. The cell lines were further identified by PCR, RT-PCR and western blot. The phagocytosis of those cell lines was analyzed for ingested fluorescent beads by flow cytometry and for phagocytized Escherichia coli (E. coli) by colony count and confocalmicroscopy.
  
  
  RESULTS
  We established successfully RAW-E6 cell line stably expressing flag-ESAT-6 and RAW-EGFP cell line stably expressing flag-EGFP. Flow cytometric analysis shows that the percentage of phagocytosis of RAW-E6 was higher than that of RAW264.7 and RAW-EGFP. Colony count and confocal microscopy test also show that RAW-E6 had higher phagocytosis ability than RAW264.7 and RAW-EGFP.
  
  
  CONCLUSIONS
  The secreted protein ESAT-6 can enhance the phagocytosis of macrophages, which provides new evidence to understand the pathogenesis of Mycobacterium tuberculosis.
authors.affiliation: Institute of Biotechnology, Academy of Military Medical Sciences, Beijing 100071, China. quye2004@163.com
authors.forename: Ye
authors.initials: Y
authors.lastname: Qu
authors.affiliation: Institute of Biotechnology, Academy of Military Medical Sciences, Beijing 100071, China.
authors.forename: Ying
authors.initials: Y
authors.lastname: Yin
authors.affiliation: Institute of Biotechnology, Academy of Military Medical Sciences, Beijing 100071, China.
authors.forename: Hao
authors.initials: H
authors.lastname: Li
authors.affiliation: Institute of Biotechnology, Academy of Military Medical Sciences, Beijing 100071, China.
authors.forename: Ju
authors.initials: J
authors.lastname: Liu
authors.affiliation: Institute of Biotechnology, Academy of Military Medical Sciences, Beijing 100071, China.
authors.forename: Xiuxu
authors.initials: X
authors.lastname: Yang
authors.affiliation: Institute of Biotechnology, Academy of Military Medical Sciences, Beijing 100071, China.
authors.forename: Dayong
authors.initials: D
authors.lastname: Dong
authors.affiliation: Institute of Biotechnology, Academy of Military Medical Sciences, Beijing 100071, China.
authors.forename: Junjie
authors.initials: J
authors.lastname: Xu
authors.affiliation: Institute of Biotechnology, Academy of Military Medical Sciences, Beijing 100071, China.
authors.forename: Wei
authors.initials: W
authors.lastname: Chen
mesh_terms: D000818:Animals; D000942:Antigens, Bacterial / Q000235:genetics* / Q000276:immunology*; D001426:Bacterial Proteins / Q000235:genetics* / Q000276:immunology*; D002460:Cell Line; D015870:Gene Expression; D008264:Macrophages / Q000276:immunology*; D051379:Mice; D009169:Mycobacterium tuberculosis / Q000235:genetics* / Q000378:metabolism; D010587:Phagocytosis; D014162:Transfection; D015854:Up-Regulation
chemical_list: D000942:Antigens, Bacterial; D001426:Bacterial Proteins; C093276:ESAT-6 protein, Mycobacterium tuberculosis