title: Macrophage Immune Response Suppression by Recombinant Mycobacterium tuberculosis Antigens, the ESAT-6, CFP-10, and ESAT-6/CFP-10 Fusion Proteins.
abstract: BACKGROUND
  Macrophage immune responses are affected by the secretory proteins of Mycobacterium tuberculosis (Mtb). This study aimed to examine the immune responses of macrophages to Mtb secretory antigens, namely ESAT-6, CFP-10, and ESAT-6/CFP-10.
  
  
  METHODS
  THP-1 cells (a human monocytic cell line) were cultured and differentiated to macrophages by phorbol 12-myristate 13-acetate. The cytotoxicity of the recombinant Mtb proteins was assessed using the MTT assay. Two important immune responses of macrophages, namely NO and ROS production, were measured in response to the ESAT-6, CFP-10, and ESAT-6/CFP-10 antigens. The data were analyzed using one-way ANOVA with SPSS, version 16, and considered significant at P<0.05.
  
  
  RESULTS
  The results showed that the ESAT-6, CFP-10, and ESAT-6/CFP-10 proteins markedly reduced macrophage immune response. The treatment of the THP-1-differentiated cells with ESAT-6, CFP-10, and ESAT-6/CFP-10 reduced NO and ROS production. The treated THP-1-differentiated cells exhibited less inducible NO synthase activity than did the untreated cells. No toxic effect on macrophage viability was observed for the applied proteins at the different concentrations.
  
  
  CONCLUSIONS
  It seems that the decline in macrophage immune response is due to the suppression of NO and ROS production pathways without any effect on cell viability.
authors.affiliation: Recombinant Protein Laboratory, Biochemistry Department, Medical School, Shiraz University of Medical Sciences, Shiraz, Iran; Histomorphometry and Stereology Research Center, Medical School, Shiraz University of Medical Sciences, Shiraz, Iran.
authors.forename: Atefeh
authors.initials: A
authors.lastname: Seghatoleslam
authors.affiliation: Recombinant Protein Laboratory, Biochemistry Department, Medical School, Shiraz University of Medical Sciences, Shiraz, Iran; Department of Biochemistry, Faculty of Medicine, Birjand University of Medical Sciences, Birjand, Iran.
authors.forename: Mina
authors.initials: M
authors.lastname: Hemmati
authors.affiliation: Recombinant Protein Laboratory, Biochemistry Department, Medical School, Shiraz University of Medical Sciences, Shiraz, Iran.
authors.forename: Saeedeh
authors.initials: S
authors.lastname: Ebadat
authors.affiliation: Recombinant Protein Laboratory, Biochemistry Department, Medical School, Shiraz University of Medical Sciences, Shiraz, Iran.
authors.forename: Bahram
authors.initials: B
authors.lastname: Movahedi
authors.affiliation: Recombinant Protein Laboratory, Biochemistry Department, Medical School, Shiraz University of Medical Sciences, Shiraz, Iran; Maternal-Fetal Medicine Research Center, Shiraz University of Medical Sciences, Shiraz, Iran.
authors.forename: Zohreh
authors.initials: Z
authors.lastname: Mostafavi-Pour
keywords: CFP-10 protein; ESAT-6 protein; Mycobacterium Tuberculosis; Reactive Oxygen Species; Recombinant Proteins