title: Flagellin contamination of recombinant heat shock protein 70 is responsible for its activity on T cells.
abstract: Heat shock proteins (Hsp) 60 and 70 have been intensively studied for their ability to activate innate immunity. Heat shock proteins had been shown to induce the activation of dendritic cells, T cells, and B cells. However, the possible contamination of endotoxin in heat shock protein preparations makes their function as an activator of immune system ambiguous. Here, we examined the ability of bacterial Hsp60 and Hsp70 to activate Jurkat T cells and primary T cells. We found that Burkholderia pseudomallei Hsp70 and Mycobacterium tuberculosis Hsp70 could costimulate Jurkat T cells to make IL-2 and signal through TLR5. This costimulatory activity is not due to endotoxin or contaminants signaling via TLR2 nor TLR4. However, recombinant Hsp70 expressed in Escherichia coli DeltafliC strain completely lost its ability to costimulate T cells. Thus, the activation of T cells by recombinant Hsp70 is ascribed to flagellin contamination.
authors.affiliation: Department of Biochemistry, National University of Singapore, Block MD7, #05-10, 8 Medical Drive, Singapore 117597, Singapore.
authors.forename: Zhiyong
authors.initials: Z
authors.lastname: Ye
authors.affiliation: Department of Biochemistry, National University of Singapore, Block MD7, #05-10, 8 Medical Drive, Singapore 117597, Singapore; Immunology Program, Yong Loo Lin School of Medicine, National University of Singapore, Block MD7, #05-10, 8 Medical Drive, Singapore 117597, Singapore. Electronic address: bchganyh@nus.edu.sg.
authors.forename: Yunn-Hwen
authors.initials: YH
authors.lastname: Gan
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics / Q000276:immunology*; D016957:Burkholderia pseudomallei / Q000235:genetics / Q000276:immunology; D018834:Chaperonin 60 / Q000235:genetics / Q000276:immunology; D003713:Dendritic Cells / Q000166:cytology / Q000276:immunology*; D004926:Escherichia coli / Q000235:genetics / Q000276:immunology; D029968:Escherichia coli Proteins / Q000235:genetics / Q000276:immunology; D005408:Flagellin / Q000276:immunology*; D018840:HSP70 Heat-Shock Proteins / Q000235:genetics / Q000276:immunology*; D006801:Humans; D007113:Immunity, Innate; D007376:Interleukin-2 / Q000276:immunology; D019169:Jurkat Cells; D008070:Lipopolysaccharides / Q000276:immunology; D008213:Lymphocyte Activation / Q000276:immunology*; D009169:Mycobacterium tuberculosis / Q000235:genetics / Q000276:immunology; D011994:Recombinant Proteins / Q000235:genetics / Q000276:immunology; D015398:Signal Transduction / Q000276:immunology*; D013601:T-Lymphocytes / Q000276:immunology*; D051193:Toll-Like Receptors / Q000276:immunology
chemical_list: D001426:Bacterial Proteins; D018834:Chaperonin 60; D029968:Escherichia coli Proteins; C516095:FliC protein, E coli; D018840:HSP70 Heat-Shock Proteins; C444642:HSP70 protein, Mycobacterium tuberculosis; C508594:IL2 protein, human; D007376:Interleukin-2; D008070:Lipopolysaccharides; D011994:Recombinant Proteins; D051193:Toll-Like Receptors; D005408:Flagellin