wrote the paper and gave the final approval of the submitted manuscript. and IB activities, leading to up-regulated HSP70 expression. Overexpression of HSP70 alone or with p38 or ERK inhibitors decreased TNF- (57%, 83% and 74%, respectively) and IL-6 (53%, 70%, and 67%, respectively) release from macrophages of TB patients. In conclusion, HSP70 modulates VCH-916 NF-B activation in AM of TB patients, through inhibiting IB- phosphorylation or acting as a chaperon molecule to prevent NF-B binding to the target genes by facilitating degradation. The upregulated HSP70 may suppress the release of pro-inflammatory cytokines during active PTB infection, and prevent overwhelming tissue damage. Introduction Tuberculosis (TB) remains a major health problem worldwide1. Clinical and pathologic features of TB depend at least in part on the orchestrated secretion of a number of pro-inflammatory cytokines, such as tumor necrosis factor (TNF)-, interleukin (IL)-1 and IL-6. The transcription factor NF-B regulates gene expression in response to various extracellular stimuli, including TNF-, IL-1 VCH-916 and lipopolysaccharide2, 3. Our previous report demonstrated that alveolar macrophages (AM)4 or monocytes5 from patients with active pulmonary TB may release pro-inflammatory cytokines TNF- and IL-1 via NF-B activation. The inflammatory responses in turn effectively eliminated the proliferation of TB bacilli by up-regulating phagocytic capacity and cytotoxicity of macrophages6, and thus limiting further mycobacterial growth by inducing granulation formation7, 8. Heat shock proteins (HSPs) are a group of stress proteins that mediate cellular and tissue protection against diverse cytotoxic stimuli9 and act as key regulators of the hosts immune system10. HSP70 delivers peptide antigen to human DCs and stimulates them to generate effective T-cell functional responses11. In mycobacterial infection, pathogen recognition by toll-like receptors (TLRs) and downstream TLR signaling play an important part in activation of innate immune cells and prevent excessive T cell-mediated swelling12. Upon activation with TLR4 ligand such as LPS downstream TLR/MyD88-dependent signaling results in activation of NF-B-mediated transcription of pro-inflammatory cytokines such as TNF- and IL-613. Users of the HSP family may cross-talk with toll-like receptors to activate pro-inflammatory signals14, and play an important part in granuloma formation and immune protection during illness. HSP70 may block the activation of NF-B2, 15, 16, and inhibit cytokine-mediated NF-B nuclear translocation and subsequent pro-inflammatory cytokine launch17. We have conducted a prospective study to investigate the part of HSP70 in suppressing NF-B-mediated TNF- and IL-6 launch. We also have explored the connection between HSP70 and NF-B by over-expression of HSP70 or inhibition of NF-B VCH-916 activation, or obstructing the activity of mitogen-activated protein kinases (MAPKs) that are required for prolonged NF-B activation18. Results Cell profiles in BAL Table?1 summarizes the BAL findings within the TB individuals and control subjects. The recovery rate of BAL was significantly lower in individuals with active pulmonary TB than in the control subjects. There was a significant increase in total cell counts in individuals with active pulmonary TB (38.6??7.4??106?cells, n?=?19) compared to those of the control subjects (8.2??0.7??106?cells, n?=?14, p? ?0.001). The proportions of lymphocytes and neutrophils were significantly higher in individuals with TB (8.7??2.4% and 13.3??4.5%, n?=?19, respectively) than in the control subjects (2.6??1.0% and 1.0??0.2%, n?=?14, p? ?0.05, respectively). Reciprocally, the percentage of alveolar macrophages (AM) was significantly lower in individuals with TB (79.0??5.0%, n?=?19) than in the control subjects (96.1??1.0%, n?=?14, p? GDF7 ?0.05). Table 1 Characteristics of bronchoalveolar lavage in control subjects and individuals with active pulmonary tuberculosis. antigen and contributes to MAPK activation mediated IFN- production. In this study, we have demonstrated NF-B activity was up-regulated in AM of VCH-916 TB individuals and was suppressed by the treatment with ERK or p38 MAPK inhibitors, suggesting ERK and p38 signaling pathways are essential in NF-B activation in AM of TB individuals. NF-B activation requires activation of IB kinase (IKK) to phosphorylate IB- and launch p65/p50.