E Toll-like receptor (TLR) family is best characterized [17,18]. Activation of pathogen sensors triggers intracellular signaling pathways which culminate in the expression and release of inflammatory cytokines such as interleukin 6 (IL-6) and 12 (IL12) and type I interferons (IFN-a/b) [17,18]. These mediators in turn stimulate the maturation of antigen 25033180 presenting cells and initiation of 
adaptive immune responses such as the development and proliferation of antigen-specific effector T cell subsets [19?1]. In the case of intracellular pathogens, effector T cells egress from lymph nodes and migrate to the site of infection where they activate infected macrophages via IFN-c [22]. Some studies suggest PAMPs also enhance 
the function of effector T cells [23]. M. tuberculosis stimulates PRRs through a number of TLR ligands and other PAMPs [24?8]. Studies in humans and mice have implicated TLR2, TLR9, and TLR signaling molecules in susceptibility to TB [17,29]. Because of their immunomodulatory properties, PRR ligands are being exploited as adjuvants in vaccine formulations and as therapeutics for infectious, autoimmune, and neoplastic disorders [30?3]. In this report we investigated whether in vitro immunomodulation of QFT-GIT with TLR agonists polyinosine-polycytidylic acid (poly(I:C); TLR3), lipopolysaccharide (LPS; TLR4), and imiquimod (IMQ; TLR7) can be used to enhance the response of T cells in individuals with LTBI. We also investigated the potential mechanisms through which TLR agonists modulate IGRA.ReagentsPRR ligands Poly(I:C), LPS and IMQ were purchased from 58-49-1 chemical information InvivoGen (San Diego, CA). IL-6 and IL-12 were purchased from R D System (Minneapolis, MN) and IFN-a was purchased from PBL Interferon Source (Piscataway, NJ). All compounds were reconstituted in endotoxin-free water and stored at 270uC. Antihuman CD45 antibody was purchased from Invitrogen (Carlsbad, CA). All other antibodies were purchased from BD Biosciences (San Jose, CA).QuantiFERON-TB Gold In-Tube assayThe QFT-GIT assay was performed with fresh blood according to package insert with some modification to accommodate addition of immunomodulators. Up to 10 ml of each agonist or an equivalent volume of endotoxin-free water was added to each Nil and TB Ag tube. Blood was collected in a 10 ml Kendall Monoject Green Stopper tube and 1 ml was quickly transferred to each QFT-GIT tube. Tubes were then mixed and placed in a 37uC incubator for 22 hours or as indicated. ELISA was performed according to package insert. The remaining plasma was stored at 270uC. Calculation of IFN-c concentrations was done with the software provided by the manufacturer. TB Antigen tubes with IFN-c.10 IU/ml were diluted in PBS to determine the exact value. The effect of immunomodulators on IFN-c response was calculated using the following formula: modulated response = [(TB Ag plus immunomodulator) minus (Nil tube plus immunomodulator)].Dose response curveIndicated concentrations of each 16574785 agonist or endotoxin-free water was added to each Nil tube. The tubes were then mixed and placed in a 37uC incubator for 22 hours. The IFN-c concentrations were measured as described above.AZ 876 site Cytokine profiling assayThe cytokine profiling assay was performed at the Human Immune Monitoring Center (HIMC) at Stanford University. 100 ml of plasma from the QFT-GIT Nil tube was subjected to cytokine profiling. Procarta Cytokine Assay custom 51-plex kit (Affymetrix, Palo Alto, CA) was used according to manufacturer’s recommendations.E Toll-like receptor (TLR) family is best characterized [17,18]. Activation of pathogen sensors triggers intracellular signaling pathways which culminate in the expression and release of inflammatory cytokines such as interleukin 6 (IL-6) and 12 (IL12) and type I interferons (IFN-a/b) [17,18]. These mediators in turn stimulate the maturation of antigen 25033180 presenting cells and initiation of adaptive immune responses such as the development and proliferation of antigen-specific effector T cell subsets [19?1]. In the case of intracellular pathogens, effector T cells egress from lymph nodes and migrate to the site of infection where they activate infected macrophages via IFN-c [22]. Some studies suggest PAMPs also enhance the function of effector T cells [23]. M. tuberculosis stimulates PRRs through a number of TLR ligands and other PAMPs [24?8]. Studies in humans and mice have implicated TLR2, TLR9, and TLR signaling molecules in susceptibility to TB [17,29]. Because of their immunomodulatory properties, PRR ligands are being exploited as adjuvants in vaccine formulations and as therapeutics for infectious, autoimmune, and neoplastic disorders [30?3]. In this report we investigated whether in vitro immunomodulation of QFT-GIT with TLR agonists polyinosine-polycytidylic acid (poly(I:C); TLR3), lipopolysaccharide (LPS; TLR4), and imiquimod (IMQ; TLR7) can be used to enhance the response of T cells in individuals with LTBI. We also investigated the potential mechanisms through which TLR agonists modulate IGRA.ReagentsPRR ligands Poly(I:C), LPS and IMQ were purchased from InvivoGen (San Diego, CA). IL-6 and IL-12 were purchased from R D System (Minneapolis, MN) and IFN-a was purchased from PBL Interferon Source (Piscataway, NJ). All compounds were reconstituted in endotoxin-free water and stored at 270uC. Antihuman CD45 antibody was purchased from Invitrogen (Carlsbad, CA). All other antibodies were purchased from BD Biosciences (San Jose, CA).QuantiFERON-TB Gold In-Tube assayThe QFT-GIT assay was performed with fresh blood according to package insert with some modification to accommodate addition of immunomodulators. Up to 10 ml of each agonist or an equivalent volume of endotoxin-free water was added to each Nil and TB Ag tube. Blood was collected in a 10 ml Kendall Monoject Green Stopper tube and 1 ml was quickly transferred to each QFT-GIT tube. Tubes were then mixed and placed in a 37uC incubator for 22 hours or as indicated. ELISA was performed according to package insert. The remaining plasma was stored at 270uC. Calculation of IFN-c concentrations was done with the software provided by the manufacturer. TB Antigen tubes with IFN-c.10 IU/ml were diluted in PBS to determine the exact value. The effect of immunomodulators on IFN-c response was calculated using the following formula: modulated response = [(TB Ag plus immunomodulator) minus (Nil tube plus immunomodulator)].Dose response curveIndicated concentrations of each 16574785 agonist or endotoxin-free water was added to each Nil tube. The tubes were then mixed and placed in a 37uC incubator for 22 hours. The IFN-c concentrations were measured as described above.Cytokine profiling assayThe cytokine profiling assay was performed at the Human Immune Monitoring Center (HIMC) at Stanford University. 100 ml of plasma from the QFT-GIT Nil tube was subjected to cytokine profiling. Procarta Cytokine Assay custom 51-plex kit (Affymetrix, Palo Alto, CA) was used according to manufacturer’s recommendations.
