Toll-like receptor mRNA levels in alveolar macrophages after inhalation of endotoxin

Abstract

Toll-like receptors (TLRs) are pattern-recognition receptors that have been implicated in the initiation of innate immune responses upon the first encounter with invading pathogens. The airways are frequently exposed to various types of lipopolysaccharide (LPS) from the environment or from pathogens. The current study was designed to determine the effect of LPS on TLR gene expression in human alveolar macrophages in vivo.In total, 16 healthy subjects were enrolled in a single-blinded, placebo-controlled study. Subjects inhaled 100 mg LPS or normal saline (n58 per group). Measurements were performed in alveolar macrophages purified from bronchoalveolar lavage fluid obtained 6 h post-challenge.Inhalation of LPS by healthy human volunteers resulted in enhanced alveolar macrophage expression of mRNAs encoding TLRs 1, 2, 7, 8 and CD14, and reduced expression of mRNAs encoding TLR4 and lymphocyte antigen 96.In conclusion, lipopolysaccharide differentially influences the toll-like receptor mRNA expression profile in human alveolar macrophages in vivo.

Comparative Analysis of the Interaction of Helicobacter pylori with Human Dendritic Cells, Macrophages, and Monocytes

“…Monocytes secrete IL-12 p40 and IL-23 upon NAP stimulation (22), and we have observed similar results. No APCs used in our study express TLR9 (39,54,74); thus, this receptor is not involved in the effects of H. pylori on APCs that we observed in our experiments. Notably, H. pylori could also be sensed by APCs through other pathogen recognition receptors.…”

The interaction of influenza H5N1 viral hemagglutinin with sialic acid receptors leads to the activation of human γδ T cells

“…45 Myeloid dendritic cells and alveolar macrophages in the lung express high levels of TLRs, such as TLR2, TLR3 and TLR4, which are important for the recognition of influenza viruses. 43,44 However, cell surface expression of TLRs in human peripheral blood cd T cells was nearly undetectable by flow cytometry, indicating that TLRs may not be involved in the response of cd T cells to influenza virus and that the PRR-mediated signaling pathway may not play an essential role in the activation of human cd T cells in influenza H5N1 virus infection. NK cells, which represent another important cell population in the innate immune response to viral infections, are activated by influenza virus HA proteins through interaction with the NKp46 receptor.…”

“…[43][44][45] Therefore, we determined whether rHA-induced cd T-cell activation is mediated by these receptors. We found no surface expression of TLR2, TLR3 or TLR4 on cd T cells (Figure 6a).…”

High-Throughput mRNA Profiling Characterizes the Expression of Inflammatory Molecules in Sepsis Caused by Burkholderia pseudomallei

“…All samples were tested with the same batch of reagents. The levels of mRNA for each gene were expressed as a normalized ratio of the peak area divided by the peak area of the ␤ 2 -microglobulin (B2M) control gene, resulting in the relative abundances of mRNAs of the genes of interest (11,16,19,22).…”

“…After isolation, leukocytes, monocytes, and granulocytes were dissolved in Trizol and stored at Ϫ80°C until used for RNA isolation. RNA was isolated and analyzed by multiplex ligation-dependent probe amplification (MLPA) as previously described (11,16,19,22). The inflammatory genes as analyzed by MLPA are listed in Table 1.…”