BACKGROUNDThe Toll-like receptors (TLRs) represent a group of single-pass transmembrane receptors expressed on sentinel cells that are central to innate immune responses.The aim of this study was to investigate the presence of soluble TLRs in pleural effusions, and the diagnostic values of TLRs for pleural effusion with various etiologies.

METHODSPleural effusion and serum samples were collected from 102 patients (36 with malignant pleural effusion, 36 with tuberculous pleural effusion, 18 with bacterial pleural effusion, and 12 with transudative pleural effusion). The concentrations of TLR1 to TLR10 were determined in effusion and serum samples by enzyme linked immunosorbent assay. Four classical parameters (protein, lactate dehydrogenase, glucose and C-reactive protein (CRP)) in the pleural fluid were also assessed. Receiver-operating characteristic curves were used to assess the sensitivity and specificity of pleural fluid TLRs and biochemical parameters for differentiating bacterial pleural effusion.

RESULTSThe concentrations of TLR1, TLR3, TLR4, TLR7 and TLR9 in bacterial pleural effusion were significantly higher than those in malignant, tuberculous, and transudative groups, respectively. Analysis of receiver operating characteristic curves revealed that the area under the curves of TLR1, TLR3, TLR4, TLR7 and TLR9 were 0.831, 0.843, 0.842, 0.883 and 0.786, respectively, suggesting that these TLRs play a role in the diagnosis of bacterial pleural effusion. Also, the diagnostic value of TLRs for bacterial pleural effusions was much better than that of biochemical parameters (protein, lactate dehydrogenase, glucose and CRP).

CONCLUSIONSThe concentrations of TLR1, TLR3, TLR4, TLR7 and TLR9 appeared to be increased in bacterial pleural effusion compared to non-bacterial pleural effusions. Determination of these pleural TLRs may improve the ability of clinicians to differentiate pleural effusion patients of bacterial origin from those with other etiologies.

Adolescent ; Adult ; Aged ; Aged, 80 and over ; Bacterial Infections ; metabolism ; Enzyme-Linked Immunosorbent Assay ; Female ; Humans ; Male ; Middle Aged ; Pleural Effusion ; metabolism ; microbiology ; Prospective Studies ; Toll-Like Receptor 1 ; metabolism ; Toll-Like Receptor 3 ; metabolism ; Toll-Like Receptor 4 ; metabolism ; Toll-Like Receptor 7 ; metabolism ; Toll-Like Receptor 9 ; metabolism ; Toll-Like Receptors ; metabolism ; Young Adult

The innate immune system provides a first line of defense against invading pathogens, in which the pattern recognition receptors (PRR) recognize pathogen-associated molecular patterns (PAMP) and initiate the downstream signaling pathways to eliminate the encountered pathogens. There are two main classes of such signaling pathways: NOD-like receptor (NLR) signaling pathway and Toll-like receptor (TLR) signaling pathway. The microbial pathogens under selective pressure have evolved numerous mechanisms to avoid and/or manipulate the NLR and TLR signal transduction for survival and replication. To evade the NLR signaling pathway, pathogens interfere and/or inhibit inflammasome activation in innate immune cells by producing virulence factors or reducing PAMPs expression. The mechanisms for pathogens to evade TLR signaling pathway include: inhibition of mitogen activated protein kinases (MAPKs) cascade reaction, inhibition of NF-КB activation, and interference of down-stream signal transduction by producing Toll/interleukin-1 receptor (TIR)-containing proteins which bind directly with TLRs or adaptor proteins in the signaling pathway.
Immunity, Innate ; NLR Proteins ; immunology ; Receptors, Interleukin-1 ; metabolism ; Signal Transduction ; Toll-Like Receptors ; immunology

Mycoplasmas, the smallest free-living, self-replicating bacteria with diameters of 200 to 800 nm, have been reported to be associated with human diseases. It is well known that the mycoplasma lipoprotein/peptide is able to modulate the host immune system, whose N-terminal structure is an important factor in inducing immunity and distinguishing Toll-like receptors (TLRs). However, there is still no clear elucidation about the pathogenic mechanism of mycoplasma lipoprotein/peptide and the signaling pathway. Some researchers have focused on understanding the structures of these proteins and the relationships between their structure and biological function. This review provides an update on the research in this field.
Lipoproteins ; chemistry ; metabolism ; Models, Biological ; Mycoplasma ; chemistry ; metabolism ; Toll-Like Receptors ; chemistry ; metabolism

Humans ; Myeloid Differentiation Factor 88 ; metabolism ; Rhinitis, Allergic ; metabolism ; Signal Transduction ; Toll-Like Receptors ; metabolism

Animals ; Drosophila Proteins ; Humans ; Lipopolysaccharides ; pharmacology ; Membrane Glycoproteins ; metabolism ; physiology ; Receptors, Cell Surface ; metabolism ; physiology ; Signal Transduction ; Toll-Like Receptor 4 ; Toll-Like Receptors

Toll like receptor (TLR) can specifically recgnize pathogen-associated molecular patterns (PAMPs) and is considered as an important link between innate and adaptive immunity. It has been shown that TLR plays an important role in the pathogenesis and pathophysiology of a variety of skin diseases. Moreover, TLR agonists have exhibited promising therapeutic effects on the disease models and are expected to be novel vaccine adjuvants. Investigations of the underlying mechanism will give new insights into these diseases. This review will discuss the relationship between TLR and pathogenesis and management of some cutaneous diseases.
Adaptive Immunity ; Immunity, Innate ; Signal Transduction ; Skin Diseases ; immunology ; metabolism ; Toll-Like Receptors ; immunology ; metabolism ; physiology

Dendritic cells (DCs), the most potent antigen-presenting cells, recognize pathogen by Toll-like receptors (TLRs) and serve as the bridge between the innate and the adaptive immune responses. TLRs-mediated signal transduction plays a crucial role in the functional maturation of DCs. This review summarizes the research progress on the expression and function of TLRs in DCs.
Dendritic Cells ; immunology ; metabolism ; Humans ; Immunity, Innate ; Signal Transduction ; Toll-Like Receptors ; metabolism ; physiology

Liver Diseases ; immunology ; metabolism ; Signal Transduction ; Toll-Like Receptors ; immunology ; metabolism

OBJECTIVETo investigate the expression of TLR4/2 mRNA in neonatal cord blood mononuclear cells (MNC).

METHODSForty-six neonates without asphyxia and 40 neonates with asphyxia were divided into groups depending on the gestational age. In the neonates without asphyxia, there were 18 full term infants (the gestational age > or = 37 weeks), 16 preterm infants whose gestational age was > or = 32 weeks but < 37 weeks, and 12 preterm infants whose gestational age was < 32 weeks. In the neonates with asphyxia, 11 were full term infants, 15 were preterm infants whose gestational age was > or = 32 weeks but < 37 weeks and 14 were preterm infants at gestational age < 32 weeks. MNCs were separated and cultured with LPS (1 microg/ml) for 3 h. Cells were collected for analysis of gene expression of TLR4/2 by RT-PCR technique. Cell supernatants were taken to measure TNF-alpha production following the ELISA protocol. Fifteen healthy adults were enrolled into the control group. In addition, the Pearson correlation analyses were carried out between the levels of TLR4, TLR2 mRNA and the levels of TNF-alpha.

RESULTSIn the neonates without asphyxia, TLR4, TLR2 mRNA and TNF-alpha levels were 0.75 +/- 0.12, 0.63 +/- 0.08, 2502.6 +/- 273.1 ng/L, separately, in the full term infants, 0.37 +/- 0.04, 0.32 +/- 0.03, 1218.8 +/- 145.7 ng/L, separately, in the preterm infants whose gestational ages were > or = 32 weeks but < 37 weeks, and 0.26 +/- 0.03, 0.20 +/- 0.03, 811.8 +/- 105.2 ng/L separately, in the preterm infants whose gestational ages were < 32 weeks. In the neonates with asphyxia, TLR4, TLR2 mRNA and TNF-alpha levels were 0.58 +/- 0.07, 0.50 +/- 0.06, 1946.4 +/- 244.2 ng/L, separately, in the full term infants, 0.29 +/- 0.03, 0.26 +/- 0.03, 970.0 +/- 94.3 ng/L, separately, in the preterm infants whose gestational age was > or = 32 weeks but < 37 weeks, and 0.17 +/- 0.02, 0.14 +/- 0.02, 652.6 +/- 60.3 ng/L, separately, in the preterm infants whose gestational age was < 32 weeks. The levels of TLR4, TLR2 mRNA and TNF-alpha in the adults were 2.71 +/- 0.75, 2.61 +/- 0.33, 9270.1 +/- 1098.3 ng/L, separately. In the preterm infants and full term infants, the levels of TLR4, TLR2 mRNA and TNF-alpha were lower in comparison to the adults. The lower the gestational age, the lower the levels of TLR4, TLR2 mRNA and TNF-alpha. There were significant differences between the levels of TLR4, TLR2 mRNA and TNF-alpha of the neonates without asphyxia and those of the neonates with asphyxia. In the neonates with asphyxia, the levels of TLR4, TLR2 mRNA and TNF-alpha were lower than those in the neonates without asphyxia (P < 0.01). Whether the neonates were asphyxic or not, the levels of TLR4, TLR2 were paralleled with the levels of TNF-alpha.

CONCLUSIONSThe expression of TLRs in the neonates, especially in the preterm infants was lower than that in the adults, which probably contributes to the susceptibility of neonates to infections.

Blood Cells ; metabolism ; Gene Expression ; Humans ; Infant ; Infant, Newborn ; RNA, Messenger ; genetics ; Toll-Like Receptor 2 ; metabolism ; Toll-Like Receptors ; metabolism ; Tumor Necrosis Factor-alpha ; immunology

Infection and antibiotic multidrug resistance have become the focal issue in clinical treatment of acute leukemia and will make anti-infection therapy facing to new challenge. Toll-like receptor (TLR) has been found a newly innate immunoreceptor. It is significant in immune response. Along with further investigation of TLR, infection and anti-infection immunity theory would gain a new breakthrough and play a guiding role in clinical treatment of acute leukemia complicated with infection. In this review, the progress in the research of TLR and its expression in acute leukemia complicated with infection were summarized.
Acute Disease ; Humans ; Infection ; complications ; immunology ; Leukemia ; complications ; immunology ; metabolism ; Toll-Like Receptor 4 ; immunology ; metabolism ; Toll-Like Receptors ; immunology ; metabolism