lipoteichoic-acid and Pneumonia--Pneumococcal

The inflammatory response in pneumococcal infection is primarily driven by immunoreactive bacterial cell wall components [lipoteichoic acid (LTA)]. An acute release of these components occurs when pneumococcal infection is treated with β-lactam antibiotics.. We hypothesized that non-lytic rifampicin compared with lytic β-lactam antibiotic treatment would attenuate the inflammatory response in patients with pneumococcal pneumonia.. In the PRISTINE (Pneumonia treated with RIfampicin aTtenuates INflammation) trial, a randomized, therapeutic controlled, exploratory study in patients with community-acquired pneumococcal pneumonia, we looked at LTA release and inflammatory and clinical response during treatment with both rifampicin and β-lactam compared with treatment with β-lactam antibiotics only. The trial is registered in the Dutch trial registry, number NTR3751 (European Clinical Trials Database number 2012-003067-22).. Forty-one patients with community-acquired pneumonia were included; 17 of them had pneumococcal pneumonia. LTA release, LTA-mediated inflammatory responses, clinical outcomes, inflammatory biomarkers and transcription profiles were not different between treatment groups.. The PRISTINE study demonstrated the feasibility of adding rifampicin to β-lactam antibiotics in the treatment of community-acquired pneumococcal pneumonia, but, despite solid in vitro and experimental animal research evidence, failed to demonstrate a difference in plasma LTA concentrations and subsequent inflammatory and clinical responses. Most likely, an inhibitory effect of human plasma contributes to the low immune response in these patients. In addition, LTA plasma concentration could be too low to mount a response via Toll-like receptor 2 in vitro, but may nonetheless have an effect in vivo.

Topics: Adolescent; Adult; Aged; Aged, 80 and over; Anti-Bacterial Agents; beta-Lactams; Community-Acquired Infections; Female; Humans; Inflammation; Lipopolysaccharides; Male; Middle Aged; Netherlands; Plasma; Pneumonia, Pneumococcal; Rifampin; Teichoic Acids; Treatment Outcome; Young Adult

Liver kinase B1 (Lkb1, gene name Stk11) functions as a tumor suppressor in cancer. Myeloid cell Lkb1 potentiates lung inflammation induced by the Gram-negative bacterial cell wall component lipopolysaccharide and in host defense during Gram-negative pneumonia. Here, we sought to investigate the role of myeloid Lkb1 in lung inflammation elicited by the Gram-positive bacterial cell wall component lipoteichoic acid (LTA) and during pneumonia caused by the Gram-positive respiratory pathogen Streptococcus pneumoniae (Spneu).. Alveolar and bone marrow derived macrophages (AMs, BMDMs) harvested from myeloid-specific Lkb1 deficient (Stk11-ΔM) and littermate control mice were stimulated with LTA or Spneu in vitro. Stk11-ΔM and control mice were challenged via the airways with LTA or infected with Spneu in vivo.. Lkb1 deficient AMs and BMDMs produced less tumor necrosis factor (TNF)α upon activation by LTA or Spneu. During LTA-induced lung inflammation, Stk11-ΔM mice had reduced numbers of AMs in the lungs, as well as diminished cytokine release and neutrophil recruitment into the airways. During pneumonia induced by either encapsulated or non-encapsulated Spneu, Stk11-ΔM and control mice had comparable bacterial loads and inflammatory responses in the lung, with the exception of lower TNFα levels in Stk11-ΔM mice after infection with the non-encapsulated strain.. Myeloid Lkb1 contributes to LTA-induced lung inflammation, but is not important for host defense during pneumococcal pneumonia.

Topics: AMP-Activated Protein Kinases; Animals; Lipopolysaccharides; Liver; Mice; Pneumonia, Bacterial; Pneumonia, Pneumococcal; Streptococcus pneumoniae; Teichoic Acids; Tumor Necrosis Factor-alpha

Common Variable Immunodeficiency (CVID) is the most common symptomatic form of primary immunodeficiencies. Current research data show altered B cells, TLRs, and cytokine profile in CVID patients. The aim of this study was to determine levels of IL-1β and IL-6 in CVID patients in response to TLRs stimulation and the association of these cytokines with subtypes of B cells and response to Pneumovax-23 vaccination.. Peripheral blood mononuclear cells of CIVD patients were stimulated with and without TLR2 and TLR4 agonist and specific inhibitors including lipopolysaccharide (LPS), lipoteichoic (LTA), and OxPAPC. The levels of IL-1β and IL-6 were assessed by ELISA in different treatment groups. Finally, association of cytokines levels was assessed among different subtypes of B cells and types of response to Pneumovax-23 vaccine.. Secretion of IL-6 and IL-1β was significantly diminished in CVID patients (p = 0.015 and p = 0.019), but ligand engagement of TLR2 and TLR4 leads to significant increase in IL-6 and IL-1β production. IL-6 was significantly lower in Pneumovax-23 hypo responder patients (p = 0.05) and significant correlations between the concentration of IL-6 and the number of switched memory and CD21. Secretion of IL-6 and IL-1β is abolished in CVID patients. However, TLR2 and TLR4 are hyper responsive to stimulation with their cognate ligands resulting in the secretion of higher levels of proinflammatory cytokines. This characteristic of CVID TLRs leads to an improvement of cytokine secretion compared to baseline levels. Also, our novel findings about the association concentrations of serum IL-6 and the frequency of with switched memory and CD21

Topics: Adolescent; Adult; B-Lymphocyte Subsets; Case-Control Studies; Common Variable Immunodeficiency; Female; Gene Expression; Humans; Interleukin-1beta; Interleukin-6; Lipopolysaccharides; Lymphocyte Activation; Male; Phosphatidylcholines; Pneumococcal Vaccines; Pneumonia, Pneumococcal; Primary Cell Culture; Streptococcus pneumoniae; Teichoic Acids; Toll-Like Receptor 2; Toll-Like Receptor 4; Vaccination

Streptococcus pneumoniae is a major causative agent in community-acquired pneumonia and sepsis. Overwhelming lung inflammation during pneumococcal pneumonia may hamper lung function. Ibrutinib is an irreversible inhibitor of Bruton's tyrosine kinase (Btk), a key signaling protein controlling the activation of various immune cells, including macrophages and neutrophils. The aim of this study was to determine whether ibrutinib treatment ameliorates acute lung inflammation during pneumococcal pneumonia.. Mice were treated orally with ibrutinib and the effect on acute pulmonary inflammation elicited by the gram-positive bacterial cell wall component lipoteichoic acid (LTA) and during ceftriaxone-treated pneumococcal pneumonia was assessed.. Treatment with ibrutinib prior to and after intranasal LTA instillation reduced alveolar macrophage activation, neutrophil influx, cytokine release and plasma leakage into the lung. Postponed treatment with ibrutinib supplementing antibiotic therapy during ongoing pneumococcal pneumonia did not impair bacterial killing in lung, blood and spleen. In this setting, ibrutinib reduced alveolar macrophage and systemic neutrophil activation and substantially diminished further monocyte and neutrophil influx in the lung. In vitro, ibrutinib inhibited macrophage TNF secretion and neutrophil activation upon LTA and pneumococcal stimulation.. Taken together, these data indicate that the Btk inhibitor ibrutinib reduces inflammatory myeloid cell responses during acute pulmonary inflammation evoked by LTA and antibiotic-treated pneumococcal pneumonia and suggest that ibrutinib has the potential to inhibit ongoing lung inflammation in an acute infectious setting.

Topics: Adenine; Agammaglobulinaemia Tyrosine Kinase; Animals; Anti-Bacterial Agents; Anti-Inflammatory Agents; Bronchoalveolar Lavage Fluid; Ceftriaxone; Lipopolysaccharides; Lung; Male; Mice, Inbred C57BL; Mice, Knockout; Myeloid Cells; Piperidines; Pneumonia, Pneumococcal; Protein Kinase Inhibitors; Pyrazoles; Pyrimidines; Teichoic Acids

Teichoic acid (TA), a crucial cell wall constituent of the pathobiont Streptococcus pneumoniae, is bound to peptidoglycan (wall teichoic acid, WTA) or to membrane glycolipids (lipoteichoic acid, LTA). Both TA polymers share a common precursor synthesis pathway, but differ in the final transfer of the TA chain to either peptidoglycan or a glycolipid. Here, we show that LTA exhibits a different linkage conformation compared to WTA, and identify TacL (previously known as RafX) as a putative lipoteichoic acid ligase required for LTA assembly. Pneumococcal mutants deficient in TacL lack LTA and show attenuated virulence in mouse models of acute pneumonia and systemic infections, although they grow normally in culture. Hence, LTA is important for S. pneumoniae to establish systemic infections, and TacL represents a potential target for antimicrobial drug development.

Topics: Animals; Cell Line; Cell Wall; Disease Models, Animal; Humans; Ligases; Lipopolysaccharides; Male; Mice; Microscopy, Electron; Mutagenesis; Peptidoglycan; Pneumonia, Pneumococcal; Sepsis; Streptococcus pneumoniae; Teichoic Acids; Virulence

IL-23, produced by dendritic cells (DCs) and macrophages, plays a critical role in innate immunity against bacterial infection. Our previous studies show that morphine disrupts the IL-23/IL-17 mediated pulmonary mucosal host defense and increases susceptibility to Streptococcus pneumoniae lung infection. To determine the mechanism by which morphine modulates IL-23 production, mouse bone marrow-derived dendritic cells (BMDCs) and macrophages (BMDMs) were treated with morphine, and infected with S. pneumoniae or stimulated with Toll-like receptor (TLR) and Nod2 ligands. We found that a significant increase in IL-23 protein production was observed in S. pneumoniae, TLR2 ligand lipoteichoic acid (LTA), and TLR4 ligand pneumolysin (PLY) stimulated BMDCs and BMDMs. Interestingly, although Nod2 ligand muramyldipeptide (MDP) alone had no effect on IL-23 production, it potentiated LTA induced IL-23 production to the same level as that observed following S. pneumoniae infection, suggesting that S. pneumoniae induced IL-23 production in DCs involves activation of both TLR2 and Nod2 signaling mechanisms. Furthermore, pretreatment of DCs with MyD88 (myeloid differentiation primary response gene 88) and IL-1 receptor-associated kinase (IRAK) 1/4 inhibitors, or TLR2 antibody diminished the S. pneumoniae induced IL-23 and abolished the inhibitory effects of morphine, indicating that S. pneumoniae induced IL-23 production depends on activation of the TLR2-MyD88-IRAK1/4 signaling pathway. Moreover, morphine decreased S. pneumoniae induced phosphorylation of interferon regulatory factor 3 (IRF3) and activating transcription factor 2 in DCs. Taken together, our study shows that morphine impairs S. pneumoniae induced IL-23 production through MyD88-IRAK1/4-dependent TLR2 and Nod2 signaling in DCs.

Topics: Animals; Dendritic Cells; Interferon Regulatory Factor-3; Interleukin-1 Receptor-Associated Kinases; Interleukin-23; Lipopolysaccharides; Macrophages; Mice; Mice, Knockout; Morphine; Myeloid Differentiation Factor 88; Narcotics; Nod2 Signaling Adaptor Protein; Pneumonia, Pneumococcal; Protein Kinase Inhibitors; Signal Transduction; Streptococcus pneumoniae; Teichoic Acids; Toll-Like Receptor 2

LPS-binding protein (LBP) can facilitate the transfer of cell wall components of both Gram-negative bacteria (LPS) and Gram-positive bacteria (lipoteichoic acid) to inflammatory cells. Although LBP is predominantly produced in the liver, recent studies have indicated that this protein is also synthesized locally in the lung by epithelial cells. To determine the role of LBP in the immune response to pneumonia, LBP gene-deficient (-/-) and normal wild-type (WT) mice were intra-nasally infected with either Streptococcus pneumoniae or Klebsiella pneumoniae, common Gram-positive and Gram-negative pathogens, respectively. Pneumococcal pneumonia was associated with a 7-fold rise in LBP concentrations in bronchoalveolar lavage fluid of WT mice; LBP-/- mice infected with S. pneumoniae showed a similar survival and a similar bacterial burden in their lungs 48 h post-infection. In Klebsiella pneumonia, however, LBP-/- mice demonstrated a diminished survival together with an enhanced bacterial outgrowth in their lungs. These data suggest that LBP is important for a protective immune response in Klebsiella pneumonia, but does not contribute to an effective host response in pneumococcal pneumonia.

Topics: Acute-Phase Proteins; Animals; Carrier Proteins; Klebsiella Infections; Klebsiella pneumoniae; Lipopolysaccharides; Membrane Glycoproteins; Mice; Mice, Knockout; Pneumonia, Pneumococcal; Streptococcus pneumoniae; Teichoic Acids

Although well-characterized in the lung, the role of platelet-activating factor (PAF) in inflammation in the central nervous system is undefined. Using rabbit models of meningitis and pneumonia, PAF was found to induce significant blood-brain barrier permeability and brain edema at doses five times lower than those required to generate leukocyte recruitment to the subarachnoid space. Both leukocytosis and increased vascular permeability occurred in response to PAF in the lung. Antibody to the CD-18 family of leukocyte adhesion molecules inhibited leukocyte recruitment in response to PAF in the brain (greater than 80%); a similar level of inhibition in the lung required treatment with a combination of a PAF receptor antagonist (L-659,989) and anti-CD18 antibody. Treatment with L-659,989 decreased abnormal cerebrospinal fluid cytochemical values induced by intracisternal challenge with pneumococci but not Haemophilus influenzae, indicating a special role for PAF in pneumococcal disease. Antibodies directed at phosphorylcholine, a unique, shared determinant of bioactivity of PAF and pneumococcal cell wall, obviated the inflammatory potential of both agents. However, no evidence for a direct PAF-like activity of pneumococcal cell wall components was detected in vitro by bioassay using platelets or neutrophils. It is concluded that PAF can induce inflammation in the subarachnoid space. In brain, PAF effects appear to be mediated through CD-18-dependent events, while in lung, PAF effects independent of CD-18 are also evident. At both sites, PAF is of particular clinical importance during inflammation induced by pneumococci apparently due to a unique proinflammatory relationship between the pneumococcal cell wall teichoic acid and PAF.

Topics: Animals; Brain; Cell Degranulation; Inflammation; Lipopolysaccharides; Lung; Meningitis, Pneumococcal; Neutralization Tests; Neutrophils; Platelet Activating Factor; Platelet Aggregation; Platelet Membrane Glycoproteins; Pneumonia, Pneumococcal; Rabbits; Receptors, Cell Surface; Receptors, G-Protein-Coupled; Streptococcus pneumoniae; Subarachnoid Space; Teichoic Acids