Pathogen Recognition and Innate Immunity

At high concentrations, free radicals and radical-derived, nonradical reactive species are hazardous for living organisms and damage all major cellular constituents. At moderate concentrations, how...

/pdf/free-radicals-in-the-physiological-control-of-cell-function-g3w3iyr0ph.pdf

Free Radicals in the Physiological Control of Cell Function

▪ Abstract The innate immune system is a universal and ancient form of host defense against infection. Innate immune recognition relies on a limited number of germline-encoded receptors. These receptors evolved to recognize conserved products of microbial metabolism produced by microbial pathogens, but not by the host. Recognition of these molecular structures allows the immune system to distinguish infectious nonself from noninfectious self. Toll-like receptors play a major role in pathogen recognition and initiation of inflammatory and immune responses. Stimulation of Toll-like receptors by microbial products leads to the activation of signaling pathways that result in the induction of antimicrobial genes and inflammatory cytokines. In addition, stimulation of Toll-like receptors triggers dendritic cell maturation and results in the induction of costimulatory molecules and increased antigen-presenting capacity. Thus, microbial recognition by Toll-like receptors helps to direct adaptive immune responses ...

/pdf/innate-immune-recognition-3eedeqyq83.pdf

Innate Immune Recognition

One of the mechanisms by which the innate immune system senses the invasion of pathogenic microorganisms is through the Toll-like receptors (TLRs), which recognize specific molecular patterns that are present in microbial components. Stimulation of different TLRs induces distinct patterns of gene expression, which not only leads to the activation of innate immunity but also instructs the development of antigen-specific acquired immunity. Here, we review the rapid progress that has recently improved our understanding of the molecular mechanisms that mediate TLR signalling.

Toll-like receptor signalling

ObjectiveTo determine the incidence, cost, and outcome of severe sepsis in the United States.DesignObservational cohort study.SettingAll nonfederal hospitals (n = 847) in seven U.S. states.PatientsAll patients (n = 192,980) meeting criteria for severe sepsis based on the International Classification

Epidemiology of severe sepsis in the United States: analysis of incidence, outcome, and associated costs of care.

Studies on the reactions of substituted D,L-erythro-β-phenylserines with lamb liver serine hydroxymethylase. Effects of substituents upon the dealdolization step

The present invention contemplates a method of reducing a bacterial endotoxin contaminant in a biologically useful macromolecule. An aqueous medium containing an endotoxin-contaminated macromolecule is admixed with a dialyzable surfactant, and the admixture so formed is contacted with an endotoxin sorbant to form a solid-liquid phase admixture. The contacting is maintained until the endotoxin is bound to the sorbant. The surfactant is dialyzed out of the aqueous liquid phase at a time no earlier than the maintenance step. The liquid phase containing the macromolecule is separated and recovered.

Method for reducing bacterial endotoxin contamination in solutions of macromolecules

The present invention concerns a method of treating sepsis comprising administering a therapeutically effective amount of anti-CD14 antibody molecules. A therapeutic composition comprising anti-CD14 antibody molecules in a pharmaceutically acceptable excipient is also contemplated.

Methods and compositions for ameliorating the symptoms of sepsis

Endotoxin, endotoxin-binding protein, and soluble CD14 are present in bronchoalveolar lavage fluid of patients with adult respiratory distress syndrome

The results from a number of clinical and experimental studies have suggested that during endotoxemia, suppression of adrenocortical steroidogenesis may occur. We have examined the possibility that macrophages are the source of a factor that suppresses adrenocortical steroidogenesis. Resident and peptone-elicited peritoneal exudate macrophages (PEM) from C3HeB/FeJ mice were incubated for 4 hr at 37 degrees C in the presence or absence of T cell hybridoma-derived lymphokine (LK) that contained high concentrations of MAF activity (assessed by induction of nonspecific tumoricidal activity in PEM). The LK was removed by rinsing, and fresh medium was added, followed by Salmonella minnesota R595 LPS (final concentration 10 micrograms/ml). After 18 hr at 37 degrees C the PEM supernatants and control medium from flasks without cells were harvested and stored at -20 degrees C. Explanted rabbit adrenocortical cells in 96-well plates were exposed to 30 microliters of PEM supernatant or control medium and ACTH (10 or 100 mU/ml) in a final volume of 120 microliters for 3 consecutive days. The adrenocortical cell supernatants were harvested each day, followed by replenishment of medium, PEM supernatant, and ACTH. Fluorogenic steroid production in wells that received control medium or supernatants from PEM not treated with LPS was normal (0.22 microgram +/- 0.010 (SD) per 5 X 10(4) cells). However, as much as 75 to 95% suppression of steroidogenesis was observed in wells that received supernatants from PEM treated with LK and LPS, compared to 40% suppression in wells that received supernatant from PEM treated with LPS alone. Continued exposure (over 3 days) of adrenocortical cells to supernatants from LPS-treated PEM resulted in progressively decreasing response to ACTH. Comparable suppressive activity was observed in supernatants from LPS-treated bone marrow-derived macrophages. In further experiments, suppression was observed in wells that were pretreated (22 hr) with the appropriate PEM supernatant, and evidence was obtained that the suppressive activity was not due to carry-over LPS. Finally, results from control experiments demonstrated that suppressive PEM supernatants neither inactivate ACTH nor interfere with the assay of fluorogenic steroids. Thus, these results suggest that during endotoxemia, products from LPS-stimulated macrophages may suppress adrenocortical function.

Richard J. Ulevitch

Papers

Studies on the reactions of substituted D,L-erythro-β-phenylserines with lamb liver serine hydroxymethylase. Effects of substituents upon the dealdolization step

Method for reducing bacterial endotoxin contamination in solutions of macromolecules

Methods and compositions for ameliorating the symptoms of sepsis

Endotoxin, endotoxin-binding protein, and soluble CD14 are present in bronchoalveolar lavage fluid of patients with adult respiratory distress syndrome

Suppression of ACTH-induced steroidogenesis by supernatants from LPS-treated peritoneal exudate macrophages.