Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0243026 (sepsis)
 52,417 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A panel of monoclonal antibodies with specificity for a wound isolate of Proteus mirabilis was established. Of nine antibodies studied in detail, three were broadly reactive with various Proteus isolates, while six reacted in a serotype-specific fashion with the strain used for immunization. Five of the six serotype-specific antibodies were reactive with lipopolysaccharide. The sixth serotype-specific antibody, 4-F (immunoglobulin G1 [IgG1]), was potently protective in a burn wound sepsis model and recognized a protein antigen. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis and Western blot (immunoblot) analysis were used to determine that 4-F was reactive with flagellar protein. Approximately 1.3 micrograms of the antibody was sufficient to provide protection against 8 50% lethal doses of wound isolate, and approximately 26 micrograms provided full protection against challenge with 333 50% lethal doses. In vitro test results indicated that 4-F inhibited the motility of the wound isolate, and in vivo testing showed that it inhibited dissemination of the inoculum from the burn site to the liver and spleen. Whereas the antibody was highly effective in preventing the death of mice subsequent to challenge at a burn site, no protection was seen following an intraperitoneal challenge. These results may therefore indicate that the protection observed in the burn model is solely a reflection of the capacity of 4-F to neutralize bacterial motility.
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PMID:Monoclonal antibody-mediated protection and neutralization of motility in experimental Proteus mirabilis infection. 265 28

For much of the last decade, an increasing number of surgeons have been interested in objective assessment of cellular contributors to host defense function. In order to study many of these processes, it is apparently desirable that the cells be isolated to the extent feasible for the purpose of analyzing a more or less pure population of cellular elements. The purpose of this paper is to describe the physiologic activation of mononuclear cells that occurs as a result of the isolation process. Therefore, it follows logically that such cells are therein intrinsically less responsive to further physiologic manipulation in vitro. Analyses of such data without an awareness of this intrinsic aberration will undoubtedly lead to misinterpretation of the capacity of such cells for further modulation by immunostimulants or by the intrinsic processes related to injury, anesthesia, and operation. Furthermore, it may indicate that certain agents, e.g., cytokines, are unable to stimulate cellular function when, in fact, the defense function of the cell has been initially stimulated by the isolation procedure. Fractionation of human peripheral blood over Hypaque-Ficoll and subsequent purification of monocytes by adherence to plastic lead to an increase in the relative density of HLA-DR on monocytes. This increase occurred when carried out in endotoxin lipopolysaccharide (LPS)-contaminated or LPS-depleted reagents. LPS, added experimentally to whole blood, enhanced HLA-DR expression on monocytes without further manipulation. Monocyte HLA-DR expression measured in whole blood was reduced in patients with major sepsis (n = 19) compared to normal subjects (n = 10).(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Experimental and clinical significance of endotoxin-dependent HLA-DR expression on monocytes. 273 99

Monoclonal antibodies (MAbs) directed against gram-negative bacterial lipopolysaccharide (endotoxin, LPS) are currently being evaluated as an adjunctive form of therapy for lethal gram-negative bacterial sepsis and shock. The exact binding site within the LPS molecule against which antibody should be directed in order to maximize both cross-reactivity among bacterial strains and protective capacity has not been established. By developing a panel of MAbs that bound to various regions of the LPS molecule (O saccharide; outer, intermediate, and inner core; lipid A), we were able to determine that some epitopes in the inner core/lipid A region of LPS were broadly shared among different genera of gram-negative microorganisms, on the basis of immunoblot analysis of MAb binding to LPS. Pretreatment with lower doses of O saccharide-specific MAbs (2 micrograms per animal) provided protection against a lethal intraperitoneal challenge of viable Salmonella minnesota bacteria, compared with core LPS-specific MAbs, which required at least 1.0 mg of MAb per mouse to provide a similar degree of immunoprotection. Although inner core LPS-specific MAbs are less protective than O saccharide-specific MAbs, these MAbs will probably be more useful in the treatment of gram-negative sepsis because of their ability to bind to many types of LPS and enhance survival during infection, which is caused by a wide variety of gram-negative bacteria.
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PMID:Treatment of experimental gram-negative bacterial sepsis with murine monoclonal antibodies directed against lipopolysaccharide. 276 23

Endotoxin (bacterial lipopolysaccharide, LPS) is paradoxically both inflammatory and antiinflammatory. A single intravenous injection of 100 micrograms Escherichia coli LPS markedly inhibits the inflammatory changes associated with cutaneous reversed passive Arthus (RPA) reactions in New Zealand white rabbits. Polymorphonuclear (PMN) leukocytes from LPS-treated rabbits exhibit diminished responsiveness in vitro to complement (C5) -derived peptides. Repeated injections of LPS render animals "tolerant", that is, refractory to the toxic and inflammatory effects of LPS. We examined whether tolerance would enhance the ability of LPS to inhibit inflammation not attributable to LPS. Surprisingly, as compared with rabbits receiving a single dose of LPS, tolerant rabbits demonstrated greater inflammatory changes (i.e., PMN exudation, vascular permeability) associated with RPA reactions. PMNs from LPS-tolerant rabbits responded in vitro to C5-derived peptides significantly more than PMNs from rabbits that received a single dose of LPS. We speculate that some antiinflammatory effects of LPS require the toxic or inflammatory effects of LPS itself. These observations might relate to the limited efficacy of fever therapy and the variable effects of gram-negative sepsis on functions of human PMNs.
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PMID:Endotoxin tolerance diminishes certain antiinflammatory effects of endotoxin. 293 63

Alterations in macrophage function may render the immunocompromised host more susceptible to infectious complications. Although allograft recipients are at increased risk of infection primarily because of pharmacologic immunosuppression, whether the process of allosensitization per se alters this risk is unknown. We therefore studied the effects of cloned allosensitized murine helper or cytotoxic T cells on both interleukin 1 (IL-1) and prostaglandin E2 (PGE2) production by syngeneic resident murine peritoneal macrophages. Endotoxin (lipopolysaccharide [LPS]) stimulated both IL-1 and PGE2 production in macrophages. Cloned T cells alone, with or without LPS pretreatment, produced neither IL-1 nor PGE2. After 48 hours of coculture with LPS-treated macrophages, cloned helper cells augmented IL-1 release by macrophages but inhibited PGE2 production. In contrast, cytotoxic T cells not only reduced IL-1 production by macrophages but also potentiated PGE2 release. These effects were not observed when macrophages were not first exposed to LPS. Thus, endotoxin renders macrophages more susceptible to allosensitized "help" (increases IL-1, decreases PGE2) or "suppression" (decreases IL-1, increases PGE2) by cytotoxic T cells. We hypothesize that, even in the absence of immunosuppression, the process of allosensitization itself may modulate the response to sepsis by altering host macrophage function.
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PMID:Allosensitized helper and cytotoxic T-lymphocyte clones differentially modulate endotoxin-stimulated macrophage function. 296 2

It is not clear which factors are responsible for the deficient resistance of human neonates to K1 E. coli sepsis and meningitis. To evaluate the relative importance of different defense mechanisms against bacterial invasion, we have analyzed the sensitivity of newborn mice with known immune deficiencies to infection after oral challenge with virulent K1 E. coli. T and B lymphocyte and complement (C5) defects had no significant effect on natural resistance. In contrast, both endotoxin-hyporesponsive mouse strains tested were highly sensitive. This susceptibility to infection was strongly age dependent. Infant endotoxin-hyporesponsive mice were killed by i.p. injection of less than ten virulent K1 E. coli cells. In contrast, endotoxin-responsive animals and F1 hybrids derived from crosses between endotoxin-responsive and hyporesponsive mice survived an injection with up to 10(4) bacteria. Mutants of a virulent 018:K1 E. coli strain defective in the synthesis of the capsular polysaccharide or the O-antigen of lipopolysaccharide were avirulent as were 01:K1 bacteria, which are under-represented among E. coli isolates from neonatal meningitis. Endotoxin-hyporesponsive mice were protected from lethal bacterial challenge by monoclonal IgG specific for the O-antigen of the challenge strain or by human recombinant interleukin 1. A fulminant bacterial multiplication in the bloodstream of endotoxin-hyporesponsive mice was observed after i.v. injection of 100 virulent K1 E. coli cells. Persistent bacteremia with 10(5) to 10(6) bacteria per ml of blood resulted in death of the animals one to two days after challenge. In the bloodstream of endotoxin-responsive mice the bacteria proliferated to a comparable extent within the first 6 h after challenge. Thereafter they were rapidly cleared from the circulation and the animals recovered from the infection.
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PMID:Host factors in the resistance of newborn mice to K1 Escherichia coli infection. 305 39

The cell walls of gram-negative bacteria contain several biologically active components, including lipopolysaccharide (LPS), lipoprotein, and protein 1. The effects of these individual components and a synthetic analog of lipoprotein, TPP, on several activation parameters of glomerular mesangial cells (MC) were examined. Prostaglandin secretion, synthesis of the autogrowth factor, mesangial interleukin-1 (IL-1), and new synthesis of cellular proteins were assessed as markers of MC activation. All bacterial cell wall components evaluated were active in varying degrees as stimulants of prostaglandin secretion. In general, PGE was the predominant product. TPP and protein 1 also induced substantial secretion of thromboxane. Each cell-wall component was effective in stimulating mesangial IL-1 secretion. The activation of MC was associated with the enhanced synthesis of many cellular proteins in addition to IL-1. Stimulation by these bacterial components was dependent on the state of the mesangial cell cycle, because nonproliferating cells did not respond to these factors. Activation of MC by gram-negative bacterial cell wall components, with release of vasoactive prostaglandins and peptide mitogens, may be responsible for some of the glomerular hemodynamic alterations and cellular proliferative events associated with sepsis or chronic bacterial infection.
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PMID:Activation of glomerular mesangial cells by gram-negative bacterial cell wall components. 305 3

We analyzed high molecular weight polysaccharide (PS) from the Fisher immunotype 2 (IT-2) strain of Pseudomonas aeruginosa for molecular composition and structure, then determined its immunogenicity in healthy adults. The PS was composed of 2-acetamido-2,6-dideoxygalactose (N-acetyl fucosamine) and glucose in a molar ratio of 2:1. Structural analysis by carbon-13 and proton nuclear magnetic resonance confirmed that the high molecular weight PS was structurally identical to that of the O-specific side chain of the lipopolysaccharide. PS differed from this material in molecular size. Immunization of 19 adult volunteers with doses of 50-100 micrograms of PS resulted in significant rises (P less than 0.04-P less than 0.0001) in binding antibody levels and killing antibody titers 2 and 4 wk postimmunization. The only reaction to the vaccine was localized tenderness at the immunization site. Analysis of the immunoglobulin isotype response to the vaccine showed a rise in specific serum IgG and IgA antibodies. Heterologous responses to other P. aeruginosa PS antigens were not seen. The antibody levels attained by vaccination were comparable with those in acute-phase serum samples of patients who survived sepsis with IT-2 P. aeruginosa and were significantly higher (P less than 0.03) than specific antibody levels in bacteremic patients who died. These results confirm that PS is a high molecular weight, immunogenic form of the P. aeruginosa IT-2 serotype antigen, eliciting levels of type-specific antibody comparable with those seen among patients surviving an episode of P. aeruginosa sepsis.
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PMID:Structural analysis and immunogenicity of Pseudomonas aeruginosa immunotype 2 high molecular weight polysaccharide. 308 Apr 77

A Pseudomonas aeruginosa polysaccharide-tetanus toxoid (Ttxd) conjugate vaccine was produced. Polysaccharide was derived from lipopolysaccharide (LPS) and covalently linked to Ttxd by using carbodiimide with adipic acid dihydrazide as a spacer molecule. The conjugate possessed a relative molecular weight of greater than 350,000 and was nontoxic and nonpyrogenic. The vaccine bound serospecific monoclonal antibodies with an avidity similar to LPS and reacted with murine and human opsonic antibody. The vaccine was immunogenic in rabbits and mice and elicited IgG antibody to both LPS and Ttxd. The vaccine was safe when parenterally administered to humans and evoked only mild, transient reactions. Mean titers of IgG antibody to LPS rose 19-fold after immunization, with 82% of the volunteers responding with a fourfold or greater rise in titer. IgG antibody to LPS evoked after immunization was opsonic and highly effective at preventing fatal experimental burn wound sepsis due to P. aeruginosa.
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PMID:Pseudomonas aeruginosa polysaccharide-tetanus toxoid conjugate vaccine: safety and immunogenicity in humans. 309 8

Lipid A-free polysaccharide (PS) isolated from Pseudomonas aeruginosa immunotype 5 lipopolysaccharide (LPS) was covalently coupled to toxin A via reductive amination. The PS-toxin A conjugate was comprised of 29.8% PS and 70.2% toxin A, possessed a molecular weight of greater than 1 X 10(6), was nontoxic for animals and was nonpyrogenic for rabbits at a dose of 50 micrograms/kg body wt when administered intravenously. The conjugate evoked only mild, transient reactions upon subcutaneous administration to human volunteers. Vaccination engendered immunoglobulin G (IgG) antibody, which neutralized the cytotoxic effect of toxin A and promoted the uptake and killing of P. aeruginosa in the presence of human polymorphonuclear leukocytes. Passively transferred IgG isolated from the serum of immunized donors was far more effective at preventing fatal P. aeruginosa burn wound sepsis than paired preimmunization serum. These studies establish the potential usefulness of such a PS-toxin A conjugate as a vaccine against P. aeruginosa.
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PMID:Safety and immunogenicity of a Pseudomonas aeruginosa O-polysaccharide toxin A conjugate vaccine in humans. 311 Feb 15


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