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Medvedev AE, Sabroe I, Hasday JD, Vogel SN. Invited review: Tolerance to microbial TLR ligands: molecular mechanisms and relevance to disease. ACTA ACUST UNITED AC 2016. [DOI: 10.1177/09680519060120030201] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Many host cell types, including endothelial and epithelial cells, neutrophils, monocytes, natural killer cells, dendritic cells and macrophages, initiate the first line of defense against infection by sensing conserved microbial structures through Toll-like receptors (TLRs). Recognition of microbial ligands by TLRs induces their oligomerization and triggers intracellular signaling pathways, leading to production of pro- and anti-inflammatory cytokines. Dysregulation of the fine molecular mechanisms that tightly control TLR signaling may lead to hyperactivation of host cells by microbial products and septic shock. A prior exposure to bacterial products such as lipopolysaccharide (LPS) may result in a transient state of refractoriness to subsequent challenge that has been referred to as `tolerance'. Tolerance has been postulated as a protective mechanism limiting excessive inflammation and preventing septic shock. However, tolerance may compromise the host's ability to counteract subsequent bacterial challenge since many septic patients exhibit an increased incidence of recurrent bacterial infection and suppressed monocyte responsiveness to LPS, closely resembling the tolerant phenotype. Thus, by studying mechanisms of microbial tolerance, we may gain insights into how normal regulatory mechanisms are dysregulated, leading ultimately to microbial hyporesponsivess and life-threatening disease. In this review, we present current theories of the molecular mechanisms that underlie induction and maintenance of `microbial tolerance', and discuss the possible relevance of tolerance to several infectious and non-infectious diseases.
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Affiliation(s)
- Andrei E. Medvedev
- Department of Microbiology and Immunology, University of Maryland, Baltimore (UMB), Baltimore, Maryland, USA,
| | - Ian Sabroe
- Academic Unit of Respiratory Medicine, Division of Genomic Medicine, University of Sheffield, Royal Hallamshire Hospital, Sheffield, UK
| | - Jeffrey D. Hasday
- Department of Medicine, University of Maryland, Baltimore (UMB), Baltimore, Maryland, USA
| | - Stefanie N. Vogel
- Department of Microbiology and Immunology, University of Maryland, Baltimore (UMB), Baltimore, Maryland, USA
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Cross AS. Invited review: Endotoxin tolerance — current concepts in historical perspective. ACTA ACUST UNITED AC 2016. [DOI: 10.1177/09680519020080020201] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Affiliation(s)
- Alan S. Cross
- Division of Infectious Diseases, Department of Medicine, University of Maryland School of Medicine, Baltimore, Maryland, USA,
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Rudbach J, Keegan D, Sowell C. Calculating therapeutic indices and therapeutic advantages for endotoxins and monophosphoryl lipid A: an evaluation of data from the scientific literature. ACTA ACUST UNITED AC 2016. [DOI: 10.1177/096805199500200410] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
This review article addresses the question of whether or not monophosphoryl lipid A offers a therapeutic advantage over smaller doses of endotoxin. Biological data were collected from a literature review and these were used to calculate therapeutic indices for monophosphoryl lipid A and endotoxin. Subsequent calculations yielded results which showed that, in humans and in other animals, monophosphoryl lipid A did have a therapeutic advantage over smaller doses of endotoxin.
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Affiliation(s)
- J.A. Rudbach
- Ribi ImmunoChem Research, Inc., Hamilton, Montana, USA
| | - D.S. Keegan
- Ribi ImmunoChem Research, Inc., Hamilton, Montana, USA
| | - C.G. Sowell
- Ribi ImmunoChem Research, Inc., Hamilton, Montana, USA
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Macrophage Genetic Reprogramming During Chronic Peritonitis is Augmented by LPS Pretreatment. J Surg Res 2012; 175:289-97. [DOI: 10.1016/j.jss.2011.04.051] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2011] [Revised: 04/08/2011] [Accepted: 04/21/2011] [Indexed: 11/18/2022]
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Xiong Y, Medvedev AE. Induction of endotoxin tolerance in vivo inhibits activation of IRAK4 and increases negative regulators IRAK-M, SHIP-1, and A20. J Leukoc Biol 2011; 90:1141-8. [PMID: 21934070 DOI: 10.1189/jlb.0611273] [Citation(s) in RCA: 90] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
TLRs mediate host defense against microbial pathogens by eliciting production of inflammatory mediators and activating expression of MHC, adhesion, and costimulatory molecules. Endotoxin tolerance limits excessive TLR-driven inflammation during sepsis and reprograms macrophage responses to LPS, decreasing expression of proinflammatory cytokines without inhibiting anti-inflammatory and antimicrobial mediators. Molecular mechanisms of reprogramming of TLR4 signaling upon in vivo induction of endotoxin tolerance are incompletely understood. We used an in vivo model of endotoxin tolerance, whereby C57BL/6 mice were i.p.-inoculated with LPS or PBS, followed by in vitro challenge of peritoneal or splenic macrophages with LPS to examine activation of IRAK4 and expression of negative regulatory molecules. Administration of LPS in vivo-induced endotoxin tolerance in peritoneal and splenic macrophages, as evidenced by decreased degradation of IκBα, suppressed phosphorylation of p38 and reduced expression of TNF-α, IL-6, and KC mRNA upon in vitro LPS challenge. Macrophages from control and endotoxin-tolerant mice exhibited comparable TLR4 mRNA levels and similar expression of IL-1RA and IL-10 genes. Endotoxin tolerization in vivo blocked TLR4-driven IRAK4 phosphorylation and activation in macrophages, while increasing expression of IRAK-M, SHIP-1, A20 mRNA, and A20 protein. Thus, induction of endotoxin tolerance in vivo inhibits expression of proinflammatory mediators via impaired activation of IRAK4, p38, and NF-κB and increases expression of negative regulators of TLR4 pathways.
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Affiliation(s)
- Yanbao Xiong
- Department of Microbiology and Immunology, University of Maryland School of Medicine, Baltimore, Maryland, USA
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Lenz AM, Qadan M, Gardner SA, Cheadle WG. Impact of microbial tolerance in persistent secondary Klebsiella pneumoniae peritonitis. Cytokine 2011; 53:84-93. [DOI: 10.1016/j.cyto.2010.08.012] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2010] [Revised: 06/25/2010] [Accepted: 08/31/2010] [Indexed: 11/29/2022]
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Lenz AM, Turina M, Alard P, Gardner SA, Cheadle WG. Microbial tolerance in secondary peritonitis is dose dependent. Cell Immunol 2009; 258:98-106. [DOI: 10.1016/j.cellimm.2009.03.018] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2009] [Revised: 03/20/2009] [Accepted: 03/25/2009] [Indexed: 10/20/2022]
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Lehner MD, Hartung T. Endotoxin tolerance-mechanisms and beneficial effects in bacterial infection. Rev Physiol Biochem Pharmacol 2002; 144:95-141. [PMID: 11987826 DOI: 10.1007/bfb0116586] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Affiliation(s)
- M D Lehner
- Universität Konstanz, Biochemische Pharmakologie, Fach M655, 78457 Konstanz, Germany
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Abstract
Absence of the spleen or splenic function predisposes individuals to risk of overwhelming infection. These infections are most often due to encapsulated organisms, especially pneumococcus, Haemophilus influenzae type b, and meningococcus, but any bacterial agent may cause the rapid onset of septicemia, meningitis, pneumonia, and shock characteristic of the asplenic-hyposplenic condition. The risk is greatest in infants and young children, but asplenic-hyposplenic adults also have an increased risk of infection. Prophylactic antibiotics and immunization with polyvalent pneumococcal, H. influenzae type b, and meningococcal vaccines have reduced the incidence of infections in asplenic-hyposplenic individuals, but even these measures have not eliminated the risk. Surgeons have adopted techniques to save as much splenic tissue as possible and some splenic functions, such as pitting red cells, have been preserved, but conservative surgery has not provided total protection against overwhelming infection. Therapies designed to interrupt the cascade of overwhelming sepsis have not yet been successful. In those cases in which the spleen is surgically removed, the underlying disease or condition leading to splenectomy influences the risk of sepsis. Splenectomy incidental to other operations, such as gastrectomy, results in the lowest risk for overwhelming infection, but this is still some 35-fold greater than the risk for overwhelming infections in the general population. In increasing order of risk, the other main indications for surgical removal of the spleen are idiopathic thrombocytopenia purpura, trauma, transplantation procedures, hereditary spherocytosis, staging Hodgkin's disease, portal hypertension with hypersplenism, and thalassemia. Pathologists should comment on the risk of overwhelming sepsis when spleens are processed as surgical specimens, and should carefully weigh all splenic tissue, including accessory spleens and splenic implants (splenosis), in autopsy cases with and without overwhelming sepsis.
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Affiliation(s)
- K Hansen
- Department of Pathology and Laboratory Medicine, Women and Infants' Hospital and Brown University School of Medicine, Providence, RI 02905, USA
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Ogle CK, Guo X, Chance WT, Ogle JD. Induction of endotoxin tolerance in rat bone marrow cells by in vivo infusion of tumor necrosis factor. Crit Care Med 1997; 25:827-33. [PMID: 9187603 DOI: 10.1097/00003246-199705000-00019] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
OBJECTIVE To determine in a rat model whether a low-dose infusion of tumor necrosis factor (TNF) affects the production of the inflammatory cytokines TNF and interleukin (IL)-6, the immunosuppressive factor prostaglandin E2 (PGE2), and complement component C3 (C3) by isolated bone marrow-adherent and -nonadherent cells, cultured in the presence of lipopolysaccharide, a component of bacterial endotoxin. DESIGN Randomized, controlled animal study. SETTING Research laboratory of a university medical center. SUBJECTS Sprague-Dawley rats (n = 18), 250 to 275 g. INTERVENTIONS Animals received a continuous infusion of one of the following three treatments for 4 days: a) TNF in saline containing bovine serum albumin; b) saline containing bovine serum albumin; and c) saline alone. MEASUREMENTS AND MAIN RESULTS After infusion, isolated bone marrow cells were cultured for 1 day and 3 days, with and without lipopolysaccharide (1 microgram/mL); culture supernatants were assayed for TNF, IL-6, PGE2, and C3. TNF infusion caused a decrease in the in vitro production of TNF, IL-6, and PGE2 by the lipopolysaccharide-stimulated adherent and nonadherent bone marrow cells. This tolerance to lipopolysaccharide stimulation was present after both 1 day and 3 days of culture. TNF infusion caused an increase in C3 production by the nonadherent cells. The production of TNF by adherent cells from saline-infused or bovine serum albumin-infused animals (controls) was greater in 3-day cultures compared with 1-day cultures, whereas the production of IL-6 and PGE2 was less. CONCLUSIONS These results indicate that TNF infusion caused cells in the bone marrow to be tolerant to lipopolysaccharide stimulation or that TNF infusion programmed the cells to become tolerant to lipopolysaccharide stimulation on differentiation and/or maturation. The results also indicate that bone marrow cells may be regulated by TNF (probably indirectly) at different phases of maturation and/or differentiation with respect to the production of different mediators. Although TNF is considered to be an inflammatory cytokine, at low concentrations it may be an important down-regulator of the inflammatory response.
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Affiliation(s)
- C K Ogle
- Department of Surgery, University of Cincinnati, College of Medicine, OH, USA
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Fahmi H, Chaby R. Differential recovery of macrophages from endotoxin-tolerant states elicited by lipopolysaccharide and enzymatic treatments. Immunol Invest 1994; 23:243-58. [PMID: 7959959 DOI: 10.3109/08820139409066821] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Exposure of macrophages to endotoxin (lipopolysaccharide, LPS) leads to a suppression of their capacity to bind LPS and to produce cytokines after reexposure to LPS. This phenomenon is termed endotoxin tolerance, or LPS-induced desensitization. LPS also stimulates the secretion of serine proteases in macrophages, and activates membrane phospholipases. We have investigated the role of trypsin (a serine protease) and of a phosphatidylinositol-specific phospholipase C (PI-PLC, which cleaves GPI-anchored molecules such as CD14), on LPS-induced desensitization. The results obtained by treatment with PI-PLC or in the presence of protease inhibitors, suggested that activation of phospholipases and proteases are not involved in LPS-induced desensitization. However, trypsin treatment of macrophages abolished both LPS binding and cytokine responses. The recovery of macrophages from this trypsin-induced tolerance (restoration of TNF-alpha synthesis without reexpression of LPS-binding sites) was very different from that following LPS-induced tolerance (reexpression of LPS-binding sites without restoration of TNF-alpha synthesis). The results are consistent with the hypothesis that signaling LPS-receptors might be synthesized de novo after trypsin degradation, whereas non-signaling LPS-receptors might be internalized and recycled after preexposure to LPS.
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Affiliation(s)
- H Fahmi
- Centre National de la Recherche Scientifique, Université de Paris-Sud, Orsay, France
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Henricson BE, Manthey CL, Perera PY, Hamilton TA, Vogel SN. Dissociation of lipopolysaccharide (LPS)-inducible gene expression in murine macrophages pretreated with smooth LPS versus monophosphoryl lipid A. Infect Immun 1993; 61:2325-33. [PMID: 8388859 PMCID: PMC280852 DOI: 10.1128/iai.61.6.2325-2333.1993] [Citation(s) in RCA: 73] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
Lipopolysaccharide (LPS) and the nontoxic derivative of lipid A, monophosphoryl lipid A (MPL), were employed to assess the relationship between expression of LPS-inducible inflammatory genes and the induction of tolerance to LPS in murine macrophages. Both LPS and MPL induced expression (as assessed by increased steady-state mRNA levels) of a panel of seven "early" inflammatory genes including the tumor necrosis factor alpha (TNF-alpha), interleukin-1 beta, type 2 TNF receptor (TNFR-2), IP-10, D3, D8, and D2 genes (the last four represent LPS-inducible early genes whose functions remain unknown). In addition, LPS and MPL were both capable of inducing tolerance to LPS. The two stimuli differed in the relative concentration required to induce various outcome measures, with LPS being 100- to 1,000-fold more potent on a mass concentration basis. Characterization of the tolerant state identified three distinct categories of responsiveness. Two genes (IP-10 and D8) exhibited strong desensitization in macrophages pretreated with tolerance-inducing concentrations of either LPS or MPL. In macrophages rendered tolerant by pretreatment with LPS or MPL, a second group of inducible mRNAs (TNF-alpha, interleukin-1 beta, and D3) showed moderate suppression of response to secondary stimulation by LPS. The third category of inducible genes (TNFR-2 and D2) showed increased expression in macrophages pretreated with tolerance-inducing concentrations of either LPS or MPL. All of the LPS-inducible genes examined exhibited modest superinduction with less than tolerance-inducing concentrations of either stimulus, suggesting a priming effect of these adjuvants at low concentration. The differential behavior of the members of this panel of endotoxin-responsive genes thus offers insight into molecular events associated with acquisition of transient tolerance to LPS.
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Affiliation(s)
- B E Henricson
- Department of Microbiology, Uniformed Services University of the Health Sciences, Bethesda, Maryland 20814
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Henricson BE, Neta R, Vogel SN. An interleukin-1 receptor antagonist blocks lipopolysaccharide-induced colony-stimulating factor production and early endotoxin tolerance. Infect Immun 1991; 59:1188-91. [PMID: 1825485 PMCID: PMC258388 DOI: 10.1128/iai.59.3.1188-1191.1991] [Citation(s) in RCA: 67] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
In this report, administration of a recombinant interleukin-1 receptor antagonist protein to mice was found to inhibit induction of colony-stimulating factor as well as induction of early endotoxin tolerance by lipopolysaccharide. These findings provide direct evidence that interleukin-1 is an intermediate in these two lipopolysaccharide-induced phenomena.
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Affiliation(s)
- B E Henricson
- Department of Microbiology, Uniformed Services University of the Health Sciences, Bethesda, Maryland
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Henricson BE, Benjamin WR, Vogel SN. Differential cytokine induction by doses of lipopolysaccharide and monophosphoryl lipid A that result in equivalent early endotoxin tolerance. Infect Immun 1990; 58:2429-37. [PMID: 1695201 PMCID: PMC258837 DOI: 10.1128/iai.58.8.2429-2437.1990] [Citation(s) in RCA: 95] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
The phenomenon of early endotoxin tolerance, which is induced by sublethal injection of lipopolysaccharide (LPS), results in a protracted period of hyporesponsiveness that is most profound at 3 to 4 days after injection and is marked by reduced cytokine production after a challenge injection of LPS. Early endotoxin tolerance is also induced by the nontoxic LPS derivative monophosphoryl lipid A (MPL), although much more of the monophosphoryl derivative is required to produce a state of tolerance equivalent to that evoked by LPS. In this study, equivalent tolerance-inducing doses of LPS and MPL were tested, and the levels of cytokines induced by LPS and MPL were compared. Although induced levels of colony-stimulating factor were comparable following doses of LPS and MPL that elicited an equivalent state of early endotoxin tolerance, levels of tumor necrosis factor, interleukin-6, and interferon were significantly lower in MPL-injected animals. These results suggest that the lowered toxicity of MPL may be related to its elicitation of significantly lower levels of potentially toxic intermediaries such as tumor necrosis factor, interferon, and interleukin-6.
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Affiliation(s)
- B E Henricson
- Department of Microbiology, Uniformed Services University of the Health Sciences, Bethesda, Maryland 20814
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Affiliation(s)
- R Burrell
- Department of Microbiology and Immunology, West Virginia, University Health Sciences Center, Morgantown
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Lavoie JP, Madigan JE, Cullor JS, Powell WE. Haemodynamic, pathological, haematological and behavioural changes during endotoxin infusion in equine neonates. Equine Vet J 1990; 22:23-9. [PMID: 2404754 DOI: 10.1111/j.2042-3306.1990.tb04198.x] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The purpose of this study was to evaluate the effects of experimentally induced sublethal endotoxaemia in equine neonates. Four foals, between two and five days of age, were infused intravenously with 0.5 microgram/kg bodyweight of Salmonella typhimurium endotoxin (LPS) over a 5 h period. A four-day-old and a five-day-old foal, similarly infused with sterile isotonic saline, served as controls. Clinical signs were monitored, blood samples obtained for evaluation of selected haematological and biochemical parameters; and haemodynamic parameters were recorded hourly during the infusion, as well as 6 and 24 h post infusion. Depression, anorexia, increased rectal temperature, leucopenia followed by leucocytosis, hypoglycaemia, increased prothrombin time, partial thromboplastin time (APTT), pulmonary artery pressure, pulmonary artery wedge pressure, right atrial pressure, pulmonary and systemic vascular resistance and mild hypoxaemia were consistent findings in the foals receiving endotoxin. There was marked variation over time in the above parameters, during the infusion. Shock was not induced, and the foals appeared to be healthy shortly after the infusion was discontinued. The return to baseline values of body temperature (3 of 4 foals), APTT (1 of 4 foals) and neutrophil count (2 of 4 foals), during endotoxin infusion, suggests induction of early tolerance. The control foals remained alert and the temperature, prothrombin time and fibrinogen remained stable during the study. Hyperglycaemia, transient increased APTT and variations in selected haemodynamic parameters were recorded in the control foals during the infusion.
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Affiliation(s)
- J P Lavoie
- Veterinary Medical Teaching Hospital, Department of Medicine, University of California, Davis 95616
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Vogel SN, Kaufman EN, Tate MD, Neta R. Recombinant interleukin-1 alpha and recombinant tumor necrosis factor alpha synergize in vivo to induce early endotoxin tolerance and associated hematopoietic changes. Infect Immun 1988; 56:2650-7. [PMID: 3262089 PMCID: PMC259625 DOI: 10.1128/iai.56.10.2650-2657.1988] [Citation(s) in RCA: 57] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
Endotoxin, the lipopolysaccharide (LPS) derived from gram-negative bacteria, invokes a wide range of responses in susceptible hosts. It is known that virtually all responses to LPS are mediated by the action of macrophage-derived cytokines (such as interleukin-1 [IL-1], tumor necrosis factor [TNF], and others) which are produced principally by macrophages and maximally within several hours of LPS administration. One manifestation of LPS administration which is not well understood is the phenomenon of "early endotoxin tolerance." In response to a single sublethal injection of LPS, experimental animals become refractory to challenge with a homologous or heterologous LPS preparation 3 to 4 days later. Animals rendered tolerant exhibit mitigated toxicity and a reduced capacity to produce circulating cytokines (i.e., colony-stimulating factor or interferon) in response to the challenge LPS injection. Previous studies have also shown that this state of transient, acquired hyporesponsiveness to LPS is accompanied by a marked increase in the size of cells in the bone marrow which are enriched in numbers of macrophage progenitors. In this study, we examined the capacity of recombinant IL-1 or recombinant TNF or both to induce early endotoxin tolerance and its associated hematopoietic changes. Neither cytokine alone was able to mimic LPS for induction of tolerance. Combined administration of recombinant IL-1 and recombinant TNF doses which were not toxic when administered individually led to synergistic toxicity (as assessed by death or weight loss). However, within a nontoxic range, the two cytokines synergized to induce a significant reduction in the capacity to produce colony-stimulating factor in response to LPS, as well as the characteristic increase in bone marrow cell size and macrophage progenitors shown previously to be associated with LPS-induced tolerance.
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Affiliation(s)
- S N Vogel
- Department of Microbiology, Uniformed Services University of the Health Sciences, Bethesda, Maryland
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