1
|
Chen W, Chen S, Zhao L, Zhang M, Geng H, Dong C, Li R. Effects of real-ambient PM 2.5 exposure plus lipopolysaccharide on multiple organ damage in mice. Hum Exp Toxicol 2022; 41:9603271211061505. [PMID: 35098763 DOI: 10.1177/09603271211061505] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Background: The toxicological effects of fine particulate matter (PM2.5) on the cardiopulmonary and nervous systems have been studied widely, whereas the study of PM2.5 on systemic toxicity is not in-depth enough. Lipopolysaccharide (LPS) can cause multiple organ damage. The combined effects of co-exposure of PM2.5 plus LPS on the stomach, spleen, intestine, and kidney are still unclear. Purpose: This study was aimed to explore the toxicological effects of co-exposure of PM2.5 and LPS on the different organs of mice. Research Design and Study Sample Using a real-ambient PM2.5 exposure system and an intraperitoneal LPS injection mouse model, we investigated multiple organ damage effects on male BALB/c mice after co-exposure of PM2.5 plus LPS for 23 weeks in Linfen, a city with a high PM2.5 concentration in China. Data Collection: Eosin-hematoxylin staining, ELISA and the biochemical assay analysed the toxicological effects. Results: The pathological tissue injury on the four organs above appeared in mice co-exposed to PM2.5 plus LPS, accompanied by the body weight and stomach organ coefficient abnormality, and significant elevation of pro-inflammatory cytokines levels, oxidative stress in the spleen and kidney, and levels of kidney injury molecule (KIM-1) increase in the kidney. There were tissue differences in the pathological damage and toxicological effects on mice after co-exposure, in which the spleen and kidney were more sensitive to pollutants. In the PM2.5 + LPS group, the superoxide dismutase inhibition and catalase (CAT) activity promotion in the kidney or spleen of mice were significant relative to the PM2.5 group; the CAT and interleukin-6 (IL-6) levels in the spleen were raised considerably compared with the LPS group. Conclusions: These findings suggested the severity and sensitivity of multiple organ injuries in mice in response to PM2.5 plus LPS.
Collapse
Affiliation(s)
- Wenqi Chen
- Institute of Environmental Science, 12441Shanxi University, Taiyuan, China
| | - Shanshan Chen
- Institute of Environmental Science, 12441Shanxi University, Taiyuan, China
| | - Lifang Zhao
- Institute of Environmental Science, 12441Shanxi University, Taiyuan, China
| | - Mei Zhang
- Institute of Environmental Science, 12441Shanxi University, Taiyuan, China
| | - Hong Geng
- Institute of Environmental Science, 12441Shanxi University, Taiyuan, China
| | - Chuan Dong
- Institute of Environmental Science, 12441Shanxi University, Taiyuan, China
| | - Ruijin Li
- Institute of Environmental Science, 12441Shanxi University, Taiyuan, China
| |
Collapse
|
2
|
Piktel E, Wnorowska U, Cieśluk M, Deptuła P, Prasad SV, Król G, Durnaś B, Namiot A, Markiewicz KH, Niemirowicz-Laskowska K, Wilczewska AZ, Janmey PA, Reszeć J, Bucki R. Recombinant Human Plasma Gelsolin Stimulates Phagocytosis while Diminishing Excessive Inflammatory Responses in Mice with Pseudomonas aeruginosa Sepsis. Int J Mol Sci 2020; 21:ijms21072551. [PMID: 32272559 PMCID: PMC7177774 DOI: 10.3390/ijms21072551] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2020] [Revised: 03/29/2020] [Accepted: 04/03/2020] [Indexed: 12/22/2022] Open
Abstract
Plasma gelsolin (pGSN) is a highly conserved abundant circulating protein, characterized by diverse immunomodulatory activities including macrophage activation and the ability to neutralize pro-inflammatory molecules produced by the host and pathogen. Using a murine model of Gram-negative sepsis initiated by the peritoneal instillation of Pseudomonas aeruginosa Xen 5, we observed a decrease in the tissue uptake of IRDye®800CW 2-deoxyglucose, an indicator of inflammation, and a decrease in bacterial growth from ascitic fluid in mice treated with intravenous recombinant human plasma gelsolin (pGSN) compared to the control vehicle. Pretreatment of the murine macrophage line RAW264.7 with pGSN, followed by addition of Pseudomonas aeruginosa Xen 5, resulted in a dose-dependent increase in the proportion of macrophages with internalized bacteria. This increased uptake was less pronounced when cells were pretreated with pGSN and then centrifuged to remove unbound pGSN before addition of bacteria to macrophages. These observations suggest that recombinant plasma gelsolin can modulate the inflammatory response while at the same time augmenting host antibacterial activity.
Collapse
Affiliation(s)
- Ewelina Piktel
- Department of Medical Microbiology and Nanobiomedical Engineering, Medical University of Bialystok, Mickiewicza 2c, 15-222 Bialystok, Poland; (E.P.); (U.W.); (M.C.); (P.D.); (S.V.P.); (K.N.-L.)
| | - Urszula Wnorowska
- Department of Medical Microbiology and Nanobiomedical Engineering, Medical University of Bialystok, Mickiewicza 2c, 15-222 Bialystok, Poland; (E.P.); (U.W.); (M.C.); (P.D.); (S.V.P.); (K.N.-L.)
| | - Mateusz Cieśluk
- Department of Medical Microbiology and Nanobiomedical Engineering, Medical University of Bialystok, Mickiewicza 2c, 15-222 Bialystok, Poland; (E.P.); (U.W.); (M.C.); (P.D.); (S.V.P.); (K.N.-L.)
| | - Piotr Deptuła
- Department of Medical Microbiology and Nanobiomedical Engineering, Medical University of Bialystok, Mickiewicza 2c, 15-222 Bialystok, Poland; (E.P.); (U.W.); (M.C.); (P.D.); (S.V.P.); (K.N.-L.)
| | - Suhanya V. Prasad
- Department of Medical Microbiology and Nanobiomedical Engineering, Medical University of Bialystok, Mickiewicza 2c, 15-222 Bialystok, Poland; (E.P.); (U.W.); (M.C.); (P.D.); (S.V.P.); (K.N.-L.)
| | - Grzegorz Król
- Department of Microbiology and Immunology, the Faculty of Medicine and Health Sciences of the Jan Kochanowski University in Kielce, Stefana Żeromskiego 5, 25-001 Kielce, Poland; (G.K.); (B.D.)
| | - Bonita Durnaś
- Department of Microbiology and Immunology, the Faculty of Medicine and Health Sciences of the Jan Kochanowski University in Kielce, Stefana Żeromskiego 5, 25-001 Kielce, Poland; (G.K.); (B.D.)
| | - Andrzej Namiot
- Department of Anatomy, Medical University of Bialystok, Mickiewicza 2b, 15-222 Bialystok, Poland;
| | - Karolina H. Markiewicz
- Institute of Chemistry, University of Białystok, Ciołkowskiego 1K, 15-245 Bialystok, Poland; (K.H.M.); (A.Z.W.)
| | - Katarzyna Niemirowicz-Laskowska
- Department of Medical Microbiology and Nanobiomedical Engineering, Medical University of Bialystok, Mickiewicza 2c, 15-222 Bialystok, Poland; (E.P.); (U.W.); (M.C.); (P.D.); (S.V.P.); (K.N.-L.)
| | - Agnieszka Z. Wilczewska
- Institute of Chemistry, University of Białystok, Ciołkowskiego 1K, 15-245 Bialystok, Poland; (K.H.M.); (A.Z.W.)
| | - Paul A. Janmey
- Institute for Medicine and Engineering, University of Pennsylvania, 3340 Smith Walk, Philadelphia, PA 19104, USA;
| | - Joanna Reszeć
- Department of Pathology, Medical University of Bialystok, Waszyngtona 13, 15-269 Bialystok, Poland;
| | - Robert Bucki
- Department of Medical Microbiology and Nanobiomedical Engineering, Medical University of Bialystok, Mickiewicza 2c, 15-222 Bialystok, Poland; (E.P.); (U.W.); (M.C.); (P.D.); (S.V.P.); (K.N.-L.)
- Department of Microbiology and Immunology, the Faculty of Medicine and Health Sciences of the Jan Kochanowski University in Kielce, Stefana Żeromskiego 5, 25-001 Kielce, Poland; (G.K.); (B.D.)
- Correspondence: ; Tel.: +48-748-54-93
| |
Collapse
|
3
|
Taddonio MA, Dolgachev V, Bosmann M, Ward PA, Su G, Wang SC, Hemmila MR. Influence of lipopolysaccharide-binding protein on pulmonary inflammation in gram-negative pneumonia. Shock 2015; 43:612-9. [PMID: 25643011 PMCID: PMC4433570 DOI: 10.1097/shk.0000000000000349] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Lipopolysaccharide-binding protein (LBP) is upregulated as part of the acute-phase response. Lipopolysaccharide-binding protein has a known multifunctional role in potentiating the recognition, clearance, and killing of gram-negative bacteria. In a Klebsiella pneumonia model, we previously demonstrated that LBP gene-deficient mice (LBP-/-) mice experience increased mortality when compared with wild-type (Wt) mice (98% vs. 59%). We hypothesize that LBP is essential to bacterial clearance from the lung, and its absence leads to alteration of the pulmonary inflammatory response to pneumonia. Twelve- to 16-week-old female C57Bl/6 Wt mice and age-matched LBP-/- mice were administered 1 × 10(3) colony-forming units of Klebsiella pneumoniae by intratracheal injection. Animals were euthanized at 6, 12, 24, or 36 h after inoculation. Lung tissue and bronchoalveolar lavage samples were obtained. Lung homogenate samples were assayed to determine quantitative bacterial load per whole lung, proinflammatory cytokine concentrations, myeloperoxidase activity, and assessment of pulmonary leukocyte populations. In vitro production of inflammatory mediators were also assayed after LPS stimulation of peritoneal macrophages isolated from Wt, Toll-like receptor 4 (TLR4)-deficient, and LBP-/- mice. The LBP-/- mice demonstrated significantly elevated levels of bacteria in the lung at 24 and 36 h when compared with Wt controls. The average lung levels of proinflammatory cytokines interleukin-1β (IL-1β), IL-6, keratinocyte-derived chemokine, and macrophage-inflammatory protein-2 were greater in the LBP mice and remained elevated longer when compared with those in the Wt mice. Myeloperoxidase activity, an indicator of neutrophil content, was significantly increased at time 36 h in the LBP mice. After in vitro stimulation of peritoneal macrophages with LPS, production of IL-1β, IL-6, IL-10, keratinocyte-derived chemokine, and macrophage-inflammatory protein-1α were suppressed in LBP and TLR4-deficient mice compared with that in Wt. Absence of a functional LBP-/- gene results in diminished clearance of gram-negative bacteria from the pulmonary system. Failure to recognize and clear gram-negative bacteria via the LBP/TLR4 axis results in an initial delayed inflammatory response. This delay in LBP-/- mice is followed by excessive amplification and prolonged elevation of proinflammatory mediators and neutrophil sequestration within the lungs.
Collapse
Affiliation(s)
- Michael A. Taddonio
- Department of Surgery, University of Michigan Medical School, Ann Arbor, Michigan
| | - Vladislav Dolgachev
- Department of Surgery, University of Michigan Medical School, Ann Arbor, Michigan
| | - Markus Bosmann
- Center for Thrombosis and Hemostasis, University Medical Center Mainz, Mainz, Germany
| | - Peter A. Ward
- Department of Pathology, University of Michigan Medical School, Ann Arbor, Michigan
| | - Grace Su
- Department of Internal Medicine, University of Michigan Medical School, Ann Arbor, Michigan
| | - Stewart C. Wang
- Department of Surgery, University of Michigan Medical School, Ann Arbor, Michigan
| | - Mark R. Hemmila
- Department of Surgery, University of Michigan Medical School, Ann Arbor, Michigan
| |
Collapse
|
4
|
Liu A, Weiss S, Fang H, Claus RA, Rödel J, Dirsch O, Dahmen U. Lipopolysaccharide-Binding Protein (LBP) Blockade Augments the Protective Effect of Granulocyte Colony-Stimulating Factor (G-CSF) in a Rat Sepsis Model. Shock 2015; 43:497-503. [DOI: 10.1097/shk.0000000000000338] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
|
5
|
Fu GH, Liu F, Xia JH, Yue GH. The LBP gene and its association with resistance to Aeromonas hydrophila in tilapia. Int J Mol Sci 2014; 15:22028-41. [PMID: 25470022 PMCID: PMC4284692 DOI: 10.3390/ijms151222028] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2014] [Revised: 11/17/2014] [Accepted: 11/24/2014] [Indexed: 01/04/2023] Open
Abstract
Resistance to pathogens is important for the sustainability and profitability of food fish production. In immune-related genes, the lipopolysaccharide-binding protein (LBP) gene is an important mediator of the inflammatory reaction. We analyzed the cDNA and genomic structure of the LBP gene in tilapia. The full-length cDNA (1901 bp) of the gene contained a 1416 bp open reading frame, encoding 471 amino acid residues. Its genomic sequence was 5577 bp, comprising 15 exons and 14 introns. Under normal conditions, the gene was constitutively expressed in all examined tissues. The highest expression was detected in intestine and kidney. We examined the responses of the gene to challenges with two bacterial pathogens Streptcoccus agalactiae and Aeromonas hydrophila. The gene was significantly upregulated in kidney and spleen post-infection with S. agalactiae and A. hydrophila, respectively. However, the expression profiles of the gene after the challenge with the two pathogens were different. Furthermore, we identified three SNPs in the gene. There were significant associations (p < 0.05) of two of the three SNPs with the resistance to A. hydrophila, but not with the resistance to S. agalactiae or growth performance. These results suggest that the LBP gene is involved in the acute-phase immunologic response to the bacterial infections, and the responses to the two bacterial pathogens are different. The two SNPs associated with the resistance to A. hydrophila may be useful in the selection of tilapia resistant to A. hydrophila.
Collapse
Affiliation(s)
- Gui Hong Fu
- Molecular Population Genetics & Breeding Group, Temasek Life Sciences Laboratory, 1 Research Link, National University of Singapore, Singapore 117604, Singapore.
| | - Feng Liu
- Molecular Population Genetics & Breeding Group, Temasek Life Sciences Laboratory, 1 Research Link, National University of Singapore, Singapore 117604, Singapore.
| | - Jun Hong Xia
- Molecular Population Genetics & Breeding Group, Temasek Life Sciences Laboratory, 1 Research Link, National University of Singapore, Singapore 117604, Singapore.
| | - Gen Hua Yue
- Molecular Population Genetics & Breeding Group, Temasek Life Sciences Laboratory, 1 Research Link, National University of Singapore, Singapore 117604, Singapore.
| |
Collapse
|
6
|
Lu XJ, Chu CQ, Chen Q, Chen J. A novel lipopolysaccharide-binding protein (LBP) gene from sweetfish Plecoglossus altivelis: molecular characterization and its role in the immune response of monocytes/macrophages. FISH & SHELLFISH IMMUNOLOGY 2014; 38:111-118. [PMID: 24594008 DOI: 10.1016/j.fsi.2014.02.021] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/08/2013] [Revised: 02/14/2014] [Accepted: 02/23/2014] [Indexed: 06/03/2023]
Abstract
Lipopolysaccharide-binding protein (LBP) belongs to the lipid transfer/LBP (LT-LBP) family, and plays a crucial role in the recognition of bacterial components that modulate cellular signals in phagocytic cells. Although several LBPs have been identified in teleosts, the effects of LBP homologs on teleost phagocytic cells are still obscure. Here, we report the cloning a novel full-length cDNA sequence of LBP-like protein (paLBP) gene from sweetfish, Plecoglossus altivelis. The paLBP cDNA encoded a 464 aa polypeptide, which was closest to that of rainbow smelt (Osmerus mordax). paLBP mRNA was detected mainly in the spleen, liver, and head kidney and levels dramatically increased in various tissues after Listonella anguillarum infection. In contrast to mammalian studies, paLBP mRNA could also be detected in sweetfish monocytes/macrophages. Recombinant paLBP showed LPS-binding activity and Western blot results revealed a significant increase of paLBP in the supernatant of sweetfish monocytes/macrophages challenged with L. anguillarum. Moreover, paLBP neutralization led to up-regulation of IL-1β and TNF-α mRNA as well as respiratory burst activity in sweetfish monocytes/macrophages in response to L. anguillarum or LPS challenge. Therefore, these results suggest that paLBP is an inducible acute-phase protein mediating the immune response of sweetfish monocytes/macrophages upon bacterial challenge.
Collapse
Affiliation(s)
- Xin-Jiang Lu
- Laboratory of Biochemistry and Molecular Biology, School of Marine Sciences, Ningbo University, Ningbo 315211, China
| | - Chang-Qing Chu
- Laboratory of Biochemistry and Molecular Biology, School of Marine Sciences, Ningbo University, Ningbo 315211, China
| | - Qiang Chen
- Laboratory of Biochemistry and Molecular Biology, School of Marine Sciences, Ningbo University, Ningbo 315211, China
| | - Jiong Chen
- Laboratory of Biochemistry and Molecular Biology, School of Marine Sciences, Ningbo University, Ningbo 315211, China.
| |
Collapse
|
7
|
Lin PJ, Tam YYC, Hafez I, Sandhu A, Chen S, Ciufolini MA, Nabi IR, Cullis PR. Influence of cationic lipid composition on uptake and intracellular processing of lipid nanoparticle formulations of siRNA. NANOMEDICINE-NANOTECHNOLOGY BIOLOGY AND MEDICINE 2013; 9:233-46. [DOI: 10.1016/j.nano.2012.05.019] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/08/2011] [Revised: 05/18/2012] [Accepted: 05/29/2012] [Indexed: 01/12/2023]
|
8
|
Massironi SMG, Arslanian C, Carneiro-Sampaio MMS, Pontes GN. Minimal concentration of human IgM and IgG antibodies necessary to protect mice from challenges with live O6 Escherichia coli. ACTA ACUST UNITED AC 2012; 63:193-201. [PMID: 22077222 DOI: 10.1111/j.1574-695x.2011.00841.x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
This work evaluated the ability of human anti-lipopolysaccharide O6 IgM and IgG antibodies to protect mice challenged with Escherichia coli serotype O6 : K2ac. Purified IgM-effluent, purified IgG, pools of normal human serum (NHS), or control group were injected into mice 18 h before challenges with O6 E. coli. Interleukin 6 and tumor necrosis factor alpha were quantified in the sera of test and control groups. All mice receiving purified IgM-effluent (66.6 mg L(-1) of anti-lipopolysaccharide O6 IgM antibodies) and NHS survived. Purified IgG (1.1 mg L(-1) of anti-lipopolysaccharide O6 IgG antibodies) protected 87.5% of the animals. The control group showed no protective ability. The minimal concentration of anti-lipopolysaccharide O6 IgM antibodies, able to protect 50% of the animals was 33.3 mg L(-1) of purified IgM-effluent, whereas purified IgG was able to protect 50% of the animals with only 1.1 mg L(-1) of anti-lipopolysaccharide O6 IgG antibodies. Serum from animals pretreated with purified IgM-effluent and purified IgG before challenges with lipopolysaccharide O6 did not have detectable pro-inflammatory cytokines. Hepatocytes of the control group were completely invaded by bacteria, whereas none was found in animals pretreated with purified IgM-effluent and purified IgG. Higher concentrations of anti-lipopolysaccharide O6 IgM antibodies as compared to anti-lipopolysaccharide O6 IgG antibodies were needed to protect mice from challenges with E. coli O6 serotype.
Collapse
|
9
|
|
10
|
Palmer CD, Mancuso CJ, Weiss JP, Serhan CN, Guinan EC, Levy O. 17(R)-Resolvin D1 differentially regulates TLR4-mediated responses of primary human macrophages to purified LPS and live E. coli. J Leukoc Biol 2011; 90:459-70. [PMID: 21653234 DOI: 10.1189/jlb.0311145] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Detection and clearance of bacterial infection require balanced effector and resolution signals to avoid chronic inflammation. Detection of GNB LPS by TLR4 on m induces inflammatory responses, contributing to chronic inflammation and tissue injury. LXs and Rvs are endogenous lipid mediators that enhance resolution of inflammation, and their actions on primary human m responses toward GNB are largely uncharacterized. Here, we report that LXA(4), LXB(4), and RvD1, tested at 0.1-1 μM, inhibited LPS-induced TNF production from primary human m, with ATL and 17(R)-RvD1, demonstrating potent inhibition at 0.1 μM. In addition, 17(R)-RvD1 inhibited LPS-induced primary human m production of IL-7, IL-12p70, GM-CSF, IL-8, CCL2, and MIP-1α without reducing that of IL-6 or IL-10. Remarkably, when stimulated with live Escherichia coli, m treated with 17(R)-RvD1 demonstrated increased TNF production and enhanced internalization and killing of the bacteria. 17(R)-RvD1-enhanced TNF, internalization, and killing were not evident for an lpxM mutant of E. coli expressing hypoacylated LPS with reduced inflammatory activity. Furthermore, 17(R)-RvD1-enhanced, E. coli-induced TNF production was evident in WT but not TLR4-deficient murine m. Thus, Rvs differentially modulate primary human m responses to E. coli in an LPS- and TLR4-dependent manner, such that this Rv could promote resolution of GNB/LPS-driven inflammation by reducing m proinflammatory responses to isolated LPS and increasing m responses important for clearance of infection.
Collapse
|
11
|
Preparation and identification of the lipopolysaccharide binding protein mimic epitope peptide vaccine that prevents endotoxin-induced acute lung injury in mice. Vaccine 2011; 29:4162-72. [PMID: 21473948 DOI: 10.1016/j.vaccine.2011.03.056] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2010] [Revised: 02/12/2011] [Accepted: 03/17/2011] [Indexed: 11/22/2022]
Abstract
The objectives of this study were to detect the immunogenicity of a lipopolysaccharide (LPS) binding protein (LBP) mimic epitope peptide vaccine and evaluate its effect on controlling excessive and uncontrolled inflammatory reactions in mice with acute lung injury. The vaccine was prepared by mixing self-made LBP mimic epitope multiple antigen peptide (MAP) and Freund adjuvants in a proper proportion. Healthy mice were inoculated with the vaccine and the dynamic changes of anti-MAP antibody were measured using ELISA. Anti-MAP antibody was prepared from the immune serum of the mice based on the standard antibody preparation program. Western blot assay was used to identify LBP specificity of anti-MAP antibody. Anti-MAP antibody bioactivity was analyzed using in vitro binding activity test. Following the vaccine inoculation, the mice were injected with LPS to induce acute lung injury. Anti-MAP antibody prepared was also used to immune the mice with LPS-induced acute lung injury. TNF-α and IL-1β contents in serum and lung tissue homogenate were measured using double antibody sandwiched ELISA at different time-points after LPS challenge. At 8h time-point, total white blood cell counts, polymorphonuclear leucocyte count and protein content in bronchoalveolar lavage fluid were measured and pulmonary morphological changes were evaluated. The antibody titer was gradually rising, reaching to its peak at 8th week and lasting to the tenth week. The antibody possessed strong immunogenicity, high specificity and favorable biologic activity. Whole range inoculation of LBP mimic epitope peptide vaccine or anti-MAP antibody intervention partly eliminates LPS-mediated acute lung injury. In conclusion, LBP mimic epitope peptide vaccine successfully induced highly specific antibody with high bioactivity in mice. LBP mimic epitope peptide vaccine and anti-MAP antibody inhibited excessive and uncontrolled inflammatory reactions from LPS-mediated acute lung injury in mice.
Collapse
|
12
|
Feng YK, Yang QH, Liu YS, Xu JC, Qian GS, Wang YH. The localization of two mimic epitopes of lipopolysaccharide binding protein and the preparation of their tandem multiple antigen peptide. J Immunol Methods 2010; 362:60-9. [DOI: 10.1016/j.jim.2010.09.003] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2010] [Revised: 08/20/2010] [Accepted: 09/01/2010] [Indexed: 10/19/2022]
|
13
|
Abstract
Myeloid differentiation factor-2 (MD-2) is a lipopolysaccharide (LPS)-binding protein usually coexpressed with and binding to Toll-like receptor 4 (TLR4), conferring LPS responsiveness of immune cells. MD-2 is also found as a soluble protein. Soluble MD-2 (sMD-2) levels are markedly elevated in plasma from patients with severe infections, and in other fluids from inflamed tissues. We show that sMD-2 is a type II acute-phase protein. Soluble MD-2 mRNA and protein levels are up-regulated in mouse liver after the induction of an acute-phase response. It is secreted by human hepatocytic cells and up-regulated by interleukin-6. Soluble MD-2 binds to Gram-negative but not Gram-positive bacteria, and sMD-2 secreted by hepatocytic cells is an essential cofactor for the activation of TLR4-expressing cells by Gram-negative bacteria. Soluble MD-2 opsonization of Gram-negative bacteria accelerates and enhances phagocytosis, principally by polymorphonuclear neutrophils. In summary, our results demonstrate that sMD-2 is a newly recognized type II acute-phase reactant, an opsonin for Gram-negative bacteria, and a cofactor essential for the activation of TLR4-expressing cells. This suggests that sMD-2 plays a key role in the host innate immune response to Gram-negative infections.
Collapse
|
14
|
Wolk K, Witte E, Hoffmann U, Doecke WD, Endesfelder S, Asadullah K, Sterry W, Volk HD, Wittig BM, Sabat R. IL-22 induces lipopolysaccharide-binding protein in hepatocytes: a potential systemic role of IL-22 in Crohn's disease. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2007; 178:5973-81. [PMID: 17442982 DOI: 10.4049/jimmunol.178.9.5973] [Citation(s) in RCA: 217] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Crohn's disease (CD) is a common, chronic, inflammatory bowel disease characterized by intestinal infiltration of activated immune cells and distortion of the intestinal architecture. In this study, we demonstrate that IL-22, a cytokine that is mainly produced by activated Th1 and Th17 cells, was present in high quantities in the blood of CD patients in contrast to IFN-gamma and IL-17. In a mouse colitis model, IL-22 mRNA expression was elevated predominantly in the inflamed intestine but also in the mesenteric lymph nodes. IL-22BP, the soluble receptor for IL-22, demonstrated an affinity to IL-22 that was at least 4-fold higher than its membrane-bound receptor, and its strong constitutive expression in the intestine and lymph nodes was decreased in the inflamed intestine. To investigate the possible role of systemic IL-22 in CD, we then administered IL-22 to healthy mice and found an up-regulation of LPS-binding protein (LBP) blood levels reaching concentrations known to neutralize LPS. This systemic up-regulation was associated with increased hepatic but not renal or pulmonary LBP mRNA levels. IL-22 also enhanced the secretion of LBP in human primary hepatocytes and HepG2 hepatoma cells in vitro. This increase was mainly transcriptionally regulated and synergistic with that of other LBP inducers. Finally, elevated LBP levels were detected in CD patients and the mouse colitis model. These data suggest that systemic IL-22 may contribute to the prevention of systemic inflammation provoked by LPS present in the blood of CD patients through its induction of hepatic LBP.
Collapse
Affiliation(s)
- Kerstin Wolk
- Interdisciplinary Group of Molecular Immunopathology, Dermatology/Medical Immunology, Campus Charité Mitte, University Hospital Charité, Charitéplatz 1, Berlin, Germany
| | | | | | | | | | | | | | | | | | | |
Collapse
|
15
|
Hemmila MR, Kim J, Sun JM, Cannon J, Arbabi S, Minter RM, Su GL, Remick DG, Wang SC. Gene therapy with lipopolysaccharide binding protein for gram-negative pneumonia: respiratory physiology. ACTA ACUST UNITED AC 2006; 61:598-605; discussion 605-6. [PMID: 16966994 DOI: 10.1097/01.ta.0000233763.18853.5b] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
BACKGROUND Lipopolysaccharide binding protein (LBP) plays an essential role in the pulmonary immune response to gram-negative bacterial infection. LBP knockout mice with gram-negative pneumonia have increased mortality compared with wild-type controls. This mortality difference can be abolished with systemic LBP gene therapy. We postulate that LBP knockout mice will develop derangements in lung physiology from gram-negative pneumonia and that these changes can be reversed with systemic LBP gene therapy. METHODS Twelve- to 16-week-old C57BL/6 wild-type mice and/or sex, age, matched LBP knockout mice were administered 1 x 10(3) colony-forming units/mouse of Klebsiella pneumoniae by intratracheal inoculation. Treated mice were administered 5 x 10(9) plaque-forming units of recombinant adenovirus containing either the gene for LBP or the irrelevant control protein beta-galactosidase by intravenous injection 2 days before bacterial inoculation. Respiratory physiology parameters were measured preinoculation and 24 hours postbacterial inoculation. RESULTS Administration of LBP by systemic gene therapy to LBP knockout mice improved 7-day survival from Klebsiella pneumonia to a level equivalent to wild-type mice exposed to the same dose of bacteria (42 vs. 43% survival). LBP knockout mice given the LBP gene therapy demonstrated increased 14-day survival from Klebsiella pneumonia when compared with controls treated with beta-galactosidase (28 vs. 0%, p < 0.001). LBP knockout mice developed significant differences in respiratory rate, minute ventilation, and enhanced pause (Penh), when compared with wild-type mice with Klebsiella pneumonia. These respiratory derangements were prevented with adenoviral delivery of the LBP gene before K. pneumoniae inoculation. CONCLUSIONS Gram-negative pneumonia produces measurable changes in mortality and respiratory physiology between wild-type and LBP knockout mice. These changes can be prevented in LBP knockout mice by systemic gene therapy to restore innate immunity.
Collapse
Affiliation(s)
- Mark R Hemmila
- Department of Surgery, University of Michigan Health System, Ann Arbor, Michigan 48109-0033, USA.
| | | | | | | | | | | | | | | | | |
Collapse
|
16
|
Pontes GN, Massironi SG, Arslanian C, Friedlander-Del Nero DL, Carneiro-Sampaio MMS, Nagao AT. Protective activity of the antilipopolysaccharide antibodies from human cord serum. FEMS IMMUNOLOGY AND MEDICAL MICROBIOLOGY 2006; 47:405-13. [PMID: 16872377 DOI: 10.1111/j.1574-695x.2006.00107.x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
We evaluated the ability of human maternal and cord serum antibodies to protect mice challenged with live Escherichia coli serotype O6:K2ac (E. coli O6). Mice received paired maternal or cord serum pools before a challenge with E. coli O6 to evaluate the mortality rate. All the pools were able to protect the animals challenged with bacteria except the test group from paired maternal and cord sera from preterm neonates containing less than 1.0 mg L(-1) immunoglobulin G antibody levels. In liver, spleen and mesenteric lymph nodes from the control group (phosphate-buffered saline), more than 10(2) CFU mL(-1) bacteria were found at 30 min and more than 10(5) CFU mL(-1) after 120 min. The test group showed lower bacterial counts in the organs, and no bacteria in the mesenteric lymph nodes during the evaluated period. Tumor necrosis factor alpha and interleukin 6 were undetectable in serum from animals pretreated with paired maternal and cord serum pools from full-term neonates and pools from preterm neonates containing high antibody and avidity levels. Our findings suggest that placental transfer of antilipopolysaccharide O6 immunoglobulin G antibodies to neonates has a high capacity to prevent lethal infection with E. coli O6 in a mouse protection model and that the degree of protection is determined by the concentration and avidity of these IgG antibodies.
Collapse
Affiliation(s)
- Gerlândia Neres Pontes
- Department of Immunology, Institute of Biomedical Sciences, Universidade de São Paulo, São Paulo, SP, Brazil.
| | | | | | | | | | | |
Collapse
|
17
|
Cheong R, Bergmann A, Werner SL, Regal J, Hoffmann A, Levchenko A. Transient IκB Kinase Activity Mediates Temporal NF-κB Dynamics in Response to a Wide Range of Tumor Necrosis Factor-α Doses. J Biol Chem 2006; 281:2945-50. [PMID: 16321974 DOI: 10.1074/jbc.m510085200] [Citation(s) in RCA: 108] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Dynamic properties of signaling pathways control their behavior and function. We undertook an iterative computational and experimental investigation of the dynamic properties of tumor necrosis factor (TNF)alpha-mediated activation of the transcription factor NF-kappaB. Surprisingly, we found that the temporal profile of the NF-kappaB activity is invariant to the TNFalpha dose. We reverse engineered a computational model of the signaling pathway to identify mechanisms that impart this important response characteristic, thus predicting that the IKK activity profile must transiently peak at all TNFalpha doses to generate the observed NF-kappaB dynamics. Experimental confirmation of this prediction emphasizes the importance of mechanisms that rapidly down-regulate IKK following TNFalpha activation. A refined computational model further revealed signaling characteristics that ensure robust TNFalpha-mediated cell-cell communication over considerable distances, allowing for fidelity of cellular inflammatory responses in infected tissue.
Collapse
Affiliation(s)
- Raymond Cheong
- Department of Biomedical Engineering, Johns Hopkins University, Baltimore, Maryland 21218, USA
| | | | | | | | | | | |
Collapse
|
18
|
Pontes GN, Massironi SG, Arslanian C, Palmeira P, Carneiro-Sampaio MMS, Nagao AT. Human IgG but not IgM antibodies can protect mice from the challenge with live O6 Escherichia coli. Scand J Immunol 2005; 62:353-60. [PMID: 16253122 DOI: 10.1111/j.1365-3083.2005.01669.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
We evaluated the ability of human anti-lipopolysaccharide (LPS) O6 immunoglobulin G (IgG) and IgM antibodies to protect mice challenged with Escherichia coli serotype O6:K2ac. Purified whole IgG, commercial gammaglobulin, whole IgM-effluent, pool of normal human serum (NHS), agammaglobulinaemic serum (test groups) or phosphate-buffered saline (control group) was injected into adult male 18 h before a challenge with viable O6 E. coli. The mortality rate was assessed over a period of 72 h. To determine the opsonic and phagocytic activity of the antibody isotypes, we incubated peritoneal macrophages from the control and test groups collected at different times after challenge with the live bacteria with acridine orange for fluorescent analysis. Tumour necrosis factor (TNF)-alpha and interleukin (IL)-6 were quantified in serum of both the test and control groups. All mice that received commercial gammaglobulin or NHS survived. Purified whole IgG (containing 1.1 mg/l of anti-LPS O6 IgG antibodies) protected 87.5% of the animals tested in this experiment, while whole IgM-enriched effluent with 1.5 mg/l of anti-LPS O6 IgM antibodies protected only 12.5%. The agamma serum showed no protective capacity compared with PBS (serving as control). The minimal concentration of anti-LPS O6 IgG antibodies able to protect 50% of animals was 0.137 mg/l of purified whole IgG. Whole IgM-enriched effluent showed no protective capacity independently of the concentration tested (0.048-17.0 mg/l of anti-LPS O6 IgM antibodies). Fluorescent analysis of peritoneal macrophages from animals pretreated with purified whole IgG showed no bacteria at 8 h after the challenge. By contrast, whole IgM effluent showed an increasing number of live bacteria at the same time. Mice that had received whole IgM effluent (1.5 mg/l of anti-LPS O6 IgM antibodies) before the challenge with LPS O6 presented 20.5 microg/l of IL-6 and 1.5 microg/l of TNF-alpha. Serum from animals pretreated with purified IgG did not present any detectable pro-inflammatory cytokine. Our findings suggest that IgG but not IgM antibodies protect animals from a challenge with E. coli O6 serotype.
Collapse
Affiliation(s)
- G N Pontes
- Department of Immunology, Universidade de São Paulo, Brazil.
| | | | | | | | | | | |
Collapse
|
19
|
Ren L, Leung WK, Loo TW, Jin L. Lipopolysaccharide-binding protein down-regulates the expression of interleukin-6 by human gingival fibroblast. J Periodontal Res 2005; 40:407-16. [PMID: 16105094 DOI: 10.1111/j.1600-0765.2005.00822.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
BACKGROUND Lipopolysaccharide-binding protein (LBP) participates in the interaction of lipopolysacchaide (LPS) with CD14 to modulate the expression of cytokines. Human gingival fibroblast may actively participate in LPS-induced immuno-inflammatory responses through CD14, toll-like receptor (TLR) superfamily, MD-2 and related adaptive proteins, leading to the expression of cytokines. OBJECTIVES The present in vitro study aimed to investigate the possible effect of LBP and E. coli LPS interaction on the expression of cellular LPS receptors and IL-6 by human gingival fibroblast. METHODS The mRNA expression of CD14, LBP, TLR-2, TLR-4, MD-2 and IL-6 in human gingival fibroblast explants was detected by reverse transcriptionpolymerase chain reaction (RT-PCR) in the presence or absence of E. coli LPS and recombinant human LBP (rhLBP), while IL-6 peptides were analyzed by ELISA and immunohistochemistry, respectively. RESULTS Human gingival fibroblast could constitutively express CD14, MD-2 and IL-6 mRNAs, but not TLR-2, TLR-4 and LBP mRNAs. E. coli LPS induced the messages expression of MD-2, TLR-2 and -4. The expression of both IL-6 message and peptide was up-regulated by E. coli LPS in a dose dependent manner. Whereas rhLBP could significantly down-regulate the expression of both mRNAs and peptides of CD14 and IL-6 but not MD-2 signals in the presence or absence of E. coli LPS. The up-regulated expression of TLR-2 and -4 by E. coli LPS no longer existed in the presence of rhLBP. CONCLUSIONS This study suggests that LBP may down-regulate the expression of IL-6 by human gingival fibroblast. Further studies are warranted to clarify the molecular mechanisms of LBP in regulation of cytokine expression by host cells and to elaborate the relevant clinical implications.
Collapse
Affiliation(s)
- Lei Ren
- Faculty of Dentistry, Periodontology, The University of Hong Kong, Hong Kong
| | | | | | | |
Collapse
|
20
|
Hemmila MR, Fan MH, Kim J, Sun JM, Steinstraesser L, Gong KQ, Arbabi S, Minter RM, Remick DG, Su GL, Wang SC. Improved survival in mice given systemic gene therapy in a gram negative pneumonia model. ACTA ACUST UNITED AC 2005; 58:1110-8; discussion 1118. [PMID: 15995456 DOI: 10.1097/01.ta.0000170855.37686.91] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
BACKGROUND We previously demonstrated an essential role for lipopolysaccharide binding protein (LBP) in the pulmonary immune response to Gram-negative bacterial infection. LBP knockout mice had significantly higher mortality, greater rates of bacteremia, and higher counts of viable bacteria in their lungs at sacrifice compared with wild-type controls. We postulate that systemic LBP gene therapy will reconstitute a protective innate immune response in LBP knockout mice and that overexpression of LBP in wild-type mice may offer a survival advantage. METHODS 12-16 week old female C57BL/6 wild-type mice and age matched LBP knockout mice were given 5 x 10(9) PFU of recombinant adenovirus containing either the gene for LBP or the irrelevant control protein beta-galactosidase by tail vein injection. 72 hours later each mouse was administered 1 x 10(3) CFU of Klebsiella pneumoniae by intratracheal injection. RESULTS Administration of LBP by systemic gene therapy to LBP knockout mice improved survival from Klebsiella pneumonia to a level equivalent or better than wild-type mice exposed to the same dose of bacteria (36 versus 25%). Wild-type mice given the LBP gene therapy demonstrated increased 7 day survival from Klebsiella pneumonia when compared with controls treated with beta-galactosidase (68 versus 30%, p = 0.03). CONCLUSIONS Systemic gene therapy with intravenous adenoviral vector transfer of LBP significantly improves survival in LBP knockout mice. Overexpression of LBP in wild-type mice improves survival from Klebsiella pneumonia. Raising levels of LBP in the setting of Gram-negative pneumonia may be of therapeutic benefit.
Collapse
Affiliation(s)
- Mark R Hemmila
- Department of Surgery, University of Michigan Health System, Ann Arbor, Michigan 48109-0033, USA.
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
21
|
Dixon DR, Bainbridge BW, Darveau RP. Modulation of the innate immune response within the periodontium. Periodontol 2000 2004; 35:53-74. [PMID: 15107058 DOI: 10.1111/j.0906-6713.2004.003556.x] [Citation(s) in RCA: 99] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Douglas R Dixon
- United States Army Dental Corps and Department of Periodontics and Oral Biology, School of Dentistry, University of Washington, Seattle, USA
| | | | | |
Collapse
|
22
|
Uronen-Hansson H, Steeghs L, Allen J, Dixon GLJ, Osman M, van der Ley P, Wong SYC, Callard R, Klein N. Human dendritic cell activation by Neisseria meningitidis: phagocytosis depends on expression of lipooligosaccharide (LOS) by the bacteria and is required for optimal cytokine production. Cell Microbiol 2004; 6:625-37. [PMID: 15186399 DOI: 10.1111/j.1462-5822.2004.00387.x] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
Group B Neisseria meningitidis is a human pathogen, for which a universally effective vaccine is still not available. Immune responses to bacteria are initiated by dendritic cells (DC), which internalize and process bacterial antigens for presentation to T cells. We show here that optimal IL-12 and TNF-alpha production by human monocyte derived DC in response to killed serogroup B N. meningitidis depends on physical contact and internalization of the bacteria by DC. The majority of DC producing cytokines had internalized N. meningitidis while inhibition of bacterial internalization markedly impaired IL-12 and TNF-alpha, but not IL-6 production. Internalization of N. meningitidis was shown to depend on lipooligosaccharide (LOS) expressed by the bacteria with poor internalization of LOS deficient bacteria compared to wild-type bacteria. Restoration of LOS biosynthesis in a LOS regulatory strain also restored both internalization and cytokine production and was enhanced in the presence of LPS binding protein (LBP). These results suggest that DC phagocytosis depends on expression of LOS within the bacteria and that optimal cytokine production, particularly IL-12, requires internalization of the bacteria. These findings have important implications for designing vaccines that will induce protective immune responses to group B N. meningitidis.
Collapse
|
23
|
Fan MH, Klein RD, Steinstraesser L, Merry AC, Nemzek JA, Remick DG, Wang SC, Su GL. An essential role for lipopolysaccharide-binding protein in pulmonary innate immune responses. Shock 2002; 18:248-54. [PMID: 12353926 DOI: 10.1097/00024382-200209000-00008] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Lipopolysaccharide (LPS)-binding protein (LBP) greatly facilitates LPS activation of monocytic cells through the CD14 receptor, triggering activation of innate immune responses. An acute phase protein, LBP is produced predominantly by the liver; however, we and others have shown that LBP is produced extrahepatically in multiple locations, including the lung. The importance of LBP in the lung has remained unclear. LBP may make the host more acutely sensitive to LPS and development of septic complications; alternatively, it may be protective, aiding in detection, opsonization, and killing of bacteria. Our objective was to determine the role LBP plays in local pulmonary immune defenses to bacterial challenge. LBP knockout mice and age-matched C57BL/6 wild-type controls were challenged with direct intratracheal inoculation of Klebsiella pneumoniae. We observed a significant increase in mortality, earlier onset of bacteremia, and greater pulmonary bacterial loads in LBP knockout mice compared with controls. Total lung myeloperoxidase (MPO) activity, neutrophil recruitment to the alveolar space, and levels of KC--a chemokine involved in neutrophil recruitment--in bronchoalveolar lavage (BAL) fluid and lung homogenates were found to be significantly diminished in knockout mice compared with controls. Together, our findings suggest that LBP is essential in local pulmonary innate immune responses against bacteria.
Collapse
Affiliation(s)
- Ming-Hui Fan
- Department of General Surgery, University of Michigan, Ann Arbor 48109, USA
| | | | | | | | | | | | | | | |
Collapse
|
24
|
Lazaron V, Leslie DB, Wasiluk KR, Dunn DL. Accelerated internalization and detoxification of endotoxin by anti-lipopolysaccharide antibody is an Fc receptor--mediated process. Surgery 2001; 130:192-7. [PMID: 11490348 DOI: 10.1067/msy.2001.115825] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
BACKGROUND Interaction between lipopolysaccharide (LPS), LPS-binding protein, and the CD14 receptor at the surface of LPS-responsive cells results in inflammatory cytokine release and internalization and detoxification of LPS. Monoclonal antibodies (mAbs) raised against the deep-core lipid A or the O-linked polysaccharide moieties of LPS accelerate internalization and detoxification of LPS without stimulating cytokine release. This study was conducted to test the hypothesis that the antibody-mediated internalization of LPS is an Fc receptor (FcR)--mediated process. METHODS Fluoroisothiocyanate (FITC)-conjugated Escherichia coli O111:B4 LPS was incubated with RAW 264.7 cells and allowed to internalize for 2 hours in the presence and absence of anti-LPS, anti-CD14, and isotype control mAbs, and Fab fragments from the anti-CD14, anti--Fc receptor, and control mAbs. Tumor necrosis factor--alpha (TNF-alpha) release was measured by WEHI 164 cell bioassay. FITC-LPS uptake was measured by flow cytometry. Statistical analysis was by analysis of variance and Fisher exact test. RESULTS Addition of anti-LPS antibodies resulted in a 30- to 40-fold acceleration of LPS internalization (P <.01) in agreement with previous studies. This increase was blunted by anti-CD14 and also by isotype control holo-antibody (P <.01), but not by Fab fragments from anti-CD14 or isotype control antibody. Both anti-FcR antibodies and Fab fragments blocked anti-LPS antibody--stimulated uptake of FITC-LPS. Both intact anti-CD14 holo-antibody and Fab fragments blocked TNF-alpha release (P <.01). CONCLUSIONS Clearance and detoxification of LPS are thought to be essential to the host response to endotoxin. It has been shown that antibodies to LPS accelerate its internalization by monocytic cell lines without increasing the elaboration of cytokines. We found that specific blockade of CD14 by Fab fragments could block TNF-alpha release but not alter the accelerated internalization of LPS produced by anti-LPS antibodies. In contrast, a nonspecific blockade of internalization was produced by competing antibody, which suggests a mechanistic role for the FcR. Specific blockade of FcR by either holo-antibody or Fab fragments blocked accelerated internalization, which confirms a FcR mechanism. We conclude that the accelerated internalization of LPS produced by anti-LPS antibody is an Fc receptor--mediated process. These results have significance for the development of adjuvant immunotherapy for gram-negative bacterial sepsis.
Collapse
Affiliation(s)
- V Lazaron
- Department of Surgery, University of Minnesota, Minneapolis, USA
| | | | | | | |
Collapse
|