Allogeneic restriction of the delayed inflammatory reaction in the rat.

Delayed-type hypersensitivity (DTH) to Listeria monocytogenes was measured in rats that were recipients of syngeneic, semisyngeneic, and allogeneic immune thoracic duct lymphocytes (TDL). DTH could be transferred only to recipients that shared at least one haplotype with the TDL donors. The restriction was expressed in an inability of sensitized lymphoblasts to localize efficiently at antigen injection sites in the pinna of the ear and peritoneal cavity. Failure of allogeneic lymphoblasts to extravasate in more than trace numbers into Listeria-antigen-induced exudates was reflected in an absence of other lymphocyte-mediated expressions of DTH. Thus, lymphocyte-dependent MCA was not detected in Listeria-antigen-induced peritoneal exudates borne by recipients of allogeneic immune TDL and blood monocytes were not recruited in increased numbers into such exudates as they were in exudates borne by syngeneic rats. But allogeneic restriction of the delayed inflammatory response to Listeria antigen was overcome, at least in part, when antigen-presenting macrophages of the same MHC type as the immune TDL donors were implanted in the peritoneal cavity. The results encourage the belief that the observed failure of immune TDL to transfer DTH to allogeneic recipients is related to the inability of sensitized donor T cells to recognize antigen displayed by allogeneic macrophages.     

Regulation of macrophage populations. I. Preferential induction of Ia-rich peritoneal exudates by immunologic stimuli

The amounts of Ia-positive and -negative macrophages were studied in peritoneal exudates of normal mice or of mice injected with various inflammatory materials, infected with Listeria monocytogenes, or injected with hemocyanin. Ia-negative macrophages predominated in exudates from normal mice or from mice given mineral oil, peptone, thioglycollate, culture media, or endotoxin. Infection with Listeria caused a very marked increase in Ia-positive macrophages. The induction of Ia-positive macrophages by Listeria inoculation resulted in great part from an immune process. The Ia-positive exudates were more readily generated in immune mice given a secondary challenge with heat-killed organisms. Furthermore, immune T cells transplanted together with heat-killed organisms into normal mice resulted in Ia-rich exudates. Injection of hemocyanin also induced Ia-rich exudates involving an immune process. We conclude that an immune reaction involving T cells regulates the Ia phenotype of the exudate macrophage population. The Ia-positive macrophages were Fc and C3 receptor positive and phagocytized latex particles.     

Conversion of human fibroblasts to tissue macrophages by the Snyder-Theilen feline sarcoma virus (ST:FeSV) is associated with the de-novo expression of IL-1 alpha, IL-1 beta, IFN-alpha, TNF-alpha, GM-CSF, and CD4.

In an earlier study, we have demonstrated the conversion of human fibroblasts (HF) to tissue macrophages (TM) by the Snyder-Theilen feline sarcoma virus (ST:(FeSV)) [1]. The present study shows that conversion of cultured HF by the ST:FeSV to TM resulted in the de-novo expression of interleukin-1 alpha, IL-1 beta, interferon-alpha, tumor necrosis factor-alpha, granulocyte-macrophage colony stimulating factor, and CD4. The conversion of HF to TM was also associated with increased expression of non-specific esterases as well as increased amount of ingested lipid material by the TM. Clonotypic and organotypic analyses of cells infected with the ST:FeSV(FeLV) showed a similar degree of conversion to TM among eleven individual clones of skin fibroblasts, and among fibroblasts obtained from eight different organs. These findings bear on the origin (heterogeneity) of TM, the nature of TM-induced cytokines, and the potential role of ST:FeSV-recruited TM during immune reactions in vivo.     

Regulatory effects of eotaxin on acute lung inflammatory injury

Eotaxin, which is a major mediator for eosinophil recruitment into lung, has regulatory effects on neutrophil-dependent acute inflammatory injury triggered by intrapulmonary deposition of IgG immune complexes in rats. In this model, eotaxin mRNA and protein were up-regulated during the inflammatory response, resulting in eotaxin protein expression in alveolar macrophages and in alveolar epithelial cells. Ab-induced blockade of eotaxin in vivo caused enhanced NF-kappaB activation in lung, substantial increases in bronchoalveolar lavage levels of macrophage inflammatory protein (MIP)-2 and cytokine-induced neutrophil chemoattractant (CINC), and increased MIP-2 and CINC mRNA expression in alveolar macrophages. In contrast, TNF-alpha levels were unaffected, and IL-10 levels fell. Under these experimental conditions, lung neutrophil accumulation was significantly increased, and vascular injury, as reflected by extravascular leak of (125)I-albumin, was enhanced. Conversely, when recombinant eotaxin was administered in the same inflammatory model of lung injury, bronchoalveolar lavage levels of MIP-2 were reduced, as was neutrophil accumulation and the intensity of lung injury. In vitro stimulation of rat alveolar macrophages with IgG immune complexes greatly increased expression of mRNA and protein for MIP-2, CINC, MIP-1alpha, MIP-1beta, TNF-alpha, and IL-1beta. In the copresence of eotaxin, the increased levels of MIP-2 and CINC mRNAs were markedly diminished, whereas MIP-1alpha, MIP-1beta, TNF-alpha, and IL-1beta expression of mRNA and protein was not affected. These data suggest that endogenous eotaxin, which is expressed during the acute lung inflammatory response, plays a regulatory role in neutrophil recruitment into lung and the ensuing inflammatory damage.     

Regulation of macrophage inflammatory protein-1 alpha expression and function by endogenous interleukin-10 in a model of acute inflammation

In this study we have determined the role of endogenous interleukin (IL)-10 on leucocyte recruitment and production of the CC chemokine macrophage inflammatory protein-1alpha (MIP-1alpha) in a murine model of acute inflammation. Intraperitoneal injection of zymosan produced a dose-dependent cellular infiltration which was concomitant with MIP-1alpha release in the lavage fluids. Release of this chemokine had a functional role since treatment of mice with a specific anti-MIP-1alpha antibody reduced both neutrophil and monocyte accumulation into the peritoneal cavity. An unexpected increase in cell influx and MIP-1alpha production was measured following depletion of resident peritoneal macrophages, as achieved by a 3-day liposome treatment. A similar result was obtained when the zymosan peritonitis response was elicited in IL-10 knock-out mice. In summary we propose a functional cross talk between endogenous IL-10 and this CC chemokine during the host inflammatory response.     

Characterization of guinea pig macrophages: I. Mobility and maturation of peritoneal cells following inflammatory stimuli

The wide spectrum of activities of macrophages may, in part, be a reflection of their different subpopulations. Sedimentation velocity was used in separate different guinea pig macrophage populations which were then compared in assays which measure some of the parameters of inflammatory responses. Normal resident, thioglycollate-induced exudates or cells elicited by ip injection of tuberculin into BCG-sensitized animals were studied. In thioglycollate exudates the small, possibly recently derived monocytes were most responsive to chemotactic agents whereas populations with high sedimentation velocity were more phagocytic, responsive to MIF and produced more LAF. By contrast, all macrophage populations or subpopulations from sensitized animals challenged with PPD were unresponsive to lymphocyte-derived chemotactic factor, endotoxin-activated serum, or to N-formyl-l-methionyl-l-phenylalanine in chemotaxis assays. In addition, macrophages from these animals did not migrate from capillary tubes in MIF assays. The lack of migration is presumably due to the action of MIF on these cells in vivo. Cells with low sedimentation velocity (predominantly lymphocytes), however, did migrate from capillary tubes. We conclude that small cells elicited by a nonspecific stimulus are probably attracted to the inflammatory site by chemotaxins and must subsequently enlarge or mature before they are able to respond to MIF, to be activated to produce LAF, or to exhibit extensive phagocytosis.     

IL-18 induces monocyte chemotactic protein-1 production in macrophages through the phosphatidylinositol 3-kinase/Akt and MEK/ERK1/2 pathways

Macrophages are activated during an inflammatory response and produce multiple inflammatory cytokines. IL-18 is one of the most important innate cytokines produced from macrophages in the early stages of the inflammatory immune response. Monocyte chemoattractant protein (MCP-1) is expressed in many inflammatory diseases such as multiple sclerosis and rheumatoid arthritis, and its expression is correlated with the severity of the disease. Both IL-18 and MCP-1 have been shown to be involved in inflammatory immune responses. However, it has been unclear whether IL-18 is involved in the induction of MCP-1. This investigation was initiated to determine whether IL-18 can induce MCP-1 production, and if so, by which signal transduction pathways. We found that IL-18 induced the production of MCP-1 in macrophages, which was IL-12-independent and was not mediated by autocrine cytokines such as IFN-gamma or TNF-alpha. We then examined signal transduction pathways involved in IL-18-induced MCP-1 production. We found that IL-18 did not activate the IkappaB kinase/NF-kappaB pathway, evidenced by no degradation of IkappaBalpha and no translocation of NF-kappaB p65 to the nucleus in IL-18-stimulated macrophages. Instead, IL-18 activated the PI3K/Akt and MEK/ERK1/2 pathways. Inhibition of either of these pathways attenuated MCP-1 production in macrophages, and inhibition of both signaling pathways resulted in the complete inhibition of MCP-1 production. On the basis of these observations, we conclude that IL-18 induces MCP-1 production through the PI3K/Akt and MEK/ERK1/2 pathways in macrophages.     

A critical role for allograft inflammatory factor-1 in the pathogenesis of rheumatoid arthritis

Rheumatoid arthritis (RA) is characterized by massive synovial proliferation, angiogenesis, subintimal infiltration of inflammatory cells and the production of cytokines such as TNF-alpha and IL-6. Allograft inflammatory factor-1 (AIF-1) has been identified in chronic rejection of rat cardiac allografts as well as tissue inflammation in various autoimmune diseases. AIF-1 is thought to play an important role in chronic immune inflammatory processes, especially those involving macrophages. In the current work, we examined the expression of AIF-1 in synovial tissues and measured AIF-1 in synovial fluid (SF) derived from patients with either RA or osteoarthritis (OA). We also examined the proliferation of synovial cells and induction of IL-6 following AIF-1 stimulation. Immunohistochemical staining showed that AIF-1 was strongly expressed in infiltrating mononuclear cells and synovial fibroblasts in RA compared with OA. Western blot analysis and semiquantitative RT-PCR analysis demonstrated that synovial expression of AIF-1 in RA was significantly greater than the expression in OA. AIF-1 induced the proliferation of cultured synovial cells in a dose-dependent manner and increased the IL-6 production of synovial fibroblasts and PBMC. The levels of AIF-1 protein were higher in synovial fluid from patients with RA compared with patients with OA (p < 0.05). Furthermore, the concentration of AIF-1 significantly correlated with the IL-6 concentration (r = 0.618, p < 0.01). These findings suggest that AIF-1 is closely associated with the pathogenesis of RA and is a novel member of the cytokine network involved in the immunological processes underlying RA.     

Human primary keratinocytes show restricted ability to up-regulate suppressor of cytokine signaling (SOCS)3 protein compared with autologous macrophages

Suppressor of cytokine signaling (SOCS)3 belongs to a family of proteins that are known to exert important functions as inducible feedback inhibitors and are crucial for the balance of immune responses. There is evidence for a deregulated immune response in chronic inflammatory skin diseases. Thus, it was the aim of this study to investigate the regulation of SOCS proteins involved in intracellular signaling pathways occurring during inflammatory skin diseases and analyze their impact on the course of inflammatory responses. Because we and others have previously described that the cytokine IL-27 has an important impact on the chronic manifestation of inflammatory skin diseases, we focused here on the signaling induced by IL-27 in human primary keratinocytes compared with autologous blood-derived macrophages. Here, we demonstrate that SOCS3 is critically involved in regulating the cell-specific response to IL-27. SOCS3 was found to be significantly up-regulated by IL-27 in macrophages but not in keratinocytes. Other STAT3-activating cytokines investigated, including IL-6, IL-22, and oncostatin M, also failed to up-regulate SOCS3 in keratinocytes. Lack of SOCS3 up-regulation in skin epithelial cells was accompanied by prolonged STAT1 and STAT3 phosphorylation and enhanced CXCL10 production upon IL-27 stimulation compared with macrophages. Overexpression of SOCS3 in keratinocytes significantly diminished this enhanced CXCL10 production in response to IL-27. We conclude from our data that keratinocytes have a cell type-specific impaired capacity to up-regulate SOCS3 which may crucially determine the course of chronic inflammatory skin diseases.     

Participation of heme oxygenase-1 in a model of acute inflammation

In this study, the role of heme oxygenase-1 (HO-1) in the inflammatory response elicited by zymosan in the mouse air pouch model has been examined. This response is characterized by a time-dependent increase in HO-1 expression in the leukocytes migrating into the exudates. At 24-48 h maximal HO-1 expression was accompanied by reduced cyclooxygenase-2 (COX-2) and nitric oxide synthase-2 (NOS-2) expression as well as low levels of inflammatory mediators. Hemin administration into the air pouch caused an elevation of HO-1 protein and bilirubin levels induced by zymosan with inhibition of COX-2 expression. In mouse peritoneal macrophages from hemin-injected mice, we also observed an increased expression of HO-1 with inhibition of COX-2 expression and prostaglandin E(2) (PGE(2)) levels. Our data suggest an anti-inflammatory role for HO-1 in the response induced by this phagocytic stimulus.     

Immunity to Haemonchus contortus and the cellular response to helminth antigens in the mammary gland of non-lactating sheep.

Cellular exudates induced by infusion with helminth antigens were examined in non-lactating mammary glands of ewes immune to infection with the abomasal nematode, Haemonchus contortus. Secondary immunological responsiveness was expressed in two ways. Firstly, antigens from adult H. contortus elicited larger eosinophil-rich cellular exudates in immune compared to non-immune ewes. In this situation, secondary responsiveness in the mammary gland must have been generated through abomasal infection with the parasite. Secondly, repeated infusion with the antigens from adult H. contortus increased the size of cellular exudates in both immune and non-immune ewes. Eosinophils predominated but numbers of macrophages and lymphocytes were also increased. In this second situation, secondary responsiveness must have been either supplemented in immune ewes or derived completely in non-immune ewes by contact with helminth antigens through the mammary gland. The helminth antigens which induce eosinophil exudates in the mammary gland may not be potently protective against H. contortus. Furthermore, eosinophil exudation may not be an in vivo correlate of immunity which is directly useful for discriminating protective antigens and applicable to vaccine development. Infusion with antigens from adult forms of either H. contortus or Trichostrongylus colubriformis elicited cellular exudates equally well in immune ewes primed by infusion with H. contortus adult antigens 7 days beforehand. In addition, antigens from infective larvae of H. contortus elicited cellular exudates more potently than antigens from adult worms. However, vaccination with irradiated larvae has shown that species-specific protective immunity for H. contortus is stronger than cross-protective immunity conferred by T. colubriformis.(ABSTRACT TRUNCATED AT 250 WORDS)     

Dietary supplementation with high dose of epigallocatechin-3-gallate promotes inflammatory response in mice

Epigallocatechin-3-gallate (EGCG) from green tea has been indicated to have anti-inflammatory activity. However, most of the evidence is in vitro studies in which EGCG is often added at levels unachievable by oral intake. With few exceptions, in vivo studies along this line have been conducted in animal models of diseases, and the results are inconclusive. In this study, we fed C57BL/6 mice a diet containing 0%, 0.15%, 0.3% or 1% (w/w) EGCG for 6 weeks. Contrary to the assumption that EGCG would reduce inflammatory response, mice fed 0.15% and 0.3% EGCG diet exhibited no change while those fed 1% EGCG diet produced more proinflammatory cytokines tumor necrosis factor-α, interleukin (IL)-6, and IL-1β and lipid inflammatory mediator prostaglandin E(2) in their splenocytes and macrophages (MΦ) and less IL-4 in splenocytes. Spleens from the mice fed 1% EGCG diet also had higher proportions of regulatory T cells, MΦ, natural killer (NK) cells and NKT cells compared to those from mice fed the other diets. These results suggest that high intake of EGCG may induce a proinflammatory response, and this change may be associated with a disturbed homeostasis of immune cells involving changes in both function and number of specific immune cell populations. While the mechanisms and clinical significance for this effect of EGCG remain to be investigated further, these data suggest the need for defining accurate EGCG dose limits to induce an anti-inflammatory effect since current data indicate that higher doses would produce an inflammatory response.     

IL-8 as antibody therapeutic target in inflammatory diseases: reduction of clinical activity in palmoplantar pustulosis

IL-8 is a chemokine that has been implicated in a number of inflammatory diseases involving neutrophil activation. HuMab 10F8 is a novel fully human mAb against IL-8, which binds a discontinuous epitope on IL-8 overlapping the receptor binding site, and which effectively neutralizes IL-8-dependent human neutrophil activation and migration. We investigated whether interference in the cytokine network by HuMab 10F8 might benefit patients suffering from palmoplantar pustulosis, a chronic inflammatory skin disease. Treatment of patients with HuMab 10F8 was well tolerated and significantly reduced clinical disease activity at all five endpoints, which included a >or=50% reduction in the formation of fresh pustules. IL-8 neutralization was monitored at the site of inflammation by assessing exudates of palmoplantar pustulosis lesions. HuMab 10F8 sequestered IL-8 in situ, as observed by rapid dose-dependent decreases of IL-8 concentrations immediately following Ab infusion. These data demonstrate a critical role for IL-8 in the pathophysiology of palmoplantar pustulosis. HuMab 10F8 is capable of interrupting IL-8 activity in vivo and represents a candidate for treatment of inflammatory diseases and other pathological conditions associated with IL-8 overproduction.     

Host response to Helicobacter pylori infection before initiation of the adaptive immune response

Helicobacter pylori persistently colonizes the human stomach. In this study, immune responses to H. pylori that occur in the early stages of infection were investigated. Within the first 2 days after orogastric infection of mice with H. pylori, there was a transient infiltration of macrophages and neutrophils into the glandular stomach. By day 10 postinfection, the numbers of macrophages and neutrophils decreased to baseline levels. By 3 weeks postinfection, an adaptive immune response was detected, marked by gastric infiltration of T lymphocytes, macrophages, and neutrophils, as well as increased numbers of H. pylori-specific T cells, macrophages, and dendritic cells in paragastric lymph nodes. Neutrophil-attracting and macrophage-attracting chemokines were expressed at higher levels in the stomachs of H. pylori-infected mice than in the stomachs of uninfected mice. Increased expression of TNFalpha and IFNgamma (Th1-type inflammatory cytokines) and IL-17 (a Th17-type cytokine) was detected in the stomachs of H. pylori-infected mice, but increased expression of IL-4 (a Th2-type cytokine) was not detected. These data indicate that a transient gastric inflammatory response to H. pylori occurs within the first few days after infection, before the priming of T cells and initiation of an adaptive immune response. It is speculated that inappropriate waning of the innate immune response during early stages of infection may be a factor that contributes to H. pylori persistence.     

NLRP3炎症体与炎症性疾病

炎症体是胱天蛋白酶的活化平台,并促进一些前炎症细胞因子如IL-1β、IL-18和IL-33的成熟,启动机体的先天性免疫防御功能。炎症体的激活和失调与人类先天及后天的炎症性疾病都密切相关。通过对NLRP1、NL-RP3、IPAF和AIM2炎症体调节机制的研究,可为家族性周期性自身炎症反应、痛风、II型糖尿病等的治疗提供新的靶点。主要就NLRP3炎症体的组成、分布和调节机制及与NLRP3炎症体相关的炎症性疾病进行了简要介绍。     

Specific expression of inflammatory genes in macrophage subpopulations

Macrophages serve as an effective component of innate immunity in their ability to recognize, engulf and kill potential pathogens. They also coordinate additional host responses by synthesizing a range of inflammatory mediators that can activate the adaptive immune response and establish protective immunity. Although they are a key component of mammalian defense system, macrophage activity is not always beneficial to the host. The centrality of macrophages in disease processes makes macrophage regulation a major target in the prevention, control and cure of inflammatory processes. Consequently, macrophage-restricted genes may be crucial targets for therapeutic intervention. A review is presented of the use of large-scale cDNA microarrays to compare macrophage inflammatory genes differentially expressed in two distinct macrophages populations--bone marrow derived macrophages (bmm) and inflammatory thioglycolate-elicited peritoneal macrophages (tepm)--to non-macrophage cell populations consisting of primary embryonic fibroblast and spleen non-adherent cells. Expression profiles indicate that macrophage inflammatory genes are associated with expected functional categories, such as lysosomal degradation, phagocytosis, host defense and homeostasis.     

Interleukin 6 knock-out mice are resistant to antigen-induced experimental arthritis

In order to assess the potential role of IL-6 in rheumatoid arthritis (RA), we have compared IL-6 deficient (IL-6 ko) mice and their wild-type (wt) counterpart for the capacity to develop methylated bovine serum albumin (mBSA)-induced arthritis. Our data show that IL-6 ko mice are not susceptible to antigen-induced arthritis (AIA). In fact, IL-6 ko mice treated by a standard protocol of immunization with mBSA did not develop joint swelling following intra-articular mBSA injection, nor revealed the characteristic joint lesions by histological examination. Conversely, wt mice treated according to the same protocol developed arthritis about 9 days after intra-articular injection, as detected by knee joint swelling and histological confirmation. We observed that the proliferative response of splenocytes to mBSA was impaired in ko mice following arthritis induction, as compared to the strong response observed in wt mice. Furthermore, anti-mBSA IgG levels were lower in ko mice as compared to wt mice. Finally, we show that sensitivity to AIA can be reconstituted in ko mice by subcutaneous injections of recombinant human IL-6 (rhIL-6). In addition, co-administration of IL-6 with mBSA by intra-articular injection into the joint was only partially effective in conferring sensitivity to AIA, suggesting the importance of a systemic effct for IL-6, but also that an additional role for this cytokine can be envisaged in the local inflammatory reaction during establishment of AIA.     

Soluble CD163 inhibits phorbol ester-induced lymphocyte proliferation.

CD163 is a member of the scavenger receptor cysteine-rich family which is expressed exclusively on human monocytes and macrophages. Upon an inflammatory stimulus the protein is shed rapidly from the membranes' surface. CD163 expression is significantly upregulated by glucocorticoids and IL-10. While the membrane-bound form of CD163 was recently identified as scavenger receptor for hemoglobin-haptoglobin complexes, there is no information about a possible role of the shed soluble CD163. It has been suggested earlier that CD163 plays a pivotal role in the downregulatory phase of inflammation. However, it has remained elusive so far as to how this protein might influence the inflammatory process. We have now identified a potential direct anti-inflammatory effect mediated by soluble CD163. The highly purified protein statistically significantly inhibits phorbol ester-induced human T-lymphocyte activation, thus attenuating the immune response to the inflammatory mediator.