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CXC chemokines IP-10 and mig expression and direct migration of pulmonary CD8+/CXCR3+ T cells in the lungs of patients with HIV infection and T-cell alveolitis.

The recruitment of cytotoxic T lymphocytes (CTL) is considered to be the major tool for the clearance of HIV from the lower respiratory tract. In this study we evaluated the pathophysiologic role of two lymphotactic CXC chemokines (IP-10 and Mig) in the lung of HIV-infected patients. These chemokines stimulate the directional migration of activated T cells and interact with a specific receptor (CXC receptor 3, CXCR3). Lymphocytes recovered from the bronchoalveolar lavage (BAL) of HIV-infected patients with high intensity T-cell alveolitis were CD8+ T cells expressing high levels of CXCR3 and IFN-gamma, a phenotype that is characteristic of Tc1 cells. Pulmonary T cells expressing CXCR3 exhibited a high migratory capability in response to IP-10 and Mig. Alveolar macrophages recovered from patients with T-cell alveolitis bore the IFN-gamma-inducible proteins IP-10 and Mig. A positive correlation was demonstrated between IP-10, Mig, and IL-15 expression by alveolar macrophages. Interestingly, macrophages isolated from the lung of HIV-infected patients with T-cell alveolitis secreted definite levels of CXCR3 ligands capable of inducing T-cell chemotaxis. Taken together, our data suggest that chemotactic ligands that bind CXCR3 contribute significantly to the accumulation of HIV-specific CTL in the lung.

Adult↗

Tanacetum parthenium and Salix alba (Mig-RL) combination in migraine prophylaxis: a prospective, open-label study.

BACKGROUND: Tanacetum parthenium (feverfew) has been used traditionally to treat migraine, and although its mechanism of action is not fully understood, serotonin 5-HT receptor blocking effects have been suggested. T. parthenium and Salix alba (white willow) either alone or in combination (Mig-RL) were recently shown to inhibit binding to 5-HT(2A/2C) receptors; T. parthenium failed to recognise 5-HT(1D) receptors, whereas S. alba or the combination did. It was hypothesised that S. alba in combination with T. parthenium may provide superior migraine prophylactic activity compared with T. parthenium alone. METHODS: A prospective, open-label study was performed in 12 patients diagnosed with migraine without aura. Twelve weeks' treatment with T. parthenium 300 mg plus S. alba 300 mg (Mig-RL) twice daily was administered to determine the effects of therapy on migraine attack frequency (primary efficacy criterion), intensity and duration (secondary efficacy criteria), and quality of life, together with tolerability for patients. RESULTS: Attack frequency was reduced by 57.2% at 6 weeks (p < 0.029) and by 61.7% at 12 weeks (p < 0.025) in nine of ten patients, with 70% patients having a reduction of at least 50%. Attack intensity was reduced by 38.7% at 6 weeks (p < 0.005) and by 62.6% at 12 weeks (p < 0.004) in ten of ten patients, with 70% of patients having a reduction of at least 50%. Attack duration decreased by 67.2% at 6 weeks (p < 0.001) and by 76.2% at 12 weeks (p < 0.001) in ten of ten patients. Two patients were excluded for reasons unrelated to treatment. Self-assessed general health, physical performance, memory and anxiety also improved by the end of the study. Mig-RL treatment was well tolerated and no adverse events occurred. CONCLUSION: The remarkable efficacy of Mig-RL in not only reducing the frequency of migraine attacks but also their pain intensity and duration in this trial warrants further investigation of this therapy in a double-blind, randomised, placebo-controlled investigation involving a larger patient population.

Adult↗

Primary hepatocytes from mice treated with IL-2/IL-12 produce T cell chemoattractant activity that is dependent on monokine induced by IFN-gamma (Mig) and chemokine responsive to gamma-2 (Crg-2).

The IFN-gamma-inducible proteins monokine induced by IFN-gamma (Mig) and chemokine responsive to gamma-2 (Crg-2) can contribute to IL-12-induced antiangiogenic and leukocyte-recruiting activities, but the extent to which leukocytes vs parenchymal cells in different organs contribute to the production of these molecules remains unclear. The results presented herein show that IFN-gamma-dependent induction of Mig and Crg-2 gene expression can occur in many nonlymphoid organs, and these genes are rapidly induced in purified hepatocytes isolated from mice treated with IL-2 plus IL-12, or from Hepa 1-6 hepatoma cells treated in vitro with IFN-gamma. In addition to depending on IFN-gamma, the ability of IL-12 or IL-2/IL-12 to induce Mig and Crg-2 gene expression in purified hepatocytes also is accompanied by the coordinate up-regulation of the IFN-gamma R alpha and beta-chains, in the absence of IL-12R components. Supernatants of primary hepatocytes obtained from mice treated in vivo with IL-2/IL-12 or from hepatocytes treated in vitro with IFN-gamma contain increased chemotactic activity for enriched human and mouse CD3(+) T cells, as well as mouse DX5(+) NK cells. The hepatocyte-derived chemotactic activity for mouse T cells but not NK cells was ablated by Abs specific for Mig and Crg-2. These results suggest that parenchymal cells in some organs may contribute substantially to initiation and/or amplification of inflammatory or antitumor responses.

Animals↗

The T cell-specific CXC chemokines IP-10, Mig, and I-TAC are expressed by activated human bronchial epithelial cells.

Recruitment of activated T cells to mucosal surfaces, such as the airway epithelium, is important in host defense and for the development of inflammatory diseases at these sites. We therefore asked whether the CXC chemokines IFN-induced protein of 10 kDa (IP-10), monokine induced by IFN-gamma (Mig), and IFN-inducible T-cell alpha-chemoattractant (I-TAC), which specifically chemoattract activated T cells by signaling through the chemokine receptor CXCR3, were inducible in respiratory epithelial cells. The effects of proinflammatory cytokines, including IFN-gamma (Th1-type cytokine), Th2-type cytokines (IL-4, IL-10, and IL-13), and dexamethasone were studied in normal human bronchial epithelial cells (NHBEC) and in two human respiratory epithelial cell lines, A549 and BEAS-2B. We found that IFN-gamma, but not TNF-alpha or IL-1 beta, strongly induced IP-10, Mig, and I-TAC mRNA accumulation mainly in NHBEC and that TNF-alpha and IL-1 beta synergized with IFN-gamma induction in all three cell types. High levels of IP-10 protein (> 800 ng/ml) were detected in supernatants of IFN-gamma/TNF-alpha-stimulated NHBEC. Neither dexamethasone nor Th2 cytokines modulated IP-10, Mig, or I-TAC expression. Since IFN-gamma is up-regulated in tuberculosis (TB), using in situ hybridization we studied the expression of IP-10 in the airways of TB patients and found that IP-10 mRNA was expressed in the bronchial epithelium. In addition, IP-10-positive cells obtained by bronchoalveolar lavage were significantly increased in TB patients compared with normal controls. These results show that activated bronchial epithelium is an important source of IP-10, Mig, and I-TAC, which may, in pulmonary diseases such as TB (in which IFN-gamma is highly expressed) play an important role in the recruitment of activated T cells.

Bronchi↗

T cell infiltration into class II MHC-disparate allografts and acute rejection is dependent on the IFN-gamma-induced chemokine Mig.

Direct evidence that cytokines with chemoattractant properties for leukocytes, chemokines, recruit alloantigen-primed T cells into transplanted allografts has been lacking. We present evidence that neutralization of a single chemokine inhibits T cell infiltration into class II MHC-disparate murine allografts and acute rejection. The chemokines IFN-gamma-inducible protein-10 and monokine induced by IFN-gamma (Mig) are expressed in allogeneic skin grafts during the late stages of acute rejection. Survival of class II MHC-disparate B6.H-2bm12 allografts is prolonged from day 14 to day 55 posttransplant when C57BL/6 recipients are given a short course treatment with an antiserum to Mig. This treatment also inhibits T cell and macrophage infiltration into the allografts. B6.H-2bm12 allografts are also not rejected by IFN-gamma-/- C57BL/6 recipients. Injection of Mig directly into B6.H-2bm12 grafts on IFN-gamma-deficient recipients restores T cell infiltration and rejection. Therefore, the inability of IFN-gamma-deficient recipients to reject the class II MHC-disparate allografts is due to the lack of intraallograft Mig production and alloantigen-primed T cell recruitment to the graft. These results indicate for the first time the potential utility of chemokine neutralization strategies in preventing T cell infiltration into allografts and abrogating acute rejection.

Acute Disease↗

Expression of the chemokines IP-10 and Mig in IL-10 transduced tumors.

Several laboratories have reported marked tumor inhibition when the cytokine interleukin-10 (IL-10) is overexpressed as a transgene in a variety of tumor cells. To identify critical effector molecules, we compared the expression of the chemokine crg-2, the murine homolog of human inducible protein 10 (human IP-10) in murine mammary tumors derived from the transplantation of six IL-10 expressing clones of tumor cell line 66.1, parental 66.1, or 66-neo-cells. We observed increased levels of IP-10 mRNA in all IL-10-expressing tumors examined in comparison to 66-neo. IP-10 mRNA was not detected in parental 66.1 tumors. The closely related chemokine Mig (monokine induced by interferon-gamma [IFN-gamma]) was also induced in all IL-10-expressing tumors. Studies of cultured tumor cells in vitro show that mammary epithelial tumor cells, in the absence of host elements, can express IP-10 and Mig in response to induction with either lipopolysaccharide (LPS) or IFN-gamma alone. The combination of LPS plus IFN-gamma resulted in even greater induction of IP-10 RNA. The kinetics of induction differ somewhat for the two chemokines, with IP-10 showing slower induction and less rapid decline. Because both Mig and IP-10 are chemotactic for tumor-infiltrating lymphocytes, we examined the presence of CD4+ and CD8+ lymphocytes in these tumors. Consistent with the upregulation of Mig and IP-10, we saw significantly increased numbers of CD8+ cells and a lesser increase in CD4+ cells in tumors with elevated levels of both chemokines.

Animals↗

Expression of the Chemokines IP-10 and Mig in IL-10 Transduced Tumors.

SUMMARY: Several laboratories have reported marked tumor inhibition when the cytokine interleukin-10 (IL-10) is overexpressed as a transgene in a variety of tumor cells. To identify critical effector molecules, we compared the expression of the chemokine crg-2, the murine homolog of human inducible protein 10 (human IP-10) in murine mammary tumors derived from the transplantation of six IL-10 expressing clones of tumor cell line 66.1, parental 66.1, or 66-neo-cells. We observed increased levels of IP-10 mRNA in all IL-10-expressing tumors examined in comparison to 66-neo. IP-10 mRNA was not detected in parental 66.1 tumors. The closely related chemokine Mig (monokine induced by interferon-gamma [IFN-gamma]) was also induced in all IL-10-expressing tumors. Studies of cultured tumor cells in vitro show that mammary epithelial tumor cells, in the absence of host elements, can express IP-10 and Mig in response to induction with either lipopolysaccharide (LPS) or IFN-gamma alone. The combination of LPS plus IFN-gamma resulted in even greater induction of IP-10 RNA. The kinetics of induction differ somewhat for the two chemokines, with IP-10 showing slower induction and less rapid decline. Because both Mig and IP-10 are chemotactic for tumor-infiltrating lymphocytes, we examined the presence of CD4+ and CD8+ lymphocytes in these tumors. Consistent with the upregulation of Mig and IP-10, we saw significantly increased numbers of CD8+ cells and a lesser increase in CD4+ cells in tumors with elevated levels of both chemokines.

Journal Article↗

MIG (CXCL9) chemokine gene therapy combines with antibody-cytokine fusion protein to suppress growth and dissemination of murine colon carcinoma.

The induction of a CTL response capable of eradicating disseminated tumor metastases and the establishment of a persistent tumor-protective immunity remain major goals of cancer immunotherapy. Here, we demonstrate for the first time that the combination of interleukin 2 (IL-2) targeted to the tumor microenvironment by a recombinant antibody-IL-2 fusion protein (huKS1/4-IL-2) with gene therapy by the murine chemokine MIG (CXCL9) markedly reduced s.c. tumor burden and decisively suppressed dissemination of experimental lung metastases of CT26-KSA colon carcinoma in syngeneic BALB/c mice. This combined therapy significantly prolonged the life span of these mice 3-4-fold by concurrently delivering MIG and IL-2 to the tumor site and thereby achieving chemoattraction of T cells together with their activation. The antitumor effect obtained was mediated predominantly by MHC class I antigen-restricted CD8(+) T cells with help from MHC class II antigen-restricted CD4(+) T lymphocytes. In addition, the MIG chemokine also induced angiostatic effects in the tumor vasculature. Taken together, this combination of MIG chemokine gene therapy with tumor-targeted cytokine IL-2 provides an approach for the rational design of novel cancer immunotherapy modalities.

Animals↗

Differential effect of aging on membrane immunoglobulin (mIg)-mediated endocytosis in the inductive and effector sites of the mucosal immune system.

The effect of aging on the endocytosis of anti-immunoglobulin (Ig) antibody as ligand by membrane Ig receptors (mIg) of B cells in the spleen, the mesenteric lymph nodes (MLN), and the Peyer's patches (PP) was investigated. Horse radish peroxidase (HRP) labelled (Fab')2 anti-mouse Ig specific for IgM, IgG, and IgA was used as the ligand. The rate of mIg mediated ligand endocytosis by aged B cells was significantly reduced in the PP as compared to the young group. In contrast, there were no age-related differences in the rate of mIg-mediated ligand endocytosis by B cells in the spleen and MLN. After 2 hr of incubation, about 70-80% of ligand added was internalized by splenic and MLN B cells from both young and old mice. Aged PP B cells showed significantly slower rate of ligand internalization as compared to those cells from young mice. This effect was pronounced at 30 and 60 min after incubation. Young PP B cells were found to internalize about 50% of the ligand within 30 min, while it took 60 min for aged B cells to internalize the same amount. The age-related rate of mIg-mediated endocytosis by B cells in the MLN, as opposed to a slower rate of endocytosis by B cells in the PP, emphasizes its distinct nature as a mucosal site.(ABSTRACT TRUNCATED AT 250 WORDS)

Aging↗

Mig and IP-10: CXC chemokines that target lymphocytes.

Mig and IP-10 are related members of the CXC subfamily of the chemokine family of cytokines. The murine Mig (MuMig), human IP-10, and the mouse homologue of IP-10, Crg-2, were all identified due to the dramatic inductions of their genes in monocytic cells treated with interferon-gamma (IFN-gamma). Studies using recombinant (r) human proteins show that, unlike most other CXC chemokines, rHuMig and rIP-10 have no activity on neutrophils but appear to target lymphocytes specifically. rHuMig and rIP-10 are active as chemotactic factors for stimulated, but not for resting, T cells. Studies done in vitro and in vivo have shown that rHuMig and rIP-10 share additional activities, including inhibition of neovascularization, inhibition of hematopoietic progenitor cells, and anti-tumor effects. rHuMig and rIP-10 show reciprocal desensitization on activated T cells and have been demonstrated to share a receptor, CXCR3. The genes for both MuMig and Crg-2 are highly expressed in multiple tissues during experimental viral and protozoan infections in mice, but their patterns of expression differ. This suggests that the Migs and IP-10/Crg-2 may play roles in host defense and that, despite their similar activities assayed in vitro, Mig and IP-10/Crg-2 may serve non-redundant functions in vivo.

Animals↗

The chemokine receptor CXCR3 mediates rapid and shear-resistant adhesion-induction of effector T lymphocytes by the chemokines IP10 and Mig.

Integrin-mediated adhesion to the vascular endothelium is an essential step in leukocyte diapedesis. We show that the chemokines 10-kDa inflammatory protein (IP10) and monokine induced by IFN (Mig) induce rapid and transient adhesion of human IL-2-stimulated T lymphocytes (IL-2 T cells) to immobilized integrin ligands through their receptor CXCR3, which is selectively expressed on activated T cells. Induction of adhesion by IP10 and Mig was already observed at subnanomolar concentrations and was maximal at 5-10 nM, resulting in three- to sixfold increase in adhesion of IL-2 T cells over background. No effect was seen with resting naive/memory T cells which lack CXCR3 and migration responses to IP10 and Mig. Both chemokines are produced in human umbilical vein endothelial cells (HUVEC) upon stimulation with IFN-gamma and TNF-alpha. These chemokines induce IL-2 T cell adhesion also when captured on the surface of endothelial cells. Under conditions of flow, IL-2 T cells roll and rapidly adhere to IP10/Mig-expressing HUVEC, and anti-CXCR3 mAb treatment reduces arrest and firm adhesion. This is the first study that shows chemokine-induced adhesion in activated memory/effector T cells which represent the fraction of T cells that are selectively mobilized in inflammation. The critical role of IFN-gamma as inducer of IP10/Mig production in HUVEC indicates that these chemokines are essential mediators of effector T cell recruitment to IFN-gamma-dependent pathologies.

Cell Adhesion↗

CXCR3-positive B cells found at elevated frequency in the peripheral blood of patients with MALT lymphoma are attracted by MIG and belong to the lymphoma clone.

Chemokine receptors mediate the migration of lymphocytes through binding of their ligands. CXCR3 is expressed in Th1 T cells; however, CXCR3 was recently reported in B-cell mucosa-associated lymphoid tissue (MALT)-type lymphoma and splenic marginal zone lymphoma. To investigate whether CXCR3-positive B lymphocytes in peripheral blood (PB) migrate to MALT and spleen, and whether the lymphoma clone is present in PB, we studied 16 cases of MALT lymphoma. In MALT cases, CXCR3-positive B lymphocytes in PB could migrate to MIG, the CXCR3 ligand. Immunohistochemical analysis showed that MALT lymphoma cells expressed CXCR3, whereas epithelial glands and/or stromal cells expressed MIG. In the PCR analysis for VH gene rearrangements, MALT lymphoma showed monoclonal or oligoclonal bands. In addition, in 8 of 16 MALT cases, the VH gene rearrangement of MALT lymphoma had the same bands as the CXCR3-positive B lymphocytes in PB. In 4 cases, the same clones of DNA sequences were confirmed in MALT lymphoma and CXCR3-positive B lymphocytes of PB. The findings support the theory that CXCR3-positive B lymphocytes in PB of MALT patients belong to the lymphoma clone and migrate to MIG-expressing mucosa-associated lymphoid tissue. It seemed to be associated with the dissemination of MALT lymphoma.

Adult↗

CXCR3, IP-10, and Mig are required for CD4+ T cell recruitment during the DTH response to HSV-1 yet are independent of the mechanism for viral clearance.

Sensitized CD4+ T cells play an essential role in delayed type hypersensitivity (DTH) elicited by HSV-1 antigen. As activated CD4+ T cells express CXCR3, we investigated whether this chemokine receptor was involved in their recruitment. Antibody blockade of CXCR3 suppressed DTH, whereas ear pinna swelling was not impaired in mice lacking the gene for CCR5, another frequently expressed chemokine receptor. CXCR3 ligands IP-10 and Mig were elevated at the DTH site. Their neutralization significantly reduced DTH ear swelling and CD4+ T cell influx. Furthermore, CXCR3 ligand expression was abrogated and DTH diminished in mice unable to make IFN-gamma, a potent inducer of IP-10 and Mig. Interestingly, neutralization of CXCR3 or its ligands did not compromise host resistance to virus replication. Collectively, these results suggest that in the sensitized host, CXCR3, IP-10, and Mig are required for optimal DTH responsiveness but are not essential for containing HSV-1 replication in the ear pinna.

Animals↗

mig-5/Dsh controls cell fate determination and cell migration in C. elegans.

Cell fate determination and cell migration are two essential events in the development of an organism. We identify mig-5, a Dishevelled family member, as a gene that regulates several cell fate decisions and cell migrations that are important during C. elegans embryonic and larval development. In offspring from mig-5 mutants, cell migrations are defective during hypodermal morphogenesis, QL neuroblast migration, and the gonad arm migration led by the distal tip cells (DTCs). In addition to abnormal migration, DTC fate is affected, resulting in either an absent or an extra DTC. The cell fates of the anchor cell in hermaphrodites and the linker cells in the male gonad are also defective, often resulting in the cells adopting the fates of their sister lineage. Moreover, 2 degrees vulval precursor cells occasionally adopt the 3 degrees vulval cell fate, resulting in a deformed vulva, and the P12 hypodermal precursor often differentiates into a second P11 cell. These defects demonstrate that MIG-5 is essential in determining proper cell fate and cell migration throughout C. elegans development.

Adaptor Proteins, Signal Transducing↗

Expression of the interferon-gamma-inducible chemokines IP-10 and Mig and their receptor, CXCR3, in multiple sclerosis lesions.

The recruitment of leucocytes to sites of inflammation is an important feature of multiple sclerosis (MS) pathology. Chemokines are involved in the activation and specific directional migration of monocytes and T-lymphocytes to sites of inflammation. Using immunocytochemistry, the expression of the alpha-chemokines, interferon (IFN)-gamma-inducible protein-10 (IP-10) and monokine induced by IFN-gamma (Mig), and their receptor CXCR3 have been examined in post-mortem central nervous system (CNS) tissue from MS cases at different stages of lesion development. In actively demyelinating lesions both IP-10 and Mig protein were predominantly expressed by macrophages within the plaque and by reactive astrocytes in the surrounding parenchyma. CXCR3 was expressed by T cells and by astrocytes within the plaque. Interferon-gamma may stimulate glial cells to express IP-10 and Mig, which continue the local inflammatory response by selectively recruiting activated T-lymphocytes into the CNS.

Adult↗

The CXCR3 activating chemokines IP-10, Mig, and IP-9 are expressed in allergic but not in irritant patch test reactions.

Differentiation between allergic and irritant contact dermatitis reactions is difficult, as both inflammatory diseases are clinically, histologically, and immunohistologically very similar. Previous studies in mice revealed that the chemokine IP-10 is exclusively expressed in allergic contact dermatitis reactions. In the present study, we investigated whether the mRNA expression of IP-10 and the related CXCR3 activating chemokines, Mig and IP-9 are also differentially expressed in human allergic contact dermatitis and irritant contact dermatitis reactions. Skin biopsies from allergic (13 cases) and sodium lauryl sulfate-induced irritant patch test reactions (13 cases), obtained 1-72 h after patch testing, were studied by means of an in situ hybridization technique. Results of chemokine mRNA expression were correlated with clinical scoring, histology, and immunohistochemical data including the proportion of inflammatory cells expressing CXCR3, the receptor for IP-10, Mig, and IP-9, and ICAM-1 and HLA-DR expression on keratinocytes. IP-10, Mig, and IP-9 mRNA were detected in seven of nine allergic contact dermatitis reactions after 24-72 h, but not in sodium lauryl sulfate-induced irritant contact dermatitis reactions. ICAM-1 expression by keratinocytes was only found in allergic contact dermatitis reactions and correlated with chemokine expression. Moreover, up to 50% of the infiltrating cells in allergic contact dermatitis expressed CXCR3, in contrast to only 20% in irritant contact dermatitis reactions. In conclusion, we have demonstrated differences in chemokine expression between allergic contact dermatitis and irritant contact dermatitis reactions, which might reflect different regulatory mechanisms operating in these diseases and may be an important clue for differentiation between allergic contact dermatitis and irritant contact dermatitis reactions.

Chemokine CXCL10↗

Targeted disruption of Mig-6 in the mouse genome leads to early onset degenerative joint disease.

Degenerative joint disease, also known as osteoarthritis, is the most common joint disorder in human beings. The molecular mechanism underlying this disease is not fully understood. Here, we report that disruption of mitogen-inducible gene 6 (Mig-6) in mice by homologous recombination leads to early onset degenerative joint disease, which is revealed by simultaneous enlargement and deformity of multiple joints, degradation of articular cartilage, and the development of bony outgrowths or osteophyte formation within joint space. The osteophyte formation appears to be derived from proliferation of mesenchymal progenitor cells followed by differentiation into chondrocytes. Absence of the Rag2 gene does not rescue the joint phenotype, excluding a role for the acquired immune system in the development of this disease. Our results provide insight into the mechanism of osteoarthritis by showing that loss of Mig-6 leads to early onset of this disease, implying that this gene or its pathway is important in normal joint maintenance. Because of the striking similarity of osteoarthritis in humans and mice, the Mig-6 mutant mouse should provide a useful animal model for studying the mechanism of this disease and for testing drugs or therapies for treating osteoarthritis.

Age of Onset↗

NF-kappa B activation mediates the cross-talk between extracellular matrix and interferon-gamma (IFN-gamma) leading to enhanced monokine induced by IFN-gamma (MIG) expression in macrophages.

In intact tissue, the extracellular matrix (ECM) provides support and helps maintain homeostasis but is considered biologically inert. In the setting of inflammation, not only is the ECM the target of inflammation, but its breakdown products modulate the magnitude and quality of an immune response. Fragments of the ECM component hyaluronan (HA) induce macrophage expression of chemokines, cytokines, and growth factors as well greatly enhance IFN-gamma-induced MIG expression. In this report, we demonstrate that the synergistic induction of MIG by HA and IFN-gamma occurs at the level of transcription via NF-kappaB. Using electrophoretic mobility shift assays and reporter assays, we have identified two NF-kappaB sites proximal to the IFN-gamma-responsive element-1 (gammaRE-1) that mediate this effect. Interestingly, our experiments also revealed a critical role for NF-kappaB in mediating IFN-gamma-induced MIG expression independent of HA. These data emphasize the ability of "degraded self" to activate/modify immune responses through the NF-kappaB pathway.

Animals↗