Showing papers in "Journal of Interferon and Cytokine Research in 2000"

Macrophage migration inhibitory factor (MIF): its essential role in the immune system and cell growth.

Abstract: Macrophage migration inhibitory factor (MIF) functions as a pleiotropic protein, participating in inflammatory and immune responses MIF was originally discovered as a lymphokine involved in delayed hypersensitivity and various macrophage functions, including phagocytosis, spreading, and tumoricidal activity Recently, MIF was reevaluated as a proinflammatory cytokine and pituitary-derived hormone potentiating endotoxemia This protein is ubiquitously expressed in various organs, such as the brain and kidney Among cytokines, MIF is unique in terms of its abundant expression and storage within the cytoplasm and, further, for its counteraction against glucocorticoids MIF has unexpectedly been found to convert D-dopachrome, an enantiomer of naturally occurring L-dopachrome, to 5,6-dihydroxyindole However, its physiologic significance remains to be elucidated It was demonstrated that anti-MIF antibodies effectively suppress tumor growth and tumor-associated angiogenesis, suggesting that MIF is involved not only in inflammatory and immune responses but also in tumor cell growth At present, MIF cannot be clearly categorized as either a cytokine, hormone, or enzyme This review presents the latest findings on the role of MIF in the immune system and in cell growth, with regard to tumorigenesis and wound repair, and discusses its potential functions in various pathophysiologic states

Endotoxin and cytokine regulation of toll-like receptor (TLR) 2 and TLR4 gene expression in murine liver and hepatocytes.

Abstract: Toll-like receptor (TLR) 2 and TLR4 are members of the interleukin-1 receptor (IL-1R) family and transduce similar signals as IL-1R in response to bacteria and bacterial components In this study, we investigated the regulation of their gene expression in murine tissues, especially in the liver and hepatocytes When mice were administered lipopolysaccharide (LPS), TLR2 mRNA was upregulated in the brain, heart, lung, liver, and kidney In contrast, it was downregulated in the spleen TLR4 mRNA was decreased in the brain In the heart and lung, it increased, and it was not affected in the liver, kidney, and spleen TLR mRNA was further analyzed in the liver and hepatocytes Like LPS treatment, administration of IL-1, IL-6, or tumor necrosis factor (TNF) upregulated TLR2 mRNA However, none of them affected the TLR4 mRNA level In primary cultured hepatocytes, TLR2 mRNA was upregulated by LPS, IL-1, or TNF but not by IL-6 or dexamethasone None of them affected TLR4 mRNA expression Similar responses were observed in the murine hepatoma cell line Hepa 1-6 These results suggest that in infection with gram-negative bacteria, LPS and proinflammatory cytokines differentially regulate gene expression of TLR2 and TLR4 in murine hepatocytes, which may lead to pathologic and host defense reactions in the liver

cDNA Cloning of Biologically Active Chicken Interleukin-18

Abstract: By searching a chicken EST database, we identified a cDNA clone that appeared to contain the entire open reading frame (ORF) of chicken interleukin-18 (ChIL-18). The encoded protein consists of 198 amino acids and exhibits approximately 30% sequence identity to IL-18 of humans and various others mammals. Sequence comparisons reveals a putative caspase-1 cleavage site at aspartic acid 29 of the primary translation product, indicating that mature ChIL-18 might consist of 169 amino acids. Bacterially expressed ChIL-18 in which the N-terminal 29 amino acids of the putative precursor molecule were replaced by a histidine tag induced the synthesis of interferon-γ (IFN-γ) in cultured primary chicken spleen cells, indicating that the recombinant protein is biologically active.

Altered cytokine production by specific human peripheral blood cell subsets immediately following space flight.

Abstract: In this study, we have attempted to combine standard immunological assays with the cellular resolving power of the flow cytometer to positively identify the specific cell types involved in spaceflight-induced immune alterations. We have obtained whole blood samples from 27 astronauts collected at three timepoints (L-10, R+0 and R+3) surrounding four recent space shuttle missions. The duration of these missions ranged from 10 to 18 days. Assays performed included serum/urine cortisol, comprehensive subset phenotyping, assessment of cellular activation markers and intracellular cytokine production following mitogenic stimulation. Absolute levels of peripheral granulocytes were significantly elevated following spaceflight, but the levels of circulating lymphocytes and monocytes were unchanged. Lymphocyte subset analysis demonstrated trends towards a decreased percentage of T cells and an increased percentage of B cells. Nearly all of the astronauts exhibited an increased CD4:CD8 ratio, which was dramatic in some individuals. Assessment of memory (CD45RA+) vs. naive (CD45RO+) CD4+ T cell subsets was more ambiguous, with subjects tending to group more as a flight crew. All subjects from one mission demonstrated an increased CD45RA:CD45RO ratio, while all subjects from another Mission demonstrated a decreased ratio. While no significant trend was seen in the monocyte population as defined by scatter, a decreased percentage of the CD14+ CD16+ monocyte subset was seen following spaceflight in all subjects tested. In general, most of the cellular changes described above which were assessed at R+O and compared to L-10 trended to pre-flight levels by R+3. Although no significant differences were seen in the expression of the cellular activation markers CD69 and CD25 following exposure to microgravity, significant alterations were seen in cytokine production in response to mitogenic activation for specific subsets. T cell (CD3+) production of IL-2 was significantly decreased after at R+O as was IL-2 production by both CD4+ and CD8+ T cell subsets for most subjects. Production of IFN(sub gamma) did not appear to be affected by microgravity exposure in either T cells in general or in the CD8+ T cell subset. There was a spaceflight-induced decrease in IFN(sub gamma) production in the CD4+ T cell subset, however it did not reach statistical significance. Serum and urine stress-hormone analysis indicated significant physiologic stresses in astronauts following spaceflight. In summary, these results demonstrate alterations in the peripheral immune system of astronauts immediately after spaceflight of 10 to 18 days duration and support continued research regarding microgravity and immunology (including in-flight sampling) prior to routine long-term spaceflight for astronauts.

Resistance to Paracoccidioides brasiliensis infection is linked to a preferential Th1 immune response, whereas susceptibility is associated with absence of IFN-gamma production.

Abstract: The secretion of interferon-gamma (IFN-gamma), interleukin-2 (IL-2), IL-4, IL-5, and IL-10 by antigen-stimulated lymph node cells, eosinophil maturation, and the antibody isotypes produced were exa...

Localization and Post-Golgi Trafficking of Tumor Necrosis Factor-alpha in Macrophages

Abstract: Tumor necrosis factor-alpha (TNF-alpha) is a proinflammatory cytokine secreted by activated macrophages. In this study, we examined the intracellular distribution and trafficking of TNF-alpha. Immunofluorescence and immunogold localization demonstrated that in lipopolysaccharide (LPS)-stimulated RAW264 macrophages, the greatest concentration of TNF-alpha is found in the perinuclear Golgi complex. Staining of the Golgi complex appeared 20 min after activation of cells and persisted for 2-12 h, and TNF-alpha appeared on the cell surface only transiently during this time. The rate of disappearance of Golgi staining correlated with the release of the cleaved, mature TNF-alpha into the medium. Pulse chase labeling and subcellular fractionation studies indicated that both 26-kDa and 17-kDa forms of TNF-alpha may be present at the level of the Golgi complex. Post-Golgi trafficking of TNF-alpha was modulated by agents that disrupt the cytoskeleton. Interferon-gamma (IFN-gamma), which primes macrophages for TNF-alpha-dependent cellular cytotoxicity, potentiated the effect of LPS by sustaining enhanced intracellular pools of TNF-alpha and also promoted redistribution of TNF-alpha into post-Golgi vesicular compartments. We propose that the primary pool of biologically active TNF-alpha in activated macrophages is held in the Golgi complex and that the cytokine is recruited directly from this intracellular pool for release in response to tumor cells or pathogens.

A polymorphism in the promoter region of the gene for interleukin-6 is associated with susceptibility to type 1 diabetes mellitus.

Abstract: Type 1 diabetes mellitus is an autoimmune disease characterized by the destruction of the insulin-producing islet beta cells. It is likely that several genetic and environmental factors contribute to this process. There is increasing evidence showing that polymorphisms in cytokine genes may play an important role in modifying the immune response. Interleukin-6 (IL-6) is a cytokine that has been implicated in a number of immune-mediated diseases. Further, there is a polymorphism at position -174 (G(-174)C) of the promoter region of the IL-6 gene that may alter the expression of the gene. In this study, the G(-174)C polymorphism was investigated in 257 Caucasoid patients with type 1 diabetes, 53 two-parent-proband trios, and 120 normal, healthy controls. DNA was amplified using amplimers that flank the G(-174)C site, and the products were digested with the restriction endonuclease NlaIII to detect the G or the C allele. The homozygous G,G(-174) genotype was increased in the patients compared with the normal controls (50.6% vs. 33.3%, p < 0.002), with a decrease in the C,C genotype in the patients compared with the controls (12.5% vs. 24.2%, respectively, p < 0.004). In the 53 trios studied, the G allele was transmitted in 29 of 53 informative meioses. There was no association with age at onset of diabetes or the presence of diabetic complications. In conclusion, these results suggest that the IL-6 gene may contribute to the genetic susceptibility to type 1 diabetes.

Viral Double-Stranded RNA, Cytokines, and the Flu

Abstract: The symptoms of the flu, such as fever, drowsiness, and malaise, are the sole means by which this common clinical syndrome is defined. The syndrome is usually the first clinical manifestation of both acute bacterial and viral infections. In the case of acute bacterial infections, several proinflammatory cytokines induced by bacterial products have been implicated as the causative agents of the flu syndrome. Viruses induce similar cytokines to bacteria, plus substantial amounts of interferon-alpha (IFN-alpha), although the direct association of these cytokines with the viral flu syndrome is less clear. Furthermore, the viral inducer(s) of cytokines has not been defined. The best candidate cytokine inducer associated with a majority of viral infections is virus-associated double-stranded RNA (dsRNA). This review examines the essential physical properties of toxic dsRNA, the cytokines induced by it, its viral and cellular sources, evidence for its presence in infected cells, its quantities in normal and infected cells, its cytotoxic mechanisms, and its cell-penetration properties. Toxic effects of viruses and dsRNA are compared. Energetics and extraction artifact issues are also discussed. Whereas most research on dsRNA toxicity has employed synthetic dsRNA, studies with virus-associated dsRNA are featured when available. Finally, a model for how viral dsRNA might initiate systemic disease is presented.

Transforming growth factor-beta mRNA and protein in hypertrophic scar tissues and fibroblasts: antagonism by IFN-alpha and IFN-gamma in vitro and in vivo.

Abstract: Hypertrophic scarring (HSc) following burn injury is a common, disfiguring, and functionally limiting form of dermal fibrosis, compromising recovery. Previously, elevated levels of transforming growth factor-beta1 (TGF-beta1), a fibrogenic cytokine, were found in wounds and serum of severely injured patients, antagonized in part by treatment with systemic interferon-alpha2b (IFN-alpha2b) both in vitro and in vivo. It is hypothesized that in wound healing after injury, platelets are an initial source of TGF-beta, but wound fibroblasts may be capable, after activation, of autoamplification of the initial response to injury by increasing TGF-beta mRNA and protein that may subsequently be responsive to IFN therapy with IFN-alpha or IFN-gamma or both. Using three pairs of site-matched HSc and normal fibroblasts from the same individuals, nonconfluent and near confluent fibroblasts were treated with TGF-beta, and cell proliferation and collagen production were assayed using cell counting and 18O2 isotopic uptake into hydroxyproline before analysis by gas chromatography-mass spectrometry (GC-MS). HSc and normal fibroblasts were assayed for the production of TGF-beta protein secretion using ELISA for TGF-beta1, TGF-beta2, and TGF-beta3 after acidification of medium samples from 96-h cultures. HSc and normal fibroblasts were treated with IFN-alpha2b or IFN-gamma or both for 96 h. Quantitative RT-PCR and Northern analysis were performed using newly synthesized internal standards for human TGF-beta1. TGF-beta stimulates both HSc and normal fibroblast proliferation. Collagen synthesis is greater in HSc than in normal fibroblasts and is maximally stimulated at 75 pM TGF-beta. TGF-beta stimulated collagen metabolism is antagonized by IFN-alpha or IFN-gamma or both in an additive fashion. HSc and normal fibroblasts not only possess the mRNA for TGF-beta1 but also secrete mature TGF-beta protein. Treatment of HSc and normal fibroblasts with IFN-alpha2b or IFN-gamma antagonizes TGF-beta protein production, and additive effects occur. RT-PCR demonstrates that after IFN treatment, downregulation of TGF-beta1 mRNA accounts in part for the reduction in protein secretion in HSc fibroblasts. Elevations of systemic TGF-beta may be due to wound fibroblasts. TGF-beta synthesis and antagonism of fibroblast TGF-beta protein secretion occurs with either IFN-alpha or IFN-gamma, in part by downregulation of TGF-beta1 mRNA levels.

Chemokine gene adjuvants can modulate immune responses induced by DNA vaccines.

Abstract: Nucleic acid immunization has been shown to induce both antigen-specific cellular and humoral immune responses in vivo. Moreover, immune responses induced by DNA immunization can be enhanced by the use of molecular adjuvants. For example, coadministration of costimulatory molecules (CD80 and CD86), proinflammatory cytokines (interleukin-1α [IL-1α], tumor necrosis factor-α [TNF-α, and TNF-β), Th1 cytokines (interleukin-2[IL-2], IL-12, IL-15, and IL-18), Th2 cytokines (IL-4, IL-5, and IL-10), and granulocytesmacrophage colony-stimulating factor (GM-CSF) with DNA vaccine constructs leads to modulation of the magnitude and direction (humoral or cellular) of the immune responses. To further engineer the immune response in vivo, we compared the induction and regulation of immune responses from the codelivery of chemokine (IL-8, interferon-γ-inducible protein-10 [γIP-10], macrophage inhibitory protein-1α [MIP-1α], and RANTES) genes with codelivery of cytokine genes. We found that as in cytokine gene codelivery, ...

Influence of Vitamin C Supplementation on Cytokine Changes Following an Ultramarathon

Abstract: The influence of vitamin C supplementation on the pattern of change in plasma cytokine concentrations was measured in 29 runners following a 90-km ultramarathon. The study was based on a 3 (groups) by 4 (blood samples at 16 prerace, postrace, and 24 h and 48 h postrace) repeated measures design. Groups included placebo control (n = 7) and two groups supplementing vitamin C at 500 mg/day (vit C-500, n = 10) or 1500 mg/day (vit C-1500, n = 12) for 7 days before the race, on race day, and for 2 days after the race. All measured plasma cytokine concentrations were significantly elevated immediately postrace, with the magnitude of increase for tumor necrosis factor-alpha (TNF-alpha) and interleukin-1beta (IL-1beta) much smaller than for IL-6, IL-10, IL-8, and IL-1 receptor antagonist (IL-1RA). Cortisol increased in all groups immediately after the race but significantly less in the vit C-1500 group. Group x time interaction statistics were not significant for any of the plasma cytokines. However, when the placebo and vit C-500 groups were combined (n = 17) and compared with the vit C-1500 group (n = 12), immediate postrace plasma concentrations were significantly lower in the vit C-1500 group for IL-1RA (-57%) and IL-10 (-57%), with a trend measured for IL-6 (-27%, p = 0.11) and IL-8 (-26%, p = 0.14). In summary, runners completing the 90-km Comrades Ultramarathon experienced strong increases in concentrations of plasma IL-6, IL-10, IL-1RA, and IL-8. These increases were attenuated in runners ingesting 1500 mg but not 500 mg vitamin C supplements for 1 week prior to the race and on race day.

Effects of hypothermia and hyperthermia on cytokine production by cultured human mononuclear phagocytes from adults and newborns.

Abstract: We have shown previously that febrile range temperatures modify cytokine production by adult macrophages. In this study, we compared the effects of moderate hyperthermia and hypothermia on the kinetics of lipopolysaccharide (LPS)-induced cytokine expression in monocytes and macrophages of newborns and adults. During culture at 40 degrees C, the initial rates of tumor necrosis factor-alpha (TNF-alpha) and interleukin-1 beta (IL-1 beta) secretion were preserved, but the duration of secretion was shorter than the duration at 37 degrees C. TNF-alpha and IL1-beta concentrations in 24-h 40 degrees C culture supernatants were reduced 18%-50%. IL-6 concentration in 24-h 40 degrees C cultures was reduced 26%-29% in all cells except adult macrophages. At 32 degrees C, changes in early (2 h) and sustained (24 h) cytokine expression were reversed compared with those caused by hyperthermia. Culturing adult macrophages at 32 degrees C blunted early secretion of TNF-alpha and IL-6 by 69% and 65%, respectively, and increased TNF-alpha concentration at 24 h by 48% compared with levels at 37 degrees C. In adult monocytes cultured at 32 degrees C, early IL-6 and IL-1 beta secretion was decreased 64% and 51%, respectively. We speculate that the burst/suppression cytokine profile at febrile temperatures might enhance early activation of host defenses and prevent prolonged exposure to potentially cytotoxic cytokines. Hypothermia, on the other hand, may worsen outcome in infections by delaying and prolonging cytokine production.

Cloning of an Mx cDNA from Atlantic halibut (Hippoglossus hippoglossus) and characterization of Mx mRNA expression in response to double-stranded RNA or infectious pancreatic necrosis virus.

Abstract: Mx proteins are GTPases that are specifically induced by type I interferons (IFN) in vertebrates. Some mammalian Mx proteins have antiviral activity against certain RNA viruses. A 2.3-kb full-length cDNA clone of an Atlantic halibut Mx gene was isolated from a liver cDNA library. The open reading frame (ORF) predicts a 622 amino acid protein of 71.2 kDa possessing a tripartite GTP binding motif, a dynamin signature, and a leucine zipper motif, which are conserved in all known Mx proteins. The C-terminal half contains a putative bipartite nuclear localization signal. The deduced halibut Mx protein showed approximately 76% sequence identity with the Atlantic salmon and rainbow trout Mx proteins, 55% identity with the human MxA, and 48% identity with the chicken Mx protein. Based on sequence comparison of 554-bp Mx cDNA fragments, the Atlantic halibut Mx showed more relationship with the perch and turbot than the salmonid Mx genes. Halibut appears to possess at least two Mx loci, as suggested by Southern blot analysis of genomic DNA. Two halibut Mx transcripts (2.2 kb and 2.6 kb) were strongly induced in vivo by the double-stranded RNA (dsRNA) poly I:C or infectious pancreatic necrosis virus (IPNV) in all organs studied.

Pharmacokinetics and Pharmacodynamics of IFN-β1a in Healthy Volunteers

Abstract: The pharmacokinetics of recombinant human interferon-β1a (IFN-β1a) (Rebif, Ares-Serono, Geneva, Switzerland) were investigated in healthy volunteers following intravenous (i.v.) administration of increasing single doses of the drug (22 μg/6 million international units [MIU], 44 μg/12 MIU, and 66 μg/18 MIU); i.v., intramuscular (i.m.), and subcutaneous (s.c.) administration of a 66-μg dose; and repeated s.c. administration of four 66-μg doses at 48-h intervals. The disposition of IFN-β1a followed triexponential decay after i.v. administration (half-lives 3 min, 42 min, and 22 h, respectively). After s.c. and i.m. administration, absorption was the rate-limiting factor in the terminal phase. The median absolute bioavailabilities were 30% and 27%, respectively. The accumulation ratio after repeated s.c. injections was 2.4, and a terminal half-life of 66 h was observed. Intracellular 2-5A synthetase activity and serum neopterin and β2-microglobulin concentrations increased after all IFN-β1a injections and rem...

Cytokine message and protein expression during lung granuloma formation and resolution induced by the mycobacterial cord factor trehalose-6,6'-dimycolate.

Abstract: Trehalose-6,6'-dimycolate (TDM), or cord factor, is a mycobacterial cell wall component that induces granuloma formation and proinflammatory cytokine production in vivo and in vitro. The purpose of this work was to better understand the mechanisms by which TDM promotes lung granuloma formation. This was accomplished by characterizing cytokine mRNA expression during TDM-induced alveolitis culminating in cohesive granuloma development. A single intravenous injection of TDM given to C57BL/6 mice produced lung granulomas that peaked in number 5 days after challenge and were nearly resolved by 14 days. mRNA in whole lung preparations was quantitated by bioluminescent RT-PCR. Tumor necrosis factor-α (TNF-α), interleukin1β (IL-1β), and IL-6 were significantly elevated during granuloma development and decreased during granuloma resolution. There were no detectable changes in mRNA for interferon-γ (IFN-γ), IL-2, IL-4, IL-5, IL10, and IL-12(p40). The level of TNF-α protein extracted from lung minces highly correlat...

Molecular regulation of constitutive expression of interleukin-8 in human pancreatic adenocarcinoma.

Abstract: Recent studies have shown that interleukin-8 (IL-8) plays an important role in the growth and metastasis of human pancreatic cancer. In the present study, we determined the molecular regulation of ...

Caspase-Dependent Apoptosis by 2′,5′-Oligoadenylate Activation of RNase L Is Enhanced by IFN-β

Abstract: The 2′,5′-oligoadenylate (2-5A) system is an interferon (IFN)-regulated RNA decay pathway that provides innate immunity against viral infections. The biologic action of the 2-5A system is mediated by RNase L, an endoribonuclease that becomes enzymatically active after binding to 2-5A. RNase L is also implicated in mediating apoptosis in response to both viral and nonviral inducers. To study the cellular effects of RNase L activation directly, 2-5A was transfected into the human ovarian cancer cell line, Hey1B. Activation of RNase L by 2-5A resulted in specific 18S rRNA cleavage and induction of apoptosis, as measured by TUNEL and annexin V binding assays. In contrast, the dimeric form of 2-5A, ppA2′p5′A, neither activated RNase L nor caused apoptosis. Treatment with IFN-β prior to 2-5A transfection enhanced cellular RNase L levels (≤ 2.2-fold) and increased the proportion of cells undergoing apoptosis (by ≤40%). However, rRNA cleavages after 2-5A transfections were not enhanced by IFN-β pretreatments, ind...

Interleukin-6 levels in tears of contact lens wearers.

Abstract: The purpose of this study was to evaluate the presence of interleukin-6 (IL-6) in basal tears of contact lens wearers (n = 18) and nonlens wearers (n = 25). Samples (5 microl) were collected with a microcapillary pipette and evaluated using PAGE electrophoresis and immunoblot analysis. Contact lens-wearing patients had a mean IL-6 level of 43.8 +/- 5.3 pg/5 microl compared with nondetectable IL-6 levels throughout the noncontact lens-wearing population. IL-6 in several patients removed from contact lens wear for 6 days became nondetectable. When these patients were returned to wearing lenses, IL-6 levels increased to their original levels within 24 h. The data presented indicate that an ocular medical device may stimulate IL-6 production.

Tumor necrosis factor-alpha and lipopolysaccharide enhance interferon-induced antichlamydial indoleamine dioxygenase activity independently.

Abstract: In macrophages, interleukin-1 (IL-1) and lipopolysaccharide (LPS) enhance the antichlamydial effect of interferon-gamma (IFN-gamma) by increasing indoleamine 2,3-dioxygenase (IDO) activity in a dose-dependent manner. Our objectives were to characterize the antichlamydial effect of tumor necrosis factor-alpha (TNF-alpha) on IFN-induced IDO activity and to establish the relationship between LPS and TNF-alpha in IDO potentiation. TNF-alpha inhibited chlamydial growth in a dose-dependent manner only in IFN-treated macrophages. Furthermore, excess tryptophan reversed the effect of combined cytokine treatment, indicating that IDO alone was responsible for chlamydial inhibition. The promonocyte THP-1 cell line, previously used to model the effect of IL-1 on IDO mRNA expression, was treated with IFN-gamma and increasing concentrations of LPS or TNF-alpha. IDO mRNA was quantified by RT-PCR, and IDO activity was measured by HPLC at 24 and 48 h after treatment, respectively. Both LPS and TNF-alpha enhanced IDO activity and IDO mRNA expression, with maximal IDO induction at 100 ng/ml LPS or 5 ng/ml TNF-alpha. Anti-TNF-alpha failed to neutralize the effects of LPS treatment, and insufficient TNF-alpha or IL-1 was produced by LPS-treated THP-1 cells to account for the enhancing effect of LPS, indicating that the effect of LPS on IDO was independent of TNF-alpha and IL-1.

Interleukin-1/Toll receptor family members: receptor structure and signal transduction pathways.

Abstract: Interleukin-1 (IL-1) is a central mediator of the inflammatory response. It plays a role in both systemic and local immune responses to invading microbes. There are two receptors (IL-1RI and IL-1RII) that mediate the cellular responses. These receptors belong to a family of receptors based on homologous receptor structure within the intracellular signaling domain. Other family members include the Drosophila protein Toll, the recently discovered mammalian Toll-like receptors (TLR), and the IL-18 receptor. Engagement of these receptors by their diverse ligands results in activation of very similar signal transduction cascades through use of common signaling intermediates. These signal transduction cascades lead to the activation of cellular responses that are known to regulate the innate immune response. Therefore, elucidating the function and redundancy of this receptor family is essential to the understanding of the innate immune response. This review examines each member of this receptor family and empha...

The capacity to produce IFN-gamma rather than the presence of interleukin-4 determines the resistance and the degree of susceptibility to Leishmania donovani infection in mice.

Abstract: The immune response against Leishmania donovani infection has been investigated in one resistant mouse strain (C3H/HeJ) and three susceptible mouse strains (C57BL/6, BALB/c, and B10D2/n) In order to correlate the strain-specific course of infection with the individual T cell response phenotype, the ex vivo cytokine secretion patterns of splenic lymphocytes were assessed by ELISA (interferon-gamma [IFN-gamma], interleukin-4 [IL4], IL-10) or by bioassay (IL-2) The strain-dependent differences in the course of infection correlated closely with the potency of T cells to produce IFN-gamma C3H/HeJ mice produced high amounts of IFN-gamma before and during infection, whereas susceptible mice produced low amounts of IFN-gamma early during L donovani infection However, C57BL/6 mice, which recovered from the infection rapidly after the acute stage, developed marked IFN-gamma response within the first 30 days of infection In contrast, in BALB/c and B10D2/n mice, the IFN-gamma production diminished during the ac

The impact of the ovulatory cycle on cytokine production: evaluation of systemic, cervicovaginal, and salivary compartments.

Abstract: To understand the impact of the menstrual cycle on immunologic parameters, we measured the level of cytokines and chemokines from plasma, cervicovaginal lavage (CVL), and saliva samples of 6 premenopausal women during the follicular and luteal phases of the ovulatory cycle. We demonstrate that the level of plasma interleukin-8 (IL-8) was 4-fold higher during the follicular phase than the luteal phase (p = 0.004), whereas plasma IL-1beta, IL-4, IL-6, IL-10, interferon-gamma (IFN-gamma), transforming growth factor-beta (TGF-beta), tumor necrosis factor-alpha (TNF-alpha), macrophage inflammatory protein-1alpha (MIP-1alpha), and TNF receptor II (TNFR II) were not altered during the ovulatory cycle. In the vaginal compartment, as measured from CVL samples, the levels of IL-6 and IL-1beta were both 5-fold higher in the follicular than the luteal phase (p = 0.0002 and 0.03, respectively). Salivary cytokine and chemokine samples were similar when measured during the luteal and the follicular phases. Additional analysis of lymphocyte subsets for phenotypic and functional markers indicated that they were not influenced by the ovulatory cycle. Collectively, these data suggest that IL-6, IL-8, and IL-1beta are differentially regulated during the ovulatory cycle.

In Vivo Neutrophil Recruitment by Granulocyte Chemotactic Protein-2 Is Assisted by Gelatinase B/MMP-9 in the Mouse

Abstract: Granulocyte chemotactic protein-2 (GCP-2) of the mouse is a potent neutrophil chemotactic and activating factor in vitro and in vivo. Gelatinase B/matrix metalloproteinase-9 is released from neutrophils within 1 h after stimulation with GCP-2. In vitro neutrophil chemotaxis by GCP-2 was not impaired by specific inhibitory monoclonal antibodies (mAb) against gelatinase B, indicating that gelatinase B is not involved in chemotaxis of neutrophils through polycarbonate filters. To investigate if gelatinase B degranulation is involved in in vivo cell migration toward GCP-2, experiments were performed with gelatinase B knockout mice. When mouse GCP-2 was injected intradermally in mice, a dose-dependent neutrophil chemotactic response was observed, and this cell migration was significantly impaired in young mice by genetic gelatinase B knockout. In adult vs. young gelatinase B-deficient mice, such compensatory mechanisms as higher basal neutrophil counts and less impairment of chemotaxis toward local GCP-2 injection were observed. These experiments prove the concept that gelatinase B release under pressure of GCP-2 is a relevant, but not exclusive, effector mechanism of neutrophil chemotaxis in vivo and that known mechanisms, other than the release of gelatinase B, allow for a full-blown chemotactic response and compensate for gelatinase B deficiency in adult life in the mouse.

Molecular Mechanism of Ultraviolet-Induced Keratinocyte Apoptosis

Abstract: This article reviews advances in the study of the molecular mechanisms for ultraviolet (UV)-induced keratinocyte apoptosis, with particular reference to the cytokines tumor necrosis factor-alpha (TNF-alpha) and Fas ligand (FasL) TNF-alpha and FasL induce their respective receptors and then activate caspase enzymes that are critically involved in the apoptotic process This activation is further amplified by intracellular mitochondria-associated mechanisms Using gene-targeted knockout mice lacking either the TNF-Rp55 or the TNF-Rp75, we have shown that TNF-alpha plays an important role in UV-induced keratinocyte apoptosis via TNF-Rp55 TNF-Rp55 shares homology with Fas and contains an intracellular death domain UV seems to directly stimulate cross-linking of Fas, resulting in the engagement of the death machinery Fas-associated death domain protein (FADD) acts as an adapter protein in both the TNF-Rp55 and Fas death-inducing cascades and is responsible for downstream signal transduction by recruiting caspases Moreover, signaling of p53 contributes to the induction of apoptosis by regulating Bcl-2 family expression and increasing surface Fas expression In addition to induction mechanisms of apoptosis, there are numerous inhibitory molecules that play a role in restricting the apoptotic pathway Thus, the ultimate determination of whether or not a cell undergoes apoptosis after UV radiation is based on the balance between agonist and antagonist pathways

Regulation of macrophage interleukin-6 (IL-6) and IL-10 expression by prostaglandin E2: the role of p38 mitogen-activated protein kinase.

Abstract: Prostaglandin E2 (PGE2) regulates production of a wide array of cytokines. We have found that PGE2 can upregulate the levels of both interleukin-10 (IL-10) and IL-6 produced by activated murine macrophages, but the molecular pathways leading to their augmentation differ. Synthesis of IL-10 in response to PGE2 is dependent on p38 MAP kinase activity, whereas synthesis of IL-6 is not. Evidence to support this derives from two experimental approaches. First, we established that PGE2 is effective in elevating IL-10 levels only when it is added to cells in which p38 kinase has been activated. In contrast, PGE2 can augment IL-6 levels regardless of whether or not p38 kinase is active. Second, we showed that inhibitors that are selective for p38 kinase prevent the IL-10 response to PGE2 but not the IL-6 response. We found that p38 kinase inhibitors are able to inhibit IL-6 production in activated macrophages, but this occurs primarily as a result of their concurrent inhibition of cyclooxygenase-2 and endogenous PGE2 synthesis. These results indicate that macrophage IL-10 and IL-6 expression is differentially regulated by PGE2 and p38 MAP kinase in murine inflammatory macrophages.

Effect of deficiency of the double-stranded RNA-dependent protein kinase, PKR, on antiviral resistance in the presence or absence of ribonuclease L: HSV-1 replication is particularly sensitive to deficiency of the major IFN-mediated enzymes.

Abstract: Control of viral replication by interferon (IFN) is thought to be principally mediated by the 2',5'-oligoadenylate synthetase (OAS)/RNAse L, double-stranded dependent protein kinase (PKR), and myxovirus resistance protein (Mx) pathways In this study, we monitored the constitutive and IFN-induced antiviral activity in mouse embryo fibroblasts lines derived from mice with targeted disruption of either PKR or PKR/RNAse L genes At high multiplicity of infection (moi = 10), the absence of PKR had no effect on replication of vesicular stomatitis virus (VSV) but moderately enhanced encephalomyocarditis virus (EMCV) growth and greatly increased replication of herpes simplex virus-1 (HSV-1) Replication of EMCV, HSV-1, and VSV was modestly higher in PKR-/- RNAse L-/- fibroblasts when compared with control cells Although the antiviral action of IFN-α was unaffected by the absence of PKR, IFN action was significantly impaired in the double knockout cells but was dependent on the stage of the virus cycle At early

Transduction and utility of the granulocyte-macrophage colony- stimulating factor gene into monocytes and dendritic cells by adeno- associated virus

Abstract: The genetic manipulation of antigen-presenting dendritic cells (DC) offers promise for stimulating the immune response, in particular for anticancer and antiviral protocols. As adeno-associated vir...

Coimmunization with IFN-gamma or IL-2, but not IL-13 or IL-4 cDNA can enhance Th1-type DNA vaccine-induced immune responses in vivo.

Abstract: As we explore the potential improvements to the current DNA vaccine strategies, it may be desirable to investigate methods to improve the level of resulting immune responses. One strategy is the use of cytokine cDNA as molecular adjuvants for DNA-based vaccines. Codelivery of these molecular adjuvants consisting of expression plasmid encoding for cytokines with DNA vaccine constructs is an effective method to modulate the magnitude and direction (humoral or cellular) of the immune responses. We have previously reported on the immunomodulatory effects of codelivering cDNA for interleukin-2 (IL-2) and IL-4 as molecular adjuvants for DNA-based vaccines. In this report, we extend these finding and compare the immunomodulatory effects of IL-2 and IL-4 with those of cDNA for prototypical Thl-type cytokine interferon-y (IFN-gamma) and Th2-type cytokine IL-13. We observed that distinct antigen-specific immune modulation can be achieved by the coinjection of IFN-gamma or IL-13 genes with DNA immunogen cassettes. We observed that IFN-gamma is a strong driver of Thl immune responses. Furthermore, in contrast to previous reports on their similarities in biologic activities, IL-13 and IL-4 cDNA coimmunizations modulated vaccine-induced immune responses differently in this model. Overall, these results further support the potential utility of this strategy as an important tool for the development of vaccines and immune therapies.

Interleukin-6 Increases Thrombopoietin Production in Human Hepatoma Cells HepG2 and Hep3B

Abstract: The concentration of circulating thrombopoietin (TPO) is relatively high in patients with thrombocytosis reactive to inflammatory diseases. We investigated whether immunomodulatory cytokines stimul...

A CA repeat polymorphism of the IFN-gamma gene is associated with susceptibility to type 1 diabetes.

Abstract: Recent studies have shown that loci outside the HLA region are involved in determining susceptibility to type 1 diabetes. Polymorphisms in the coding and noncoding regions of the genes encoding cytokines may be involved in modulating the immune response to self and nonself antigens. There is increasing evidence that an imbalance and disruption of the Th1 and Th2 T cell subsets play a key role in the development of experimental and clinical type 1 diabetes. The aim of this study was to investigate the frequency of a CA dinucleotide repeat polymorphism in the interferon-gamma (IFN-gamma) gene (IFNG) and a C(-590)T polymorphism of the interleukin-4 (IL-4) gene in 236 Caucasoid patients with type 1 diabetes. There was a highly significant increase in the 3/3 IFNG genotype in the patients compared with normal healthy controls (34.3% vs. 13.5%, p< 0.0001) as well as a significant increase in allele 3 of the IFNG locus in the patients compared with controls (51.9% vs. 31.7%, p< 0.00001). In contrast, no signific...