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The involvement of TNF, IL-1 and IL-6 in the immune response to protozoan parasites.

One early reaction of the host to infection with protozoan parasites is the secretion of an array of potent cytokines including tumor necrosis factor (TNF), interleukin (IL-1) and IL-6. The combined action of these cytokines causes fever, leukocytosis and the production of acute phase proteins such as C-reactive protein (CRP). These early responses contribute significantly to the outcome of infection by influencing the course of infection directly and by regulating the specific immune response to the parasite.

Acute-Phase Proteins↗

Cell-mediated immunity to Epstein-Barr-virus-transformed lymphoblastoid cells in acute infectious mononucleosis.

Mononuclear peripheral blood leukocytes from 21 patients with infectious mononucleosis and 16 healthy controls were tested in a 51Cr-release assay for cytotoxicity against two human lymphoblastoid cell lines derived from the same donor. One line contained the Epstein-Barr virus (EBV); the other did not. Acute-phase leukocytes were significantly more cytotoxic against the EBV-infected cell line than were control leukocytes. Mean (+/- S.E.) lysis at a leukocyte-target-cell ratio of 100:1 was 10.6 +/- 1.6 per cent for patients and 3.4 +/- 0.6 per cent for controls (P less than 0.0005). Cytotoxicity correlated with the percentage of atypical lymphocytes. Cells of three patients with acute mononucleosis-like illnesses failed to show killing activity above those of normal controls. Cytotoxicity against the EBV-negative line was not significantly different for each group. The finding of cytotoxic cells in infectious-mononucleosis patients with atypical lymphocytes suggests that these cells operate in vivo to limit the proliferation of altered EBV-transformed B lymphoblasts.

Acute Disease↗

Transient immunoglobulin M antibody response to hepatitis C virus capsid antigen in posttransfusion hepatitis C: putative serological marker for acute viral infection.

The development of serological assays for hepatitis C virus (HCV) has made specific diagnosis possible. However, markers useful in indicating acute-phase HCV infection have not been identified. By an immunoblotting method, we characterized the IgM and IgG antibody response against HCV capsid antigen in patients with HCV infection. Among 88% of patients with acute posttransfusion hepatitis C recruited in a prospective study, there was a transient IgM antibody response. The IgM antibody appeared shortly after onset of hepatitis (average 3.7 weeks), persisted for several months (average 18 weeks), and then disappeared. In contrast, the IgG antibody persisted long-term once it appeared. Among patients with chronic hepatitis C with milder disease activities (serum aminotransferase increase above normal levels of less than 4-fold), the IgM antibody was negative in the majority (72%). In those with acute exacerbations (aminotransferase increase of greater than 10-fold), about 55% were negative for the IgM antibody. The reactivity of the IgM antibody in the rest was weaker or became negative upon further dilution of serum. The results suggest that IgM anti-capsid antibody may serve as a marker indicating acute or active HCV infection.

Acute Disease↗

Regulation of major acute-phase plasma proteins by hepatocyte-stimulating factors of human squamous carcinoma cells.

Human squamous carcinoma (COLO-16) cells release factors which specifically stimulate the synthesis of major acute-phase plasma proteins in human and rodent hepatic cells. Anion exchange, hydroxyapatite, lectin, and gel chromatography of conditioned medium of COLO-16 cells result in separation into three distinct forms of hepatocyte-stimulating factors (designated HSF-I, HSF-II, and HSF-III) with apparent molecular weights of 30,000, 50,000 and 70,000, respectively. None of the preparations contains detectable amounts of thymocyte-stimulating activity. Each of the three HSF forms stimulates the accumulation of mRNA for alpha 1-antichymotrypsin in the human hepatoma cell line, HepG2. When the same factors were added to primary cultures of adult rat hepatocytes, the expression of the same set of plasma proteins was modulated as by nonfractionated medium. The hormonally induced accumulation of mRNA for acute phase proteins is qualitatively comparable to that occurring in the liver of inflamed rats. Unlike in human cells, in rat liver cells dexamethasone acts additively and synergistically with HSFs. The only functional difference between the three HSF forms lies in the level of maximal stimulation. HSF-I represents the predominant form produced by normal human keratinocytes and closely resembles in molecular size and isoelectric point the activity produced by activated peripheral blood monocytes while the larger molecular weight forms are more prevalent in human as well as mouse squamous carcinoma cells. The observation that HSFs from different sources elicit essentially the same pleiotropic response in hepatic cells led to the hypothesis that the species-specific reaction of adult liver cells to inflammatory stimuli is pre-programmed and that the function of any HSF is to trigger and tune the execution of this fixed cellular process.

Animals↗

Localization of hepatitis A antigen in marmoset organs during acute infection with hepatitis A virus.

Twelve marmosets (Saguinus mystax) were inoculated intravenously (iv) with hepatitis A virus (HAV). One died early (day 12); seven were sacrificed at the time of elevation in level of alanine aminotransferase (serum glutamic-pyruvic transaminase), and four without elevation were not sacrificed but seroconverted. In the seven marmosets sacrificed during the acute stage of illness, hepatitis A antigen (HA Ag) was detected in the liver by immunofluorescence in all cases, by immune electron microscopy in four, and by enzyme-linked immunosorbent assay (ELISA) in three. The HA Ag appeared by immunofluorescence as very fine granules in the cytoplasm of hepatocytes and Kupffer cells. The HA Ag could not be detected by immunofluorescence in biopsy specimens taken from the duodenum, jejunum, ileum, or transverse colon in any of eight marmosets in which necropsy was performed during the acute or preacute stage of illness. These findings suggest that the gut is not involved during the acute phase of HAV infection following iv inoculation into marmosets. The ELISA results showed that only three of 12 marmoset livers obtained during the acute phase of HAV infection could be used as an antigen source in serologic testing for antibody to HA Ag. Thus, marmoset livers were no better as a source of HA Ag than acute-phase stools from patients with type A hepatitis.

Acute Disease↗

Enzyme-linked immunosorbent assay for detection of hepatitis A antigen in stool and antibody to hepatitis A antigen in sera: comparison with solid-phase radioimmunoassay, immune electron microscopy, and immune adherence hemagglutination assay.

Previously described techniques for detection of hepatitis A antigen (HA Ag) and antibody (anti-HA) have required purified HA Ag and expensive equipment. Herein is described an enzyme-linked immunosorbent assay (ELISA) for specific detection of HA Ag in human stool filtrates and of anti-HA in sera by using selected HA Ag-containing human stool filtrates as the antigen source. Because human stools often react nonspecifically in serological tests for HA Ag, blocking with preexposure and hyperimmune anti-HA sera from a chimpanzee inoculated with hepatitis A virus was used to confirm specific detection of HA Ag. The sensitivity of ELISA was found to be comparable to that of solid-phase radioimmunoassay (SPRIA) and immune electron microscopy (IEM). Of 37 acute-phase stools collected from nine patients, 16 were positive for HA Ag by ELISA. In 13 of these, HA Ag particles were found by IEM, and an additional 3 stools negative by ELISA contained HA Ag particles by IEM. Eight control stools were negative by both ELISA and IEM. Anti-HA was measured in sera by demonstrating its ability to block binding of the enzyme conjugate to HA Ag in a stool without detectable nonspecificity. This test (blocking ELISA) was as sensitive and specific as blocking SPIRA, IEM, and immune adherence hemagglutination and, like SPRIA and IEM, detected early-developing antibody. The ELISA is simple to perform and requires only a minimum of equipment. It is useful for screening stools for HA Ag and for monitoring HA Ag during purification, as well as for detecting early and late anti-HA in sera.

Acute Disease↗

The value of acute phase protein measurements in clinical practice.

There is clearly a role for the measurement of acute phase proteins and other indices of the acute phase reaction but it is equally clear that no one laboratory test is suitable for use in all clinical situations. The choice of acute phase protein measurement depends on the diagnostic sensitivity and specificity of the measurement in the particular clinical situation. The choice of measurement must also include a decision on time of sampling and whether single or serial sampling would be more appropriate. In most situations where acute phase measurement is useful CRP is the assay of choice with alpha 1-antichymotrypsin also being useful in inflammatory bowel disease and other situations where a wider time window is required. The ESR or plasma viscosity can be useful to screen for disease. Cytokine and enzyme-inhibitor complex measurements may be important assays in the future.

Acute-Phase Proteins↗

Observations on the interleukin-6 and acute phase protein profiles in the disease course of patients with lupus erythematosus.

In vitro models have shown that interleukin-6 (IL-6) is the main dominator of the stimulation of the full spectrum of acute phase proteins. This study describes IL-6 levels in relation to levels of acute phase proteins in 15 systemic lupus erythematosus (SLE) patients, with special attention given to those patients with increased serum levels of IL-6. Three episodes with elevated levels of IL-6 were observed in a period shortly after a flare-up of SLE, in three of the 15 patients. In one of these three patients a clear increase in the C-reactive protein (CRP) level, preceded by an IL-6 increase, was observed. In the other two patients, CRP levels remained unchanged. It is speculated that, next to IL-6, another signal is operative or needed for the start of an acute phase reaction. However, influences of the disease itself or of the administered therapy cannot be excluded as the cause of the described discrepancy between IL-6 and acute phase protein profiles in these two SLE patients.

Acute-Phase Proteins↗

Synergistic enhansons located within an acute phase responsive enhancer modulate glucocorticoid induction of angiotensinogen gene transcription.

The hepatic transcription of the angiotensinogen gene is regulated by both glucocorticoids and cytokines generated as products of the acute phase reaction. We have identified a multimodular enhancer in the 5'-flanking region of the rat angiotensinogen gene that mediates these responses and consists of an acute phase response element (APRE) flanked on both sides by adjacent glucocorticoid response element consensus motifs (GREs). Induction of transcription by the cytokine interleukin-1 (IL-1) is glucocorticoid dependent and mediated through the APRE. The APRE binds in a mutually exclusive manner a cytokine/phorbol ester-inducible protein (BPi), indistinguishable from nuclear factor kB, and a family of constitutive liver proteins (BPcs) related to the heat-stable transcription factor C/EBP. Using mutated 5'-flanking sequences of the angiotensinogen gene fused to a firefly luciferase reporter gene transfected into hepatoblastoma (HepG2) cells, we have mapped enhanson sequences required for the transcriptional response to glucocorticoids. Two functionally distinct GREs are identified by deletion and site-directed mutagenesis, both of which mediate glucocorticoid-stimulated transcription in vivo. Glucocorticoid-induced transcription mediated by the angiotensinogen gene enhancer is, furthermore, dependent on the occupancy of the APRE by either the BPi or a member of the BPc family because a mutant APRE that binds neither BPi nor BPc exhibits an attenuated glucocorticoid responsiveness. Mutant APREs that permit exclusive binding of either BPi or BPc synergistically transmit the glucocorticoid response mediated by one or the other of the adjacent GREs. Thus, the induction of angiotensinogen gene transcription involves interaction between the glucocorticoid receptor and either one of the APRE-binding proteins: either the cytokine-inducible NFkB or the constitutive family of C/EBP-like proteins, bound to adjacent enhansons in a mutually synergistic enhancer complex.

Acute-Phase Proteins↗

[Serum lipoprotein (A) in patients with myocardial infarction and aortoarteritis].

To elucidate the physiological role of lipoprotein (a), a new independent atherosclerosis risk factor, the levels of lipoprotein (a) and 5 proteins of an acute phase were measured in acute (myocardial infarction, n = 21) and chronic (non-specific aortoarteritis, n = 15) tissue lesions. Blood was taken for analysis from patients with myocardial infarction when they were admitted to hospital for anginal attacks and then 4 times during a month and from patients with aortoarteritis at the stage of exacerbation 1 month before and after therapy. The findings indicate that in acute and chronic tissue lesions, there is a change in blood lipoprotein (a) levels, which is largely similar to that in the levels of acute phase proteins. One cause of such changes may be an increase in the synthesis of apolipoprotein (a) that is identical to that of other glycoproteins--acute phase proteins--in the reaction of the acute phase and then in the regeneration of damaged tissues.

Acute-Phase Proteins↗

Cis-urocanic acid as a mediator of ultraviolet-light-induced immunosuppression.

Treatment of an organism with UVB light or PUVA (8-methoxypsoralen + UVA light) not only leads to alterations in the irradiated skin but also to systemic immunomodulation, due to the release of several chemical mediators of immunosuppression like prostaglandins, acute-phase proteins, IL-1 inhibitor, alpha-melanocyte-stimulating hormone, propiomelanocorticotropin or other cytokines. A recently described mediator is urocanic acid, which is transformed by UV light in the skin from the trans- to the cis-isomer and that exerts a systemic immunomodulatory effect. In our experiments, treatment with PUVA or with cis-urocanic acid prevents the rejection of rat heart allografts in 50% and 40% of cases, respectively. Control grafts are rejected in fewer than 10 days. PUVA treatment of donor leukocytes before transfusion into the prospective recipient inhibits only their sensitizing, not their graft-protecting, effect on subsequent skin grafts in mice. PUVA treatment also prevents acute lethal GVH disease in mice after irradiation with a sublethal dose of x-rays and transfusion of semiallogeneic spleen cells. Treatment of recipient mice with cis-urocanic acid has the same effect. The humoral immune response to sheep erythrocytes is not influenced by cis-urocanic acid. These results demonstrate that PUVA treatment or its chemical mediator, cis-urocanic acid, may be used in transplantation and hematology as naturally occurring immunosuppressive agents, especially for the control and manipulation of GVH leukemia reaction.

Animals↗

Regulation of hepatic acute phase plasma protein genes by hepatocyte stimulating factors and other mediators of inflammation.

The hepatic response to systemic injury is characterized by a co-ordinated increase in the expression of several, functionally essential plasma proteins. The factors responsible for initial hepatic stimulation have been identified and include the cytokines IL-1 (interleukin-1), tumor necrosis factor alpha (TNF alpha), IL-6 (interleukin-6), hepatocyte-stimulating factor-III (HSF-III) as well as corticosteroids. The absolute level of expression of the regulated proteins appears to be modulated by the pre-existing hepatic hormonal environment and changes to that environment that occur during acute phase reactions. The specific effects of glucocorticoids, IL-1 and activation of protein kinase C are addressed in this study. In order to predict the phenotype of liver response in acute phase, the hepatic activities of all inflammatory cytokines present must be established. Moreover, it must be recognized that the hepatic environment itself can modulate the anabolic response of the liver to these cytokines. The same considerations are needed when determining the changes seen during the progression to chronic inflammation.

Acute-Phase Proteins↗

Interleukin 6 is a negative regulator of the acute phase alpha 1-inhibitor III gene.

The broad-range proteinase inhibitor alpha 1-inhibitor III (alpha 1I3), a member of the complement C3/alpha 2-macroglobulin protein family, is the prototype of a negatively regulated acute phase protein. During an acute inflammatory reaction alpha 1I3 plasma protein and liver mRNA concentrations are decreased three- to fourfold in rats, and in chronic inflammations the protein concentration is reduced between ten- and 20-fold. In search of a cell culture model to study the regulation of the alpha 1I3 gene by mediators of inflammation, five well-established rat hepatoma cell lines were examined. All five lines constitutively expressed the gene, a marker for a highly differentiated hepatic phenotype, although at less than one-tenth the level of its expression in vivo. In the three hepatoma lines FAZA, FTO2B and FAO1, alpha 1I3 mRNA was decreased by treatment with interleukin 6 (IL6) and glucocorticoids. Among these lines untreated FAO1 cells produced the highest constitutive concentrations of alpha 1I3 mRNA and in FAO1 cells alpha 1I3 mRNA concentrations were decreased up to fourfold in a dose-responsive and time-dependent manner after treatment with IL6 alone or with combinations of IL6 and the synthetic glucocorticoid dexamethasone. Thus, IL6 alone was sufficient to negatively regulate alpha 1I3 mRNA levels in hepatoma cells with similar characteristics as occur during an inflammatory response in the liver. A number of other acute phase mRNA species, including alpha 1-acid glycoprotein, T2-kininogen, gamma-fibrinogen and alpha 2-macroglobulin were induced to higher levels by the same hormonal treatments in FAO1 cells. The fourfold reduction of alpha 1I3 mRNA concentrations in FAO1 cells could be reversed by treatment with 1 microM of a water-soluble derivative of forskolin, an activator of the cyclic AMP pathway. Thus, the effect of IL6 on the expression of the alpha 1I3 gene may involve the activation of the cyclic AMP pathway. In contrast, T2 kininogen mRNA levels were not altered by treatment of FAO1 cells with forskolin, suggesting that IL6 may act on this gene through a different mechanism.

Acute-Phase Proteins↗

Reciprocal expression of NF-IL6 and C/EBP in hepatocytes: possible involvement of NF-IL6 in acute phase protein gene expression.

The initial phase of inflammation is accompanied by dramatic changes in the concentrations of certain plasma proteins. Interleukin-6 (IL-6) is an important inducer of these acute phase proteins at the transcriptional level. The recently cloned nuclear factor NF-IL6, a potent trans-acting regulator of IL-6 gene expression, has a region that is highly homologous to the liver-specific transcriptional factor C/EBP. Both factors recognize the same nucleotide sequence. In this study the recombinant NF-IL6 was shown to interact with the IL-6-responsive elements (IL-6REs) identified in the promoter region of several acute phase protein genes whose activity increases during the acute phase reaction. Furthermore, in competition experiments, formation of all the DNA-protein complexes by the IL-6RE and IL-6-treated hepatoma cell extracts was specifically decreased by adding either the 14-bp NF-IL6 binding motif identified in the IL-6 promoter or the antibody against the recombinant NF-IL6. NF-IL6 was expressed at a minor level in mouse liver, but was dramatically induced after stimulation with IL-6. In contrast, the amount of C/EBP mRNA decreased considerably after IL-6 stimulation. These results indicate that the NF-IL6 that regulated IL-6 expression was also involved in regulation of expression of the acute phase protein genes. The ability of NF-IL6 to replace C/EBP may explain the positive and negative acute phase responses induced by IL-6.

Acute-Phase Proteins↗

The effect of aging on constitutive mRNA levels and lipopolysaccharide inducibility of acute phase genes.

Eukaryotic organisms possess natural defense processes associated with their response to injury, inflammation and pollutants. One of these, the acute phase (AP) host response, is characterized by a series of hepatic physiological reactions triggered by factors released as a result of bacterial infection, inflammation or tissue injury and is believed to be the mechanism by which cells and tissues are protected against further damage and injury. The capacity to respond to these physiological insults is known to be affected by aging. We propose that the AP response represents a series of intrinsic processes and interactions that may be affected by aging. Furthermore, we propose that this may be due to the progressive failure of the acute phase response. In this study we examine the relationship between aging and the expression of both positive and negative acute phase reactants, i.e., acute phase serum proteins whose levels are increased or decreased in response to systemic injury and infection. The mRNA levels of the positive acute phase reactants, alpha 1-acid glycoprotein (AGP), alpha 1-antitrypsin (AT), and the negative acute phase reactant, albumin were measured in both normal and inflammation-induced mice of ages 2, 7, 12, and 24 months. A significant decrease in the constitutive levels of AT and albumin mRNAs occurred as a function of increased age. Furthermore, aging decreased the ability of the AGP and albumin genes to respond to inflammation. Our studies indicate that aging may affect the transcription of these genes, processing of their mRNA or stability of the mRNA levels.

Acute-Phase Proteins↗

Regulation of acute phase reaction by transforming growth factor beta in cultured murine hepatocytes.

Transforming growth factor-beta (TGF beta 1), a multipotent immunoregulatory peptide produced by human platelets, has been shown to stimulate the synthesis of fibrinogen, contrapsin, complement component C3, and alpha-1-proteinase inhibitor by murine hepatocytes cultured for 2 days in DMEM containing 1 microM insulin and dexamethasone and 0.2% BSA. In the range of 10 pg to 10 ng/ml TGF-beta 1 did not elicit any change in albumin secretion. Two main inflammatory cytokines: interleukin-6 (IL-6) and interleukin-1 (IL-1), known to stimulate two different subsets of murine acute phase plasma proteins, failed to increase contrapsin and alpha-1-proteinase inhibitor production. Epidermal growth factor (EGF) in the concentration 1 ng to 10 ng/ml effectively counteracted the stimulatory effect of TGF-beta 1 on acute phase protein production. TGF-beta 1-induced fibrinogen protein levels were associated with increased beta-fibrinogen mRNA content. TGF-beta 1 appears to be an additional physiological factor responsible for the direct stimulation of normal mouse hepatocytes to acute phase response.

Acute-Phase Proteins↗

[Parameters of cellular and humoral immunity in patients with severe acne].

Severe forms of acne, characterized by predominance of inflammatory reactions and persistence of the disease for years, still present therapeutic problems. The purpose of our study was to investigate the role of the immune system in severe persisting forms of acne by means of determination of cellular and humoral immunobiological parameters. The study was performed on 52 patients (47 males and 5 females) having suffered from severe acne for six years on an average, including papulopustular acne grade IV resistant to therapy, nodulocystic acne, conglobate acne, and acne tetrade. The results were compared with those of 52 healthy controls of the same age showing no inflammatory diseases, who were tested on the same day. In 56% of the acne patients, one or more parameters showed pathological values, while in nodulocystic and conglobate acne there were similar results with regard to cellular defects and acute phase reactants. The lymphocytic proliferation induced by mitogens was significantly decreased in 35% of the acne patients. We assume that the immunodeficiency observed in these patients may be mainly secondary; however, it may contribute to the perpetuance of the disease and its resistance to therapy.

Acne Vulgaris↗

[Inflammatory syndrome and changes in plasma proteins].

Inflammation can be considered as a reactional process towards an injury of any etiology. It is clinically characterized by the four major points described by Celse. The symptoms are usually associated with fever and with a biological syndrome including an increased sedimentation rate related to an elevation of inflammatory plasma proteins. The Acute Phase Reactant Proteins (orosomucoid, alpha 1-antitrypsin, alpha 1-antichymotrypsin, haptoglobin, ceruloplasmin, C reactive protein and fibrinogen) are released by the hepatocytes. The complement components C3 and C4, transferrin and alpha 2-macroglobulin can also be generated by the macrophages. At inflammation sites, the activated host phagocytes release a Leukocytic Endogenous Mediator (LEM) or Interleukin I. A circulating cleavage product of Interleukin I, called "Proteolysis Inducing Factor" induces an increased muscle proteolysis and hepatic amino acids uptake for inflammatory proteins synthesis, principaly in the form of Acute Phase Reactant Proteins. Furthermore, this monokin stimulates the T4 helpers lympocytes production of a lymphokin: Interleukin II. There is no "inflammation protein" characterized by the 5 criteria of the Clinical Biology French Society. Therefore the association of a high turn over protein (CRP) and a low turn over one (orosomucoid and/or haptoglobin) is usefull for the detection of an inflammatory process and to evaluate a therapeutic efficiency. These proteins are usually selected for early diagnosis of neonatal bacterial infections and for the diagnosis of myocardial infarction. In the present time, numerous studies using statistical methods try to separate inflammatory processes according to their etiology.

Acute-Phase Proteins↗