Chemotactic activity of lymphotoxin and tumour necrosis factor alpha for human neutrophils.

Lymphotoxin (TNF beta) and tumour necrosis factor alpha (TNF alpha) stimulate locomotion and chemotaxis of human blood neutrophils as measured in three assays. Both cytokines stimulate morphological polarization of neutrophils in suspension; both stimulate locomotion of neutrophils into micropore filters; both cause orientation of neutrophils towards a gradient source. Orientation in a gradient suggests a chemotactic effect. The action of both cytokines is similar but is not as strong as that of formyl peptide used as a positive control. Myelomonocytic cell lines (U937 and HL-60) develop responsiveness to formyl peptides on maturation but not to TNF alpha or beta.     

Increased gastric production of interleukin-8 and tumour necrosis factor in patients with Helicobacter pylori infection.

AIMS--To investigate the role of interleukin-8 (IL-8) and tumour necrosis factor (TNF) in patients infected with Helicobacter pylori. METHODS--The study population comprised 52 patients with dyspepsia attending for upper gastrointestinal endoscopy. Of these patients, 35 were infected with H pylori. IL-8 and TNF concentrations in plasma, gastric juice, and gastric biopsy homogenate supernatant fluid were measured by radioimmunoassay and L929 cell bioassay, respectively. RESULTS--The concentrations of IL-8 and TNF in gastric juice and gastric biopsy homogenates were substantially greater in patients infected with H pylori. In H pylori positive patients IL-8 concentrations in gastric juice and gastric biopsy homogenates were higher in those with moderate gastritis than in those with mild gastritis. There was a positive correlation between IL-8 and TNF concentrations in gastric juice and gastric biopsy homogenate supernatant fluid from H pylori positive patients. There were no significant differences between H pylori positive and negative patients with respect to IL-8 and TNF plasma concentrations. CONCLUSION--This study suggests that increased gastric production of IL-8 and TNF may be implicated in the pathogenesis of H pylori associated gastroduodenal disease.     

Distribution of endogenous tumour necrosis factor alpha in gliomas.

AIMS: To determine the distribution and cellular origin of endogenous tumour necrosis factor alpha (TNF alpha) in the cellular components of human gliomas. METHODS: Frozen sections of 26 gliomas (four astrocytomas (As); two oligoastrocytomas (OA); one ansplastic astrocytoma (AA); one anaplastic oligoastrocytoma (AOA); 18 glioblastomas (GB)) were examined immunohistochemically using antihuman TNF alpha and anti-Leu-M5 (CD11c) antibodies. Additional studies with double immunohistocchemical procedures were performed with anti-glial fibrillary acidic protein and anti-neurofilament antibodies. RESULTS: Eighty per cent of the AA, AOA, and GB (16 of 20) had a positive reaction for TNF alpha, but only 17% of As and OA (one of six) were positive. Positive cells were seen in both the tumour tissue and adjacent brain tissues. TNF alpha protein was detected not only in the tumour cells but also in the endothelium of tumour vessels as well as reactive astrocytes and neurons. CONCLUSIONS: Endogenous TNF alpha is present in cells of various origins in glial tumours including tumour vessels; however, the role of TNF alpha may be different in different types of cells or altered microenvironment.     

Stimulators of tumour necrosis factor production released by damaged erythrocytes.

We sought to characterize factors released by sonicated human erythrocytes that stimulate peripheral blood mononuclear cells (PBMC) to release tumour necrosis factor-alpha (TNF). This response is not inhibited by polymyxin B, indicating that contaminating lipopolysaccharide (LPS) is not responsible. When erythrocyte lysates are fractionated by reverse-phase chromatography using a gradient of n-propanol on Sep-Pak C18 cartridges, the TNF-inducing activity elutes as a single peak. The erythrocyte-derived TNF-inducing activity is unaffected by digestion with proteases but is destroyed by mild base hydrolysis or digestion by lipases, indicating that compounds containing ester-linked acyl chains may be essential. These properties are similar to those of TNF stimulators that we have previously identified in erythrocytes infected with malaria parasites, except that the TNF-inducing activity per cell is about 200 times higher in parasitized erythrocytes than in uninfected erythrocytes. Lipase-digested erythrocyte lysates inhibit the TNF-inducing factors of both normal and malaria-infected erythrocytes, suggesting that lipase digestion creates partial structures which compete with active components for macrophage receptors. Such receptors may recognize a common structure that contains an inositol monophosphate (IMP)-like component, as IMP also inhibits the TNF response to erythrocyte-derived factors and to parasite lysates whereas it does not affect the response to LPS. We conclude that lysed erythrocytes release specific cytokine-inducing factors that may contribute to the fever response to non-infectious tissue injury.     

Tumor necrosis factor production in patients with leprosy.

The spectrum of host responses to Mycobacterium leprae provides a model for investigating the role of cytokines in the pathogenesis of mycobacterial disease. Of particular interest is tumor necrosis factor (TNF), a cytokine which may have both antimycobacterial and immunopathologic effects. To evaluate the potential role of TNF in leprosy, we measured TNF production in response to M. leprae and its defined constituents by peripheral blood mononuclear cells from patients across the spectrum of disease. The levels of TNF induced through the stimulation of cells with M. leprae or its dominant "lipopolysaccharide," lipoarabinomannan, were higher in patients with the tuberculoid form of the disease than in those with the lepromatous form. In patients with erythema nodosum leprosum (ENL), a reactional state of lepromatous leprosy, the levels of TNF release by peripheral blood mononuclear cells were higher than in any other form of the disease. Treatment of ENL patients with thalidomide reduced TNF secretion by more than 90%. The mycolylarabinogalactan-peptidoglycan complex of Mycobacterium species, the protein-peptidoglycan complex, and muramyl dipeptide all elicited significant TNF release. Therefore, TNF release appears to be triggered by at least two major cell wall structural constituents of M. leprae, lipoarabinomannan and segments of the cell wall skeleton. The prominent TNF release in patients with the paucibacillary tuberculoid form of the disease compared with that in patients with the multibacillary lepromatous form suggests that this cytokine contributes to a resistant immune response to mycobacterial infection. However, the marked TNF release in patients with ENL indicates that TNF may also mediate immunopathologic effects, such as fever and tissue damage.     

Increased lipopolysaccharide-induced tumour necrosis factor levels and death in hypercholesterolaemic rabbits.

Nutritional-induced hypercholesterolaemia in New Zealand rabbits causes increased susceptibility to experimental infections. Rabbits fed cholesterol (0.5 g%) for 8 weeks were injected intravenously with varying doses of Escherichia coli 0127: B8 lipopolysaccharide (LPS; 3-100 micrograms/kg). The levels of cholesterol, triglycerides, tumour necrosis factor (TNF), and the survival rates of treated rabbits were then measured. Rabbits fed either normal chow or chow impregnated with sesame oil were used as controls. LPS induced higher serum TNF levels in hypercholesterolaemic rabbits than in normal rabbits or rabbits fed with chow containing sesame oil. TNF levels rose faster in hypercholesterolaemic rabbits than in normal rabbits, reaching maximum levels at 60 min and 120 min, respectively, after LPS injection. The survival rate of hypercholesterolaemic rabbits (1/11) was lower than in normal rabbits (6/7) or rabbits fed with the sesame oil chow (4/4) at the higher LPS doses. No death occurred at lower doses. One possible interpretation of these results, also supported by neutralization experiments, is that increased TNF secretion in hypercholesterolaemic rabbits raises the host's susceptibility to experimental endotoxaemia and possibly to Gram-negative infection.     

Association between tumour necrosis factor gene polymorphisms and the clinical types of patients with chronic hepatitis B virus infection

A PCR restriction fragment length polymorphism assay was used to analyse single-nucleotide polymorphisms in the tumour necrosis factor (TNF)-alpha and TNF-beta genes of 56 patients with chronic severe hepatitis B virus (HBV) infection, 71 patients who either had chronic mild HBV infection or who were asymptomatic carriers, and 90 healthy controls. The serum TNF-alpha concentrations in patients with chronic severe HBV infection were compared to those of 30 healthy controls by radioimmunoassay. The frequencies of the TNF1/2 genotype and the TNF2 allele were greater in patients with chronic severe HBV infection than in healthy controls (25% vs. 11.1%, p 0.015; 12.5% vs. 5.6%, p 0.036, respectively) and patients with chronic mild HBV infection and asymptomatic carriers (25% vs. 8.8%, p 0.011; 12.5% vs. 4.2%, p 0.015, respectively). Heterozygotes carrying the TNF2 allele had higher levels of serum TNF-alpha than homozygotes for the wild-type allele among all patients with chronic severe HBV infection (p <0.01). The genotype distribution and allele frequency of TNF-beta were similar for patients with chronic severe HBV infection and healthy controls, but the frequency of the TNF-beta*2/2 genotype in patients with chronic mild HBV infection and asymptomatic controls was lower than for healthy controls (9.9% vs. 22.4%, p 0.043) or patients with chronic severe HBV infection (9.9% vs. 26.8%, p 0.043), although this was not significant after correction for multiple testing. It was concluded that TNF-alpha gene polymorphisms may play an important role as a host factor in the progression of HBV infection.     

Tumor necrosis factor alpha stimulates killing of Mycobacterium tuberculosis by human neutrophils

The ability of human neutrophils to aid in defense against pulmonary infection with Mycobacterium tuberculosis is controversial. In this study, we have shown that neutrophils respond to and phagocytose M. tuberculosis in human lesions. Neutrophils from healthy individuals were able to kill significant fractions of an inoculum of M. tuberculosis within 1 h of phagocytosis, and this ability was enhanced by tumor necrosis factor alpha but not by gamma interferon. The mycobactericidal mechanism was nonoxidative, as inhibitors of reactive oxygen or reactive nitrogen intermediates did not interfere with killing. However, the mycobactericidal mechanism was associated with increased exposure of intracellular M. tuberculosis to neutrophil defensins. In vitro, human neutrophil peptides 1 to 3 were not able to kill the bacilli even at much higher levels. These studies support the concept that human neutrophils are directly involved in defense against infection with M. tuberculosis.     

Priming and stimulation of bovine neutrophils by recombinant human interleukin-1 alpha and tumor necrosis factor alpha.

We have examined the in vitro effects of two recombinant human monokines, interleukin-1 alpha (rHuIL-1 alpha) and tumor necrosis factor alpha (rHuTNF alpha), on bovine neutrophil functions. Both rHuIL-1 alpha (10 to 1,000 ng/ml) and rHuTNF alpha (5 to 50 ng/ml) directly stimulated the oxidative burst of bovine neutrophils as measured by Luminol-dependent chemiluminescence, superoxide anion generation, and hydrogen peroxide production. In addition, both rHuIL-1 alpha (1 to 1,000 ng/ml) and rHuTNF alpha (0.5 to 50 ng/ml) primed bovine neutrophils for an enhanced oxidative burst to subsequent stimulation with opsonized zymosan. Neutrophils pre-treated with either monokine exhibited an earlier, as well as stronger, zymosan-stimulated Luminol-dependent chemiluminescence response, as compared to untreated neutrophils. Exposure of bovine neutrophils to combinations of suboptimal doses of rHuIL-1 alpha (10 and 100 ng/ml) and rHuTNF alpha (0.5 and 5 ng/ml) resulted in a synergistic stimulation of Luminol-dependent chemiluminescence, whereas, no synergism was observed when using optimal doses of each monokine. Pre-incubation of bovine neutrophils with an optimal concentration of recombinant bovine interferon gamma (100 U/ml), and either rHuIL-1 alpha or rHuTNF alpha, further augmented the maximal oxidative response of neutrophils stimulated with opsonized zymosan. Bovine neutrophils released both primary and secondary granules in response to rHuIL-1 alpha and rHuTNF alpha, and also exhibited enhanced adherence in the presence of either monokine.     

The production of tumour necrosis factor a (TNF-{alpha}) by human endometrial cells in culture

The production of tumour necrosis factor a (TNF-) by culturedhuman endometrial epithelial and stromal cells prepared fromendometrium obtained at different stages in the menstrual cyclehas been investigated. TNF- was not detectable in the supernatantsof stromal cell cultures prepared from endometrial tissue obtainedat any time in the menstrual cycle. TNF- production by endometrialepithelial cells in culture varied depending on the time inthe cycle at which the endometrial tissue was taken. Cells preparedfrom tissue obtained during the late proliferative phase ofthe cycle produced more TNF- than those prepared from tissueobtained at other times in the cycle. In addition, a small increasein TNF- production was seen by cells prepared from tissue obtainedduring the mid-secretory phase of the cycle. Interieukin 1 (IL-1)(1.4–140 pmol/1) caused a dose-dependent increase in TNF-production by cells prepared from both proliferative and secretoryendometrium. Maximum LL-1-stimulated increases in TNF- productionwere similar in cells from both proUferative and secretory endometriumand typically reached from four to 10 times basal values. Highdoses of progesterone, either alone or in the presence of oestradiol,also affected TNF-a production by epithelial cells. TNF- productionby cells prepared from proliferative endometrium was increasedby progesterone. In contrast, TNF- production by cells preparedfrom secretory endometrium was decreased in the presence ofprogesterone. The effects of steroids on TNF- production wereless marked than that of IL-1, with values increasing or decreasingto a maximum of three times the basal value. Placental protein14 (PP14) (0.18 and 1.8 nmol/1) also increased TNF- productionby cells prepared from proliferative tissue, but had no effecton its production by cells prepared from secretory endometrium.PP14-stimulated TNF- levels typically only reached a maximumof two times basal values.     

Glucocorticoids suppress the production of tumour necrosis factor by lipopolysaccharide-stimulated human monocytes.

We have investigated the modulating effect of steroids on the in vitro production of tumour necrosis factor (TNF) by lipopolysaccharide (LPS)-stimulated human monocytes. Dexamethasone, at concentrations ranging from 10(-8) to 10(-6) M, and cortisol, at concentrations 10(-7) and 10(-6) M, suppressed the TNF production in a dose-dependent manner. The highest concentrations of dexamethasone or cortisol reduced the TNF production to 21 +/- 2% and 48 +/- 8% of the control value, respectively. The effect of dexamethasone was time dependent, and an incubation time of 48 hr was required to reduce the TNF production to 21% of control. The effect of dexamethasone decreased when the incubation time became shorter, and the mean TNF production ranged from 49% to 72% of control when dexamethasone was added later than 8 hr before LPS addition, at the time of LPS addition, or within 1 hr after LPS addition. The magnitude of the TNF-suppressing effect of dexamethasone varied greatly from donor to donor. Only the glucocorticoids, and not the sex steroids or the mineralocorticoids, significantly reduced the TNF production.     

Increased soluble p55 and p75 tumour necrosis factor-alpha receptors in patients with hepatitis C-associated mixed cryoglobulinaemia

To investigate whether tumour necrosis factor alpha (TNFalpha) plays a role in the pathogenesis of hepatitis C virus-associated mixed cryoglobulinaemia (HCV-MC), we measured soluble TNFalpha and its soluble p55 (sTNFR1) and p75 (sTNFR2) receptors in the serum of patients with HCV-MC. TNFalpha, sTNFR1 and sTNFR2 were measured in the serum of 32 patients with HCV-MC, 18 patients with hepatitis C without MC (HCV) and 18 healthy volunteers, using specific immunoassays. Correlations between clinical and biological parameters and the concentrations of TNFalpha and sTNFRs were established by studying detailed clinical records of the 32 HCV-MC patients. Although higher, TNFalpha levels were not significantly different in HCV-MC patients compared with healthy or HCV controls. sTNFR1 and sTNFR2, however, were significantly higher in HCV-MC compared with controls or with HCV patients, and higher concentrations of sTNFR1 and sTNFR2 were observed in patients with severe visceral vasculitis, compared with patients with limited purpura. sTNFR1 concentrations positively correlated with fibrinogen levels but TNFalpha, sTNFR1 and sTNFR2 did not correlate with other biological parameters such as rheumatoid factor concentrations, CH50 or C4 values. These data suggest a role for TNFalpha in the pathogenesis of the immune complex-mediated vasculitis associated with HCV-MC.     

Immunohistochemical studies of intrahepatic tumour necrosis factor alpha in chronic liver disease.

To determine the intrahepatic production of tumour necrosis factor alpha (TNF alpha) in chronic liver disease three monoclonal antibodies were used against TNF alpha in immunohistochemical studies of liver tissue sections from patients with chronic liver disease. All three monoclonal antibodies stained infiltrating mononuclear cells. Monoclonal antibody II 7C2 also stained the cytoplasm or nucleus, or both, of a varied number of hepatocytes from nine patients with chronic hepatitis B virus infection, suggesting that the antigenic epitope related to hepatitis B core antigen (HBcAg) crossreacted with II7C2. The other two monoclonal antibodies, III2F3 and IV3E5, stained significantly larger numbers of mononuclear cells in cases of chronic active hepatitis B than in chronic persistent hepatitis B, or hepatitis B related liver cirrhosis. III2F3 stained significantly larger numbers of mononuclear cells in non-A, non-B chronic active hepatitis than in chronic persistent hepatitis B or hepatitis B related liver cirrhosis. These results indicate that TNF alpha is produced and secreted by infiltrating mononuclear cells in focal inflammatory areas of the liver, and suggest that TNF alpha may have a role in the inflammatory activity of chronic liver disease.     

Interleukin-1 and tumour necrosis factor mRNA expression in rheumatoid arthritis: prolonged production of IL-1 alpha.

In rheumatoid arthritis there is a chronic immune and inflammatory reaction which can lead to the destruction of the diseased joint. Cytokine gene expression was studied in synovial cells using cDNA probes specific for human interleukin 1 (IL-1), -alpha and IL-1 beta, tumour necrosis factor (TNF), -alpha and TNF beta (lymphotoxin); protein molecules which induce cartilage degradation and bone resorption. In all cases studied, IL-1 mRNA was present in freshly isolated synovial cells from fluid or membrane. Compared to levels of IL-1 mRNA found in optimally activated normal blood mononuclear cells, the levels of IL-1 alpha mRNA were high in seven of the nine patients studied, whereas IL-1 beta mRNA, the dominant form in blood, was relatively lower. TNF alpha and TNF beta mRNA were also detected. Rheumatoid synovial cells, cultured without any stimulus, continued to express high levels of IL-1 alpha mRNA for up to 5 days, compared to the 24 h response of activated blood cells; IL-1 beta mRNA in culture was also prolonged. Cultures of rheumatoid joint cells produced IL-1 bioactivity, with roughly equal amounts of IL-1 alpha and beta, as assessed using neutralizing antibodies. TNF bioactivity was also detected which may be of importance as TNF induces the production of IL-1. The finding of these mediators produced in large amounts in active rheumatoid synovial cells suggests that mutually stimulatory cell interactions, mediated by these molecules, may be important in the chronic inflammation and tissue destruction in rheumatoid arthritis.     

Hepatic expression of tumour necrosis factor-alpha in chronic hepatitis B virus infection.

AIM--To determine the hepatic expression of tumour necrosis factor-alpha (TNF alpha) in patients with chronic hepatitis B virus (HBV) infection. METHODS--Frozen liver biopsy sections from 19 patients with chronic HBV infection were studied, 12 of whom were HBeAg positive and 10 serum HBV DNA positive. Hepatic expression of TNF alpha was determined using immunohistochemistry. RESULTS--Only infiltrating mononuclear cells showed immunoreactive staining for TNF alpha (median 2, range 0-3; n = 19) which appeared as diffuse positive staining material in the cytoplasm. Patients with active liver disease, assessed histologically and biochemically, had a higher level of expression, both in the number of TNF alpha positive cells and the proportion of TNF alpha positive infiltrating mononuclear cells. There was no correlation between the expression of TNF alpha and serological parameters of viral infection (HBeAg and HBV DNA status and HBV DNA concentrations). CONCLUSION--Hepatic expression of TNF alpha is increased in chronic HBV infection and is related to the activity of liver disease and not to the level of HBV replication.     

Increased expression and occupancy of receptors for tumour necrosis factor on blood monocytes from tuberculosis patients.

Blood monocytes from tuberculosis patients release high amounts of tumour necrosis factor-alpha (TNF-alpha). Because the biological efficiency of TNF-alpha would depend on the expression of TNF-alpha receptors on target cells, we thought to analyse the capacity of blood monocytes from a group of patients with pulmonary tuberculosis to bind 125I-TNF-alpha. We report a slight but not significant enhancement in specific binding of 125I-TNF-alpha on monocytes of 15 consecutively studied patients compared with 10 controls. Per cent cell surface bound and internalized 125I-TNF-alpha was identical in the two groups. To evaluate the receptor occupancy by endogenously generated TNF-alpha, similar experiments were performed after cell exposure to low-pH glycine buffer. Under these conditions, specific binding of 125I-TNF-alpha was significantly higher on tuberculosis monocytes compared with control monocytes. Moreover, the occupancy of TNF-alpha receptors by endogenously generated TNF-alpha that was found to be significantly higher on tuberculosis monocytes than on control monocytes, was directly related to the enhanced capacity of mononuclear cells to generate TNF-alpha in vitro. It normalized after 3 months of antituberculous therapy. Scatchard analysis of the binding data revealed that tuberculosis infection caused a significant increase in high affinity 125I-TNF-alpha binding to monocytes without any significant change in the dissociation constant. Collectively, these results indicate an up-regulation of TNF-alpha generation and binding to blood monocytes in patients with pulmonary tuberculosis. They provide support to the hypothesis that TNF-alpha is of critical importance in the pathogenesis of this infection.     

Production of tumor necrosis factor alpha by monocytes from patients with pulmonary tuberculosis.

We studied the production of tumor necrosis factor alpha (TNF-alpha) by peripheral blood monocytes taken from patients with pulmonary tuberculosis and from healthy controls. It was found that the monocytes from patients with newly diagnosed tuberculosis released significantly greater amounts of TNF-alpha in vitro in response to lipopolysaccharide than did those from healthy controls (P less than 0.05). However, the monocytes from patients with chronic refractory tuberculosis released significantly lower amounts of TNF-alpha than did those from patients with newly diagnosed tuberculosis (P less than 0.005). Even when the cells were primed for 24 h with 500 U of recombinant interferon gamma per ml, the same pattern of results was observed. The depressed TNF-alpha production by the monocytes from patients with chronic refractory tuberculosis was also shown in response to Mycobacterium bovis BCG. This depressed TNF-alpha production did not recover, even when cultured for 1 to 7 days in the sera of healthy individuals. The sera from patients with chronic refractory tuberculosis did not have any suppressive effect on the lipopolysaccharide-induced TNF-alpha production. Thus, it was demonstrated that the levels of TNF-alpha produced by monocytes were related to the disease states of pulmonary tuberculosis and that the depressed TNF-alpha production by monocytes in patients with chronic refractory tuberculosis might not be acquired.