LPS-induced Tumor Necrosis Factor Production Research Articles

Effect of corticosteroid treatment on interleukin-1 and tumour necrosis factor secretion by monocytes from subjects with asthma.

Peripheral blood monocytes (PBM) may be activated in asthmatic patients, a condition usually reverted by corticosteroid (CS) treatment. In the present research we have evaluated the spontaneous or lipopolysaccharide (LPS)-induced production of interleukin 1 (IL-1) and tumour necrosis factor (TNF) by PBM obtained from 14 asthmatic subjects during an asthmatic attack and after 1 week of CS treatment. The control group included 20 healthy volunteers. PBM obtained during severe asthma showed a pattern of IL-1 and TNF secretion similar to that of normal subjects. After CS treatment, IL-1 levels did not change significantly in comparison to baseline values, while LPS-induced TNF production was apparently related to the degree of airway obstruction after CS treatment. In fact, TNF production by PBM from CS-responsive subjects was significantly decreased in comparison to the levels determined before CS treatment, while PBM from CS-resistant subjects produced the same cytokine levels regardless of CS treatment. The present study suggests that the determination of LPS-induced TNF secretion by PBM could be used to confirm the effectiveness of CS treatment in asthma.

Priming effect of dextran sulphates on lipopolysaccharide-induced tumour necrosis factor production in mice

Dextran sulphate (DS) 500 (M.W. 500 000) is commonly used as a reticuloendothelial (RE) blocker. We found that lipopolysaccharide (LPS)-induced tumour necrosis factor (TNF) production in sera was enhanced when mice were pretreated with DS500. When mice were pretreated with DS1000 (M.W. 1 000 000), TNF activity in sera was also significantly enhanced by the LPS injection in comparison with the saline-treated group, but not by the pretreatment with the low molecular weight of DS5 (M.W. 5 000), neutral dextran (Dex) 500, or positively-charged diethylaminoethyl dextran (DEAE-Dex) 500. The enhancement of LPS-induced TNF production occurred from 2 h after DS500 pretreatment. Pretreatment with DS500 or DS1000 significantly suppressed the carbon clearance from the blood in mice from 2 h after DS injection, but this suppression was not detected by the pretreatment with DS5, Dex500, or DEAE-Dex500. We suggest that negative-charge and high molecular weight are essential for dextran derivatives to enhance LPS-induced TNF production, and that the enhancing effect of DS is closely related to the suppression of the RE function.

Priming effect of dextran sulphates on lipopolysaccharide-induced tumour necrosis factor production in mice.

Dextran sulphate (DS) 500 (M.W. 500,000) is commonly used as a reticuloendothelial (RE) blocker. We found that lipopolysaccharide (LPS)-induced tumour necrosis factor (TNF) production in sera was enhanced when mice were pretreated with DS500. When mice were pretreated with DS1000 (M.W. 1,000,000), TNF activity in sera was also significantly enhanced by the LPS injection in comparison with the saline-treated group, but not by the pretreatment with the low molecular weight of DS5 (M.W. 5,000), neutral dextran (Dex) 500, or positively-charged diethylaminoethyl dextran (DEAE-Dex) 500. The enhancement of LPS-induced TNF production occurred from 2 h after DS500 pretreatment. Pretreatment with DS500 or DS1000 significantly suppressed the carbon clearance from the blood in mice from 2 h after DS injection, but this suppression was not detected by the pretreatment with DS5, Dex500, or DEAE-Dex500. We suggest that negative-charge and high molecular weight are essential for dextran derivatives to enhance LPS-induced TNF production, and that the enhancing effect of DS is closely related to the suppression of the RE function.

Enhancement of lipopolysaccharide-induced tumor necrosis factor production in mice by carrageenan pretreatment

Tumor necrosis factor (TNF) is a cytokine which mediates endotoxin shock and causes multiple organ damage. It is thought that macrophage (MP) activation is necessary to increase lipopolysaccharide (LPS)-induced TNF production and lethality. Carrageenan (CAR) is sulfated polygalactose which destroys MP; it is used as a MP blocker. We found that CAR pretreatment can increase both endotoxin-induced TNF production and the mortality rate in mice. The ddY mice (7 to 8 weeks old) were injected intraperitoneally with CAR (5-mg dose) and challenged intravenously with LPS 24 h later. Without CAR pretreatment, LPS doses of less than 10 micrograms did not induce TNF in sera. After pretreatment, however, about 3 x 10(3) to 4 x 10(4) U of TNF per ml was produced after LPS injection at doses of 0.1 to 10 micrograms, respectively. TNF production was significantly increased by CAR pretreatment at LPS doses of more than 10 micrograms. CAR pretreatment rendered the mice more sensitive to the lethal effect of LPS; 50% lethal doses of LPS in CAR-pretreated mice and nonpretreated mice were 26.9 and 227 micrograms, respectively. The mortality of the two groups was significantly different at doses of 50, 100, and 200 micrograms of LPS. CAR increased LPS-induced TNF production and mortality within 2 h, much earlier than MP activators, which needed at least 4 days. Our results made clear that TNF production is enhanced not only by a MP activator but also by a MP blocker.

Impaired production of tumor necrosis factor in breast cancer

Spontaneous and lipopolysaccharide (LPS)-induced production of tumor necrosis factor (TNF) by peripheral blood macrophages was investigated in breast cancer. Whereas spontaneous TNF production by macrophages derived from patients with breast cancer was comparable with the one found in healthy controls (P greater than 0.1), LPS-stimulated macrophages derived from patients in the disease-free interval as well as with metastatic breast cancer were found to produce significantly lower amounts of TNF, as compared with macrophages derived from healthy control individuals (P less than 0.0005). However, the production of TNF did not significantly differ between the two patient populations (P greater than 0.05). The impairment of LPS-induced TNF production did not depend upon such characteristics of the primary tumor as size, axillary lymph node and estrogen receptor status, or upon the fact of administration of adjuvant chemotherapy and, in patients with metastatic disease, hormone treatment. To further investigate cytokine production by macrophages, spontaneous and LPS-induced interleukin-1 (IL-1) production was investigated also. However, no difference was found between patients and controls concerning IL-1 generation. The authors thus conclude that LPS-induced TNF production was impaired in breast cancer independent of the presence of detectable metastatic disease, whereas IL-1 production remained unimpaired.

Concentrations of immunoreactive human tumor necrosis factor alpha produced by human mononuclear cells in vitro.

The concentrations of tumor necrosis factor (TNF) produced by human peripheral blood mononuclear cells (MNC) were measured using a radioimmunoassay (RIA) for human TNF. This was developed using a rabbit antiserum against human recombinant TNF (Hu rTNF), and Hu rTNF labeled with Na125I by a modification of the chloramine T method. This RIA does not detect human lymphotoxin, interleukin-1 alpha or beta, interleukin 2, interleukin 6, interferon alpha or gamma, granulocyte-macrophage-colony stimulating factor, and C5a des arg. A good correlation (r = 0.89) was found between the RIA and the cytolytic bioassay for TNF. The sensitivity of the RIA is between 3 and 78 pg/ml (median 11 pg/ml). The mean concentration of TNF in 24-h culture supernatants of human MNC exposed to different concentrations of lipopolysaccharide (LPS) was found to increase in dose-dependent fashion and then level off between 50 and 100 ng/ml. The concentrations of IL-1 beta and alpha detected by specific RIAs in these supernatants were between 0.2 and 19 ng/ml and 0.04 and 1 ng/ml, respectively. The amount of TNF produced by human MNC in vitro was determined in a cohort of 50 normal volunteers. Without exogenous stimuli, TNF concentrations were almost always below the detection limit; with 0.5 ng/ml LPS, the median concentration of TNF was 2 ng/ml, and with PHA the median was 3.8 ng/ml. In cultures performed in the presence of indomethacin significantly (p less than 0.005) more TNF was produced. Using this RIA, we could detect TNF in the circulation of mice injected with Hu rTNF. When plasma samples of patients with febrile illnesses were added directly to the RIA, TNF was not detectable, with the exception of patients with malaria. These studies demonstrate the range and sensitivity of LPS-induced and mitogen-induced production of immunoreactive TNF by human MNC in vitro without interference of similar cytokines in bioassays.