Biomedical subjects

M J Thomassen

Publications and source records attributed to M J Thomassen.

At least 37 records · Page 2Linked to original sources

PubMed1997

Perflubron decreases inflammatory cytokine production by human alveolar macrophages.

OBJECTIVE: To determine whether inflammatory cytokine production by stimulated human alveolar macrophages is affected by perflubron exposure. DESIGN: Controlled laboratory investigation of alveolar macrophage function in vitro. SETTING: Research laboratory. SUBJECTS: Cultured alveolar macrophages obtained by bronchoalveolar lavage from eleven normal volunteers. INTERVENTIONS: Endotoxin-stimulated alveolar macrophages were treated with perflubron. MEASUREMENTS AND MAIN RESULTS: Alveolar macrophages were stimulated for 1 hr with lipopolysaccharide and then treated with perflubron for 23 hrs. Cell-free supernatants were collected and cytokines were assayed by enzyme-linked immunosorbent assay. Tumor necrosis factor-alpha, interleukin-1, and interleukin-6 were stimulated by lipopolysaccharide (endotoxin) and all of these cytokines were significantly (p < .05) inhibited by perflubron. Cell viability was not affected by perflubron. Basal cytokine concentrations from unstimulated alveolar macrophages were not altered by perflubron. CONCLUSIONS: Exposure of stimulated human alveolar macrophages to perflubron in vitro decreases cytokine production. This observation suggests that perflubron may have anti-inflammatory activity.

Bronchoalveolar Lavage↗

PubMed1997

Decreased Cu,Zn-SOD activity in asthmatic airway epithelium: correction by inhaled corticosteroid in vivo.

To investigate the antioxidant response of respiratory epithelium to the chronic airway inflammation in asthma, the major intracellular antioxidants [copper and zinc-containing superoxide dismutase (Cu,Zn-SOD) and manganese-containing SOD (Mn-SOD), catalase, and glutathione peroxidase] were quantitated in bronchial epithelial cells of healthy control and asthmatic individuals. Although catalase and glutathione peroxidase in bronchial epithelium of asthmatics were similar to control SOD activity in asthmatics not on inhaled corticosteroid (-CS) was lower than asthmatics on inhaled corticosteroid (+CS) and controls. Investigation of Mn-SOD and Cu,Zn-SOD activities revealed that the lower SOD activity in asthmatics -CS was because of decreased Cu,Zn-SOD activity. However, Mn-SOD and Cu,Zn-SOD mRNA and protein levels were similar among asthmatics -CS, asthmatics +CS, and controls. Importantly, Cu,Zn-SOD specific activity in asthmatics -CS was decreased in comparison with control and asthmatics +CS. Furthermore, in paired comparisons of asthmatics -CS and +CS, inhaled corticosteroids resulted in normalization of bronchial epithelial Cu,Zn-SOD specific activity. These findings suggest loss of Cu,Zn-SOD activity in asthma is related to inflammation, perhaps through oxidant inactivation of Cu,Zn-SOD protein.

Administration, Inhalation↗

PubMed1997

Nitric oxide inhibits inflammatory cytokine production by human alveolar macrophages.

High levels of nitric oxide (NO) have been reported in exhaled air of asthmatic individuals. Because alveolar macrophages (AM) are major producers of cytokines, and bronchoalveolar lavage fluid (BALF) from asthmatic individuals contains increased levels of inflammatory cytokines, this study was undertaken to determine whether NO modified the production of inflammatory cytokines by human AM. AM were obtained from normal volunteers by fiberoptic bronchoscopy. Tumor necrosis factor-alpha (TNF-alpha) production stimulated by lipopolysaccharide (LPS; 0.5 microg/ml) was measured with an enzyme-linked immunosorbent assay (ELISA). NO generated from 2,2-(hydroxynitrosohydrazono)-bis-ethanamine (DETA NONOate) (0.1 to 1.0 mM) inhibited TNF-alpha secretion in a dose-dependent manner. At 1 mM DETA NONOate, mean inhibition (+/- SEM) of TNF-alpha secretion was 56 +/- 4% (P = 0.002). To determine whether this effect was cytokine specific, interleukin-1beta (IL-1beta) and macrophage inflammatory protein-1alpha (MIP-1alpha) were evaluated, and DETA NONOate was also found to inhibit both of these cytokines. Basal cytokine levels from unstimulated AM were unaffected by NO. These findings indicate that NO is a potent inhibitor of cytokine production by stimulated human AM.

Cell Survival↗

PubMed1996

Activation of alveolar macrophage TNF and MCP-1 expression in vivo by a synthetic peptide of C-reactive protein.

Administration of multilamellar vesicles (MLV) encapsulating a synthetic peptide (RS-83277) derived from human C-reactive protein (CRP) augments anti-tumor activity of murine alveolar macrophages and reduces established pulmonary metastases of experimental tumors. To explore mechanisms involved in these phenomena, we investigated cytokine and integrin (CDllb) expression of bronchoalveolar lavage (BAL)-derived alveolar macrophages in control (blank MLV) and RS-83277-MLV-treated C57BI mice. Alveolar macrophage production of tumor necrosis factor alpha (TNF-alpha) and monocyte chemoattractant bioactivity increased at 48 h after treatment with RS-83277-MLV but not control MLV. Chemoattractant activity was neutralized by antibody to monocyte chemoattractant protein-1 (MCP-1), but not irrelevant immunoglobulin G(IgG). Changes were reflected by augmented TNF-alpha and MCP-1 mRNA levels in pulmonary tissue and enhanced CD11b expression on mononuclear leukocytes derived from total lung tissue, but not on BAL-derived alveolar macrophages. Results suggest that RS-83277-MLV treatment is associated with activation of alveolar macrophage TNF-alpha and MCP-1 production and up-regulation of adhesion molecules on pulmonary mononuclear leukocytes but not on alveolar macrophages.

Amino Acid Sequence↗

PubMed1996

Regulation of human alveolar macrophage inflammatory cytokine production by interleukin-10.

Alveolar macrophages are the primary source of inflammatory cytokine production in the lung. Both site-specific and differentiation-specific factors play a role in cytokine production, and regulation of this activity in alveolar macrophages is distinctly different from that of circulating blood monocytes. Interleukin-10 (IL-10) inhibits the production of inflammatory cytokines [tumor necrosis factor (TNF)-alpha, interleukin-1 (IL-1), interleukin-6 (IL-6), and interleukin-8 (IL-8)] and enhances production of interleukin-1-receptor antagonist (IL-1ra) from endotoxin-stimulated human monocytes, but the effect of IL-10 on such activity in alveolar macrophages is unknown. This study was undertaken to determine the effect of recombinant IL-10 on endotoxin-stimulated cytokine production by human alveolar macrophages. TNF, IL-1, IL-6, and IL-8 secretions were significantly (P < 0.05) stimulated by endotoxin [lipopolysaccharide (LPS)] and were all significantly (P < 0.05) inhibited (median inhibition = 43%) by IL-10 (10 ng/ml). In contrast, IL-1ra was not stimulated by LPS and basal levels were not affected by IL-10. LPS also did not significantly elevate alveolar macrophage IL-10 secretion (< 100 pg/ml) and basal levels were undetectable (< 15 pg/ml). This potent inhibitory activity of IL-10 on inflammatory cytokine production by human alveolar macrophages suggests that exogenous IL-10 may be useful in treatment of inflammatory lung diseases such as adult respiratory distress syndrome.

Cytokines↗

PubMed1996

Surfactant downregulates synthesis of DNA and inflammatory mediators in normal human lung fibroblasts.

The initial inflammatory event in the adult respiratory distress syndrome (ARDS) is followed by fibroproliferation and a cascade of fibroblast-derived mediators. Because lung fibroblasts may be exposed to surfactant as well as inflammatory cytokines during ARDS, we hypothesized that surfactant might modulate fibroblast activity. We previously demonstrated that surfactant inhibited production of inflammatory cytokines from endotoxin-stimulated human alveolar macrophages. In the current study the effects of surfactant on normal human lung fibroblast proliferative capacity and mediator production were examined. Both synthetic (Exosurf) and natural (Survanta) surfactant inhibited fibroblast [3H]thymidine incorporation. Examination of pre-S-phase events indicated stimulation of the immediate response gene, c-fos, and no effect on the G1/S cyclin, cyclin D1, suggesting that the surfactant block occurred elsewhere before S phase. The antioxidant N-acetyl-L-cysteine (NAC), like surfactant, inhibited [3H]thymidine incorporation. Furthermore, menadione, a generator of intracellular H2O2, stimulated fibroblast [3H]thymidine incorporation, and this was inhibited by surfactant. Interleukin-1 (IL-1)-stimulated secretion of the inflammatory mediators, IL-6 and prostaglandin E2, was also inhibited by surfactant. These data suggest that surfactant may modify lung fibroblast participation in ARDS sequelae by downregulating DNA synthesis and secondary inflammatory mediator production.

Antioxidants↗

PubMed1996

Surfactant suppresses NF-kappa B activation in human monocytic cells.

In addition to biophysical properties, pulmonary surfactant has immunomodulatory activity. We previously demonstrated that both synthetic (Exosurf) and modified natural surfactant (Survanta) downregulated endotoxin-stimulated inflammatory c ytokine mRNA levels and protein products (tumor necrosis factor-alpha [TNF], interleukin-1-beta [IL-1], interleukin-6 [IL-6]) in human alveolar macrophages. In this study, we report that both Exosurf and Survanta suppress TNF mRNA and secretion (85 +/- 4% mean percent inhibition +/- SEM by Exosurf; 71 +/- 6% by Survanta) by endotoxin-stimulated THP-1, a human monocytic cell line. Because surfactant downregulated inflammatory cytokine production similarly in both normal human alveolar macrophages and the THP-1 cell line, we used this cell line to investigate whether surfactant affected transcriptional mechanisms. Specifically, we examined nuclear factor-kappa B (NF-kappa B) activation because it is crucial in transcriptional regulation of many inflammatory cytokine genes including TNF, IL-1, and IL-6. Electrophoretic mobility shift assays showed that both surfactants decreased activation of NF-kappa B. The presence of both p65 and p50 NF-kappa B components in LPS-activated THP-1 cells was confirmed by specific antibody induction of supershifts in mobility assays. These results are the first to suggest that surfactant's suppressive effects on inflammatory cytokine production may involve transcriptional regulation through inhibition of NF-kappa B activation.

Base Sequence↗

PubMed1995

Human monocytes produce monocyte chemoattractant protein 1 (MCP-1) in response to a synthetic peptide derived from C-reactive protein.

We reported previously that a synthetic peptide (RS-83277) derived from human C-reactive protein (CRP) augmented human monocyte/macrophage tumoricidal activity and cytokine production. RS-83287, a synthetic peptide derived from a different CRP site, was ineffective. Because chemoattractant properties have been attributed to some CRP-derived peptides, we hypothesized that RS-83277, in addition to activating effects, might promote human monocyte chemotaxis. Results indicated that neither CRP peptide RS-83277 nor RS-83287 was, itself, a chemoattractant. RS-83277, but not RS-83287, however, elicited time-dependent production of monocyte chemoattractant activity in conditioned media (CM) of cultured human mononuclear leukocytes and purified, adherent monocytes (MO). CM from nonadherent MO contained no activity, indicating that adherence was required for monocyte response. Monocyte chemoattractant activity was dose-dependent and was removed by treatment with immobilized antibody to human monocyte chemoattractant protein 1 (MCP-1) but not by irrelevant IgG. These results indicate that a specific peptide segment of CRP acts upon human adherent monocytes to promote production of the autocrine chemotactic and activating factor MCP-1. Data suggest that degraded CRP represents a complex source of biologically active peptides which, among other effects, may amplify monocyte recruitment to sites of injury.

C-Reactive Protein↗

PubMed1995

Regulation of human alveolar macrophage inflammatory cytokines by tyloxapol: a component of the synthetic surfactant Exosurf.

We previously demonstrated that the synthetic surfactant Exosurf and a modified natural surfactant, Survanta, both down-regulated endotoxin-stimulated production of inflammatory cytokines (tumor necrosis factor-alpha, interleukin-1 beta, interleukin-6) in human alveolar macrophages. To further characterize the source of the inhibitory effect of surfactant, the three individual components of Exosurf were evaluated. Dipalmitoylphosphatidylcholine had no effect on endotoxin-stimulated cytokine secretion. Cetyl alcohol (spreading agent) compromised macrophage function as measured by adherence. However, at concentrations equivalent to those found in the complete surfactant (Exosurf) preparation, tyloxapol (nonionic dispersing agent) was inhibitory in a dose-dependent manner. The viability of alveolar macrophages as assessed by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide cleavage assay was not affected by incubation in Exosurf or any of its individual components. Cytokine secretion and mRNA levels of endotoxin-stimulated alveolar macrophages were decreased by tyloxapol. These data suggest that tyloxapol alone, like Exosurf, has an inhibitory effect on cytokine production which may be pretranslationally mediated.

Cells, Cultured↗

PubMed1994

Combination therapy with a synthetic peptide of C-reactive protein and interleukin 2: augmented survival and eradication of pulmonary metastases.

A synthetic peptide (RS-83277) derived from the structure of human C-reactive protein (CRP) was previously shown to have antitumor activity in three different murine tumor models when administered in multilamellar vesicles (MLV). The therapeutic effects were comparable to those seen with MLV-encapsulated native CRP. The present study evaluated the therapeutic and immunomodulatory effects of administering CRP peptide RS-83277 MLV simultaneously with low-dose recombinant interleukin-2 (IL-2) to C57Bl/6 mice bearing established pulmonary metastases of fibrosarcoma T241. Results demonstrated that the capacity of RS-83277 MLV to inhibit tumor metastases and prolong survival was significantly augmented by combination with 10,000 U/day IL-2 i.p. Treated animals showed no evidence of toxicity. By immunohistochemistry, increased Thy 1.2+ cells were detectable in lungs of RS-83277 MLV/IL-2-treated animals compared to those receiving RS-83277 MLV alone. Circulating tumor necrosis factor alpha (TNF) and interferon (IFN) were not detectable in animals receiving RS-83277 MLV alone, but TNF was significantly elevated in animals receiving IL-2. In the presence of combination therapy, however, circulating TNF was not detectable. Results suggest that the combination of synthetic CRP peptide RS-83277 MLV and low-dose IL-2 offers a therapeutic advantage over either agent alone.

Animals↗

PubMed1994

Characterization of exosurf (surfactant)-mediated suppression of stimulated human alveolar macrophage cytokine responses.

Previous studies in our laboratory demonstrated that the synthetic surfactant Exosurf (Burroughs Wellcome Co.) inhibited endotoxin-stimulated cytokine secretion from human alveolar macrophages in vitro. The purpose of the present study was to further characterize the suppressive effects of Exosurf, which consists of dipalmitoylphosphatidylcholine (DPPC), cetyl alcohol (spreading agent), and tyloxapol (nonionic dispersing agent). Suppression was not stimulus specific in that Exosurf also significantly reduced cytokine production elicited by either Staphylococcus aureus or recombinant interleukin-1. Suppression was also mediated by a modified bovine surfactant (Survanta), which, in contrast to Exosurf, contains the surfactant-associated proteins B and C, and several different phospholipids, but no cetyl alcohol or tyloxapol. This suggests that suppression of macrophage cytokines is not specific to Exosurf. Both cell associated and secreted tumor necrosis factor and interleukin-1 were reduced by Exosurf, indicating that Exosurf is not simply blocking cytokine release. At 3 h, cytokine mRNA levels were not different between Exosurf-treated and untreated cells. However, at 8 and 24 h, cytokine mRNA levels were lower in Exosurf-treated cells. The observations that mRNA levels were decreased at 8 and 24 h and that cellular cytokine release was not blocked suggest that Exosurf's effect may in part be pretranslationally mediated. Collectively, these data add to previous work indicating that pulmonary surfactant may play a critical role in reducing inflammatory cytokine production associated with the adult respiratory distress syndrome and similar disorders.

Adult↗

PubMed1993

Phase I trial of recombinant granulocyte-macrophage colony-stimulating factor in patients with lung cancer: clinical and immunologic effects.

Recombinant granulocyte-macrophage colony-stimulating factor (rhuGM-CSF) may enhance the functional activity of monocytes and macrophages in vitro and in vivo and thereby have antitumor activity. A phase I trial using rhuGM-CSF was performed; the trial included 17 patients with unresectable and/or metastatic lung cancer. rhuGM-CSF was administered as a continuous infusion for 14 days at four dose levels: 60 micrograms/m2, 125 micrograms/m2, 250 micrograms/m2, and 500 micrograms/m2. Dose-limiting toxicity was pulmonary and occurred at 500 micrograms/m2, with the maximal tolerated dose (MTD) identified as 250 micrograms/m2. The hematologic effects of rhuGM-CSF included leukocytosis with significant correlations between dose level and the numbers of neutrophils, monocytes, eosinophils, and lymphocytes. Bronchoalveolar lavage was performed for 14 patients, and no effect on alveolar macrophage numbers was detected. Tumor biopsies were obtained in two patients, and no changes in macrophage infiltrates were detected with use of immunohistochemical studies. Serum levels of GM-CSF reached a steady state during week one and decreased or were undetectable during week two. No evidence of tumor regression was seen. rhuGM-CSF when administered as a continuous infusion was well tolerated and appears to modulate monocyte numbers and function in vivo.

Adult↗

PubMed1993

Therapeutic effects of a synthetic peptide of C-reactive protein in pre-clinical tumor models.

Previous studies have shown that multilamellar vesicles (MLV) or other carriers containing purified human C-reactive protein (CRP) have therapeutic activity in preclinical tumor models. Here we evaluated the therapeutic effects of MLV containing novel synthetic peptides, derived from the structure of CRP, on the extent of (a) established lung metastases of fibrosarcoma T241 in C57Bl/6 mice, (b) survival of C57Bl/6 mice bearing established liver metastases of colon carcinoma MCA-38, and (c) primary tumor growth of Renca renal carcinoma in Balb/c mice. In all cases, a single synthetic CRP peptide, RS-83277, demonstrated significant antitumor effects comparable to that seen with intact CRP. Two other synthetic CRP peptides, RS-83287 and RS-83147, showed no therapeutic activity and were comparable to control MLV containing only buffer. None of the peptides contained sequences homologous with that of the phagocyte stimulant, tuftsin. Activity of MLV-encapsulated RS-83277 was dose-dependent, and a comparable dose of the soluble peptide, given either alone or following injection of buffer-MLV, was ineffective. These results demonstrate immunotherapeutic potential for a novel synthetic peptide derived from CRP, and endogenous acute-phase protein.

Adenocarcinoma↗

PubMed1993

Activation of human monocytes and alveolar macrophages by a synthetic peptide of C-reactive protein.

We have previously shown that native human C-reactive protein (CRP) produces antitumor effects in experimental animals, and that these effects are mediated primarily through macrophages. More recently, we have observed that RS-83277, a synthetic peptide derived from CRP, appears to mimic the antitumor effects of native CRP. The purpose of this study was to determine the effects of RS-83277 on normal human monocyte and alveolar macrophage tumoricidal activity, and cytokine secretion. At optimal doses of 250-500 micrograms/ml, RS-83277 significantly enhanced tumoricidal activity of both monocytes and macrophages. RS-83287, a CRP peptide derived from a different site, had no effect at these doses. Specificity of RS-83277 for monocyte/macrophage-mediated cytotoxic activity was demonstrated by the failure of RS-83277 to enhance either natural killer (NK) or lymphokine-activated killer (LAK) cell-mediated activity. RS-83277 also augmented secretion of interleukin-1-beta (IL-1 beta) and interleukin-6 (IL-6) by monocytes. These data suggest a role for synthetic CRP peptide, RS-83277, as a novel biological response modifier in cancer therapy.

C-Reactive Protein↗

PubMed1993

Immunomodulatory effects of recombinant interleukin-3 treatment on human alveolar macrophages and monocytes.

The purpose of these studies was to examine the effects of in vivo and in vitro recombinant IL-3 treatment on alveolar macrophage and monocyte activities associated with antitumor and antimicrobial properties. Alveolar macrophages and blood monocytes from 6 patients receiving IL-3 (125-500 micrograms/m2/day) subcutaneously were isolated before therapy and at various times during the 15 days of therapy. Results indicated that tumor necrosis factor-alpha (TNF), interleukin-1 beta (IL-1), and interleukin-6 (IL-6) secretion were enhanced from monocytes of all patients and from alveolar macrophages of patients receiving 500 micrograms/m2/day IL-3. Constitutive cytokine gene expression was present before therapy, but further enhancement was not detectable during therapy, suggesting a rapid time course of cytokine gene transcription and translation. Serum neopterin levels were elevated 2-5 fold in all patient compatible with the presence of augmented monocyte/macrophage activity. Peak levels of neopterin did not coincide with peak levels of cytokine secretion. In vitro studies of IL-3-treated normal alveolar macrophage and monocyte population demonstrated that IL-3 significantly augmented TNF and IL-6 secretion in monocytes, but not in alveolar macrophages. These differences in alveolar macrophage cytokine secretion observed after in vivo and in vitro IL-3 treatment may reflect the involvement of other cell populations in IL-3 modulation of alveolar macrophages in vivo. Monocytes, in contrast were comparably activated by IL-3 whether presented in vitro or in vivo.

Biopterins↗

PubMed1992

Synthetic surfactant (Exosurf) inhibits endotoxin-stimulated cytokine secretion by human alveolar macrophages.

Tumor necrosis factor-alpha (TNF), interleukin-1 beta (IL-1), interleukin-6 (IL-6), and interleukin-8 (IL-8) are inflammatory cytokines produced by alveolar macrophages (AMs) and implicated in sepsis-related adult respiratory distress syndrome (ARDS). Preliminary findings from clinical trials suggest that aerosolized delivery of the synthetic surfactant Exosurf (Burroughs Wellcome Co.) reduces mortality in patients with sepsis-induced ARDS. The purpose of the present study was to examine the effect of Exosurf on inflammatory cytokine secretion from AMs in vitro. AMs were obtained from normal nonsmoking adult volunteers. Secreted TNF, IL-1, IL-6, and IL-8 were measured by enzyme-linked immunoassays in 24 h culture fluids of AMs. Exosurf inhibited LPS-stimulated TNF, IL-1, and IL-6 secretion in a dose-dependent fashion. IL-8 secretion was not affected by Exosurf under these conditions. However, if AMs were preincubated for 24 h in media and then LPS-stimulated, IL-8 secretion was inhibited by Exosurf. Regulation of IL-8 production may differ from TNF, IL-1, and IL-6. Unstimulated cytokine secretion was not affected by any of the tested concentrations of Exosurf. The inhibitory effect of Exosurf on endotoxin-induced cytokine secretion by human AMs suggests that Exosurf may modulate inflammatory cytokine production in the lung.

Cytokines↗

PubMed1991

Induction of cytokine messenger RNA and secretion in alveolar macrophages and blood monocytes from patients with lung cancer receiving granulocyte-macrophage colony-stimulating factor therapy.

Human granulocyte-macrophage colony-stimulating factor (GM-CSF) promotes the proliferation and differentiation of hematopoietic progenitor cells. Although preliminary data are available from clinical trials, the effect of GM-CSF on gene expression of immunocompetent cells in treated patients has not been studied. We previously demonstrated that in vitro treatment with GM-CSF also enhances maturation-related anti-tumor activities in mononuclear phagocytes. The purpose of the present study was to examine the effects of in vivo recombinant GM-CSF therapy on alveolar macrophages and blood monocytes, to determine if these cells demonstrated differential expression of cytokine genes, cytokine production, and tumoricidal activity. Alveolar macrophages and blood monocytes were isolated from 13 patients receiving a range of GM-CSF doses (60-250 micrograms/m2/day) by continuous infusion over a 2-week period. Both monocytes and macrophages were isolated prior to therapy and at day 10 of the infusion. Monocytes, in addition, were isolated on day 3 of infusion. Results indicated that GM-CSF therapy enhanced expression of tumor necrosis factor, interleukin 1, and interleukin 6 mRNA in both monocytes and alveolar macrophages. Differential responses, however, were observed in cytokine secretion; monocytes demonstrated enhanced secretion of all three cytokines by day 3 of treatment, but alveolar macrophages showed only enhanced interleukin 6 secretion at day 10. Monocyte tumoricidal activity after in vitro lipopolysaccharide stimulation was also significantly elevated by day 3 of treatment, but at day 10 activity was not statistically different from pretreatment values in either monocytes or alveolar macrophages. These data indicate that GM-CSF exerts striking time-dependent modulatory effects on gene expression and functional activities of monocytes and alveolar macrophages in vivo, although the responses of the two cell types differ with respect to cytokine secretion.

Gene Expression Regulation, Neoplastic↗

PubMed1991

Monocyte tumoricidal activity and tumor necrosis factor production in patients with malignant brain tumors.

Monocyte-mediated tumoricidal activity, tumor necrosis factor alpha (TNF alpha) secretion and gene expression were examined in astrocytoma patients, patients with other types of brain tumors (primary or metastatic), and normal individuals. The spontaneous monocyte-mediated tumoricidal activity of either patient group against an astrocytoma cell line was significantly greater than normal. There was no difference between patient groups. When monocytes were stimulated with lipopolysaccharide in vitro, tumoricidal activity increased in all patient groups. Patient monocyte activity tested shortly (48 h) after surgery was not different from that before surgery. Both spontaneous and stimulated monocyte cytocidal activities were tumor-cell-restricted: melanoma and astrocytoma cells were equally susceptible but non-neoplastic glial cells were not affected. Examination of monocyte TNF alpha secretion and mRNA expression indicated that patient activity was comparable to or greater than normal. These results demonstrate that, despite steroid therapy, circulating monocytes in astrocytoma and other brain tumor patients retain intact functional activity.

Adult↗