Cultures Of Alveolar Macrophages Research Articles

The Effect of Fiber Length on the Dissolution by Macrophages of Rockwool and Glasswool Fibers

The effect of fiber length on the dissolution of experimental rockwool and commercial glasswool fibers in rat alveolar macrophage (AM) culture and in mere culture medium was studied. The ultrastructure of macrophages after their exposure to fibers and the suitability of macrophage-type cell line P388D1 culture in dissolution studies were also explored. The fiber samples included short (ground) and long (untreated) rockwool and glasswool fibers. The fibers were incubated in rat AM cultures, in P388D1 culture, or in mere culture medium for 4 or 8 days. The dissolution of the fibers was determined by measuring the amounts of silicon (Si), iron (Fe), and aluminum (Al) in the medium. There were no differences in the diameter of the fibers, but a clear difference existed in the length of the short and long fibers. The dissolution of Si, Fe, and Al was more pronounced from experimental rockwool than from commercial glasswool fibers. The dissolution of Si was always greater in mere culture medium than in rat AM culture. Moreover, the dissolution of Si was greater from the long fibers than from the short ones. On the contrary, the dissolution of Pe and Al in AM culture exceeded that in mere culture medium. The dissolution of Si, Fe, and Al from both fibers in P388D1 culture was similar to their dissolution in rat AM culture. The fibers were also effectively phagocytized by the macrophages. The present results together suggest that the intracellular and the extracellular dissolutions of man-made vitreous fibers differ from each other.

Iron and reactive oxygen species in the asbestos-induced tumor necrosis factor-alpha response from alveolar macrophages.

Free radicals and other reactive oxygen species (ROS) are important mediators in asbestos-induced lung toxicity. Asbestos fibers are thought to stimulate cells to generate ROS via iron that is present on fibrous silicates. The pathophysiologic responses in the lung after asbestos exposure are characterized by the accumulation of macrophages at the site of fiber deposition and the release of growth factors and proinflammatory cytokines, such as tumor necrosis factor-alpha (TNF-alpha). We have examined the role of iron-catalyzed ROS in asbestos induction of TNF-alpha from rat alveolar macrophages. Treatment of alveolar macrophage cultures with asbestos stimulated dose-dependently TNF-alpha secretion, which was inhibited by the addition of deferoxamine, an iron chelator. Asbestos fibers, pretreated with deferoxamine to remove iron from the fibers before addition to alveolar macrophages, also significantly reduced the TNF-alpha response. Consistent with the role of iron on asbestos fibers in catalyzing hydroxyl radical generation, membrane-permeable hydroxyl radical scavengers (tetramethylthiourea, dimethyl sulfoxide) inhibited the asbestos-induced TNF-alpha response. The asbestos-induced increase in TNF-alpha, as well as in interleukin-1 alpha, and their inhibition by tetramethylthiourea occurred at the transcriptional level. The role of ROS in signaling TNF-alpha stimulation was confirmed by use of free radical-generating systems (hypoxanthine-xanthine oxidase, hydrogen peroxide, glucose-glucose oxidase, or ferrous plus hydrogen peroxide). These results suggest that intracellularly generated ROS can stimulate TNF-alpha in alveolar macrophages and that asbestos-induced TNF-alpha gene expression and secretion are mediated by iron-catalyzed product of ROS.

Relationship between oxygen-induced alveolar macrophage injury and cell antioxidant defence.

Exposure to hyperoxia causes alveolar macrophage (AM) injury. The present study investigates the roles of intracellular antioxidant enzymes and of glutathione in the protection of AMs against hyperoxia in a biphasic cell culture system in aerobiosis. The effect of normoxia or hyperoxia on the integrity of AMs was related to indices of cell injury (ATP cell content and lactate dehydrogenase release into culture medium) and cell mass (protein content of AMs). Antioxidant activities were measured in guinea-pig AMs exposed to 95% O2 or to normoxia (control cells) for 3 days. A 3-day AM culture in normoxia showed a significant decrease in protein and catalase, whereas ATP cell content, superoxide dismutase (SOD) (both Cu,Zn-SOD and Mn-SOD) and glutathione peroxidase (GPx) activities significantly increased. The content of reduced glutathione (GSH) did not change. Using the ATP content in AMs expressed as a cell injury index (CII), AM injury increased with increasing O2 exposure time (1 day: 13 +/- 4.4%; 2 days: 34 +/- 3.8%; 3 days: 40 +/- 4.1%; 4 days: 55 +/- 7.3%; 6 days: 87.5 +/- 5.4%). Exposure to 95% O2 for 3 days was associated with a significant decrease in ATP cell content, protein, catalase and GSH to the total glutathione ratio, whereas SOD, GSH and total glutathione did not change significantly. The GPx activities increased significantly. There was no significant correlation between the AM CII and SOD or GPx content. In contrast, a significant correlation was observed between hyperoxia-induced AM CII and catalase content (r = 0.71) and glutathione content (r = 0.71).(ABSTRACT TRUNCATED AT 250 WORDS)

豚からの豚繁殖・呼吸障害症候群ウイルスの分離

During a period from autumn 1992 to through summer 1993 in the North-Eastern Chiba Prefecture, appeared a syndrome characterized by respiratory disorders in 1-to 5-month old piglets, and anorexia and fever in sows with abortion, and delivery of stillborne, mummified, premature or weakborne piglets. From the affected pigs on 8 farms, viral agents were isolated on swine alveolar macrophage cultures and identified as porcine reproductive and respiratory syndrome (PRRS) virus. The antigenicity of the virus was closely related to that of the American PRRS virus. The retrospective antibody survey of the virus by indirect immunofluorescence revealed an epizootic in this area in 1988.

Dissolution of Man-Made Vitreous Fibers in Rat Alveolar Macrophage Culture and Gamble's Saline Solution: Influence of Different Media and Chemical Composition of the Fibers

Dissolution of Man-Made Vitreous Fibers in Rat Alveolar Macrophage Culture and Gamble's Saline Solution: Influence of Different Media and Chemical Composition of the Fibers

Compartmentalized cytokine production within the human lung in unilateral pneumonia.

The in situ inflammatory response developing in the human lung during a localized bacterial infection was studied in 15 patients with unilateral community-acquired pneumonia (CAP). The local response in the involved lung was compared with that in the contralateral, noninvolved lung as well as with the systemic blood response. Eight healthy volunteers served as control subjects. Concentrations of tumor necrosis factor-alpha (TNF-alpha), interleukin-1 beta (IL-1 beta), and interleukin-6 (IL-6) were measured by ELISA in bronchoalveolar lavage (BAL) fluids (n = 15), serum (n = 15), and alveolar macrophage and monocyte culture supernatants (n = 8). The concentrations of TNF-alpha, IL-beta and IL-6 in BAL fluid were significantly higher in the involved lung than in the paired noninvolved lung (p < or = 0.01) or in healthy subjects (p < or = 0.02, p < or = 0.01, and p < or = 0.001, respectively). Serum IL-6 concentrations were higher in patients than in control subjects, whereas IL-1 beta and TNF-alpha concentrations did not differ in the two groups. Alveolar macrophages from the involved lung spontaneously released higher concentrations of IL-1 beta, IL-6, and TNF-alpha (p < or = 0.05) than did macrophages from the noninvolved lung, which served as controls. However, macrophages were hyporesponsive in terms of cytokine production to further stimulation by lipopolysaccharide (LPS) in the noninvolved and involved lung compared with controls, whereas peripheral blood monocytes were not.(ABSTRACT TRUNCATED AT 250 WORDS)

Interleukin-10 is a potent inhibitor of tumor cytotoxicity by human monocytes and alveolar macrophages

The effects of purified human interleukin-10 (IL-10) on the expression of antitumor activity of human monocytes and alveolar macrophages (AMs) obtained by centrifugal elutriation and bronchoalveolar lavage, respectively, from the same healthy donors were examined. Monocytes and AMs were incubated for 16 h in medium with lipopolysaccharide (LPS) in the presence or absence of IL-10 or IL-4, and then their tumoricidal activity was assayed by measuring 125I-IUdR release from human melanoma (A375) cells. Addition of IL-10 to cultures of monocytes or AMs with LPS resulted in dose-dependent suppression of their cytotoxicity against A375 cells, the suppression of the activity of monocytes being the higher. IL-10 also suppressed the synergistic effects of interferon-gamma and desmethyl muramyldipeptide in activation of monocytes. IL-10 inhibited the early induction phase of monocyte activation but not the effector phase (monocyte-mediated cytotoxicity). IL-10 plus IL-4 inhibited the antitumor activities of AMs and monocytes much more than either IL-10 or IL-4 alone. IL-10 and IL-4 at suboptimal concentrations also showed synergistic inhibitory effects. These findings suggest that IL-10 may be important in vivo in down-regulating the antitumor activities of monocytes and AMs in the lung by inhibiting their productions of antitumor effector molecules.

Constitutive and stimulated MCP-1, GRO alpha, beta, and gamma expression in human airway epithelium and bronchoalveolar macrophages

Constitutive expression of mRNAs for GRO alpha, GRO beta, GRO gamma, and MCP-1, belonging to the chemokine family of 8- to 10-kDa cytokines with chemotactic properties for granulocytes and monocytes, has been identified in freshly isolated human nasal and bronchial epithelium, and in bronchoalveolar macrophages (AM). Expression of GRO alpha, GRO gamma, and MCP-1, but not GRO beta, was found in airway epithelial cells. AM expressed all three GRO genes in addition to MCP-1. On reverse transcription, chemokine mRNAs yielded 0.5-30 cDNA molecules/cell, depending on the chemokine and cell type, as determined by a semiquantitative reverse transcriptase-polymerase chain reaction technique. When chemokine mRNA expression in AM and bronchial epithelium from healthy nonatopic individuals was compared, AM expressed more GRO alpha, but similar levels of GRO gamma, MCP-1, and interleukin-8 (IL-8), as in the bronchial epithelial cells. Modulation of chemokine expression by tumor necrosis factor-alpha (TNF-alpha; 10 ng/ml) or endotoxin [lipopolysaccharide (LPS), 100 ng/ml] exposure was studied in primary nasal epithelial cell and alveolar macrophage cultures. In epithelial cells, LPS did not induce chemokine expression but GRO alpha, IL-8, and MCP-1 were upregulated approximately 100-fold by TNF alpha; GRO gamma expression was elevated only 1.5- to 4-fold. In AM cultures, all three GROs were strongly induced by LPS with peak mRNA expression 24 h after stimulation (approximately 50- to 100-fold increase compared with control cultures). MCP-1 mRNA expression, on the other hand, was not increased by LPS in AM. GRO protein was present in supernatants of stimulated epithelial cells and AM.(ABSTRACT TRUNCATED AT 250 WORDS)

Effect of assay conditions on measurement of elastolytic activity of alveolar macrophages in culture and characterization with proteinase inhibitors

We have investigated whether varied assay conditions account for the conflicting reports on measured alastolytic activity of alveolar macrophages (AM) cultured in direct contact with the 3H-elastin substrate coated onto 16-mm wells in serum-containing media. The data indicate that measured elastolytic activity in this assay system was dependent on the amount of 3H-elastin/culture well. 3H-elastin >350 μg/well, in contrast to the ⩽200 μg/well commonly used in this assay system, resulted in optimal measurement of elastolytic activity that was linear with respect to culture time (up to 72 h examined) and was directly proportional to number of AM/well (up to 1.0 × 10 6 examined). The sensitivity of measured elastolytic activity to tissue inhibitor of metalloproteinases (TIMP) and to Z-phe-phe (a specific cysteine proteinase inhibitor) was not affected by amount of 3H-elastin/well, but appears to be dependent on the time period of AM culture. TIMP (at 5 μM, maximal dose examined) inhibited the measured elastolytic activity by 25% in 24-h cultures compared to 69% in 72-h cultures; Z-phe-phe (at 10 μM, dose at which maximal effect was obtained) inhibited the elastolytic activity by 45% in the 24-h cultures compared to 34% in the 72-h cultures. These findings indicate that differences in substrate levels and in culture time have a significant effect on the results obtained in measurement of AM-mediated elastolytic activity in culture, which may account for the conflicting reports in the literature. Thus standard optimal assay condition are required for valid interpretation of results of AM-mediated elastolytic activity measurements.

Effects of a Corticosteroid, Budesonide, on Alveolar Macrophage and Blood Monocyte Secretion of Cytokines: Differential Sensitivity of GM-CSF, IL-1β, and IL-6

Summary: Down-regulation of cytokine production in activated human blood monocytes (BMs) and alveolar macrophages (AMs) can be achieved in vitro by treatment with corticosteroids. The inhibition of cytokine secretion by corticosteroids may have important therapeutic consequences in e.g. asthma. However, relatively little is known about possible differences in the sensitivity of different cytokines to corticosteroid treatment. Homologous BMs and AMs were obtained from six healthy volunteers. Secretion of interleukin-1β (IL-1β), interleukin-6 (IL-6) and granulocyte-macrophage colony-stimulating factor (GM-CSF) in the cultures of lipopolysaccharide (LPS) stimulated adherent BMs and AMs was analysed using specific immunoassays. Sensitivity of the IL-1β, IL-6, and GM-CSF secretion to the in vitro treatment with a synthetic corticosteroid, budesonide, was compared. BMs and AMs displayed significant differences in both cytokine secretion and susceptibility to regulation by budesonide. When added to the BM cultures concomitantly with LPS, budesonide suppressed IL-1β and IL-6 only partially (to 30% of the control level). In contrast, GM-CSF release in these cultures was almost totally inhibited by budesonide (⩾10 -8 M). The IC 50 for inhibition of the GM-CSF secretion was as low as 2 × 10 -10 M. In the AM cultures, budesonide had very little effect on IL-1β and IL-6 secretion (inhibition to 80% and 60% of control levels, respectively), while GM-CSF secretion was suppressed to 20% of control by budesonide concentrations ⩾10 -7 M. These in vitro studies suggest that GM-CSF secretion from BMs and AMs is more sensitive to corticosteroid treatment than IL-1β and IL-6 secretion. Moreover, these data support the view that human monocytes derived from different compartments or at different stages of differentiation exhibit different responsiveness to corticosteroids.

Développement et utilisation d'une épreuve immuno-enzymatique pour le diagnostic courant du syndrome dysgénésique et respiratoire du porc

An indirect enzyme-linked immunosorbent assay was developed for rapid detection of serum antibodies against the virus responsible for the porcine reproductive and respiratory syndrome (PRRS). This test is more sensitive than the reference technique (immunoperoxidase test applied to cultures of alveolar macrophages), particularly for detecting animals at the stage of seroconversion. It is also very specific for PRRS virus, because all specific hyperimmune sera against other porcine viruses, and all serum samples taken from herds before the disease appeared in western France were negative. The test has been used for routine diagnosis of PRRS. The results obtained during nine months from over 21,000 samples have confirmed the value of the test for diagnosis and epidemiological surveillance of the disease.

Capture immunoassay for ruminant tumor necrosis factor-α: comparison with bioassay

Monoclonal antibodies and IgG purified from rabbit polyclonal antiserum, raised against recombinant bovine tumor necrosis factor-alpha (TNF-α), have been employed in ELISA procedures to quantitate bovine TNF-α. These antibodies were potent in neutralizing the biological activity of recombinant as well as natural bovine TNF-α. The monoclonal antibodies were used as capture antibodies and were either passively adsorbed or covalently linked to ELISA plates. Polyclonal rabbit anti-TNF IgG was used as the detecting antibody in combination with a biotinylated anti-rabbit serum and a streptavidin-horseradish peroxidase conjugate. The detection limit for recombinant TNF-α medium was 10 pg ml −1 and in bovine or ovine serum was 35 pg ml −1. A good correlation was found between the ELISA and the WEHI-164 Clone 13 biologic assay when TNF-α was measured in medium containing serum or in serum. This capture ELISA was also capable of detecting ovine, but not porcine. TNF in supernatants from cultures of lipopolysaccharide-stimulated pulmonary alveolar macrophages.

Isolation of a Lelystad virus-like agent from British pigs and scanning electron microscopy of infected macrophages

Six, one-week-old gnotobiotic piglets were inoculated with tissues or sera collected from field cases of porcine reproductive and respiratory syndrome. The piglets showed little or no illness, and two that were necropsied at 8 and 9 days post infection appeared grossly normal. However, a Lelystad virus-like agent was isolated from most of the inoculated pigs using porcine alveolar macrophage cultures. Seroconversion to the Lelystad virus was observed and some animals developed microscopically detectable interstitial pneumonias. Scanning electron microscopy was used to study the in vitro cytopathic effect of the Lelystad virus on porcine alveolar macrophages.

Effects of pseudorabies virus infection upon cytotoxicity and antiviral activities of porcine alveolar macrophages

Alveolar macrophages (AM) infected with Pseudorabies virus (PRV) were compared to noninfected AM for cytotoxicity against foreign or transformed cells and production of interferon (IFN). Five PRV strains were used to infect AM including strains that are known to be highly virulent for pigs, i.e. strain 4892 and strain S-62 as well as strains that are regarded as mild or nonvirulent, i.e. BUK and Bartha. The multiplicity of infection ranged from 0.005 to 0.05 TCID 50/cell. The target cells in the cytotoxicity assays were either chicken red blood cells, PRV-infected vero cells, or human myeloblastoma cells (K562 cell line). For the producton of IFN, AM cultures were treated with polyinosinic: polycytidylic acid (Poly I:C) diluted in tissue culture media at a concentration of 5 μg/10 6 cells. Culture supernatants were collected at various times poststimulation and tested for antiviral activity using the Vesicular Stomatitis Virus replication inhibition test. Swine AM were able to lyse chicken red blood cells in an antibody-independent way but not in an antibody-dependent way, whereas lysis of PRV-infected vero cells was accomplished both ways. The cytotoxicity against chicken red blood cells was reduced in the PRV-infected AM as compared to noninfected cells, particularly in AM infected with virulent PRV strains. Specific 51Cr release values for AM infected with S-62 and 4892 strains were 14 and 19, while the noninfected AM had values of 36. Similarly, in the antibody-dependent cytotoxicity assay against PRV-infected vero cells there was no activity of AM against K562 cells. The production of IFN was readily stimulated with Poly I:C. The optimal time for supernatant collection was between 12 and 16h poststimulation. The antiviral activity was abrogated by treatment of the supernatant with antiserum against human leukocyte IFN; it was therefore considered to be due to interferon-alpha (IFNα) released from the macrophages. The antiviral activity present in supernatants of PRV-infected AM was reduced compared to noninfected AM. The difference between AM cultures infected with virulent strains of PRV and noninfected AM cultures was statistically significant at P ⩽ 0.025. The results provide support to the premise that the role of AM in lung defense can be compromised by PRV infection.

Thymomodulin increases release of granulocyte-macrophage colony stimulating factor and of tumour necrosis factor in vitro

To evaluate the effects of thymomodulin (TMD), a thymic biological response modifier derived from calf thymus, on the release of various cytokines involved in the lung immune reactions, human alveolar macrophages (AM) and peripheral blood lymphocytes (PBL) were cultured either alone or in co-cultures. In co-cultures of AM with PBL, TMD did not induce any change in gamma-interferon (gamma-IFN) and interleukin-1 (IL-1) secretion, while it was able to increase the level, of tumour necrosis factor (TNF) (TMD 100 micrograms.m-1, p < 0.05 vs control cultures), and of granulocyte macrophage colony-stimulating factor (GM-CSF) (TMD 1, 10 and 100 micrograms.ml-1 p < 0.05, < 0.05 and < 0.01, respectively, vs control cultures). In cultures of AM alone, TMD did not induce changes in the levels of any of the tested cytokines, whilst in supernatants from PBL lymphocyte cultures, TMD at 1, 10 and 100 micrograms.ml-1 increased the amounts of GM-CSF (p < 0.01 each comparison vs control cultures). Thus, TMD seems to directly stimulate lymphocytes to secrete GM-CSF and to modulate macrophage-lymphocyte interactions, resulting in the release of TNF and GM-CSF.

Hydrogen peroxide increases the availability of arachidonic acid for oxidative metabolism by inhibiting acylation into phospholipids in the alveolar macrophage.

Reactive oxygen species stimulate metabolism of arachidonic acid (AA) to eicosanoids in a variety of cells and tissues, yet the pathway(s) by which oxidants increase the availability of AA for oxidative metabolism are not known. Thus, we explored the effects of hydrogen peroxide (H2O2) on deacylation and reacylation of AA to determine the enzymatic mechanism(s) by which this oxidant increases levels of free, unesterified AA, and thereby its oxidative metabolism to eicosanoids, in the rat alveolar macrophage (AM). Over the range from 0.1 to 0.5 mM, H2O2 caused marked time- and dose-dependent inhibition of incorporation of [3H]AA into macrophage phospholipids, whereas calcium ionophore A23187 and zymosan particles did not cause such inhibition. Within this concentration range, there was an almost exact reciprocal correlation between inhibition of [3H]AA acylation and H2O2-stimulated accumulation of free [3H]AA in prelabeled AM cultures. Thimerosal, which blocks AA reacylation but spares deacylation via phospholipase A2 (PLA2), did not affect accumulation of free [3H]AA in prelabeled cells stimulated with H2O2, while markedly augmenting [3H]AA release in response to A23187 and to zymosan. Despite its ability to block AA acylation almost completely, H2O2 did not directly inhibit arachidonoyl CoA synthetase or arachidonoyl CoA:lysophosphatide acyltransferase, which catalyze AA incorporation into phospholipids. However, H2O2 (0.1 to 0.5 mM) markedly depleted AMs of ATP, required for synthesis of the acylation intermediate arachidonoyl CoA, suggesting that this was the means by which H2O2 inhibited acylation. Notably, H2O2 (0.03 to 3 mM) failed to stimulate macrophage PLA2 activity. We conclude that H2O2, in contrast to A23187 and zymosan, inhibits incorporation of AA into phospholipids, and that this represents the major mechanism by which the oxidant increases the availability of free AA for oxidative metabolism in the AM. This may be an important basis for release of eicosanoids in oxidant-induced inflammation and injury of the lung.

Effect of pyocyanine, a pigment of Pseudomonas aeruginosa, on production of reactive nitrogen intermediates by murine alveolar macrophages.

In this study we investigated the effect of pyocyanine, a pigment produced by Pseudomonas aeruginosa, on production of reactive nitrogen intermediates by macrophages. We found that addition of pyocyanine to cultures of murine alveolar macrophages inhibited the capacity of these cells to produce reactive nitrogen intermediates (measured as nitrite) in a dose-dependent manner without altering cell viability, cytokine-induced Ia expression, or production of tumor necrosis factor.

Intracellular Particle Dissolution in Alveolar Macrophages

Aerosol particles deposited in the lungs that are not readily soluble in the epithelial lining fluid will be phagocytized by alveolar macrophages (AM). Inside the phagolysosomal vacuole, the constituents of the plasma allow dissolution of a variety of compounds at a higher rate than dissolution in extracellular lung fluids. Chelator concentration and a pH value of about 5 were found to control intracellular particle dissolution (IPD). Hence, IPD is the initial step of translocation of dissolved material to blood, which is an important lung clearance mechanism for particles retained long term. IPD rates of uniform test particles determined in human, baboon, and canine AM cultures were similar to initial translocation rates determined in lung clearance studies of the same species after inhalation of the same test particles. IPD rate in cultured AM proved to be a sensitive functional parameter of AM, which was used to identify changes in the clearance mechanism of translocation during different exposure conditions.

Intracellular particle dissolution in alveolar macrophages.

Aerosol particles deposited in the lungs that are not readily soluble in the epithelial lining fluid will be phagocytized by alveolar macrophages (AM). Inside the phagolysosomal vacuole, the constituents of the plasma allow dissolution of a variety of compounds at a higher rate than dissolution in extracellular lung fluids. Chelator concentration and a pH value of about 5 were found to control intracellular particle dissolution (IPD). Hence, IPD is the initial step of translocation of dissolved material to blood, which is an important lung clearance mechanism for particles retained long term. IPD rates of uniform test particles determined in human, baboon, and canine AM cultures were similar to initial translocation rates determined in lung clearance studies of the same species after inhalation of the same test particles. IPD rate in cultured AM proved to be a sensitive functional parameter of AM, which was used to identify changes in the clearance mechanism of translocation during different exposure conditions.

Inhibitory Effects of α1 Protease Inhibitor on the Production of IL-1 and TNFα by Alveolar Macrophages in Patients with Lung Cancer

In the present study, we investigated the effect of alpha 1 protease inhibitor (alpha 1PI) on the production of interleukin-1 alpha (IL-1 alpha, ELISA), IL-1 beta (ELISA), and tumor necrosis factor alpha (TNF alpha, ELISA) by alveolar macrophages (AM) recruited by bronchoalveolar lavage (BAL) from patients with lung cancer and benign pulmonary diseases. Levels of BALF alpha 1PI were significantly increased in patients with lung cancer compared with benign pulmonary diseases. When BALF AM were cultured and stimulated by LPS (20 micrograms/ml) for 48 hours, production of IL-1 alpha and IL-1 beta was less marked in patients with lung production showed a similar tendency, but the difference between patients with lung cancer and benign pulmonary diseases was not significant. Addition of alpha 1PI to the LPS-stimulated AM culture system inhibited production of these cytokines dose-dependently. Thus, the local increase of alpha 1PI in lung cancer may act as a humoral inhibitor against the production of IL-1 and TNF by AM.