A human erythrocyte-derived growth-promoting factor with a wide target cell spectrum: identification as catalase

We have reported previously that a factor with a molecular weight of 53,000 under SDS-polyacrylamide gel electrophoresis purified from human erythrocyte extracts promoted the growth of a wide variety of cell types from different species, including T cells, B cells, myeloid leukemia cells, melanoma cells, and mastocytoma cells, as well as normal and transformed fibroblast cells. In the present study, amino acid sequence analysis revealed that this factor has homology with human catalase. The purified factor exhibited catalase activity. Catalases derived from human erythrocytes, bovine liver, Aspergillus niger, and recombinant rat liver catalase are all able to promote the growth of cells. Antibody against human catalase absorbed both the growth-promoting activity and the enzyme activity of the purified factor. In addition, treatment of the factor with an irreversible enzyme inhibitor, aminotriazole, resulted in abrogation of both the growth-promoting activity and enzyme activity. These results indicate that the growth-promoting factor is catalase, and its activity is associated with the decomposition of hydrogen peroxide.

Ubiquitous interleukin-1 alpha in fetal bovine serum may mislead the experimental results in vitro

Fetal bovine sera (FBS) from several commercial suppliers were fractionated by gel filtration. Interleukin-1 (IL-1) activity was bioassayed using the IL-1-specific murine T cell line D10(N4)M. All the sera examined contained IL-1-like activity, with molecular weights (M(r)) of 30 kDa and 15-10 kDa. Under isoelectric focusing (IEF), the majority of IL-1 activity in either 30 kDa or 15-10 kDa fractions was focused into a position of pl 5. The activity recovered from either IEF or gel filtration was inhibited by either recombinant human IL-1 receptor antagonist (rhlL-1ra) or by the antibody against human IL-1 alpha. These biological and physicochemical properties strongly suggest that the active molecules were bovine IL-1 alpha and its precursor. There was no correlation between the amount of endotoxin and IL-1 activity. Quantification of the fractionated IL-1 indicated its presence in concentrations of 200-5000 pg/ml equivalent to human IL-1. However, high levels of IL-1 were not apparent in unfractionated FBS. Proliferation of T cells in the presence of FBS absorbed with protein A-Sepharose was greater than that of cells in original FBS. Therefore, the activity in FBS as a whole appeared to result from the balance between IL-1 and the inhibitory molecule(s). These results suggest that data obtained from experiments conducted in the presence of FBS may be influenced by the effect of bovine IL-1.

Down regulation of Ia expression in macrophages following incubation with mycobacteria

Macrophages are known to release cytokines in response to various kinds of stimulators. In the present study, peritoneal macrophages from C3H/He or C3H/HeJ mice were incubated in vitro with heat-killed M. lepraemurium, M. intracellulare or M. gordonare for 3 days followed by harvest culture supernatant to analyze cytokine activities. It, therefore, seems that macrophages phagocytizing these mycobacteria, released interleukin-1 (IL-1) and tumor necrosis factor (TNF) in culture media. The amount of release was dose dependent on mycobacteria employed. In addition, macrophages, as already have reported elsewhere, treated with IFN for 2 to 3 days showed enhanced expression of surface Ia; although the expression was inhibited if the cells phagocytized mycobacteria. Similarly, the reduced expression of Ia was observed in peritoneal macrophages from MRL/lpr mice after 3 day-culture with mycobacteria in vitro. More importantly, in the presence of the supernatant obtained from macrophages incubated with mycobacteria, IFN gamma-treated normal macrophages exhibited suppressed expression of Ia. These results demonstrate that cytokine release and reduced expression of surface Ia in macrophages are simultaneous phenomena after phagocytosis of mycobacteria. Suppression of Ia may be in part induced by Ia suppressive factor(s) released from mycobacterium-phagocytized macrophages.

Purification and characterization of a human erythrocyte-derived growth factor with a wide target cell spectrum

A cell extract from human erythrocytes promoted the growth of a wide variety of cell types, namely human and mouse myeloid cells, human and mouse T cells, human B cells, human melanoma cells, mouse transformed fibroblast cells, mouse mastocytoma cells, human lung fibroblast cells, and mouse bone marrow fibroblast/stroma-like cells. The growth-promoting activity was acid- and heat-labile and sensitive to proteases, indicating the proteinaceous nature of the molecule. The activity was also lost upon exposure to 2-mercaptoethanol. The novel growth-promoting factor, termed basic growth factor because of its fundamental effect and a wide target cell spectrum, was purified by sequential anion-exchange, hydrophobic, gel filtration, hydroxylapatite, and reverse-phase high performance liquid chromatographies. The purified factor has an apparent molecular mass of 53 kDa on sodium dodecyl sulfate-polyacrylamide gel electrophoresis under reducing and nonreducing conditions. The factor migrated at 270 kDa on native gradient polyacrylamide gel electrophoresis. Therefore, the factor consists of a homopolymer of a single polypeptide chain. The purified factor promoted the growth of the same cell types as the cell extract, except for bone marrow cells.

Meeting report of the International Symposium of Molecular Cell Biology of Macrophages '94

The International Symposium of Molecular Cell Biology of Macrophages '94 was held on February 10-11, 1994 at Kanazawa University, Kanazawa, Japan. Fifteen speakers including 4 speakers from Europe and the United States were invited to this symposium. In spite of unusual heavy snow and chilly weather, 150 macrophage scientists gathered and had hot discussions. In the meeting reception, a special recognition speech entitled "Dawn of Cytokines--Discovery of a Blastogenic Factor in the Early 1960's" was given by a discoverer of blastogenic factor, Dr. Shinpei Kasakura. This symposium was initiated in 1991 with the intention of bringing together experts of macrophage investigation once a year to discuss progress in the field of molecular cell biology of macrophages.

Binding of Legionella pneumophila to macrophages increases cellular cytokine mRNA

Infection of macrophages with Legionella pneumophila induces formation of interleukin 1 beta (IL-1 beta), but the molecular basis of this is not understood. Binding of bacteria to macrophage surfaces is the first step in an infection process. Therefore, we examined whether this step was sufficient to increase the cellular level of mRNAs for IL-1 beta and other cytokines. To assess the effect of binding of L. pneumophila on the steady-state levels of cytokine mRNAs, cultures of thioglycolate-elicited macrophages from L. pneumophila-susceptible A/J mice were treated with cytochalasin D and infected with L. pneumophila and the total RNA was extracted for analysis by reverse transcription-PCR with primers for IL-1 alpha, IL-1 beta, IL-6, tumor necrosis factor alpha, granulocyte macrophage colony-stimulating factor, and beta interferon (IFN-beta). L. pneumophila treatment increased the cellular steady-state mRNA levels of all cytokines except IFN-beta. To determine the specificity of this effect, macrophage cultures were treated with cytochalasin D and either bacterial lipopolysaccharide, bovine serum albumin-sensitized latex, Salmonella typhimurium, or Escherichia coli. Lipopolysaccharide treatment increased all mRNAs, bovine serum albumin-sensitized latex had no significant effect, and treatment with S. typhimurium or E. coli increased all mRNAs except that of IFN-beta. These results suggested that the binding of gram-negative bacteria to the macrophage surface was sufficient to induce a unique pattern of cytokine mRNAs. Additional studies that examined the characteristics of the bacterial ligands involved indicated involvement of both heat-labile and heat-stable surface ligands.

Development of glycosylated human interleukin-1 alpha, neoglyco IL-1 alpha, coupled with D-mannose dimer: synthesis and biological activities in vitro

Interleukin 1 (IL-1) is a nonglycosylated cytokine with pleiotropic effects on various cell types. In order to investigate the effect of carbohydrate introduction on IL-1 activity and to develop IL-1 with less deleterious effects recombinant human IL-1 alpha was chemically coupled with mannose dimers, alpha-D-Man1-6-D-Man[Man2(alpha 1,6)] and alpha-D-Man1-4-D-Man[Man2(alpha 1,4)]. About 5 molecules of mannose dimers were introduced per molecule of IL-1. Anti-IL-1 alpha antibody reacted only weakly with the glycosylated IL-1s. Conversely, antibody against the mannose dimer reacted with only glycosylated IL-1. The effect of glycosylation on IL-1 activity was evaluated by measuring a variety of IL-1 activities in vitro, including proliferative effect on T cells, antiproliferative effect on melanoma cells, stimulatory effect on IL-6 synthesis by melanoma cells, and stimulatory effect on prostaglandin E2 synthesis by fibroblast cells. Glycosylated IL-1s exhibited reduced activities, which were 10-fold to more than several hundred-fold lower than those of the original IL-1 alpha depending upon different aspects of activities addressed. Man2(alpha 1,6)-introduced IL-1 exhibited lower activity than Man2(alpha 1,4)-introduced IL-1. The competitive binding of 125I-IL-1 alpha to mouse T cells with unlabeled IL-1s suggests that the reduced activity of glycosylated IL-1s is due, at least partially, to the decrease of their receptor binding abilities.

Differences in interleukin 1 (IL-1), IL-6, tumor necrosis factor and IL-1 receptor antagonist production by human monocytes stimulated with muramyl dipeptide (MDP) and its stearoyl derivative, romurtide

The immunostimulatory reagents muramyl dipeptide (MDP) and its stearoyl derivative romurtide [MDP-Lys(L18)] were assessed for cytokine inducing activity in human monocytes. Both MDP and romurtide stimulated the production of interleukin-1 (IL-1), IL-6, tumor necrosis factor (TNF) and IL-1 receptor antagonist (IL-1Ra). Kinetics study indicated that IL-1, TNF and IL-1Ra were induced after 4 h stimulation but IL-6 was produced at a later phase. Romurtide induced these cytokines for longer period that MDP. Dose-response study indicated that romurtide was far more potent than MDP in induction of IL-1, IL-6 and TNF. Although the magnitude of the IL-1 and IL-6 induction was almost the same, that of TNF induction was greater in romurtide-stimulated monocytes than in MDP-stimulated cells. Among IL-1, IL-1 beta appeared to be a major product. In contrast to other cytokines, IL-1Ra was induced by MDP and romurtide in a similar dose and time dependent manner with similar magnitude of response. These studies indicate that MDP and romurtide, especially romurtide, are very potent inducers of both immunostimulatory and immunosuppressive cytokines by human monocytes but with different efficacy and kinetics.

Interleukin-1 down-regulates type I interleukin 1 receptor mRNA expression in a human fibroblast cell line TIG-1 in the absence of prostaglandin E2 synthesis

We have shown that interleukin-1 (IL-1) up-regulates transcription of its own receptor and number of cell surface IL-1 receptor (IL-1R) type I molecule through induction of prostaglandin E2 (PGE2) synthesis and subsequent intracellular cAMP accumulation in a human lung fibroblast cell line (TIG-1). In this study, the effect of IL-1 on IL-1R mRNA expression was investigated in the absence of PGE2 synthesis. In the presence of indomethacin, an inhibitor of cyclooxygenase, IL-1 inhibited the expression of IL-1R mRNA within 4 h after treatment, and the inhibition sustained at least for 24 h. IL-1 beta as well as IL-1 alpha at higher than 1 U/ml exhibited the inhibitory effect. The inhibitory effect of IL-1 was inhibited by cycloheximide suggesting that de novo protein synthesis is required. IL-1 appeared to destabilize IL-1R mRNA within 30 min after treatment of the cells. Furthermore, this effect of IL-1 was not observed in a synthetic medium and was dependent on serum concentrations indicating that a serum component(s) is involved. These results indicate that IL-1 regulates IL-1R mRNA expression in both a positive and negative manner, and that the negative effect represents a negative feedback mechanism.

Novel growth promoting activity with a wide target cell spectrum is present in extracts of various cell types

Cell extracts from a variety of cell lines, myeloid, T, B, mastocytoma, fibroblast, melanoma and breast carcinoma of human, mouse and guinea pig promoted the growth of a wide variety of cell types, namely human myeloid cells HL-60, human B cells Daudi, human melanoma cells A375-C6, mouse transformed-fibroblast cells L929, human myelomonocytic cells THP-1. Among them, the activities in extracts from U937, A375-C6 and Daudi were characterized because these extracts exhibited much more potent activity. These growth promoting activities were acid-labile, sensitive to 2-mercaptoethanol and to heat treatment at 50C or 70C for 5 min. The activities were also sensitive to proteases indicating the proteinous nature of these active entities. The molecular weight of activities from A375 and Daudi cells were estimated to be 100,000-150,000 daltons by gel filtration high performance liquid chromatography, while that from U937 cells was 60,000-70,000 daltons. The isoelectric point of these activities were 5.5-6.5.

Resistance to the anti-proliferative effect of IL-1 on human melanoma cell line is associated with endogenous production of IL-1 and IL-6

A human melanoma cell line (A375-6) became resistant to the anti-proliferative effect of human IL-1 after a long period of culture. Two stable resistant sub-clones were obtained, and the mechanism of the IL-1 resistance was investigated. Resistant cells, but not sensitive cells, appeared to produce constitutively IL-1 activity. The activity was neutralized by anti-IL-1 alpha antibody but not by anti-IL-1 beta antibody. Resistant cells expressed IL-1 alpha but not IL-1 beta mRNA. Therefore, the resistant cells appeared to produce IL-1 alpha mRNA for IL-1 receptor antagonist (IL-1Ra) was not detected in resistant cells, indicating that the resistance is not attributable to IL-1Ra. These resistant cells were also resistant to the anti-proliferative effect of human IL-6, but not to that of human TNF. Resistant cells appeared to produce constitutively IL-6 more than sensitive cells, and IL-6 production both in sensitive and in resistant cells was augmented by exogenous IL-1. Furthermore, constitutive production of IL-6 in resistant cells was inhibited by IL-1Ra. Type I IL-1 receptor (IL-1R) mRNA was expressed equally in resistant and sensitive cells. These data indicate that the resistance is not the result of loss of functional IL-1R and that IL-1 induces IL-6 in an autocrine manner. It is, therefore, conceivable that endogenous IL-1 and IL-6 contribute to IL-1 resistance.

Differential production of interleukin 1 (IL-1), IL-6, tumor necrosis factor, and IL-1 receptor antagonist by human monocytes stimulated with Mycobacterium leprae and M. bovis BCG

Human blood monocytes cultured in various serum conditions were stimulated with Mycobacterium leprae or M. bovis BCG and their cytokine-inducing abilities were compared. BCG, either live or killed, induced production of interleukin 1 (IL-1), IL-6, tumor necrosis factor (TNF), and IL-1 receptor antagonist (IL-1ra). Live BCG at a lower bacterial number was more potent than killed BCG in the induction of IL-6 and TNF. In contrast to BCG, killed M. leprae induced few cytokines except for IL-1ra. Similar results were obtained when monocytes were cultured in the presence of untreated or heat-inactivated fetal bovine serum (FBS). When FBS and human serum (HS) were compared and the effect of heat inactivation was investigated, monocytes in HS produced the most cytokines, then those in FBS, irrespective of heat inactivation, and those in heat-inactivated HS produced the least cytokines. There were no differences between live and killed M. leprae, and BCG were far more potent than M. leprae in all of our experimental conditions, indicating that the poor cytokine (IL-1, IL-6 and TNF)-inducing ability of M. leprae was not due to their viability. Cytokine production was partially in parallel with the phagocytosis of the mycobacteria. These results suggest that M. leprae favor their infection by evoking little host reaction through the induction of only low levels of immunostimulatory or proinflammatory cytokines but a substantial amount of immunosuppressive cytokine.

Development of neoglycoproteins conjugated with natural oligosaccharides through carboxyl residues of proteins and its application to recombinant human interleukin 1

In order to develop glycosylated cytokines, neoglycoproteins were synthesized utilizing naturally occurring oligosaccharides. High mannose type oligosaccharide-asparagine (Asn)s, containing Man8GN2-Asn, Man7GN2-Asn and Man6GN2-Asn, were obtained from quail ovalbumin and were coupled to bovine serum albumin (BSA) by carbodiimide-mediated coupling. Major reaction occurred between amino residues of oligosaccharide-Asns and carboxyl residues of BSA. Approximately one molecules of oligosaccharides-Asns were coupled to per molecule of BSA with 50% yield of glycosylation. Among the oligosaccharides, Man6GN2-Asn appeared to be conjugated predominantly. While this strategy was applied to recombinant human interleukin 1 alpha (IL-1 alpha), three molecules of oligosaccharide-Asns were introduced into per molecule of IL-1 with 10% yield of glycosylation.

Purification and substrate specificity of beta-xylosidase from sycamore cell (Acer pseudoplatanus L.): application for structural analysis of xylose-containing N-linked oligosaccharides

A beta-xylosidase was purified 51-fold from culture medium of sycamore (Acer pseudoplatanus L.) cells using p-nitrophenyl beta-D-xylopyranoside as a substrate. This enzyme can remove a xylose residue from asparagine-linked oligosaccharides, derivatized with 2-aminopyridine. A pentasaccharide, Xy1 beta 2Man beta 4GlcNAc beta 4(Fuc-alpha 3)GlcNAc was the favorite substrate in N-linked oligosaccharides, but a xylose residue in Xy1 beta 2(Man-alpha 3)Man beta sequence could not be removed by the enzyme. We also propose an efficient method for detection of xylose residue in N-linked oligosaccharides by a combination of the two-dimensional sugar mapping technique and the xylosidase digestion.

Human myelomonocytic cell line THP-1 produces a novel growth-promoting factor with a wide target cell spectrum

Conditioned medium from a human myelomonocytic cell line THP-1 promoted the growth of a wide variety of cell types, i.e., human and mouse myeloid cells (HL-60, U937, K562, and M1), mouse T-cells (EL-4), human B cells (Daudi and Raji), mouse mastocytoma cells (IC-2), human melanoma cells (A375-C6), mouse transformed fibroblast cells (L929), human lung fibroblast cells (TIG-1), and mouse bone marrow fibroblast/stromal-like cells. The growth-promoting activity was acid-labile. The activity was resistant to 50 degrees C for 5 min but completely lost in 5 min at 70 degrees C. The activity was resistant to treatment with trypsin but sensitive to chymotrypsin alpha, Pronase E, and proteinase K, indicating the proteinous nature of this activity. The activity was lost by dithiothreitol and 2-mercaptoethanol. Molecular weight (M(r) 50,000-70,000) was estimated by gel filtration-high performance liquid chromatography. After the sequential anion exchange, hydrophobic, and hydroxylapatite high performance liquid chromatography, the partially purified factor exhibited the same target cell spectrum as the conditioned medium.

Meeting report of the International Symposium of Molecular Cell Biology of Macrophages '92

The International Symposium of Molecular Cell Biology of Macrophages '92 was held on October 15th and 16th in Kanazawa, Japan. Nineteen speakers including 4 speakers from Europe and the USA were invited. The total number of participants was limited to 100. This symposium was initiated last year with the intention of bringing together experts of macrophage investigation once a year to discuss progress in the field of molecular cell biology of macrophages.

Occurrence of heterogeneity of N-linked oligosaccharides attached to sycamore (Acer pseudoplatanus L.) laccase after excretion

The N-linked oligosaccharide moieties of sycamore (Acer pseudoplatanus L.) laccase are known to be highly heterogeneous. We confirmed that this oligosaccharide heterogeneity was caused not only during the oligosaccharide biosynthesis in Golgi apparatus, but also after the excretion of laccase protein into a culture medium. The culture medium for the sycamore cells (Acer pseudoplatanus L.) contained beta-galactosidase, alpha-L-fucosidase, beta-N-acetylglucosaminidase, alpha-mannosidase and beta-xylosidase activities. We showed that the largest sugar chain in laccase, oligosaccharide F, [formula: see text] was degraded to [formula: see text] by a crude exoglycosidase mixture in the culture medium.

Regulation by dietary essential fatty acid balance of tumor necrosis factor production in mouse macrophages

Increasing the dietary alpha-linolenate (18:3n - 3)/linoleate (18:2n - 6) ratio results in an increase in lipopolysaccharide (LPS)-stimulated tumor necrosis factor (TNF) production in mouse resident and casein-induced peritoneal macrophages [3]. We found that prostaglandin E2 (PGE2) production is inversely related to TNF production and that indomethacin abolishes the effect of changing the essential fatty acid balance in resident macrophages. The resident macrophages enriched in n - 3 did not produce a significant amount of PGE3. Accordingly, the decreased production of PGE2 appears to be a major negative regulatory factor for enhancement of TNF production in the n - 3 enriched resident macrophages. In casein-induced macrophages the situation is more complex. Indomethacin decreased PGE2 production and increased TNF production; however, the differences in TNF production between the n - 6 enriched and n - 3 enriched macrophages were not completely abolished by indomethacin treatment. Lysosomal acid phosphatase activity, a marker of activation/maturation stages, was elevated in the n - 3 enriched compared to the n - 6 enriched casein-induced macrophages but was similar in the resident macrophages of the two dietary groups. Expression of CD14, which is a receptor for LPS, was not different in casein-induced macrophages of the two dietary groups. Thus, the differences in production of TNF between the n - 3 and n - 6 enriched resident macrophages can be accounted for mostly by a difference in the production of a negative feedback effector, PGE2. However, a significant portion of the TNF production in casein-induced macrophages is regulated by a factor(s) other than PGE2 and LPS receptor; advanced activation/maturation stages induced by the diet high in alpha-linolenate may underlie the enhanced TNF production in casein-induced macrophages.

Cyclic AMP mimics IL-1 action in augmenting the differentiation of a mouse myeloid leukemic cell line (M1)

We have shown previously that recombinant human interleukin 1(IL-1) and interleukin 6 (IL-6) inhibited the proliferation of a mouse myeloid leukemic cell line (M1), and that IL-6 induced differentiation of the cells into macrophage-like cells and that IL-1 augmented this differentiation. Using this model we investigated the action mechanisms of IL-1 and IL-6. IL-6, but not IL-1, stimulated prostaglandin E2 (PGE2) production. The differentiative effect of IL-6 however, was not suppressed by indomethacin, although PGE2 induction by IL-6 was completely inhibited. Exogenously added PGE2 neither augmented the differentiative effect of IL-6 nor induced differentiation in combination with IL-1. Therefore, stimulation of PGE2 production did not appear to be essential for differentiative effects of these cytokines. Dibutyryl cAMP, 8-Br-cAMP and two adenylate cyclase-activating reagents, cholera toxin (CT) and forskolin (FK), all exhibited the similar augmenting effects as IL-1. These reagents augmented M1 cell differentiation by IL-6, and they did not induce differentiation in combination with IL-1. cAMP derivatives, CT, FK, IL-1 and IL-6 all inhibited the proliferation of M1 cells. CT and FK increased the intracellular cAMP levels. However, neither IL-1 nor IL-6 increased the cAMP levels. In contrast to the cAMP derivatives and reagents that activate adenylate cyclase activity, phorbol 12-myristate 13-acetate (PMA) and calcium ionophore neither induced nor augmented the differentiation in combination with either IL-1 or IL-6. Intracellular Ca2+ concentration was not altered by IL-1 or IL-6 suggesting that Ca2+/Calmodulin kinase and protein kinase C activation are not involved in this signal transduction pathway. Therefore, the present study suggests that IL-1 exhibits an effect similar to that of cAMP without affecting intracellular cAMP level.

[Monokine production by mouse peritoneal macrophages after phagocytosis of mycobacteria]

It is well known that monokines, IL-1 (Interleukin-1) and TNF (Tumor Necrosis Factor), are produced by macrophages after stimulated with various agents. These cytokines are involved in various aspects of the inflammatory process and immunological response in addition to their original activities to proliferate T lymphocytes and causing tumor necrosis, respectively. Recently, there have been reported that IL-1 and TNF also play an important role in mycobacterial infections such as granuloma formation. In the present study, IL-1 and TNF productions were observed by mouse peritoneal exudate and resident macrophages after incubation with heat-killed M. lepraemurium and M. avium in vitro. The production was enhanced by phagocytosis of these mycobacteria in a dose dependent manner, and the time course of the production was maximum within 24 hr after phagocytosis of these mycobacteria. It was also shown of morphological changes and enhanced glucose consumption in media by these macrophages. Above results suggest that phagocytosis of mycobacteria by macrophages leads to monokine production, which would not only causes well known immunological reactions but also makes characteristic phenomena to be observed in mycobacterial infections.

Interleukin-1 up-regulates transcription of its own receptor in a human fibroblast cell line TIG-1: role of endogenous PGE2 and cAMP

The regulation of interleukin-1 receptor (IL-1R) mRNA expression by IL-1 in a human lung fibroblast cell line (TIG-1) was investigated. After 2 h of stimulation with human recombinant IL-1 alpha or IL-1 beta, the levels of T cell/fibroblast-type IL-1R mRNA increased, and the elevation was sustained for at least 72 h. IL-1 also stimulated synthesis of prostaglandin E2 (PGE2) and secondary cAMP accumulation. Exogenously added PGE2 increased the levels of both IL-1R mRNA and intracellular cAMP. Forskolin, cholera toxin and 8-Bromo adenosine (8-Br-cAMP) all increased IL-1R mRNA levels. Indomethacin blocked IL-1 stimulation of IL-1R mRNA expression, PGE2 production and cAMP. 125I-labeled IL-1 alpha-binding studies showed that this cell line expresses 2.6 x 10(4) IL-1R per cell with a Kd of 5.1 x 10(-10) M. After treatment of the cells with IL-1, the level of IL-1R increased over that of control cells. PGE2 also increased IL-1R without alteration in its affinity. Cross-linking experiments indicate that this cell line expresses the 80-kDa receptor molecule before and after treatment with PGE2; the molecular mass corresponds to the T cell/fibroblast type I IL-1R. These results indicate that IL-1 does not directly stimulate expression of IL-1R mRNA or cell surface IL-1R, but only indirectly by stimulation of endogenous PGE2.

Effect of dietary alpha-linolenate/linoleate balance on lipopolysaccharide-induced tumor necrosis factor production in mouse macrophages

We examined the effect of dietary alpha-linolenate (18:3n-3)/linoleate (18:2n-6) balance on lipopolysaccharide (LPS)-induced tumor necrosis factor (TNF) production in mouse macrophages. Resident and casein-induced peritoneal macrophages from mice fed a high alpha-linolenate diet produced a higher amount of TNF than in the high linoleate diet group. However, TNF production was not affected by the dietary alpha-linolenate/linoleate balance when thioglycollate- and complete Freund's adjuvant-induced macrophages were stimulated with LPS. Serum TNF levels of mice intraperitoneally injected with LPS was also higher in the high alpha-linolenate group than in the high linoleate group. These diets affected the n-3/n-6 ratios of 20 and 22 carbon highly unsaturated fatty acids in macrophage lipids. Thus, the dietary enrichment with alpha-linolenate was found to enhance TNF production of macrophages isolated under limited conditions.

[The kinetics of interleukin 1 and prostaglandin concentrations in human amniotic fluid]

In order to understand the role of Interleukin 1 (IL-1) in human amniotic fluid (AF), the amount of IL-1 in normal human AF at various gestational ages was measured using ELISA. Materials were divided into three groups based on gestational ages. Group 1, less than 22 weeks (n = 16), consisted of AF samples which were collected by amniocentesis. Group 2, greater than or equal to 36 weeks (n = 54), consisted of AF samples collected transvaginally at delivery. Group 3, greater than or equal to 36 weeks (n = 9), transabdominally collected AF samples from elective cesarean section without labor. IL-1 alpha was present in AF of early gestational age in group 1 and appeared to increase with gestational age in group 3. In contrast, IL-1 beta was not detectable in either group 1 or 3. However, the concentration of IL-1 in group 2 was extremely high (IL-1 alpha 201.0 +/- 299.3 pg/ml, IL-1 beta 1,024.1 +/- 1,321.9 pg/ml) when compared to the other groups. Moreover, the IL-1 alpha and IL-1 beta concentrations correlated with those of Prostaglandin E2 and F2 alpha in AF, measured by RIA. These findings suggest that IL-1 has an important role during pregnancy and during labor in particular.

Antiproliferative effect of interleukin 1 (IL-1) on tumor cells: G0-G1 arrest of a human melanoma cell line by IL-1

Interleukin 1 (IL-1) has been shown to have antiproliferative or cytocidal effects on several tumor cell lines and this effect is closely related to the induction of terminal differentiation of the target tumor cells. In this study we analyzed the antiproliferative effect of recombinant human IL-1 alpha on a human melanoma cell line A375 in relation to cell cycle. Nutrient-starved cells, most of which were in G0 + G1, were stimulated by culturing in fresh medium, causing them to enter S. IL-1 treatment induced a slight decrease in the first cell cycle progression from G0 + G1 to S. In addition IL-1 retarded progression of the cells through G2M and inhibited progression of the second cell cycle from G0 + G1 to S. Therefore we concluded that IL-1 exerts its antiproliferative effect by arresting the cells in G0 + G1.

Changes in interleukin 1 levels in human amniotic fluid with gestational ages and delivery

In order to understand the role of interleukin 1 (IL-1) in pregnancy, the amount of IL-1 in normal human amniotic fluid (AF) from various gestational ages and delivery was measured using an ELISA. AF samples were divided into three groups of varying gestational ages. Group 1 of AF was collected by amniocentesis from gestational ages less than 24 weeks (n = 13). Group 2 was collected transvaginally during delivery following labor greater than or equal to 36 weeks (n = 36). Group 3 was transabdominally collected from elective cesarean section without labor greater than or equal to 36 weeks (n = 8). IL-1 alpha was present in AF of early gestational age, 19.2 +/- 21.7 pg/ml, in group 1, and appeared to increase with gestational age, 63.4 +/- 50.1 pg/ml, in group 3. In contrast, IL-1 beta was not detectable in either group 1 or 3. However, the concentrations of IL-1 in group 2 was extremely high (IL-1 alpha, 233.1 +/- 351.9 pg/ml; IL-1 beta, 1,093.5 +/- 1,369.7 pg/ml) compared to the other groups. Moreover, these concentrations tended to increase with the duration of labor. IL-1 alpha and IL-1 beta concentrations in AF were intimately related. These findings suggest that IL-1 has some roles during pregnancy and especially during labor.

Regulation of fibronectin synthesis by interleukin-1 and interleukin-6 in rat hepatocytes

The authors have observed previously that recombinant human interleukin-1 (rhIL-1) administered into rats increased plasma fibronectin (Fn) level concomitant with the increase of Fn in the liver. Because IL-1 induces interleukin-6 (IL-6) in certain cell types, the IL-1 effect might be mediated by IL-6. To evaluate this possibility, the effect of recombinant human interleukin-6 (rhIL-6), rhIL-1 alpha, and rhIL-1 beta on Fn synthesis in cultured rat hepatocytes was studied. It was shown that rhIL-6 increased Fn synthesis in hepatocytes, in contrast, rhIL-1 alpha, rhIL-I beta and TNF did not have any effect on Fn synthesis. When we studied the interaction of IL-1 and IL-6, IL-1 did not exhibit any synergistic effect with IL-6. Conditioned medium (CM) from rhIL-1 stimulated peripheral blood monocytes (PBM) increased the Fn synthesis, and its activity was neutralized significantly by anti-rhIL-6 antibodies. The CM from rhIL-1-stimulated PBM was analyzed by enzyme linked immunosorbent assay and revealed the increase of IL-6. Furthermore, it was found that intraperitoneal administration of rhIL-1 induced IL-6 into blood. The administration of rhIL-6 into rats increased circulating Fn levels. These results strongly suggest that the in vivo effect of IL-1 on Fn synthesis is mediated by IL-6.

Contribution of IL-6 to the antiproliferative effect of IL-1 and tumor necrosis factor on tumor cell lines

The role of IL-6 in the antiproliferative effect of IL-1 for tumor cell lines was investigated using IL-1-sensitive cell lines. Human recombinant IL-1 alpha and IL-6 both inhibited the growth of an IL-1-sensitive cloned human melanoma cell line (A375-C6). However, IL-1 has greater maximum growth inhibitory activity than IL-6. Conditioned medium of the tumor cells that were treated with IL-1 contained IL-6 as determined by ELISA. Northern blot analysis revealed that IL-6 mRNA expression increased in IL-1-treated cells. In addition, antibody against human IL-6 neutralized about 50% of the antiproliferative effect of IL-1. The growth of an IL-1-resistant clone of A375 cells (A375-C5), which cannot be shown to express any detectable IL-1R, was inhibited by IL-6 to the same degree as A375-C6 cells. The A375-C5 cell line did not produce IL-6 or increase IL-6 mRNA after stimulation with IL-1. These results indicate that IL-6 mediates in part the antiproliferative effect of IL-1 on A375-C6 cells by acting as an autocrine antiproliferative factor. IL-1 also inhibited the growth of a malignant human mammary cell line (MDA-MB-415). IL-6 exhibited only slight growth inhibition in this cell line. Neither IL-6 production nor IL-6 mRNA expression was induced in this cell line by IL-1. Antibody against IL-6 did not neutralize the antiproliferative effect of IL-1. Therefore, for MDA-MB-415 cells IL-6 appeared not to be involved in the antiproliferative effect of IL-1. These results indicate that the antiproliferative effect of IL-1 involves at least two pathways, one IL-6 dependent and another IL-6 independent. The contribution of IL-6 to the antiproliferative effect of TNF was also examined. IL-6 appeared not to play a role in the antiproliferative effect of TNF in these cell lines.

Contribution of IL-6 to the antiproliferative effect of IL-1 and tumor necrosis factor on tumor cell lines

The role of IL-6 in the antiproliferative effect of IL-1 for tumor cell lines was investigated using IL-1-sensitive cell lines. Human recombinant IL-1 alpha and IL-6 both inhibited the growth of an IL-1-sensitive cloned human melanoma cell line (A375-C6). However, IL-1 has greater maximum growth inhibitory activity than IL-6. Conditioned medium of the tumor cells that were treated with IL-1 contained IL-6 as determined by ELISA. Northern blot analysis revealed that IL-6 mRNA expression increased in IL-1-treated cells. In addition, antibody against human IL-6 neutralized about 50% of the antiproliferative effect of IL-1. The growth of an IL-1-resistant clone of A375 cells (A375-C5), which cannot be shown to express any detectable IL-1R, was inhibited by IL-6 to the same degree as A375-C6 cells. The A375-C5 cell line did not produce IL-6 or increase IL-6 mRNA after stimulation with IL-1. These results indicate that IL-6 mediates in part the antiproliferative effect of IL-1 on A375-C6 cells by acting as an autocrine antiproliferative factor. IL-1 also inhibited the growth of a malignant human mammary cell line (MDA-MB-415). IL-6 exhibited only slight growth inhibition in this cell line. Neither IL-6 production nor IL-6 mRNA expression was induced in this cell line by IL-1. Antibody against IL-6 did not neutralize the antiproliferative effect of IL-1. Therefore, for MDA-MB-415 cells IL-6 appeared not to be involved in the antiproliferative effect of IL-1. These results indicate that the antiproliferative effect of IL-1 involves at least two pathways, one IL-6 dependent and another IL-6 independent. The contribution of IL-6 to the antiproliferative effect of TNF was also examined. IL-6 appeared not to play a role in the antiproliferative effect of TNF in these cell lines.

Cytokines produced in lymph follicles

The events occurring inside lymph follicles during a germinal center reaction are poorly understood. Using B and T lymphoid cell populations prepared from human tonsillar lymph follicles, and enriched or not in macrophages or in follicular dendritic cells, we examined the production of cytokines by these cells in vitro. Interleukin 6 (IL-6) and tumor necrosis factor (TNF) were found in the supernatants of cultures stimulated with phytohemagglutinin or pokeweed mitogen. IL-1 beta was occasionally detected; its secretion apparently depends on the origin of the tonsils, the stimulation, and the cell populations. IFN-gamma and IL-2 were not produced in significant amounts by these lymph follicle cells. IL-4 was only found in very low concentrations in the supernatant of the different cell cultures. The cell populations containing follicular dendritic cells produced more IL-6 and TNF than the others, especially than those composed of only B and T cells.

Synergistic regulatory effects of interleukin 6 and interleukin 1 on the growth and differentiation of human and mouse myeloid leukemic cell lines

We analyzed the effect of recombinant human interleukin 6 (IL-6), in combination with human recombinant interleukin 1 alpha (IL-1 alpha), on the growth and differentiation of several human and mouse myeloid leukemic cell lines, specifically U937, HL-60, M1, and its subclone M1-3b-N, into macrophage-like cells. IL-6 and IL-1 inhibited the growth of U937, M1, and M1-3b-N in a dose-dependent manner. Treatment of these cells with both IL-6 and IL-1 resulted in either an additive or a synergistic growth inhibition. IL-6 alone induced moderate differentiation of U937 and M1-3b-N, but the combination of IL-6 and IL-1 synergistically augmented this differentiation. In M1, only the combination of IL-1 and IL-6 resulted in differentiation. These two cytokines, whether alone or in combination, did not influence the growth and differentiation of HL-60. Therefore IL-6 in conjunction with IL-1 can induce differentiation in several human and mouse myeloid leukemic cell lines, although this effect varies with cell type. IL-6 did not stimulate the expression of IL-1 mRNA or IL-1 activity in U937 cells. IL-1 also failed to stimulate IL-6 production. Furthermore, the differentiation of U937 cells induced by IL-6 was not neutralized by antibody against either IL-1 alpha or IL-1 beta. The minimal differentiative effect of IL-1 was not affected by anti-IL-6 antibody. Therefore IL-6 and IL-1 appear to provide distinct signals for differentiation.

Recombinant interleukin-1 triggers the increase of circulating fibronectin level in rats

Interleukin-1 (IL-1) is one of the mediators responsible for the acute phase protein response during inflammation. We evaluated the effect of recombinant IL-1 alpha given intra-abdominally on rat circulating fibronectin (Fn) levels. Circulating Fn level, sampled between 3 h and 7 days after injection, was maximum at 24-48 h in Wistar rats treated with IL-1 at doses of 10 U and 100 U/100 g body weight (BW), respectively. Circulating Fn level in rats injected with 100 U/100 g BW IL-1 was higher than that of rats given 10 U/100 g BW IL-1. Circulating Fn level peaked at 24 h, whereas albumin levels decreased by 10% at this time. When frozen tissue sections of rat liver were examined using anti-Fn antibodies, the immuno stainings were denser in IL-1-treated animals than in controls. These findings suggest that IL-1 triggers plasma Fn production by the liver.

Purification of guinea pig tumor necrosis factor (TNF): comparison of its antiproliferative and differentiative activities for myeloid leukemic cell lines with those of recombinant human TNF

Recently, we suggested that the effect of differentiation inducing factor (D-factor) which is found in the supernatant of macrophages, and induced the differentiation of a mouse myeloid leukemic cell line, M1, into macrophage-like cells, may be a result of the cooperative effects of tumor necrosis factor (TNF) and interleukin 1 (IL-1). In this study, we purified guinea pig (G.P.) TNF secreted from peritoneal macrophages and compared the antiproliferative and differentiative effects of the G.P. TNF with those of recombinant human TNF (rHuTNF). The purification scheme consisted of ultrafiltration, gel filtration-high performance liquid chromatography (HPLC), DEAE-HPLC, and reverse-phase HPLC. The cytotoxic activity of the purified substance was approximately 1.5 x 10(8) U/mg. The isoelectric point was 5.2. The molecular weight was 40 to 45 kDa as estimated by gel filtration and 18 kDa by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The NH2-terminal amino acid sequence was determined to be Ser-Ala-Ser-Gln-Asn-Asp . . . . Approximately 76 or 71% homology between G.P. TNF and mouse or human TNF exists in the NH2-terminal 21 residues. The purified G.P. TNF and rHuTNF demonstrated D-factor activity only in the presence of recombinant human IL-1 alpha in M1 cells. We also determined the effect of TNF on two human myeloid leukemic cell lines (THP-1 and U937). The purified G.P. TNF and rHuTNF inhibited the growth of U937 cells, but did not induce their differentiation. In THP-1 cells, TNF slightly inhibited the growth and induced differentiation. In mouse cell lines G.P. TNF was more effective than rHuTNF for differentiation.(ABSTRACT TRUNCATED AT 250 WORDS)

Augmentation of DNA synthesis in guinea pig bone marrow cells by platelet-activating factor (PAF)

When guinea pig bone marrow cells were incubated in the presence of 10(-7) to 10(-5) M platelet-activating factor (PAF) for 24 to 72 hours, [3H]thymidine incorporation of cells was time-dependently augmented. The enantiomer of PAF and lysoPAF, a major metabolite of PAF, did not show significant enhancement. A non-metabolizable potent PAF agonist, 1-O-octadecyl-2-O-(N,N-dimethylcarbamoyl)-sn-glycero-3-phospholine, enhanced the [3H]thymidine incorporation at 10(-10) to 10(-8) M. This augmentation of DNA synthesis in bone marrow cells was abolished by specific PAF antagonists, CV-6209 or FR-900452. When the conditioned medium of PAF-stimulated bone marrow cells was added to another culture of bone marrow cells, the augmentation of DNA synthesis was also observed. These results suggest that PAF may affect the proliferation of one or some classes of guinea pig bone marrow cells through release of soluble factor(s).

Existence of both IL-1 alpha and beta in normal human amniotic fluid: unique high molecular weight form of IL-1 beta

We investigated the possible existence of IL-1 in human amniotic fluid (AF). Since AF from most full-term deliveries appeared to contain an inhibitor(s) for thymocyte proliferation, AFs were fractionated by gel filtration prior to IL-1 assay. IL-1 activities eluted in two peaks at positions of 90,000-60,000 MW and 20,000-15,000 MW. Growth inhibitory activity eluted at the position of 70,000-50,000 MW, and its effect appeared to be non-specific because these fractions inhibited the growth of various cell lines. Using isoelectric focusing (IEF) techniques, pI values of 6.8-7.3 for the higher MW IL-1 as well as 4.9-5.5 and 6.7-7.0 for the lower MW IL-1 were obtained. Antibody against human IL-1 alpha partially neutralized the activity of the lower MW IL-1, though it exhibited little effect on the higher MW IL-1. In contrast, antibody against human IL-1 beta almost completely neutralized the activity of the higher MW IL-1 and partially neutralized the activity of the lower MW IL-1. These results suggest that most of the higher MW IL-1 is beta-type, and the lower MW IL-1 is a mixture of alpha and beta-types. IL-1 beta appeared to exist as a complex (combined with AF components) or as an aggregate of the lower MW IL-1 forms. These findings indicate that both IL-1 alpha and IL-1 beta are present in normal human AF from full-term deliveries, though IL-1 beta exists as a higher MW form aggregated with an unknown molecule.

Role of ornithine decarboxylase in the regulation of cell growth by IL-1 and tumor necrosis factor

Ornithine decarboxylase (ODC) is a rate-limiting enzyme in polyamine synthesis, and polyamines are required for cell growth. As an approach to clarifying the mechanism of action IL-1, the effects of IL-1 on ODC activity were examined in various cell lines whose proliferation was either suppressed or enhanced by IL-1. The proliferation of all cell types used in these experiments was markedly suppressed by a specific ODC inhibitor, alpha-difluoromethyl ornithine (DFMO), substantiating the crucial role of ODC activity for cell proliferation. ODC activity also was considerably suppressed by IL-1 in those cells on which IL-1 exerts an antiproliferative effect, such as a human melanoma cell line (A375) and malignant human mammary cell lines (MCF-7 and T-47D). On the other hand, ODC activity was stimulated in cells that are stimulated to proliferate in response to IL-1, such as a mouse helper T cell line (D10.G4.1), a NK cell-like cell line (YT), and a human glioblastoma cell line (U373 MG). The effect of IL-1 on ODC activity preceded and directly correlated in a dose-dependent manner with its effect on DNA synthesis. Furthermore, putrescine, a product of the ODC reaction and a precursor of polyamines, was able to overcome most, but not all, the antiproliferative action of IL-1 in A375 melanoma cells, which were the most sensitive to suppression by IL-1. However, putrescine did not reverse the cytostatic effect of IL-1 on MCF-7 and T-47D cell lines. In contrast, putrescine, like IL-1, exhibited some co-mitogenic activity on D10.G4.1 cells. Because the biological activities of TNF and IL-1 show considerable overlap, the effect of TNF on ODC activity also was examined. TNF had an antiproliferative effect on A375 cells and stimulated the proliferation of U373 MG cells. The ODC activity in A375 cells was suppressed by TNF, and the ODC activity in U373 MG cells was stimulated by TNF. Putrescine also partially overcame the inhibitory effect of TNF. These results suggest that the regulation of ODC activity may be a key component in the antiproliferative and proliferative action of IL-1 and TNF in some tumor cell types.

Role of ornithine decarboxylase in the regulation of cell growth by IL-1 and tumor necrosis factor

Ornithine decarboxylase (ODC) is a rate-limiting enzyme in polyamine synthesis, and polyamines are required for cell growth. As an approach to clarifying the mechanism of action IL-1, the effects of IL-1 on ODC activity were examined in various cell lines whose proliferation was either suppressed or enhanced by IL-1. The proliferation of all cell types used in these experiments was markedly suppressed by a specific ODC inhibitor, alpha-difluoromethyl ornithine (DFMO), substantiating the crucial role of ODC activity for cell proliferation. ODC activity also was considerably suppressed by IL-1 in those cells on which IL-1 exerts an antiproliferative effect, such as a human melanoma cell line (A375) and malignant human mammary cell lines (MCF-7 and T-47D). On the other hand, ODC activity was stimulated in cells that are stimulated to proliferate in response to IL-1, such as a mouse helper T cell line (D10.G4.1), a NK cell-like cell line (YT), and a human glioblastoma cell line (U373 MG). The effect of IL-1 on ODC activity preceded and directly correlated in a dose-dependent manner with its effect on DNA synthesis. Furthermore, putrescine, a product of the ODC reaction and a precursor of polyamines, was able to overcome most, but not all, the antiproliferative action of IL-1 in A375 melanoma cells, which were the most sensitive to suppression by IL-1. However, putrescine did not reverse the cytostatic effect of IL-1 on MCF-7 and T-47D cell lines. In contrast, putrescine, like IL-1, exhibited some co-mitogenic activity on D10.G4.1 cells. Because the biological activities of TNF and IL-1 show considerable overlap, the effect of TNF on ODC activity also was examined. TNF had an antiproliferative effect on A375 cells and stimulated the proliferation of U373 MG cells. The ODC activity in A375 cells was suppressed by TNF, and the ODC activity in U373 MG cells was stimulated by TNF. Putrescine also partially overcame the inhibitory effect of TNF. These results suggest that the regulation of ODC activity may be a key component in the antiproliferative and proliferative action of IL-1 and TNF in some tumor cell types.

Recombinant human interleukin 6 (B-cell stimulatory factor 2) is a potent inducer of differentiation of mouse myeloid leukemia cells (M1)

Recombinant human interleukin 6 (IL-6), a lymphokine involved in the final differentiation of activated B-cells into antibody-forming cells, greatly suppressed proliferation and induced differentiation of murine myeloid leukemia cells (M1) into mature macrophage-like cells. When M1 cells were treated with IL-6, their growth was completely arrested as early as on day 2, and they were induced to differentiate morphologically into macrophage-like cells. Differentiation-associated properties such as phagocytic activity, adherence to the dish surface, Fc and C3 receptors, were also induced within 24 h by IL-6, and they reached their respective maximal levels on day 2 or 3. The potency of IL-6 in suppressing proliferation and inducing differentiation was much greater than that of 1 alpha,25-dihydroxyvitamin D3 one of the most potent inducers of M1 cells. The present report indicates that IL-6 is involved in the differentiation of not only B-cells but also myeloid leukemia cells.

Synergistic interactions of interleukin 1, interferon-beta, and tumor necrosis factor in terminally differentiating a mouse myeloid leukemic cell line (M1). Evidence that interferon-beta is an autocrine differentiating factor

The effect was investigated of combinations of cytokines known to be cytostatic for some tumor cells, namely interleukin 1 alpha (IL-1 alpha), interferon-beta (IFN-beta), and tumor necrosis factor (TNF), on the growth and differentiation of the mouse myeloid leukemic cell line, M1, cells. IL-1 alpha, IFN-beta, and TNF by themselves are antiproliferative for M1 cells. Treatment of cells with a mixture of any two of the three cytokines resulted in at least additive growth inhibition. None of these cytokines by themselves induced differentiation of M1 cells as assessed by increased expression of Fc receptors (FcR), stimulation of phagocytic activity and by morphologic criteria. However, as little as 1 U/ml IL-1 alpha in conjunction with IFN-beta or TNF increased FcR expression, phagocytic activity and morphologic changes in addition to inhibiting the growth of M1 cells. The combination of IFN-beta and TNF did not induce differentiation, although the growth of the cells was markedly inhibited. Both TNF and lipopolysaccharide (LPS) induced the in vitro production of IFN activity by M1 cells. Furthermore, the induction of differentiation of M1 cells by a combination of IL-1 alpha with either IFN-beta, TNF, or LPS was inhibited by antibody against mouse IFN-beta. Therefore, it appears that IFN-beta provides one of the two required signals for differentiation of M1 cells by these combinations of stimulants, the other being IL-1. Furthermore, the cytostatic effect of TNF by itself on M1 cells was also partly blocked by anti-IFN-beta antibody, suggesting that IFN-beta is also involved in the growth inhibitory effect of TNF for M1 cells. In contrast, the cytostatic effect of IL-1 on M1 cells was not blocked by anti-IFN-beta antibody. In conclusion, both the cytostatic and differentiative effect of TNF appear to be mediated by IFN-beta. Thus, the combination of IL-1 and IFN-beta or inducers of IFN-beta resulted in terminal differentiation of M1 cells. Northern blot analysis using cDNAs for murine IFN-beta1 or human IFN-beta2 showed an increased expression of mRNA for IFN-beta1 but not for IFN-beta2 by stimulation with TNF or LPS, strongly suggesting that IFN-beta 1 rather than IFN-beta 2 is responsible for TNF or LPS effects.

Synergistic interactions of interleukin 1, interferon-beta, and tumor necrosis factor in terminally differentiating a mouse myeloid leukemic cell line (M1). Evidence that interferon-beta is an autocrine differentiating factor

The effect was investigated of combinations of cytokines known to be cytostatic for some tumor cells, namely interleukin 1 alpha (IL-1 alpha), interferon-beta (IFN-beta), and tumor necrosis factor (TNF), on the growth and differentiation of the mouse myeloid leukemic cell line, M1, cells. IL-1 alpha, IFN-beta, and TNF by themselves are antiproliferative for M1 cells. Treatment of cells with a mixture of any two of the three cytokines resulted in at least additive growth inhibition. None of these cytokines by themselves induced differentiation of M1 cells as assessed by increased expression of Fc receptors (FcR), stimulation of phagocytic activity and by morphologic criteria. However, as little as 1 U/ml IL-1 alpha in conjunction with IFN-beta or TNF increased FcR expression, phagocytic activity and morphologic changes in addition to inhibiting the growth of M1 cells. The combination of IFN-beta and TNF did not induce differentiation, although the growth of the cells was markedly inhibited. Both TNF and lipopolysaccharide (LPS) induced the in vitro production of IFN activity by M1 cells. Furthermore, the induction of differentiation of M1 cells by a combination of IL-1 alpha with either IFN-beta, TNF, or LPS was inhibited by antibody against mouse IFN-beta. Therefore, it appears that IFN-beta provides one of the two required signals for differentiation of M1 cells by these combinations of stimulants, the other being IL-1. Furthermore, the cytostatic effect of TNF by itself on M1 cells was also partly blocked by anti-IFN-beta antibody, suggesting that IFN-beta is also involved in the growth inhibitory effect of TNF for M1 cells. In contrast, the cytostatic effect of IL-1 on M1 cells was not blocked by anti-IFN-beta antibody. In conclusion, both the cytostatic and differentiative effect of TNF appear to be mediated by IFN-beta. Thus, the combination of IL-1 and IFN-beta or inducers of IFN-beta resulted in terminal differentiation of M1 cells. Northern blot analysis using cDNAs for murine IFN-beta1 or human IFN-beta2 showed an increased expression of mRNA for IFN-beta1 but not for IFN-beta2 by stimulation with TNF or LPS, strongly suggesting that IFN-beta 1 rather than IFN-beta 2 is responsible for TNF or LPS effects.

Growth inhibition and augmentation of mouse myeloid leukemic cell line differentiation by interleukin 1

The effect of interleukin 1 (IL 1) on the growth and differentiation of mouse myeloid leukemic cell line (M1) cells into macrophages has been studied. Purified human IL 1 beta appeared to be growth inhibitory (maximum, 50%) for M1 cells based on cell counts and [3H]thymidine incorporation. The replication of M1 cells was also inhibited by lipopolysaccharide (LPS), and as little as 1 unit/ml IL 1 augmented the growth inhibition by LPS. Although IL 1 inhibited M1 cell growth, it did not induce cell differentiation by the criteria of either effect on expression of Fc receptors or on phagocytic ability. However, IL 1 augmented M1 cell differentiation in conjunction with LPS. At low doses of LPS, addition of IL 1 induced differentiation even though LPS and IL 1 by themselves did not induce differentiation. Cells treated with IL 1 for 1 day and then with LPS for an additional 2 days showed considerable augmentation of Fc receptor expression, while cells treated with the same stimuli in the reverse sequence exhibited only a low level of differentiation. Cells treated with medium alone followed by LPS showed moderate increase in Fc receptor expression. In addition, exposure of cells to IL 1 for at least 16 h was required for IL 1 augmenting effect. Therefore, IL 1 appeared to primarily influence M1 cells to become more sensitive to LPS. Treatment with both of IL 1 and LPS induced differentiation of a LPS-resistant clone of M1 cells, and IL 1 pretreatment rendered the resistant clone to become responsive to the differentiation inducing effect of LPS. Culture supernatants of M1 cells after stimulation with LPS contained IL 1-like activity by thymocyte comitogenic assays. In addition, mouse recombinant IL 1 alpha appeared to have the same activity as purified human IL 1 beta on the growth and differentiation of M1 cells. These results suggest that IL 1 may play an important role in mouse myeloid leukemic cell differentiation by acting as an autostimulating factor. IL 1 has been shown to be growth inhibitory and cytocidal for several tumor cell lines. Our results therefore suggest that the effects of IL 1 may result in the induction of terminal differentiation of some tumor cells.

Tumor necrosis factor as an interleukin 1-dependent differentiation inducing factor (D-factor) for mouse myeloid leukemic cells

Experiments were conducted to purify the differentiation-inducing factor (D-factor), which induces differentiation of mouse myeloid leukemic cell line, Ml, into macrophage-like cells, in a conditioned medium of guinea pig peritoneal macrophages stimulated with lipopolysaccharide. On gel filtration under high performance liquid column chromatography (HPLC), D-factor eluted at the position of 45-15 KD. By the subsequent separation on DEAE HPLC the D-factor activity disappeared. However, in the presence of recombinant human IL 1 alpha the D-factor activity appeared at a position where tumor necrosis factor (TNF) eluted. Even after fractionation on hydroxyapatite HPLC the IL 1-dependent D-factor was co-chromatographed with TNF. Recombinant human TNF as well as the partially purified guinea pig TNF induced differentiation of Ml cells in conjunction with either the partially purified guinea pig IL 1 or recombinant human IL 1 alpha, although these factors by themselves did not induce differentiation. These findings suggest that a part of D-factor activity in the conditioned medium resulted from the cooperative effects between TNF and IL 1.

Purification and biochemical characteristics of two distinct human interleukins 1 from the myelomonocytic THP-1 cell line

An effective induction protocol for the production of interleukin 1 (IL 1) by human myelomonocytic cell line (THP-1) cells was developed, and two biochemically distinct human IL 1 peptides were purified. Lipopolysaccharide, silica, and hydroxyurea by themselves did not induce IL 1 production, but these three stimulants in combination had a synergistic effect on the production of IL 1 by THP-1 cells. A 17-kilodalton (kDa) form of human IL 1 with a pI of 7.0 (IL 1-beta) was purified to homogeneity by sequential chromatography on DEAE-Sephacel, Sephacryl S-200, CM high-performance liquid chromatography (HPLC), and hydroxyapatite HPLC. The recovery of IL 1-beta activity was 45%, and the specific activity was 2.3 X 10(7) units/mg. Both IL 1-beta and a second 17-kDa IL 1 moiety with a pI of 5.0 (IL 1-alpha) were also extracted from stimulated THP-1 cells and purified to homogeneity by sequential chromatography on Sephacryl S-200, ion exchange HPLC, and hydroxyapatite HPLC. The recovery of IL 1-beta from cell extracts was 5.6%, and the specific activity was 3 X 10(7) units/mg. In contrast, only 0.85% of IL 1-alpha was recovered with a specific activity of 5.3 X 10(7) units/mg.(ABSTRACT TRUNCATED AT 250 WORDS)

Comparative evaluation of multiple lymphoid and recombinant human interleukin-2 preparations

Six lymphoid human interleukin-2s (nIL-2s) [four from peripheral blood mononuclear cells (PBMC) and two from JURKAT cells] and six recombinant IL-2s (rIL-2s) were obtained for comparative evaluation. The main issues addressed were possible differences among the preparations in potency in T cell growth assays and other functional assays, and the possible presence of other cytokine activities or contaminants. Each preparation was assigned a standardized IL-2 activity in reference units (RU) by comparing its T cell growth promoting activity against the Biological Response Modifiers Program IL-2 (JURKAT) reference reagent. Relative to the IL-2 unitage indicated by the suppliers, the RU varied from 110-fold less to 38.5-fold more for the various preparations. Two nIL-2s and two rIL-2s contained significant levels of endotoxin. One nIL-2 contained low levels of both alpha and gamma interferon (IFN), and one nIL-2 had a high level of gamma IFN. All other IL-2s were negative for IFN activity. All IL-2 preparations significantly augmented human natural killer (NK) activity, although the amount of RU required varied from 0.1 to 50 RU. Four nIL-2s and three rIL-2s induced human PBMC to produce gamma IFN, whereas two nIL-2s and one rIL2 did not. All nIL-2s had substantial amounts of B cell growth factor activity, whereas none of the rIL-2s consistently displayed this activity. All IL-2s stimulated the tritiated thymidine [3H]TdR incorporation of human PBMC in the absence of other stimuli, in addition to augmenting the response to mitogen or alloantigens. Some nILs and IL-2s had effects on human monocytes such as inhibiting migration, inducing cytotoxic or growth inhibitory activity against tumor cells, and causing changes in cell surface markers. The IL-2s were also tested for activity in vitro and in vivo in mice. Although there was a 12-fold variation in activity among the preparations, all but one of the IL-2s showed augmentation of the mixed lymphocyte reaction activity and all IL-2s tested stimulated macrophage cytotoxicity in vitro. All IL-2s tested enhanced the mixed lymphocyte-allogeneic tumor cell reaction resulting in greater production of cytotoxic T cells. However, significant quantitative differences in potency were evident among the various IL-2 preparations, especially the nIL-2s. Only very high doses of IL-2 (intraperitoneal injection of 100,000 RU/animal) induced in vivo augmentation of splenic or peritoneal NK cells, although all IL-2s tested increased NK activity against tumor target cells in vitro with substantially lower doses (10-100 RU/ml).(ABSTRACT TRUNCATED AT 400 WORDS)