Interleukin 1 is more than an interleukin

Translating molecular insights in autoimmunity into effective therapy

Autoimmunity and the pathogenesis of autoimmune diseases were a major focus of the Walter and Eliza Hall Institute, where I started my research career. After my initial studies on immune cell culture and immune regulation, I returned to an analysis of the pathogenesis of human autoimmunity in London. Linking upregulated antigen presentation to autoimmunity led to an investigation of the role of cytokines in rheumatoid arthritis (RA), in collaboration with Ravinder Maini. These experiments defined the concept of a TNF-dependent cytokine cascade driving the manifestations of RA, which led to successful clinical trials of anti-TNF monoclonal antibody in RA patients, heralding a major change in medical practice. This success was made possible by enthusiastic support from many laboratory and clinical colleagues and taught us that cytokines are important rate-limiting steps and hence good therapeutic targets. My current scientific challenge is exploring the hypothesis of whether all major medical needs can be approached via cytokine blockade.

Differences of Cell Growth and Cell Cycle Regulators Induced by Basic Fibroblast Growth Factor Between Nifedipine Responders and Non-responders

Differences of cell proliferation, cell cycle, and G(1)/S transition regulatory proteins of gingival fibroblasts derived from nifedipine-reactive patient (NIFr) and nifedipine-non-reactive patient (NIFn) in the presence of basic fibroblast growth factor (bFGF) were investigated to elucidate the mechanism of gingival overgrowth associated with nifedipine, one of the Ca(2+)-channel blockers. The proliferation rate of NIFr cells in the presence of bFGF significantly increased than NIFn cells. The proportion of NIFr cells that had undergone progression to the S and G(2)/M phases from the G(0)/G(1) phase significantly increased compared to that in NIFn cells. Increases of pRB (Ser807/811), pCDK2 (Thr160), CDK2, and cyclin E protein levels in NIFr cells were greater than those in NIFn cells. The elevations of pRB (Ser780), RB, and cyclin A protein levels in NIFr cells did not differ from those of NIFn cells. The growth of NIFr cells was greater than that of NIFn cells as a result of the active G(1)/S transition of NIFr cells, as assessed by the increments of cyclin E, pCDK2, and pRB (ser807/811) protein in NIFr cells.

IL-1 Can Act as Number One

Both interleukin-1 receptor (IL-1R) and toll-like receptor 2 (TLR2) signal via the adapter molecule MyD88. However, in response to a cutaneous infection challenge, the downstream signaling events diverge and IL-1R, but not TLR2, proves to be essential for host defense.

The effect of IL-l.ALPHA. and nifedipine of cell proliferation and DNA synthesis in cultured human gingival fibroblasts

The effect of nifedipine and interleukin-alpha (IL-1alpha) on the cell proliferation and DNA synthesis was studied in human gingival fibroblasts derived from 5 patients who developed gingival overgrowth (nifedipine responders) and 5 patients who did not develop gingival overgrowth (nifedipine non-responders) in response to nifedipine. Epidermal growth factor was used as a positive control. The fibroblasts derived from nifedipine responders tended to have a numerically greater rate of cell proliferation and DNA synthesis (3H-thymidine incorporation) than those from nifedipine nonresponders in the presence of nifedipine and IL-lalpha. Fibroblasts derived from nifedipine responders showed significantly higher cell proliferation rate in the presence of nifedipine and IL-1alpha, than nifedipine or IL-lalpha alone on both the second and the fourth day of incubation (P < 0.05). A combination of IL-1alpha and epidermal growth factor also showed significantly greater cell proliferation than IL-lalpha alone on the second day (P < 0.05). The DNA synthesis rate with a combination of nifedipine and IL-1alpha was higher than that for nifedipine alone on the second day (P < 0.01), and IL-1alpha alone on the fourth day (P < 0.05) in gingival fibroblasts originating from nifedipine responders. These results suggest that the interaction between nifedipine and gingival inflammation might play an important role in the pathogenesis of nifedipine-induced gingival overgrowth.

Cytokines: past, present, and future

This review provides an historical account of the discovery and development of cytokines. Cytokines are soluble extracellular proteins or glycoproteins that are crucial intercellular regulators and mobilizers of cells engaged in innate as well as adaptive inflammatory host defenses, cell growth, differentiation, cell death, angiogenesis, and development and repair processes aimed at the restoration of homeostasis. Although cytokines are occasionally produced constitutively, they are usually produced by virtually every nucleated cell type in response to injurious stimuli. Cytokines act on cells expressing complementary receptors. Cytokines have been assigned to various family groups based on the structural homologies of their receptors. This review shows how cytokine research evolved from phenomenological to molecular stages and from a focus on ligands to characterization of cytokine receptors. The advent of molecular biology, monoclonal antibodies, and microsequencing made it possible to obtain pure recombinant cytokine preparation for experimental and therapeutic applications. The development of targeted gene deletions revealed many cytokines to have unexpected pathophysiological functions. The identification of "virokines," homologues that mimic cytokine ligands and receptors, has provided impetus to the founding of biotechnology companies aimed at developing cytokine agonists and antagonists for therapeutic applications. The discipline of cytokinology is now endowed with several journals, multiple annual meetings, and many devoted investigators. The explosion in cytokine information over the past 40 years has been enormous and full of surprises. If past be prologue, with the advent of genomics and proteomics the future should witness even greater progress.

Macrophage function in deer

Macrophage inflammatory and immune functions were characterised in red deer (cervus elaphus), for use as a model for natural infection with bovine tuberculosis. Highly enriched populations of deer macrophages were obtained from 14 day cultures of plastic-adherent peripheral blood mononuclear cells. Cervine macrophages produced superoxide anion in response to respiratory burst stimuli (serum-opsonised zymosan and phorbol myristic acetate), but nitric oxide production could not be detected under the conditions tested. The lysosomal enzymes acid phosphatase and lysozyme were detected at the intercellular and extracellular level. Stimulation with bacterial lipopolysaccharide extract (Escherichia coli LPS) enhanced the production of superoxide and acid phosphatase with a peak increase in activity observed after 2h. Production of interleukin 1 (IL-1) and tumour necrosis factor (TNF), determined using cytokine-sensitive cell lines and mRNA analysis (Northern blotting), indicated maximal secretion of both cytokines after 24 h stimulation with LPS, preceded by a peak in message accumulation at 2-6 h post-stimulation. Cervine macrophages stimulated proliferative responses in T cell-enriched lymphocyte populations derived from the peripheral blood of autologous animals that had been primed to mycobacterial antigens (Mycobacterium bovis Bacille Calmette-Guerin, BCG). Macrophages were able to stimulate responses after pulsing with particulate (BCG) or soluble (purified protein derivative) mycobacterial antigens. These results indicate that macrophage inflammatory and immune responses in red deer are similar to those in other mammalian species, and that macrophages may play an important role in resistance to mycobacterial infection.

Immortalized hemopoietic cells with stem cell properties

We have established a hemopoietic cell line, BL3, that possesses a rearranged retroviral genome, which we used as a genetic tag for their engraftment into lethally irradiated mice. Analysis of recipients up to 7 months after engraftment indicates that the marker was present in differentiated cells of various hemopoietic organs, in colony-forming cells, pre-CFU-S-forming cells, and in organs of secondary recipients from bone marrow cells of primary recipients. BL3 cells are Thy-1+, Sca-1+, B220-, Mac-1-, and Gr-1-. They express GATA-1 and are able to develop "cobblestones" with stromal cells. They do not express and respond to several hemopoietic growth factors known to facilitate marrow recovery. However, they are negatively regulated by TGF beta and can be stimulated by mitogen-stimulated spleen cell-conditioned medium. We conclude that BL3 cells possess properties of hemopoietic stem cells, including their capability to contribute to long-term repopulation.

Induction of interleukin-1 in various brain regions after peripheral and central injections of lipopolysaccharide

The presence of bioactive interleukin-1 (IL-1) in various brain regions (cerebellum, cortex, brainstem, diencephalon or hippocampus) after either intraperitoneal (i.p.) or intraventricular (i.c.v.) injection of lipopolysaccharide (LPS) was studied in the rat. To detect IL-1, extracellular fluid and cell lysate were fractionated by gel exclusion chromatography and fractions tested for thymocyte stimulation; presence of IL-1 was confirmed by blockade of stimulation by addition to the assay of a monoclonal antibody (mAb) to IL-1 receptor. When LPS was infused i.c.v., IL-1 was detected in the brainstem and diencephalon 2 h after injection, and in all the brain regions except cerebellum 6 h after injection; IL-1 was not detected in the plasma of these animals. When LPS was injected i.p., IL-1 was detected in the plasma but not in the brain 2 h after the injection, and in all brain regions but not in the plasma 6 h after the injection. In all of these cases, IL-1 was found in extracellular fluid; in some cases (cortex, cerebellum) cell lysate of the region did not produce detectable bioactivity, thereby indicating that IL-1 in these brain regions is processed to active peptide during release, as has been reported in the periphery. In those cases where bioactivity was detected in cell lysate (brainstem, diencephalon), bioactivity was not blocked by IL-1 receptor mAb, indicating presence of a non-IL-1 stimulating factor. These results further support the idea that IL-1 is secreted by cells in the brain, and indicate that it is found in the extracellular fluid of many brain regions following an appropriate stimulus in the periphery as well as in the brain.

Production of interleukin-1 alpha and interleukin-2 by separate, phenotypically different leukaemia and human T cell lymphotropic virus-1-transformed T cell clones

The relationship between interleukin-1 (IL-1) and interleukin-2 (IL-2) production and immunophenotype marker profiles was studied in a panel of 29 leukaemia and human T cell lymphotropic virus-1 (HTLV-1)-transformed T cell lines. Culture supernatants from six of the 29 T cell lines tested increased IL-2 production by the MOLT-16 cell line in a manner similar to that of rIL-1 alpha or rIL-1 beta. The enhancing activity in the cell culture supernatants was inhibited by antibody against IL-1 alpha. Anti-IL-1 beta antibody had no inhibitory effect. All the cell lines producing IL-1 alpha had characteristics of activated mature T cells. They were terminal deoxyribonucleotidyl transferase (TdT)-, CD4+, CD8-, HLA-DR+ and all were strongly positive for IL-2R alpha (Tac antigen) expression. However, none of the IL-1 alpha producing cell lines secreted detectable IL-2. A significant quantity of IL-2 was found, after stimulation with phytohaemagglutinin, in supernatants from nine of the 29 cell lines tested. The majority of IL-2 producing cell lines originated from less mature, non-activated T cells, as they were characterized by the expression of TdT, lack of HLA-DR antigens and > 50% had no detectable IL-2R alpha. The results thus show that separate, phenotypically different leukaemia and HTLV-1-transformed T cell clones produce IL-1 alpha and IL-2.(ABSTRACT TRUNCATED AT 250 WORDS)

Modulation by bryostatin 1 of the in vitro radioprotective effects of the GM-CSF/IL-3 fusion protein, PIXY 321, on normal human myeloid progenitors

We have examined the effect of the macrocyclic lactone PK-C activator, bryostatin 1, on the in vitro radioprotective capacity of the GM-CSF/IL-3 fusion protein, PIXY 321, toward normal committed myeloid progenitors (day 14 CFU-GM). Preincubation of CD 34+ cells for 24 h with 10 ng/ml PIXY 321 exerted significant radioprotective effects on these progenitors, (D = 1.403 vs 0.715 for controls), which were at least as great as those previously reported for higher concentrations (e.g., 50 ng/ml) or rGM-CSF. In contrast to the results of earlier studies involving rGM-CSF, preincubation of cells with both PIXY 321 and 10 nM bryostatin 1 did not lead to an increase in radioprotective effect when the total number of day 14 colonies was assessed. However, combinations of PIXY 321 and bryostatin 1 (or the tumour-promoting PK-C activator, PDBu) significantly increased the relative percentage and absolute number of surviving non-eosinophilic colonies (e.g., pure neutrophil, pure monocyte-macrophage, or mixed neutrophil-macrophage) at each radiation dose level. A similar pattern of response was noted in cells irradiated without a preconditioning interval, and in cells exposed to divided radiation doses. These results indicate that the GM-CSF/IL-3 fusion protein PIXY 321 exhibits significant in vitro radioprotective effects toward normal human bone marrow myeloid progenitors, and that co-administration of PK-C activators such as bryostatin 1 of PDBu selectively augments the radioprotective capacity of this hybrid cytokine toward non-eosinophilic elements.

The role of biological response modifiers in disease control

Immune responses to infectious agents involve a complex set of interactions between cells and the factors they produce that culminate with disease resolution or death. Therefore, the manipulation of the immune system may have a great impact on the preservation and restoration of animal health. Biological response modifiers are agents that modify the host's response to pathogens with resultant beneficial prophylactic or therapeutic effects. The best known example of biological response modifiers are vaccines, by which administration of a nonpathogenic form of a microorganism prepares the immune system to produce a more effective response upon subsequent infection with the pathogenic form. Nevertheless, the use of biological response modifiers other than vaccines that enhance the immune response is now the focus of many investigations. In this review, a brief overview of the immune system is presented, and special emphasis is placed on possible areas of intervention with biological response modifiers and a description of the prophylactic and therapeutic potential of biological response modifiers. Specific examples are presented to demonstrate examples of disease modification by biological response modifiers through stimulation of nonspecific and antigen specific immunities.

Multiple clinical and biological autoimmune manifestations in 50 workers after occupational exposure to silica

OBJECTIVES

A self referred group of four workers from a factory producing scouring powder with a high silica content showed a surprisingly high number of features compatible with a connective tissue disease. Further subjects working at the same factory were subsequently studied to evaluate the relation between this exposure and the development of autoimmune processes.

METHODS

A total of 50 subjects (44 women, six men; mean (SD) age 43.7 (5.5) years; mean duration of employment 6.1 years) underwent a prospective study including clinical history and physical examination, an immunobiological study, HLA typing, radiological and functional oesophageal and respiratory examination, ophthalmological examination, and isotopic testing of salivary glands.

RESULTS

Symptoms of a systemic illness were present in 32 (64%) subjects: six with Sjögren's syndrome; five with the criteria for systemic sclerosis; three with systemic lupus erythematosus (SLE); five with an 'overlap syndrome'; and 13 with undifferentiated findings not meeting the criteria for a defined disease. Antinuclear antibodies were present in 36 (72%) subjects; four had antibodies to native DNA, including two subjects with SLE, one with systemic sclerosis associated with secondary Sjögren's syndrome, and one with overlap syndrome. Anticentromere antibodies were not detected. The frequency of HLA-DR3 was increased in the clinically affected subjects, but did not reach statistical significance.

CONCLUSIONS

This descriptive study emphasises the high probability of workers occupationally exposed to silica developing a multiple spectrum of clinical and serological autoimmune manifestations.

Potentiation of in vivo antitumor effects of recombinant interleukin-1 alpha by gelatin conjugation

Chemical conjugation of a recombinant human interleukin-1 alpha (IL-1) with gelatin was conducted using a water-soluble carbodiimide in an attempt to augment the indirect effect of IL-1 on in vivo tumor cell growth in mice. Chromatographic studies of the IL-1-gelatin conjugate demonstrated that the apparent molecular weight of IL-1 was increased by the gelatin conjugation and about 60% of IL-1 activity was retained in the prepared conjugate. Intraperitoneal (i.p.) injection of the conjugate significantly suppressed the intraperitoneal growth of a subline of Meth A fibrosarcoma cells (RR1 cells), compared with the effect of free IL-1 at the same dose, although the cells per se were resistant not only to free IL-1 but also to gelatin-conjugated IL-1. Simple mixing of gelatin with free IL-1 did not augment the in vivo antitumor effect as compared with that of free IL-1. Gelatin conjugation improved the in vivo stability of IL-1. Prolonged retention of IL-1 activity in the peritoneal cavity as well as the circulation of mice was observed after i.p. injection of the IL-1-gelatin conjugate in comparison with free IL-1 injection, irrespective of the presence of tumor cells. Gelatin conjugation was effective in augmenting the in vivo antitumor effects of IL-1 to activate host cells, e.g. macrophages (M phi). The i.p. injection of the conjugate enhanced M phi infiltration into the peritoneal cavity of tumor-bearing mice and peritoneal M phi were strongly activated to inhibit the in vitro growth of RR1 cells. Thus, gelatin conjugation was effective in augmenting the indirect effect of IL-1 via host cells, leading to a high suppressive effect on in vivo growth of tumor cells.

Synergistic enhancement by interleukin-1 alpha of cisplatin-mediated antitumor activity in RIF-1 tumor-bearing C3H/HeJ mice

Administration of interleukin-1 alpha (IL-1 alpha) plus certain cytotoxic drugs causes substantially greater clonogenic tumor-cell kill and tumor-regrowth delay than does treatment with either agent alone. IL-1 alpha itself has little effect on tumor growth despite its ability to induce acute hemorrhagic necrosis, restrict tumor blood flow, and cause microvascular injury in a variety of murine model systems. To investigate further IL-1 alpha's ability to enhance the antitumor activity of cytotoxic drugs, we initiated studies to examine the effect of IL-1 alpha on cisplatin (cDDP)-mediated cytotoxicity using the RIF-1 tumor system. The antitumor activity of IL-1 alpha and cDDP was quantitated through standard clonogenic tumor-cell survival assays, a tumor hemorrhagic necrosis assay and tumor-regrowth delay studies, with the interaction between IL-1 alpha and cDDP being analyzed through median dose-effect. In vitro, IL-1 alpha had no enhancing effect on the cDDP-mediated tumor-cell kill. For examination of the in vivo efficacy of this regimen, RIF-1 tumor-bearing C3H/HeJ mice (14 days postimplantation) were treated concurrently with single i.p. injections of IL-1 alpha and/or cDDP at various doses. The increased clonogenic tumor-cell kill obtained with IL-1 alpha/cDDP was dose-dependent, with significant enhancement by IL-1 alpha being observed (P < 0.001), even at the lowest doses tested (2 mg/kg and 6 micrograms/kg for cDDP and IL-1 alpha, respectively), but it did not correlate with an increase in tumor hemorrhage. Using median dose-effect analysis, this interaction was determined to be strongly synergistic. When treated animals were monitored for long-term antitumor effects, combinations with IL-1 alpha significantly increased the tumor-regrowth delay and decreased the fractional tumor volume (P < 0.001). These results demonstrate that IL-1 alpha synergistically enhances cDDP mediated in vivo antitumor activity and suggest that the combination of IL-1 alpha and cDDP may have potential therapeutic application in the design of effective treatment modalities for cancer.

Image analysis in the evaluation of biomaterials

An examination regime, based on a computer-aided image analysis system, has been developed for the quantitative evaluation of the local tissue response to biomaterials. This procedure involves the immunoenzymic staining of tissue sections using monoclonal antibodies specific for certain inflammatory cell types. An avidin-biotin-horseradish peroxidase staining method is used to identify antibody binding sites and the sections are assayed using a computer-aided image analysis system. This regime facilitates the rapid and accurate measurement of 30 cell related parameters in sections stained for macrophages, polymorphonuclear leucocytes, and other cells.

Purification of interleukin-1 beta converting enzyme, the protease that cleaves the interleukin-1 beta precursor

We have purified the IL-1 beta converting enzyme from the THP-1 cell line using standard chromatographic techniques and obtained the N-terminal amino acid sequence of this novel protein. After stimulation of THP-1 cells with lipopolysaccharide, hydroxyurea, and silica, the protease was solubilized by multiple freeze/thawing. The protein was purified by ion-exchange chromatography, affinity chromatography on blue agarose, gel filtration, and chromatofocusing. The molecular weight of the protein is approximately 22,000 Da and the pI is between 7.1 and 6.8. The overall yield for this procedure was 16% of the activity found in the initial cell lysates. An antiserum raised against a peptide based on the N-terminus was used to precipitate the protease, confirming our identification of the 22,000-Da protein as the IL-1 beta converting enzyme.

Macrophage functions in cats experimentally infected with feline immunodeficiency virus and Toxoplasma gondii

It was suspected that feline immunodeficiency virus (FIV) infection would affect the function of feline macrophages, and that the concomitant infection of cats with FIV and Toxoplasma gondii would cause even greater changes in macrophage function. Sixteen specific-pathogen-free kittens, four per group, were infected either with FIV, T. gondii, both pathogens, or neither pathogen. After the cats had been infected with FIV for 14 weeks (8 weeks after T. gondii infection), peritoneal macrophages were collected. Some macrophages were stimulated with lipopolysaccharide and supernatants were collected for the measurement of interleukin-1 production. Other macrophages were infected with T. gondii in a microbiocidal assay. Peritoneal macrophages from cats infected with FIV had decreased interleukin-1 secretion and increased antimicrobial activity. Co-infection with T. gondii apparently had no effect on these modifications of macrophage activity. Thus, acute FIV infection alone caused significant changes in macrophage functions that were not affected by concomitant T. gondii infection.

Quantitative assessment of the tissue response to implanted biomaterials

The tissue response to a small number of polymeric biomaterials was studied using monoclonal antibodies specific for certain inflammatory cell types, to develop a reliable and accurate method for the quantitative evaluation of biocompatibility. The sites of antibody binding were identified using an avidin-biotin staining procedure and the sections evaluated using a computer-aided image analysis system. The staining technique successfully demonstrated both polymorphonuclear leucocytes and macrophages in tissue samples containing polymeric biomaterials. The image analysis system facilitated the measurement of up to 30 cell-related parameters and allowed a large number of cells to be analysed.

Toxic epidermal necrolysis (Lyell syndrome)

Toxic epidermal necrolysis is perhaps the most formidable disease encountered by dermatologists. Uncommon but not rare, toxic epidermal necrolysis occurs in 60 to 70 persons per year in France. It remains as puzzling a disorder as it was 34 years ago, when described by Lyell. Whether or not toxic epidermal necrolysis is the most severe form of erythema multiforme is still the subject of discussion. The physiopathologic events that lead to this rapidly extensive necrosis of the epidermis are not understood. Indirect evidence suggests a hypersensitivity reaction, but the search for potential immunologic mechanisms has resulted in little data to support this hypothesis. Accumulated clinical evidence points to drugs as the most important, if not the only, cause of toxic epidermal necrolysis. Sulfonamides, especially long-acting forms, anticonvulsants, nonsteroidal anti-inflammatory agents, and certain antibiotics are associated with most cases of toxic epidermal necrolysis. Many other drugs have been implicated in isolated case reports. All organs may be involved either by the same process of destruction of the epithelium as observed in the epidermis or by the same systemic consequences of "acute skin failure" as seen in patients with widespread burns. Sepsis is the most important complication and cause of death. Approximately 20% to 30% of all patients with toxic epidermal necrolysis die. Elderly patients and patients with extensive lesions have a higher mortality rate. Surviving patients completely heal in 3 to 4 weeks, but up to 50% will have residual, potentially disabling ocular lesions. The prognosis is improved by adequate therapy, as provided in burn units, that is, aggressive fluid replacement, nutritional support, and a coherent antibacterial policy. Corticosteroids, advocated by some in high doses to halt the "hypersensitivity" process, have been shown in several studies to be detrimental and should be avoided.

Interleukin-1: biology, pathophysiology, and clinical prospects

Interleukin-1 (IL-1) is a cytokine with multiple biologic activities. Since its first description in 1972, significant work has been done, leading to an understanding of the biology of IL-1, which plays a central role in many important functions of the immune system. The biologic activities of IL-1 make it an attractive factor for use in clinical oncology, both as an antitumor agent and for the hematologic recovery of cancer patients receiving other forms of therapy. In this review the biologic effects of IL-1 are summarized. The possible involvement of IL-1 in the pathogenesis of some diseases is reviewed. Future prospects for the use of IL-1 in the treatment of malignancies are discussed.

Interaction of monocytes and T cells in the regulation of normal human megakaryocytopoiesis in vitro: role of IL-1 and IL-2

Autologous or allogeneic peripheral blood T cells can stimulate the human megakaryocyte progenitor cell (CFU-Meg)-derived colony formation in a dose-dependent fashion in agar cultures of nonadherent (NA), T cell-depleted (NT) bone marrow (BM) cells. Low concentrations of monocytes and T cells can collaborate in the stimulation of CFU-Meg colony formation or in the production of megakaryocyte colony stimulating factor (Meg-CSF) by T cells in the presence of mitogens or IL-2. Monocytes alone can produce only negligible Meg-CSF under any conditions. When monocyte conditioned medium (CM) was added to T cell-stimulated NA, NT BM cell cultures, CFU-Meg colony growth was appreciably increased compared with that stimulated by T cells alone. Dose-dependent increase in CFU-Meg colony growth was noted when varying concentrations of IL-1 were added to T cell-stimulated NA, NT cell cultures, although IL-1 itself could support no CFU-Meg colony growth in the absence of T cells. These data suggest that a synergistic interaction between T cells and monocytes during the production of Meg-CSF by T cells could be partly mediated by IL-1. IL-2 was found to stimulate Meg-CSF production by T cells in the presence or absence of mitogens. IL-2-stimulated Meg-CSF production by T cells was augmented by the addition of monocytes. Although IL-2 itself had no stimulatory effect on CFU-Meg colony growth, dramatic augmentation in the CFU-Meg colony number was noted when IL-2 was added to T cell-stimulated NA, NT cell cultures. High concentrations of monocytes and prostaglandin E (PGE) inhibited the CFU-Meg colony formation. These results suggest that IL-1 and IL-2 may play a stimulatory role on the normal human in vitro megakaryocytopoiesis, and may be involved in the development of reactive thrombocytosis and bone marrow megakaryocytic hyperplasia in various inflammatory diseases.

Evidence for the involvement of the central adrenergic system in the febrile response induced by interleukin-1 in rats

We have studied the effect of noradrenaline- and serotonin-depleting agents on the febrile response induced by an intracerebroventricular (i.c.v.) injection of interleukin-1 (IL-1) in rats. Pretreatment with an injection into the lateral ventricle of the catecholamine-depleting agent, 6-hydroxydopamine (6-OHDA), abolished the febrile response induced by IL-1. Injection of 6-OHDA into the ventral noradrenergic ascending bundle (VNAB) did not affect the pyrogenic effect of IL-1. Pretreatment with the serotonin-depleting agent, 5,7-dihydroxytryptamine (5,7-DHT), did not inhibit the febrile response to IL-1. In addition, pretreatment with a beta-adrenergic blocker (propranolol) but not an alpha-adrenergic blocker (yohimbine) attenuated the fever induced by an i.c.v. injection of IL-1. These results suggest that the integrity of the central catecholaminergic system is important in mediating the IL-1-induced fever in rats. The central serotonergic system, as well as noradrenergic neurotransmission at the hypothalamus, do not appear to participate in this endogenous pyrogen-induced febrile response.

T cell inhibitor secreted by macrophages and endothelial cells

On stimulation with lipopolysaccharide (LPS), normal human macrophages (M phi) and endothelial cells (EC) produced factors which inhibited interleukin 2 (IL-2)-dependent lymphocyte proliferation and PHA plus interleukin 1 (IL-1)-dependent mouse thymocyte proliferation but not IL-1-dependent human fibroblast proliferation, suggesting that they were inhibitors of the IL-2 response. In addition, these factors inhibited the production of IL-2 by normal human peripheral blood mononuclear cells (PBMC). The factors also inhibited PBMC proliferation in response to PHA and concanavalin (Con A) but did not inhibit the proliferation of EC, U937 cells, or Epstein-Barr virus-transformed B cells. On Sephadex G200 gel filtration, the inhibitory factors from both M phi and EC were detected almost entirely in a 130- to 150-kDa fraction, but active material was also detected in a 15- to 20-kDa fraction. On isoelectric chromatofocusing of the 130- to 150-kDa fraction, inhibitory activity was associated with fractions eluted at three isoelectric points, pH 7.0, 5.4, and 4.8. The isoelectric fractions isolated from M phi and EC showed similar patterns of inhibition. When 130- to 150-kDa fractions from Sephadex G200 of the M phi and EC supernatants were treated with an antibody against a macrophage-derived suppressor factor produced by the human monocytic leukemia cell line THP-1, the activity of both fractions was neutralized. The above findings suggest that normal M phi and EC secrete an identical or closely related inhibitor of IL-2 synthesis and IL-2 response, and this inhibitor regulates these IL-2-related functions by a suppressive action on the T lymphocyte.

Generation of IL-1-like activity in response to biomedical polymer implants: a comparison of in vitro and in vivo models

Of the many factors determining host biocompatibility responses to implanted biomedical polymers, the cellular interactions at the tissue/material interface have been recognized to be some of the most important. The present study has combined results both from an in vitro cell culture system and from an in vivo animal model to examine this host response. In vitro results suggest that a variety of polymer materials can differentially activate human monocytes to produce a protein(s) having different biological activities. The polymers tested induce the production of the regulatory inflammatory protein interleukin 1 as well as a factor that enhances fibroblast proliferation and collagen synthesis. The observed activities of these factors appear to be related but not identical, and are dependent upon the specific polymer. Evaluation of exudate and tissue responses to these same polymer materials in an in vivo model are also presented. Both in vitro and in vivo results support the hypothesis that monocyte/macrophage activation with subsequent synthesis of regulatory factors such as interleukin 1 plays a significant role in determining the host response to biomedical polymer implants.

Neopterin and alpha and beta interleukin-1 levels in sera of patients with human immunodeficiency virus infection

Levels of neopterin and alpha and beta interleukin-1 (IL-1) in sera of normal controls, asymptomatic intravenous drug abusers, homosexuals, and patients with lymphadenopathy or acquired immunodeficiency syndrome were measured. Neopterin levels were elevated in the sera of human immunodeficiency virus (HIV)-seronegative intravenous drug abusers and homosexuals, as well as in the sera of HIV-seropositive patients. Alpha IL-1 was the most predominant form of IL-1 found in the sera of all groups, and its level in HIV-seronegative intravenous drug abusers was elevated compared with the level in controls, whereas its levels in asymptomatic HIV-seropositive intravenous drug abusers and asymptomatic HIV-seronegative and HIV-seropositive homosexuals were decreased relative to the level in controls. Beta IL-1 levels in sera in all groups were not significantly different from the control value, except for the HIV-seropositive homosexual group; in this group the beta IL-1 level was significantly decreased compared with the control value.

In vitro stimulation of fibroblast activity by factors generated from human monocytes activated by biomedical polymers

Biomedical polymers used in constructing implantable artificial devices may affect host responses to the material and ultimately contribute to the success or failure of a device via mechanisms of cell-polymer interactions. Human peripheral blood monocytes (MO) cultured in the presence of several such biomedical polymers released factors that stimulated fibroblast proliferation and/or collagen synthesis. The factors that stimulated fibroblast proliferation were differentially released from monocytes cultured in the presence of Dacron, polyethylene, expanded polytetrafluoroethylene (ePTFE), polydimethylsiloxane, and polystyrene (control). Supernatants obtained from monocytes cultured in the presence of Biomer, a segmented polyetherurethane, were unable to stimulate fibroblast proliferation. However, supernatants from all cultures, including MO-Biomer cultures, were able to induce collagen production from the same target fibroblasts. These same supernatants also were shown to contain interleukin 1 (IL1) activity. Neutralization of the fibroblast stimulatory potential (FSP) activity with antibodies directed against human IL1 and human PDGF demonstrated that IL1 and not PDGF was responsible for the FSP activity. Results of this study show that by affecting macrophage activation, different biomedical polymers can affect host biocompatibility responses by altering fibroblast proliferation and function.

A sensitive IL-1 thymocyte co-stimulator assay using a novel beta-D-galactoside specific lectin from the beetle, Allomyrina dichotoma

A sensitive thymocyte co-stimulator assay of IL-1 using a beta-D-galactoside specific lectin (allo A) obtained from the beetle (Allomyrina dichotoma) is reported here. Allo A stimulated [3H]thymidine uptake of mouse thymocytes in the presence of IL-1. The allo A assay was more sensitive than the PHA or PNA- thymocyte assay, especially at low doses of IL-1. Optimal conditions for the allo A assay were as follows: allo A, 2.5-5.0 micrograms/ml; whole thymocytes, 0.5-1.0 x 10(6) cells/well; incubation time, 72-96 hr. The assay is sensitive and convenient and can easily be performed in any laboratory.

Effect of interleukin-1 on adrenocortical activity in intact and hypothalamic deafferentated male rats

The present study was designed to elucidate the site of action of interleukin 1 (IL-1) modulation of the hypothalamic-hypophyseal-adrenal (HHA) axis. An intraperitoneal injection of recombinant human IL-1 beta (160 U/rat) significantly elevated serum levels of ACTH and corticosterone (CS). In rats with complete mediobasal hypothalamic deafferentation, the HHA response to IL-1 was inhibited. An intracerebroventricular injection of rIL-1 (2 U/rat) caused a marked increase in serum ACTH and CS. These results suggest that IL-1 activates the HHA axis by a direct effect upon the brain, and that intact neural connections between the mediobasal hypothalamus and extrahypothalamic brain regions are essential for IL-1-induced HHA responses.

Identification of a human bone marrow-derived immunoenhancing factor, BDEF

In this report we describe the production and biological activity of human bone marrow-derived enhancing factor (BDEF). This factor is the constitutive product of cultured human BMC and could initially be recovered by ultrafiltration of cell-free BM supernatants to yield a crude fraction of Mr greater than 10,000 Da. This preparation can enhance the Ab response of human tonsillar cells, as well as murine spleen cells, to SRBC. HPLC fractionation of BM supernatants enriches for enhancing activity in a peak with an approximate Mr of 60 kDa. PAGE gel analysis reveals two protein bands which migrate to this area, one of 60 kDa, and a slightly smaller protein at 55 kDa. Antibodies generated against the above two proteins were shown to be specific by Western blotting and could recognize the native BM proteins as determined by ELISA. The antibodies were used to affinity purify the respective proteins, p60 and p55. The BM protein p60, but not p55, was able to enhance Ab synthesis in vitro and was also mitogenic for murine BMC and thymocytes. The addition of anti-p60 Ab to human tonsillar cells cultured with SRBC and human BDEF preparations resulted in abrogation of enhancement. These findings support the notion that the BM protein p60 is BDEF and that it may represent a novel enhancing molecule produced by normal human BM.

IL-1 and PGE2 productions by the regional lymph node cells from DNFB-sensitized mice

Interleukin 1 (IL-1) and Prostaglandin E2 (PGE2) are mainly produced by macrophage/monocytes. In this experiment, we investigated the immunological role of macrophage/monocytes in the lymph nodes (LNs) by measuring IL-1 and PGE2 productions of regional LN cells from dinitrofluorobenzene (DNFB)-sensitized and -tolerant mice. LN cells from sensitized mice produced IL-1 in remarkable amounts after in vitro antigen stimulation. On the other hand, the LN cells from tolerant mice failed to produce IL-1 or PGE2. These data indicate that, by modifying cytokine production, macrophage/monocytes in the regional LNs play a key role in the pathomechanism of contact hypersensitivity.

Preparation and application of polyclonal antibodies to recombinant human interleukin-1 alpha and interleukin-1 beta

We report the preparation and application of polyclonal antisera to the analysis and quantitation of human interleukin-1 alpha (IL-1 alpha) and human interleukin-1 beta (IL-1 beta). The anti IL-1 alpha antibodies specifically react with the alpha form of IL-1 and do not cross react (less than 0.1%) with the beta form of IL-1 and vice versa. Data reported here demonstrate that detection of human IL-1 alpha or beta by a radioimmunoassay technique is sensitive enough to measure picogram levels of these lymphokines. The practical application of using these highly specific antisera for radioimmunoassays was established by measuring exogenously added IL-1 alpha or IL-1 beta to human plasma. Potential benefits of these reagents and the radioimmunoassay procedures described herein are discussed in relation to the biological assays which cannot distinguish between human IL-1 alpha and human IL-1 beta.

Recombinant human interleukin 1 alpha is cytotoxic for and increases surface expression of HLA-A,B,C antigens of a human hepatoma cell line, PLC/PRF/5

Our study was undertaken to determine whether human recombinant interleukin 1 alpha (rIL 1 alpha) has any effect on the proliferation and expression of HLA-A,B,C antigens of human liver cell lines. The addition of rIL 1 alpha reduced the cell number of the human hepatoma cell line, PLC/PRF/5. This effect was determined to be cytotoxic, but not growth inhibitory, rIL 1 alpha did not change the number of Chang cell or SK-Hep-1 at a concentration as, high as 25,000 U/ml. rIL 1 alpha enhanced the expression of HLA-A,B,C antigens on PLC/PRF/5, but had no effect on Change cell or SK-Hep-1. Receptor binding studies showed that 125I-rIL 1 alpha bound to PLC/PRF/5 in a specific and saturable manner, but did not bind to Chang cell or SK-Hep-1. Scatchard plot analysis of the binding to PLC/PRF/5 revealed a single type of high affinity binding site with an apparent dissociation constant of approximately 5 x 10(-5) M and the presence of approximately 150 binding sites per cell. These findings suggest that IL 1 alpha may play a role in host defense against some hepatomas as cytotoxic factor and may be an enhancer of expression of HLA-A,B,C antigens on tumor cells.

Human T-cell mediated response to homologous lens antigen

T-Cell response to a suspension of homologous whole lens antigen was investigated in three groups: (1) adults with normal eyes; (2) patients with mature and hypermature cataract with an intact lens capsule; and (3) patients, who had had extracapsular cataract surgery or lens injury, some of whom had clinical evidence of severe lens-induced inflammation. The results show that sensitized T-cells occur only in some patients in the third group. To our knowledge, this is the first direct evidence of a difference in the response to T-cells to lens antigen released from mature and hypermature lenses, and to lens antigen exposed by lens injury or extracapsular cataract surgery. The test may be useful to confirm clinical suspicion of delayed hypersensitivity to lens antigen in patients with severe sterile purulent inflammation or milder delayed sterile non-purulent inflammation following lens injury or extracapsular surgery, in the absence of histological proof.

Intimal changes in the aorta of prehypertensive rats

Intimal changes were quantitated in several rat models of arterial hypertension. One kidney-one clip rats drinking water (1K-1C-water), one-kidney rats treated with deoxycorticosterone acetate and drinking 1% NaCl (1K-DOCA-salt), and two-kidney rats drinking 1% NaCl (2K-salt) were studied after 1 to 8 weeks. The thoracic aorta was examined en face and by electron microscopy. Surprisingly, all 2K-salt, most 1K-DOCA-salt (17 out of 19), and two-thirds of 1K-1C-water rats (12 out of 18) had normal arterial pressure at sacrifice. In these normotensive 2K-salt, 1K-1C-water, and 1K-DOCA-salt animals, intimal mononuclear cells (which emigrated from the blood) increased between three- and ninefold. In these same normotensive 1K-1C-water and 1K-DOCA-salt rats, endothelial cell mitoses increased three- to sixfold with a corresponding increase in endothelial cell numbers. In the latter two groups, there was no evidence of endothelial cell denudation or changes in aortic circumference, and the subendothelial space widened mainly with reticular basement membrane presumably synthesized by the endothelium. In normotensive 1K-DOCA-salt rats, most of the endothelial cells were thick and there were several intercellular gaps. Endothelial proliferation, synthesis of macromolecules, and gap formation, as well as increased mononuclear cell emigration, indicate functional changes in mononuclear cells and in endothelial cells. We suggest that the experimental procedures designed to produce hypertension also generate factor(s) which activates mononuclear cells and/or endothelial cells. This cellular activation leads to intimal changes independent of hypertension.

Regulation of alpha 1-acid glycoprotein plasma concentration by sex steroids and adrenal-cortical hormones during experimental inflammation in the rat

Treatment of adult intact rats with sex steroids (estradiol-17 beta, ethynylestradiol, dihydrotestosterone) raises the concentration of serum acute-phase alpha 1-acid glycoprotein (AGP). Estrogens are more effective than dexamethasone, and experimental inflammation causes an additive effect on AGP synthesis when ethynylestradiol is given simultaneously. Adrenaline is also able to increase the AGP level. Experiments with adrenalectomized and adrenalectomized plus castrated rats result in a 50% reduction in the serum level of AGP as compared with that in normal and hypophysectomized rats. Although ethynylestradiol is the strongest inducer of AGP synthesis in intact animals, it is unable to enhance significantly the AGP level in adrenalectomized rats, contrary to dexamethasone. Adrenalectomized rats are incapable of undergoing a substantial increase in plasma AGP level following experimental inflammation, and ethynylestradiol or adrenaline cannot take the place of dexamethasone in inducing high levels of AGP in these inflamed rats. These results indicate that glucocorticoids play an obligatory role in modulating AGP synthesis either by directly regulating the AGP gene or in modulating AGP synthesis by increasing the stability of AGP mRNA. Finally, it is suggested that glucocorticoids may also act in unmasking receptor binding sites at the AGP gene level for other mediators such as sex steroids and putative inflammatory factors.

Ontogeny and cellular origin of an interleukin-1-like factor in the reproductive tract of the male rat

We have recently isolated an interleukin-1 (IL-1)-like factor from the rat testis, which originates from the seminiferous tubules and is a protein with an MW of 17,000 and a pI of 5-6. This paper reports on the appearance of the IL-1-like factor during postnatal development and investigates its cellular origin further. IL-1 activity was measured by a murine thymocyte proliferation assay. Very low IL-1 activity was present in culture medium conditioned by seminiferous tubules from rats aged 10 or 20 days. From 30 days of age, increasing amounts were detected, reaching a maximum level in adult animals (60-90 days). No IL-1 activity was found in medium conditioned by peritubular cells. Sertoli cell-enriched seminiferous tubules obtained from experimentally cryptorchid or from prenatally irradiated rats produced much higher levels of IL-1 activity than did those obtained from intact testes. IL-1 activity was detected in efferent duct fluid after ligation of the efferent ducts for 24 h, indicating that the IL-1-like factor was secreted into the tubular lumen. Low levels of IL-1 activity were detected in extracts of epididymal tissue and epididymal sperm, whereas ejaculated seminal plasma, seminal vesicle fluid and extracts of seminal vesicles (together with the coagulating glands) and ventral and dorsolateral prostate lacked IL-1 activity. Instead, seminal plasma inhibited testicular IL-1 activity dose-dependently without affecting cell viability in the thymocyte cultures. Although its biological function remains to be defined, our results indicate that the testicular IL-1-like factor is produced by Sertoli cells and that its appearance during development coincides with the initiation of active spermatogenesis in the rat testis.

Thymic accessory cells required for the increased responsiveness of thymocyte subpopulations to interleukin 1-like monokine in guinea pigs

The proliferative response of guinea-pig thymocytes to co-mitogenic stimulation with phytohaemagglutinin and the guinea-pig interleukin 1 (IL-1)-like lymphocyte-activating monokine was lost by removing the cells that adhere to a Sephadex G-10 (G-10) column or the cells of low density in a Ficoll-Conray gradient. The diminished response in the G-10 non-adherent thymocyte or high-density thymocyte fraction was restored by the addition of a macrophage-depleted G-10 adherent thymocyte fraction or a low-density, Ia-positive thymocyte fraction but not by the addition of peritoneal macrophages. These results suggest that the accessory cells which mediate the increased responsiveness of thymocytes to the IL-1-like monokine existed in G-10 adherent cell fractions and the cells with this accessory function were not macrophages. The accessory cells were shown to be of low density, glass-non-adherent, G-10-adherent, Fc receptor-negative, and Ia-positive. These results also suggest that the G-10-non-adherent and high-density thymocyte subpopulation, which is unresponsive or responds very little to the IL-1-like monokine by itself, acquires responsiveness to the monokine and proliferates by stimulation with the IL-1-like monokine and lectin in the presence of the accessory cells.