Synthesis of interleukin-1, interleukin-6, and basic fibroblast growth factor by human cataract lens epithelial cells

PURPOSE

To assay the following cytokines in an incubation medium of cultured lens epithelial cells (LECs) derived from human cataracts: interleukin-1 alpha (IL-1), interleukin (IL-6), basic fibroblast growth factor (b-FGF), tumor necrosis factor-alpha (TNF-alpha), and epidermal growth factor (EGF).

SETTING

Nishi Eye Hospital, Jinshikai Medical Foundation, Osaka, Japan.

METHODS

The anterior lens capsule with attached LECs was obtained by capsulotomy during cataract surgery and cultured. The incubation medium was changed on days 1 and 2 of culture and thereafter weekly up to 7 weeks. The media collected from a specific number of cultures at each medium change were pooled and assayed for cytokines by enzyme-linked immunosorbent assay.

RESULTS

Interleukin-1 alpha was detected in one of the two pools of the 2 week cultures (207 pg/10(6) cells), in two of the three pools of the 3 week cultures (120 pg/10(6) and 139 pg/10(6) cells), and in one of the two pools of the 4 week cultures (111 pg/10(6) cells). Interleukin-6 was detected in one pool of the 1 week cultures (195 pg/10(5) cells) and in one pool of the 7 week cultures (81.6 pg/10(5) cells). Basic FGF was detected in the incubation media from three series of samples during the culture time course: 87 pg/ml in the 1 day cultures in the first series; 478, 310, and 269 pg/ml in the 1 day, 2 day, and 1 week cultures, respectively, in the second series; and 98 and 83 pg/ml in the 1 and 2 day cultures, respectively, in the third series. The TNF-alpha and EGF were not detected in any sample.

CONCLUSION

After cataract surgery, IL-1, IL-6, and b-FGF may be produced in vivo by residual LECs, causing postoperative inflammation and LEC proliferation.

Systemic chemotherapy alters interleukin-1 beta and its receptor antagonist production by human alveolar macrophages in lung cancer patients

The purpose of this study was to determine whether cytotoxic chemotherapy influences the number and function of alveolar macrophages (AM) in patients with lung cancer. AM were obtained by bronchoalveolar lavage from 24 patients with lung cancer and 17 control patients. The functional integrity of AM was determined by their ability to produce interleukin-1 beta (IL-1 beta) and interleukin-1 receptor antagonist (IL-1ra) before and after platinum-containing systemic chemotherapy. The productions of IL-1 beta and IL-1ra were quantitated by enzyme immunoassays. The proportions of multinucleated cells among AM were significantly decreased after systemic chemotherapy in lung cancer patients. No significant difference in spontaneous and lipopolysaccharide (LPS)-stimulated IL-1 beta or IL-1ra production by AM was observed between lung cancer patients and control patients. Significant increase of IL-1 beta and significant decrease of IL-1ra production by AM were demonstrated in patients with small cell lung cancer who experienced response to systemic chemotherapy. These results suggest that systemic chemotherapy may influence functional roles of AM in the lung, and consideration of influence of systemic chemotherapy on host functions is important in cancer treatment.

Effects of the cytokines on the proliferation of and collagen synthesis by human cataract lens epithelial cells

AIMS

To assess the effects of the cytokines, interleukin-1 (IL-1), IL-1 receptor antagonist (IL-1ra), transforming growth factor-beta 2 (TGF-beta 2) and basic fibroblast growth factor (b-FGF), on the mitosis of and collagen synthesis by lens epithelial cells (LECs) of human cataracts.

METHODS

The anterior lens capsule with attached LECs was obtained by capsulotomy during cataract surgery and cultured. The cultures at 2 to 3 weeks before confluency were used for the experiments. To quantify the mitosis and collagen synthesis, the incorporation of 3H-thymidine and 3H-proline, respectively, into the LECs was measured by a scintillation counter at 48 hours and 24 hours, respectively, after addition of the cytokine at various concentrations into the incubation medium.

RESULTS

IL-1 and b-FGF increased the mitosis and collagen synthesis significantly, but IL-1ra significantly decreased the mitosis while leaving the collagen synthesis intact. TGF-beta 2 decreased the mitosis significantly, but increased the collagen synthesis significantly.

CONCLUSION

These cytokines may play an important role in an autocrine or paracrine pathway in the proliferation of residual LECs after cataract surgery. Elucidation of the role of these cytokines may lead to the development of new therapies for the prevention of secondary cataract.

The correlation of thymidine phosphorylase activity with the expression of interleukin 1 alpha, interferon alpha and interferon gamma in human colorectal carcinoma

Thymidine phosphorylase (dThdPase) is an angiogenic enzyme and seems to be related to an angiogenesis in human colorectal carcinoma. The incidence of dThdPase-positive cells was significantly correlated with microvessel count in 21 human colorectal carcinomas. Interleukin 1 alpha (IL-1 alpha), tumor necrosis factor alpha (TNF-alpha), interferon alpha (IFN-alpha) interferon gamma (IFN-gamma) induce dThdPase activity in human cancer cell lines. To study whether this phenomenon occurs in the human colorectal carcinomas, we examined the correlation between dThdPase activity and the expression levels of IL-1 alpha, TNF-alpha, IFN-alpha and IFN-gamma in colorectal carcinoma tissues. dThdPase activity was assayed by the methods of Friedkin and Robert, and the expression level of IL-1 alpha, TNF-alpha, IFN-alpha and IFN-gamma was determined by ELISA. dThdPase activity was significantly correlated with the amount of IL-1 alpha (n = 19, r = 0.347, P = 0.0001), INF-alpha (n = 18, r = 0.717, P = 0.008), and IFN-gamma (n = 4, r = 0.9777, P = 0.0234) in human colorectal carcinomas. However, the dThdPase activity was not correlated with the amount of TNF-alpha (n = 21, r = 0.235, P = 0.2682). These results suggested that the expression levels of IL-1 alpha, IFN-alpha and IFN-gamma are correlated with dThdPase activity in human colorectal carcinomas and that these cytokines may cause angiogenesis by inducing the expression of dThdPase.

Serum autoantibody against interleukin-1 alpha is unrelated to the etiology or activity of liver disease but can be raised by interferon treatment

OBJECTIVE

To clarify the clinical significance of serum levels of interleukin-1 alpha autoantibody in liver disease and their change during interferon therapy for chronic hepatitis.

METHODS

By radioimmunoassay, we studied the incidence of serum interleukin-1 alpha autoantibody in 838 healthy controls and 180 patients with liver disease and monitored the change in antibody titer during the interferon therapy for chronic hepatitis.

RESULTS

We detected the interleukin-1 alpha autoantibody in 12.6% (106/838) of healthy controls. In patients with liver disease, we found the antibody in 15.6% (5/32) in patients with acute hepatitis, 16.3% (13/80) in patients with chronic hepatitis, 18.8% (9/48) in patients with liver cirrhosis, and 15% (3/20) in patients with autoimmune liver disease. The incidence was not related to either etiology or inflammatory activity of liver disease. Two of three chronic hepatitis patients with initially high serum levels of the antibody (> 2000 ng/ml) showed transient increase in antibody titers during interferon therapy.

CONCLUSION

The serum level of interleukin-1 alpha autoantibody was unrelated to the etiology or activity of liver disease. Interferon therapy can cause transient elevation of serum interleukin-1 alpha autoantibody levels.

Contrasting effect of interleukin-13 on interleukin-1 receptor antagonist and proinflammatory cytokine production by human alveolar macrophages

We investigated the effect of interleukin-13 (IL-13) on production of IL-1 receptor antagonist (IL-1ra) and proinflammatory cytokines by human alveolar macrophages (AM). AM were obtained by bronchoalveolar lavage from healthy donors. The production of IL-1ra and proinflammatory cytokines, such as IL-1 beta, IL-6, and tumor necrosis factor-alpha (TNF-alpha), were quantitated by enzyme immunoassays. AM spontaneously produced IL-1ra, and this production was significantly augmented by IL-13. On the other hand, IL-13 alone did not affect production of proinflammatory cytokines by freshly isolated AM. Upon stimulation with lipopolysaccharide (LPS), AM produced a significantly amount of proinflammatory cytokines as well as IL-1ra, but this production was suppressed by IL-13 in a dose-dependent manner. In contrast, IL-13 caused a small but reproducible increase in LPS-induced IL-1ra production. These regulatory effects of IL-13 were also observed in blood monocytes and macrophages generated in vitro by maturation of blood monocytes with granulocyte/macrophage colony-stimulating factor. These observations suggest that IL-13 may act as an anti-inflammatory cytokine through regulation of cytokine production by AM in the lung.

Effect of interleukin 1 receptor antagonist on the blood-aqueous barrier after intraocular lens implantation

Interleukin 1 (IL-1) possesses as an intercellular signal a wide spectrum of inflammatory, metabolic, haematopoetic, immunological, and reparative properties and can be a mediator not only of host defence but also of disease. Reduction of IL-1 can decrease the inflammatory host response. A human recombinant IL-1 receptor antagonist (IL-1ra) was used to block IL-1 after intraocular lens implantation in rabbits. Seventeen rabbits underwent intercapsular phacoemulsification and posterior chamber lens implantation. A 100 micrograms dose (0.1 ml) of IL-1ra (1 mg/ml) was injected into the anterior chamber at the end of surgery in seven rabbits. The 10 rabbits serving as the controls received no IL-1ra. Postoperatively, all rabbits were observed with a slit-lamp, and the aqueous flare intensity was measured with a laser flare cell meter at 12 hours, 1, 2, 3, and 4 days and thereafter at 1, 2, 3, and 4 weeks. Aqueous flare intensity was significantly lower on days 2 and 3, and fibrin deposition much less marked in the eyes treated with IL-1ra, compared with the controls. The results suggest that IL-1 is involved in the postoperative inflammation that occurs after intraocular lens implantation and the use of the IL-1ra would be valuable for reducing this problem.

Detection of immunoglobulin binding factor by enzyme-linked immunosorbent assay using two monoclonal antibodies

Immunoglobulin binding factor (IgBF) found in human seminal plasma may be involved in suppressing antibody production against sperm in the female and male genital tracts. In the present study an enzyme-linked immunosorbent assay (ELISA) for IgBF was developed using monoclonal anti-IgBF antibodies. The sensitivity of the method was 20 pg/ml. The method was used to quantify IgBF in sera from women. In addition high levels of IgBF was found in cervical mucus of the uterus and in bronchial washings. The present results suggest that IgBF is found in tissues that are exposed to the external environment and may be a component of the local immunity system.

Cytokine-mediated antitumor effect of bacillus Calmette-Guérin on tumor cells in vitro

Intravesical instillation therapy of bacillus Calmette-Guérin (BCG) is a useful modality for recurrent superficial transitional-cell carcinoma (TCC) of the urinary bladder. The mechanism of BCG effect has not yet been well characterized. BCG was tested in vitro for cytokine-mediated antiproliferative activity against T24 and KK47 cells (cell lines established from human TCC of the urinary bladder), and ACHN cells (cell line established from human renal cell carcinoma) using a modified human tumor clonogenic assay. Continuous exposure of cells to BCG at concentrations of more than 5 micrograms/ml in the presence of peripheral blood mononuclear cells (PBMC) consisting of a mixture of 5 x 10(4) monocytes/dish and 5 x 10(5) lymphocytes/dish, obtained from healthy donors, significantly inhibited colony formation of T24 and ACHN cells in comparison with growth inhibition in the absence of PBMC (P < 0.05). Slightly inhibited colony formation was observed with KK47 cells under the same conditions. At the same time various cytokines were measured in supernatants when BCG and the same conditioned PBMC were co-cultured. Tumor necrosis factor alpha (TNF alpha) and interleukin-1 beta (IL-1 beta) were detected at markedly high levels at 24 h, and interferon gamma (IFN gamma) was detected at 120 h. IL-2 and macrophage-colony-stimulating factor were not detected. Neutralizing anti-TNF alpha monoclonal antibody significantly reduced the anti-proliferative activity of ACHN cells, and anti-IFN gamma antibody reduced that of T24 cells. The results obtained suggest that cytokines mediated by BCG play an important role in the antitumor activity of BCG and that the sensitivity of bladder cancer cells to the cytokines induced by BCG may differ considerably.

Serum levels of macrophage colony stimulating factor (M-CSF) in liver disease

We investigated the serum level of macrophage colony stimulating factor in acute and chronic liver disease. Levels of macrophage colony stimulating factor (mean +/- SD, ng/ml) were significantly higher in acute hepatitis (5.67 +/- 1.01, p < 0.01) and chronic active hepatitis (3.34 +/- 1.19, p < 0.01) than in healthy volunteers (1.90 +/- 0.25), asymptomatic hepatitis B virus carriers (1.98 +/- 0.40), and chronic persistent hepatitis (2.34 +/- 0.43). Levels of macrophage colony stimulating factor showed a highly significant correlation with the serum alanine aminotransferase levels in acute hepatitis (p < 0.01, rs = 0.903) and in chronic active hepatis (p < 0.01, rs = 0.672). Levels of macrophage colony stimulating factor in patients with cirrhosis (cirrhosis; 3.11 +/- 0.93 and hepatocellular carcinoma; 3.30 +/- 0.74) were significantly higher than in patients with chronic persistent hepatitis although the alanine aminotransferase levels were not significantly different. In cirrhosis, levels of macrophage colony stimulating factor correlated positively with the serum alanine aminotransferase levels (p < 0.05), total bilirubin levels (p < 0.05), and indocyanine green clearance (p < 0.05). An immunohistochemical study showed an increased number of macrophage colony stimulating factor positive mononuclear cells in portal areas in acute hepatitis. Our findings suggest that; (a) the serum levels of macrophage colony stimulating factor represent ongoing hepatocellular necrosis in acute and chronic liver disease, (b) the source of the increase in the serum macrophage colony stimulating factor levels in hepatic inflammation may be, in part, its production by infiltrating mononuclear cells in the liver, and (c) cirrhosis also causes elevated serum levels of macrophage colony stimulating factor.

[Development of immunoassay for cytokines and its clinical significance]

As measurement systems of cytokines have recently been developed, there are many reports indicating the relationship between cytokines and various diseases. We have also developed various new measurement systems using gene technology and hybridoma technology. The measurement system is composed of the following 5 steps. (1) Cloning of cytokines, (2) Expression of cytokines, (3) Purification of cytokines, (4) Preparation of antibodies (monoclonal and polyclonal antibodies), (5) Development of immunoassay. Cytokines are measured not only in the cytokine itself but also in the receptor, receptor antagonist, and autoantibody. We established the measurement system of cytokines using ELISA (antibody is labeled by enzyme.) for the cytokine itself and RIA (antigen is labeled by isotope.) for the autoantibody to cytokines. The blood concentration of cytokines is low because cytokines are utilized immediately after production and excreted into the urine. Therefore, the immunological responses of individuals can be determined by an ex vivo measurement of the production of cytokines by stimulation of whole blood with LPS not by simply measuring the cytokine itself in plasma. We call this method "Whole Blood Induction Method". This method is positioned as one of the methods which shows the immunological response of cytokines to the outer body at the time of infection using a low volume of human blood. Finally, studies of cytokines have been carried out not only in immunological systems but also in hormone systems which are closely related to cytokines. Studies have also expanded to fields which, to date, have not been thought to be related by investigating adherence factors.(ABSTRACT TRUNCATED AT 250 WORDS)

Increased plasma M-CSF concentration in patients with adult T cell leukemia: clinical correlation

Plasma concentration of M-CSF was measured in 35 patients with adult T cell leukemia (ATL), using a radioimmunoassay (RIA). ATL patients showed elevated levels of plasma M-CSF concentration when compared with healthy adult volunteers. Higher M-CSF levels were observed in acute ATL patients than in patients with chronic or smouldering ATL (P < 0.0001). There was a significant positive correlation of M-CSF concentration with serum lactic dehydrogenase (LDL) level, a reliable marker for assessing the grade of malignancy in ATL (P = 0.0003). There was, however, no correlation of M-CSF concentration with total counts of peripheral blood ATL cells, neutrophils or monocytes, or with serum calcium levels. Although there was a significant positive correlation of M-CSF concentration with body temperature (P = 0.003), there was not a significant correlation of M-CSF concentration with C-reactive protein (CRP), a protein indicative of the severity of inflammation (P = 0.063). These results indicate that plasma M-CSF concentration reflects the disease activity of ATL, and can thus serve as a marker in the clinical subclassification of ATL patients.

Effect of IL-1 receptor antagonist and antiserum to TNF-alpha on LPS-induced plasma ACTH and corticosterone rise in rats

Using an antiserum against tumor necrosis factor (TNF)-alpha and an interleukin (IL-1) receptor antagonist, we studied putative roles of these cytokines in mediating the endotoxin-induced elevation of plasma adrenocorticotropic hormone (ACTH) and corticosterone levels in freely moving rats. Intravenous administration of Escherichia coli lipopolysaccharide (LPS) increased plasma ACTH and corticosterone levels in a dose-dependent manner. The plasma corticosterone reached to its highest level among a series of experiments after the administration of even the smallest dose (0.03 microgram/kg) tested. Plasma ACTH and corticosterone levels in these rats were completely inhibited by the intravenous administration of anti-murine TNF-alpha-rabbit antiserum (anti-TNFAS) after the administration of LPS but not by the intravenous administration of IL-1 receptor antagonist (IL-1RA). On the other hand, both recombinant human IL-1RA and anti-TNFAS significantly inhibited plasma ACTH increase stimulated with 10 micrograms/kg LPS. These findings indicate that 1) when the plasma corticosterone increase induced by intravenous LPS remains below its maximum, the effect is exclusively mediated by TNF-alpha, and 2) when a larger amount of LPS is administered, both IL-1 beta and TNF-alpha participate at least in part in the hypothalamic-pituitary-adrenal axis activation.

Establishment of radioimmunoassay for human macrophage colony-stimulating factor using recombinant human macrophage colony-stimulating factor as tracer and immunogen

A sensitive and reliable radioimmunoassay (RIA) for human macrophage colony-stimulating factor (M-CSF) was developed using recombinant human M-CSF (rhM-CSF) as tracer and immunogen. The assay was quantitative over the range of 50 pg/ml and 5.0 ng/ml for M-CSF in human urine and serum, and more sensitive and specific than the murine bone marrow assay. The average level of human M-CSF in urine from normal males (N = 71) and females (N = 46) was 3.94 +/- 1.78 ng/ml (2.85 +/- 1.15 micrograms/g creatinine), and 3.53 +/- 1.70 ng/ml (3.31 +/- 1.12 micrograms/g creatinine), respectively. The serum levels were 1.95 +/- 0.38 ng/ml for males (N = 117), and 1.93 +/- 0.49 ng/ml for females, (N = 16). The results with the urine and sera showed that there was no difference in the M-CSF levels due to age or gender.

The structure of recombinant human carboxy-terminal-truncated macrophage colony-stimulating factor derived from mammalian cells

The structure of recombinant human carboxy-terminal-truncated macrophage colony-stimulating factor expressed in CHO cells was investigated. The bioactive protein ([-32-153]M-CSF), expressed from a nucleotide sequence that encoded a signal peptide of 32 amino acids and N-terminal amino acids numbers 1-153, was heterogeneous in terms of molecular mass, as analyzed by SDS-PAGE, because of the presence of N-linked sugar moieties. The primary structure of the polypeptide was determined by sequence analysis and amino acid analysis of the fragments obtained from lysylendopeptidase digests of reduced and alkylated M-CSF, and from pepsin digests of the intact molecule. A sugar chain was located only at Asn-122 of the two putative sites of N-glycosylation that were present per subunit. The homodimeric structure appeared to have seven disulfide bonds, formed by inter- or intra-molecular linkages, since there were no free thiol groups in the molecule. The assignment of disulfide bonds by sequence analysis using peptide fragments indicated the combinations of Cys7-Cys90, Cys48-Cys139, and Cys102-Cys146. Gel-filtration analysis of Ser31[-32-153]M-CSF, in which the remaining Cys31 was replaced by Ser and which was expressed in COS cells, suggested that the mutein existed as a monomer. Our study shows that the disulfide-bond pairings of [-32-153]M-CSF that is expressed and post-translationally modified in mammalian cells are identical to those of Escherichia coli-derived [3-153]M-CSF with only one intermolecular disulfide bond, namely, Cys31-Cys31.

Direct and indirect effects of human interferon alpha on renal cell carcinoma: a new in vitro assay system for evaluating cytokine-mediated antitumor effects

A highly purified natural alpha-interferon (nIFN alpha) was tested in vitro for direct and indirect antiproliferative activity against renal cell carcinoma (RCC), using a modified human tumor clonogenic assay and clinically achievable concentrations. In preclinical experiments, the indirect (cytokine-mediated) antiproliferative activity of nIFN alpha was investigated using ACHN cells (established human RCC cell line). Continuous exposure to nIFN alpha at concentrations of more than 5 IU/ml in the presence of feeder cells (a mixture of 5 x 10(4) monocytes/dish and 5 x 10(5) lymphocytes/dish, obtained from healthy donors) significantly inhibited colony formation of ACHN cells in comparison with growth inhibition in the absence of feeder cells (P < 0.05). Various cytokines were measured in the supernatants lying over the medium on the feeder-layer agarose containing the same conditioned feeder cells. With IFN alpha at 500 IU/ml, tumor necrosis factor alpha (TNF alpha) and IFN gamma were detected at markedly high levels for 2-24 h. Neutralizing anti-TNF alpha monoclonal antibody significantly reduced the indirect antiproliferative activity. Using our modified human tumor clonogenic assay technique, sufficient numbers of colonies for drug testing were observed in 19 of 31 surgical specimens (61.3%). In these clinical materials, nIFN alpha at a clinically achievable concentration (50 IU/ml) significantly inhibited colony growth in the presence of feeder cells consisting of 5 x 10(4) monocytes/dish and 5 x 10(5) lymphocytes/dish, obtained from the patient whose tumor was examined (P < 0.05). In colony-forming cases, a significant correlation between the percentage colony survival and TNF alpha concentration in the supernatant was observed (r = -0.95, P < 0.01). These results suggest that this assay system may be an appropriate technique for evaluating the antiproliferative activities of nIFN alpha involving cytokine-mediated action, and that TNF alpha may play an important role in this cytokine-mediated activity.

Purification and characterization of recombinant human macrophage colony-stimulating factor expressed in Chinese hamster ovary cells

We expressed human macrophage colony-stimulating factor (M-CSF) in Chinese hamster ovary (CHO) cells by introducing an expression plasmid coding for a 554-amino-acid M-CSF precursor and dihydrofolate reductase (DHFR) gene, and by amplifying the sequence. A cell line was obtained that secreted approximately 200,000 units/ml after 6 days in culture. The expressed recombinant human M-CSF (rhM-CSF) primarily consisted of two molecular species, a main 80-90 kD M-CSF as a homodimer and a molecular form higher than 150 kD. Purification of a main rhM-CSF gave an apparently homogeneous protein disulfide-bonded from 42-kD subunits, but one of the purified rhM-CSFs was composed of two subunit species with molecular masses of 44 and 42 kD. These purified rhM-CSFs had substantially the same specific activity (1 to 4 x 10(7) units/mg protein). Deglycosylation experiments with the latter rhM-CSF using chemical (trifluoromethanesulfonic acid) and enzymatic methods found a terminal neuraminic acid in addition to N- and O-glycosylation, but the two subunit species did not coalesce into a single molecule.

Predominant production of amniotic interleukin-1 alpha in cases with premature rupture of the membranes

PROBLEM

The physiological significances of the two known subtypes of interleukin-1 (IL-1) in amniotic fluid (AF) were examined by measurements of their concentrations and detection of their location.

METHOD

Each IL-1 subtype in AF collected from 61 patients were examined by newly developed enzyme-linked immunosorbent assay with high sensitivity. Placenta and umbilical cord from 17 patients were examined immunohistochemically for localization of IL-1.

RESULTS

Different types of IL-1 were predominant in AF; the mean (+/- SE) concentration of IL-1 beta (412.8 +/- 105.4 pg/ml) was significantly higher (P < 0.01) than that of IL-1 alpha (116.4 +/- 26.7 pg/ml) in cases with spontaneous vaginal delivery, whereas the concentration of IL-1 alpha (243.1 +/- 81.4 pg/ml) was significantly higher (P < 0.01) than that of IL-1 beta (139.7 +/- 59.4 pg/ml) in cases with premature rupture of the membranes (PROM) without intrauterine infection. In these cases, immunohistochemical studies revealed the presence of IL-1 alpha in the trophoblastic layer of the placenta and epithelium of the umbilical cord.

CONCLUSION

Amniotic IL-1 alpha was detected predominantly in cases with PROM, and it is thought to be produced in placenta and fetal skin keratinocyte.

Giant endocardial blood cyst in left ventricle resected by transaortic valve approach

A 57-year-old man had a histologically proven giant blood cyst in the left ventricle. An encapsulated mobile cystic tumor (3 x 3 x 4 cm), which was attached to the anterolateral papillary muscle by a stalk, was successfully resected by a transaortic valve approach for preserving cardiac function.

Glucose as regulator of glucose transport activity and glucose-transporter mRNA in hamster beta-cell line

To investigate the role of glucose in regulating glucose transporters in pancreatic beta-cells, we studied the hamster clonal beta-cell line HIT-T15, which retains responsiveness to glucose. Northern blot analysis demonstrates that GLUT2 and GLUT1 mRNA are abundant in HIT cells. After a 24-h culture with various concentrations of glucose (0-22.2 mM [0-400 mg/dl]), the GLUT2 mRNA level in HIT cells increased by 40% at 22.2 mM (400 mg/dl) glucose compared with 11.1 mM (200 mg/dl) without a change in mRNA stability. It also decreased proportionally to the reduction of glucose concentration. Glucose deprivation resulted in a decrease of GLUT2 mRNA to an almost undetectable level, with a marked increase in the degradation rate of mRNA. In contrast, the GLUT1 mRNA was not affected by glucose. We show that glucose uptake is highest in HIT cells incubated at 2.8-5.5 mM (50-99 mg/dl) glucose for 24 h, and that levels in cells cultured at 0 mM (0 mg/dl) and 22.2 mM (400 mg/dl) glucose decrease to approximately 20% of the maximum level. This decrease is consistent with the effects of glucose on glucose-stimulated insulin secretion in HIT cells. Our results indicate that glucose is involved in regulating GLUT2 mRNA and glucose uptake activity and that the glucose responsiveness of the insulin secretion correlates with the glucose-induced change in glucose uptake activity in HIT cells.

Induction of cytokines in human peripheral blood mononuclear cells by mycoplasmas

Various species of mycoplasmas were tested for their ability to induce cytokine production in human peripheral blood mononuclear cells (PBMC). Human PBMC were incubated with Mycoplasma pneumoniae, M. hyorhinis, M. arginini, M. salivarium, M. orale, M. gallisepticum or A. laidlawii for 48 hr, and the activities of interleukin-1 beta (IL-1 beta), IL-2, IL-4, IL-6, tumor necrosis factor-alpha (TNF-alpha) and interferon (IFN) in the supernatants were determined by ELISA or bioassay. All mycoplasma species induced IL-1 beta, IL-6 and TNF-alpha, although IL-2 was induced only by M. pneumoniae. IFN was induced by 5 of the 7 species, and the IFN produced was antigenically confirmed to be mainly IFN-alpha. On the other hand, mycoplasma-stimulated cultures did not contain detectable amounts of IFN-beta and IL-4 activities. Furthermore, the cytokines were induced by mycoplasmal contaminating cells in human PBMC as well as by mycoplasma alone. These results suggest that many kinds of cytokines induced by mycoplasma contamination in cell culture affect immunological experiments in vitro.

Identification and characterization of specific receptors for the LD78 cytokine

LD78 is a small secreted protein that has a sequence similar to a number of other polypeptides, including murine macrophage inflammatory protein 1 alpha (MIP-1 alpha), interleukin 8 (IL-8), Act-2, monocyte chemoattractant protein 1 (MCP-1), and others. These polypeptides are members of a novel cytokine superfamily that is involved in the inflammatory response, wound healing, hematopoiesis, and tumorigenesis. Specific receptors for purified clonal LD78 protein were measured using four cell lines (HL-60, U937, Jurkat, and MJ). 125I-labeled recombinant LD78 bound most efficiently to U937 cells. We therefore characterized the receptors as being on the surface of U937 cells. Binding reached an equilibrium after incubation for 60 min at 4 degrees C. Scatchard analysis showed that there were two classes of binding sites on U937 cells, high affinity sites (Kd = 5.3 x 10(-9) M) and low affinity sites (Kd = 9.3 x 10(-8) M), with the average number of binding sites per cell being approximately 30,000 and approximately 90,000, respectively. These receptors for LD78 were distinct from the receptors for gamma-IFN and for IL-8. SDS-PAGE analysis of chemically crosslinked 125I-labeled LD78 receptor complexes identified a single band of 52 kDa. The ability to detect specific LD78 receptors should prove valuable in efforts to molecularly clone these receptors and to dissect the biological actions of LD78.