Trehalose-producing operon treYZ from Arthrobacter ramosus S34

Arthrobacter ramosus S34, which produces trehalose from maltooligosaccharide, was isolated. A trehalose-producing operon, treYZ, was cloned from the genome. Expression experiments with treY and treZ confirmed that they coded malto-oligosyltrehalose synthase and malto-oligosyltrehalose trehalohydrolase, respectively. The amino acid sequence of TreY from A. ramosus S34 and that from Arthrobacter sp. Q36 did not show high identity, nor did those of TreZ.

Cell differentiation and apoptosis of monocytic and promyelocytic leukemia cells (U-937 and HL-60) by tryptanthrin, an active ingredient of Polygonum tinctorium Lour

Tryptanthrin, a bioactive ingredient of Polygonum tinctorium Lour., is a member of the Indigo plant family and has potent cytocidal effects on various human leukemia cells in vitro. At low concentrations, tryptanthrin enhanced the expression of cell differentiation (CD) markers in human monocytic (U-937) and promyelocytic (HL-60) leukemia cells indicative of differentiation to monocytes/macrophages. Furthermore, nitroblue tetrazolium (NBT) reductive and alpha-naphthyl butyrate esterase (NBE) activities were markedly increased after treatment. Tryptanthrin was more potent than dimethyl sulfoxide (DMSO) at inducing U-937 cell differentiation into monocytes/macrophages. After treatment with higher concentrations of tryptanthrin for 24 h, cytoplasmic vacuolation and destruction of mitochondria were observed. The leukemia cells died via apoptosis 48 h after treatment. Cytoplasmic vacuolation and apoptotic changes correlated with the dysfunction of mitochondria. Electron microscopic observations revealed marked swelling and destruction of mitochondria after exposure of the leukemia cells to tryptanthrin. Exposure to tryptanthrin enhanced Fas-induced apoptosis and increased caspase-3 activity before induction of apoptosis. These results show that low concentrations of tryptanthrin can induce differentiation of leukemia cells but higher concentrations will kill leukemia cells through apoptosis, possibly through a caspase-3/Fas antigen pathway.

Pulmonary carcinogenesis induced by ferric nitrilotriacetate in mice and protection from it by Brazilian propolis and artepillin C

In experiments using the renal carcinogen ferric nitrilotriacetate (Fe-NTA) in male ddY mice, primary pulmonary cancers were also induced in bronchiolar and alveolar tissues. 4-Hydroxy-2-nonenal (4-HNE) and 8-hydroxy-2'-deoxyguanosine (8-OHdG), products of oxidative processes, increased in bronchiolar and alveolar cells after administration of Fe-NTA. These substances disappeared after oral administration of propolis or artepillin C, as shown histochemically, and correlated with an anticancer prophylactic effect of propolis and artepillin C. From our investigation, lipid peroxidation seems to play an important role in pulmonary carcinogenesis. Malignant progression from adenoma of bronchiolar or alveolar origin to malignant tumors has been proposed to involve a stepwise transformation. In our study, adenomas developed into adenocarcinomas and large cell carcinomas after treatment with Fe-NTA. In contrast, after oral administration of propolis or artepillin C, adenomas did not progress to carcinomas. Instead of developing into large cell cancers, as induced by Fe-NTA in control mice, adenomas showed remarkable proliferation of macrophages and local anti-oxidant activity after treatment with either propolis or artepillin C. Propolis and artepillin C therefore appear to inhibit lipid peroxidation and the development of pulmonary cancers.

Levels of interleukin-18 and its binding inhibitors in the blood circulation of patients with adult-onset Still's disease

OBJECTIVE

Interleukin-18 (IL-18) is a proinflammatory cytokine that is involved in immunologically mediated tissue damage, but its bioactivity is regulated in vivo by its soluble decoy receptor, IL-18 binding protein (IL-18BP). This study was undertaken to determine levels of IL-18 and IL-18 binding inhibition in the blood of patients with adult-onset Still's disease (ASD).

METHODS

Serum concentrations of IL-18 in ASD patients were compared by enzyme-linked immunosorbent assay (ELISA) with those in patients with other systemic rheumatic diseases and healthy controls. The biologically active mature protein of IL-18 was detected by Western blot analysis with anti-IL-18 antibody and its induction of interferon-gamma (IFNgamma) secretion from IL-18-responding human myelomonocytic KG-1 cells. The inhibitory activity on IL-18 binding to its receptor was determined by 125I-IL-18 binding inhibition assay using the Chinese hamster ovary cell line transfected with a murine IL-18 receptor (CHO-K1/mIL-18R).

RESULTS

Concentrations of serum IL-18 were extremely elevated in patients with active ASD compared with those in patients with rheumatoid arthritis, systemic lupus erythematosus, systemic sclerosis, polymyositis/dermatomyositis, Sjogren's syndrome, or healthy individuals. Levels of IL-18 were found to correlate with serum ferritin values and disease severity in ASD. Western blot analysis revealed that serum samples from patients with active ASD contained an 18-kd polypeptide of IL-18, corresponding in size to the mature form. Accordingly, the samples were able to induce IFNgamma secretion from KG-1 cells, which was largely abolished by neutralizing anti-IL-18 antibody. However, the level of IL-18 bioactivity was more than 10-fold weaker than the concentration of IL-18 protein measured by ELISA. Serum samples from patients with active ASD showed an inhibitory effect on the binding of 125I-IL-18 to CHO-K1/mIL-18R cells, and this activity was associated with elevation of IL-18.

CONCLUSION

These data indicate that systemic overproduction of IL-18 may be closely related to the pathogenesis of ASD, despite the restriction on its inflammatory activity by IL-18 binding inhibitors such as IL-18BP. The disease activity appears to be determined on the basis of the relative levels of IL-18 and its specific inhibitors.

Interleukin 18 induces a synergistic enhancement of interferon gamma production in mixed murine spleen cell-tumor cell cultures: role of endogenous interleukin 12

Interleukin 18 (IL-18) reportedly synergizes with IL-12 and IL-10 for interferon gamma (IFN-gamma) synthesis and natural killer (NK) cell activity, respectively. Here we show that IL-18 alone induces low level IFN-gamma production by unstimulated Balb/c mouse spleen cells, but production is enhanced synergistically in cocultures of spleen cells and allogeneic living or fixed Yac-1 cells. Spleen cells could be primed with IL-18 prior to coculture with Yac-1 cells for IFN-gamma production, which also was observed in cocultures containing either syngeneic or xenogeneic tumor cells. IFN-gamma production in stimulated cocultures was abrogated almost completely by anti-IL-12 antibody and was unrelated to spleen cell lytic activity. IL-10 moderately inhibited IFN-gamma production induced by IL-18. Therefore, in spleen cell and tumor cell cocultures exposed to IL-18, high levels of IFN-gamma are produced by the spleen cells arising from a synergistic interaction between the exogenous IL-18 and endogenous IL-12; however, this activity is unrelated to the spleen cell lytic activity.

Tissue factor and cancer procoagulant expressed by glioma cells participate in their thrombin-mediated proliferation

The relationship between coagulation cascade activation and glioma cell proliferation was examined. The human glioma cell lines T98G, TM-1 and normal human astrocyte cell strain (NHA) were examined. Using anti-tissue factor (TF) antibody, immunocytochemical detection of TF antigen was obtained in both cell lines and cell strain. TF antigen in cell lysates was also measured by enzyme linked immunosorbent assay (ELISA). In a one-stage clotting assay, T98G, TM-1 and NHA revealed procoagulant activity (PCA) in normal human plasma and factor VII deficient plasma. PCA in normal human plasma was significantly inhibited by both inhibitory anti-TF antibody and cysteine protease inhibitor HgCl2. This result indicates that T98G, TM-1 and NHA cells express not only TF but also cancer procoagulant (CP) at the same time. In a cell proliferation assay, thrombin induced proliferation in T98G and TM-1 cells in a dose-dependent fashion and in NHA cell in a bell-shaped fashion. This mitogenic stimulant was inhibited by the specific thrombin inhibitor hirudin. The combinations of coagulation factors II, V, and X with or without factor VII induced proliferation in T98G, TM-1, and NHA cells. The maximal mitogenic stimulatory effects were larger in glioma cells than in NHA. These mitogenic stimulatory effects were also inhibited by hirudin. Each coagulation factor on its own or in any other combination of coagulation factors had no proliferative effect. Thus, these mitogenic stimulatory effects were considered to be the effect of thrombin. In conclusion, T98G and TM-1 human glioma cells express two different types of procoagulants TF and CP. In the presence of coagulation factors, these glioma cells can generate thrombin and this thrombin generation is capable of inducing glioma cell proliferation in vitro.

Antitumor effects on mouse melanoma elicited by local secretion of interleukin-12 and their enhancement by treatment with interleukin-18

To investigate the mechanism of the antitumor effect of locally secreted interleukin-12 (IL-12), we introduced the IL-12 p35 and p40 cDNAs into mouse B16 melanoma cells. IL-12 gene-transfected B16 melanoma (B16/IL12) showed marked retardation of tumor growth when implanted subcutaneously into syngeneic mice. In these mice, depletion of not only Natural Killer (NK) cells but also CD8+ T cells diminished the antitumor effect of locally secreted IL-12. Immunohistochemical analysis showed that NK cells and macrophages accumulated more densely at the center and periphery of B16/IL12 tumors than that of parental B16 tumors, whereas CD4+ T cells and CD8+ T cells accumulated sparsely only at the periphery of both transfected and untransfected tumors. Systemic treatment with interleukin-18 (IL-18) markedly inhibited the growth of B16/IL12 but did not influence the tumor growth of parental B16 cells in vivo. These results suggest that local IL-12 secretion can retard the growth of B16 melanoma mediated primarily by NK cells and indirectly by CD8+ T cells and that its antitumor effect is augmented by systemic treatment with the novel cytokine IL-18.

Establishment and characterization of a novel malignant astrocytoma cell line derived from a tumor removed in a patient with neurofibromatosis type 1

OBJECT

Patients with neurofibromatosis Type 1 (NF1) have a predisposition to development of a variety of benign and malignant tumors including neurofibromas, astrocytomas, pheochromocytomas, and malignant peripheral nerve sheath tumors. The availability of an astrocytoma cell line derived from NF1 would be useful in studies in which sporadic astrocytomas could be compared with NF1-derived astrocytomas. In this article the authors describe a novel astrocytoma cell line, TM-31, that they established from a tumor removed in a 42-year-old woman with NF1.

METHODS

The TM-31 cell line was prepared from a surgical specimen of malignant astrocytoma and was serially subcultured over 250 times throughout a 6-year period without showing any sign of cell senescence. Immunocytochemical analyses demonstrated that TM-31 cells are negative for glial fibrillary acidic protein but positive for vimentin and S-100 protein. The TM-31 cells display little neurofibromin expression when subjected to immunoblotting, indicating that there is an NF1 gene mutation. Polymerase chain reaction-single-strand conformational polymorphism analysis revealed that TM-31 cells harbor a p53 point mutation in exon 7, codon 238. Chemosensitivity testing of TM-31 cells revealed a resistance to 1-(4-amino-2-methyl-5-pyrimidinyl)methyl-3-(2-chloroethyl)-3-nitrosourea, although they are sensitive to cisplatin and etoposide. In addition, TM-31 cells displayed no morphological differentiation after all-transretinoic acid and dibutyryl cyclic adenosine monophosphate treatments. Pharmacological inhibition of farnesyltransferase of the Ras oncoprotein led to decreased proliferative activity and inhibition of anchorage-independent growth of TM-31 cells in soft agar.

CONCLUSIONS

The TM-31 cell line is an immortalized astrocytoma cell line derived from a tumor obtained in a patient with NF1. Ras activation may be the major event of proliferative activity and of the transformed phenotype of TM-31 cells, and the farnesyltransferase inhibitor may be potentially important as a novel antiproliferative therapy for NF1-derived astrocytomas.

Interferon-gamma-inducing activity of interleukin-18 in the joint with rheumatoid arthritis

OBJECTIVE

To examine the levels of interleukin-18 (IL-18) bioactivity within the rheumatoid arthritis (RA) joint, and the differential effects of IL-12 and IL-18 on interferon-gamma (IFNgamma) production by T cell infiltrates.

METHODS

Expression of IL-18 protein and messenger RNA (mRNA) was determined by enzyme-linked immunosorbent assay and reverse transcriptase-polymerase chain reaction, respectively. The biologic activity of IL-18 was detected on the basis of IFNgamma secretion from IL-18-responding human myelomonocytic KG-1 cells. To determine the extent of inhibitory activity on binding of IL-18 to its receptor, a [125I]-IL-18 binding inhibition assay was performed, using a Chinese hamster ovary cell line transfected with a murine IL-18 receptor.

RESULTS

The amount of IL-18 protein detected in both the serum and synovial fluid of RA patients was markedly larger than that detected in the serum and synovial fluid ofosteoarthritis (OA) patients, and serum IL-18 levels correlated with the levels of serum C-reactive protein. IFNgamma production by KG-1 cells was more strongly stimulated in synovial fluid samples from RA patients than in samples from OA patients, and this activity was largely diminished in the presence of anti-IL-18 antibody. In contrast, the activity of IL-18 binding inhibition in the serum and synovial fluid of RA patients was not significantly elevated compared with that in OA patients. RA synovial tissues showed increased expression of IL-18 mRNA and increased IL-18 protein synthesis compared with that in OA tissues. Purified CD14+ macrophages, but not activated fibroblast cell lines, from RA synovium were able to release mature IL-18, although both cell types expressed its transcripts. IL-18 alone showed a negligible effect on IFNgamma production by RA synovial tissue cells, in contrast to IL-12, which was directly stimulatory. However, IL-12-induced IFNgamma production was synergistically enhanced by IL-18, and yet was >50% reduced by neutralization of endogenous IL-18 with anti-IL-18 antibody.

CONCLUSION

These results indicate that IL-18, produced predominantly by tissue macrophages, primarily potentiates IL-12-induced IFNgamma production by T cell infiltrates in RA synovium. Detection of significant IL-18 bioactivity in the joints, despite the presence of IL-18 binding inhibitors, supports an integral role of this cytokine in perpetuating the IFNgamma-dominant T cell cytokine response in RA.

Interferon gamma induction in human melanoma cell/allogeneic leukocyte co-cultures is enhanced by interleukin 18 but drug resistant melanoma cells are poorer inducers of IFN-γ

Human melanoma Colo 679 cells were made resistant to doxorubicin (adriamycin, ADM) by continuous exposure to ascending concentrations of the drug and Colo/ADM80; a variant which grew continuously in the presence of 80 ng/ml of ADM was thus established. Human peripheral blood mononuclear cells (PBMC) produced interferon gamma (IFN-gamma) when cultured with mitomycin C (MMC)-treated parental Colo 679 cells. The synthesis of IFN-gamma was synergistically enhanced by adding interleukin-18 (IL-18) and this was IL-12-dependent because a neutralizing antibody against IL-12 almost completely inhibited IFN-gamma production while control antibodies (Abs) were inactive. The cellular sources of IFN-gamma were found to be B cells, CD8+ T cells and CD4+ T cells as revealed by flow cytometry after double staining for surface antigens and staining for intracellular IFN-gamma. Interestingly, the resistant cell line induced much less IFN-gamma production than the parental cell line under the same co-culture conditions; however, IL-18 could still enhance the production of IFN-gamma. In conclusion, our study shows that acquired resistance to anti-cancer agents can also reduce immune responses to cancer cells. However, the immunostimulatory cytokine IL-18 could still enhance IFN-gamma production in drug resistant tumor cell-PBMC cultures indicating that such immunostimulatory agents could still be beneficial in immunotherapy for patients with recurrent drug resistant tumors.

IL-12 and IL-18 are increased and stimulate IFN-gamma production in sarcoid lungs

Sarcoidosis is a systemic chronic granulomatous disease of unknown cause. Recent investigations revealed that the cytokine profile in inflamed lesions of sarcoidosis is Th1 dominant. To obtain better immunopathologic understanding of sarcoidosis, we examined the expression of IL-12 and IL-18 and their roles in IFN-gamma production in pulmonary sarcoidosis. Sarcoid cases had significantly elevated levels of IL-12 (p40 and p70) and IL-18 in bronchoalveolar lavage (BAL) fluids compared with healthy subjects. IL-12 p70 and IL-18 were immunohistochemically expressed in the epithelioid cells and giant cells of sarcoid granulomas. Significant induction of IFN-gamma, IL-12 p70, and IL-18 was observed from sarcoid BAL fluid cells with LPS stimulation, whereas LPS tended to induce only IL-12 p70 in BAL fluid cells from healthy subjects. Sarcoid cases had significantly greater IFN-gamma induction with LPS stimulation than healthy subjects did. IL-18 mRNA expression was observed in freshly isolated sarcoid BAL fluid cells as well as in LPS-stimulated sarcoid BAL fluid cells, but IFN-gamma and IL-12 mRNA expression was observed only in LPS-stimulated BAL fluid cells. Treatment with anti-IL-12- and anti-IL-18-neutralizing Abs significantly inhibited IFN-gamma production from LPS-stimulated BAL fluid cells of sarcoid cases. Coadministration of rIL-12 or rIL-18 induced greater IFN-gamma production in sarcoid BAL fluid cells than in normal BAL fluid cells. We concluded that bioactive IL-12 and IL-18 were produced in sarcoid BAL fluid cells and synergistically induced IFN-gamma production, indicating important cytokines in the Th1 response of sarcoidosis.

Apoptosis of human leukemia cells induced by Artepillin C, an active ingredient of Brazilian propolis

Artepillin C (3,5-diprenyl-4-hydroxycinnamic acid) is an active ingredient of Brazilian propolis that possesses anti-tumor activity. When Artepillin C was applied to human leukemia cell lines of different phenotypes, namely, lymphocytic leukemia (7 cell lines of T-cell, 5 cell lines of B-cell), myeloid and monocytic leukemia and non-lymphoid non-myeloid leukemia cell lines in vitro, Artepillin C exhibited potent cytocidal effects and induced marked levels of apoptosis in all the cell lines. The most potent effects were observed in the T-cell lines. Apoptotic bodies and DNA fragmentation were induced in the cell lines after exposure to Artepillin C. DNA synthesis in the leukemia cells was clearly inhibited and disintegration of the cells was confirmed microscopically. Apoptosis of the leukemia cells may be partially associated with enhanced Fas antigen expression and loss of mitochondrial membrane potential. In contrast, although Artepillin C inhibited the growth of pokeweed mitogen (PWM)-stimulated normal blood lymphocytes, it was not cytocidal to normal unstimulated lymphocytes. These results suggested that Artepillin C, an active ingredient of Brazilian propolis, has anti-leukemic effects with limited inhibitory effects on normal lymphocytes.

Antibacterial action of tryptanthrin and kaempferol, isolated from the indigo plant (Polygonum tinctorium Lour.), against Helicobacter pylori-infected Mongolian gerbils

We evaluated the effect of tryptanthrin and kaempferol, both isolated from Polygonum tinctorium Lour., against Helicobacter pylori colony formation in vitro and in H. pylori-infected Mongolian gerbils. H. pylori suspension was mixed with solution of tryptanthrin and/or kaempferol and placed onto agar plates. These plates were incubated at 37 degrees C, under 10% CO2 for 5 days, and the H. pylori colonies were counted. For the in vivo experiment, Mongolian gerbils were inoculated with H. pylori ATCC 43504 orally. After 4 weeks, the infected gerbils were given tryptanthrin and/or kaempferol, administered orally, twice a day for 10 days. The animals were killed and the number of live H. pylori in their stomachs was determined. In vitro both tryptanthrin and kaempferol significantly decreased the numbers of H. pylori colonies a dose-dependent manner. An additive effect on colony formation was observed with the combined use. In the in vivo experiment, oral administration of tryptanthrin and/or kaempferol significantly decreased the numbers of colonies in the gerbils' stomachs. We concluded that tryptanthrin and kaempferol were effective against H. pylori in vivo.

Enzymatic Synthesis of Novel Oligosaccharides from L-Sorbose, Maltose, and Sucrose Using Kojibiose Phosphorylase

Glucosyl-L-sorbose, -maltose, and -sucrose were synthesized using kojibiose phosphorylase (KPase) from Thermoanaerobacter brockii ATCC35047 with beta-D-glucose-1-phosphate (beta-G1P) as a glucosyl donor. One disaccharide and two trisaccharides thus synthesized were isolated by Toyopearl HW-40S column chromatography. The results of KPase digestion, methylation analysis, and 13C-NMR studies indicated that these oligosaccharides were alpha-D-glucopyranosyl-(1-->5)-alpha-L-sorbopyranose, alpha-D-glucopyranosyl-(1-->2)-alpha-D-glucopyranosyl-(1-->4)-D-glucopyranose (4-alpha-D-kojibiosyl-glucose), and alpha-D-glucopyranosyl-(1-->2)-alpha-D-glucopyranosyl-(1-->2)-beta-D-fructofuranoside, which are all novel oligosaccharides. Glucosyl-L-sorbose was partially hydrolyzed to glucose and L-sorbose by alpha-glucosidases, while glucosyl-sucrose and glucosyl-maltose were not hydrolyzed by glucoamylase, alpha-glucosidases, or CGTase.

[Systemic non-Hodgkin lymphoma initially presented with visual disturbance due to intrasellar lymphoma--a case report]

A case with systemic non-Hodgkin lymphoma involving the sella turcica and kidney is reported. A 69-year-old man presented with a progressive two month history of visual disturbance and headache. Neurological examination revealed bilateral visual disturbance and right optic atrophy. MRI showed a contrast-enhancing mass in the sella turcica. The tumor extended to the right optic nerve. Without extensive studies for systemic disease, the patient immediately underwent transsphenoidal surgery. The slightly firm, fibrous and vascular-rich tumor was subtotally removed. The histopathological examination revealed a malignant lymphoma, diffuse-large-cell type with B-cell phenotype. The postoperative course was uneventful and the patient's symptoms subsided gradually. The patient received radiation therapy and the tumor disappeared. Postoperative CT examinations of the abdomen and pelvis revealed a large mass at the upper portion of the left kidney. Ga-scan also suggested the mass to be consistent with the abdominal CT. However, the patient suddenly died of acute heart failure with unknown cause just before starting chemotherapy for systemic lymphoma. Patients presenting primary central nervous system lymphoma (PCNSL) may have systemic non-Hodgkin lymphoma. To exclude systemic non-Hodgkin lymphoma, systemic investigation is essential for the initial management of patients presenting PCNSL.

Intramedullary spinal teratoma with spina bifida

Spinal intramedullary teratoma is a rare tumor. We report a case of intramedullary teratoma of the conus medullaris with spina bifida. A 5-year-old boy was admitted to our hospital for removal of a lumbosacral tumor sited in an intramedullary location at the conus medullaris, which was totally resected with neuroendoscopic assistance. The pathological diagnosis was mature teratoma consisting of three germ cell layers. The pathogenesis of spinal intramedullary teratoma is discussed with special reference to spina bifida.

Proteasome-dependent degradation of cytosolic chaperonin CCT

The chaperonin containing t-complex polypeptide 1 (CCT) is a heterooligomeric molecular chaperone that assists in the folding of actin, tubulin, and other cytosolic proteins. We show here that degradation of CCT in mammalian cells is inhibited by a proteasome-specific inhibitor, lactacystin. When CCT synthesis was inhibited by growth arrest of cells, the decrease in CCT levels was much slower in the presence of lactacystin than in its absence. Pulse-chase experiments indicated that degradation of CCT is inhibited 2- to 2.5-fold by addition of lactacystin. In addition, CCT degradation rate in ts85 cells that produce thermolabile ubiquitin-activating enzyme E1 was reduced 3-fold at the nonpermissive temperature compared to the degradation at the permissive temperature. These results indicate that the ubiquitin-proteasome system is involved in CCT degradation.

Indirubin inhibits inflammatory reactions in delayed-type hypersensitivity

Polygonum tinctorium Lour. (P. tinctorium) is known to have the ability to suppress inflammation. We attempted to isolate the active compounds from P. tinctorium based on their inhibitory effects on the production of interferon-gamma, which is a well-known inflammatory cytokine. We thus isolated indirubin, an isomer of indigo. Indirubin exerted its inhibitory effects not only on interferon-gamma production by human myelomonocytic HBL-38 cells but also on interferon-gamma and interleukin-6 production by murine splenocytes with no influence on the proliferation of either cells. Because of its inhibitory activity on interferon-gamma production, we further investigated the effects of indirubin on 2,4, 6-trinitro-l-chlorobenzene (TNCB)-induced delayed-type hypersensitivity as a representative inflammatory reaction. When injected intraperitoneally, indirubin significantly inhibited the ear swelling of TNCB-elicited mice. The amount of interferon-gamma in the culture supernatants of elicited mouse lymphocytes was inhibited by indirubin treatment. These results suggest that indirubin is a compound with anti-inflammatory effects.

Deficient Th1-type immune responses via impaired CD28 signaling in ultraviolet B-induced systemic immunosuppression and the restorative effect of IL-12

A single large dose (15 kJ/m(2)) of UVB-irradiation induces systemic immunosuppression and tolerance. We previously reported that IL-12 promotes the accessory cell function of epidermal Langerhans cells. In this study we have examined whether IL-12-pretreated antigen-presenting cells (APC) could restore the diminished T-cell response in mice irradiated with a single large dose of UVB. Spleen cells from UVB-irradiated mice showed reduced IFN-gamma production in a hapten-specific response but the function of APC in non-exposed skin of UVB-irradiated mice was not impaired. The pretreatment of APC with IL-12 did not restore the impaired IFN-gamma production by T cells from UVB-irradiated mice. Neither IL-10 nor TGF-beta was found to be involved in the suppression. Instead, we observed that anti-CD3 mAb-induced IFN-gamma production by T cells from UVB-irradiated mice was not augmented in the presence of anti-CD28 mAb, whereas IL-4 production was enhanced by the addition of anti-CD28 mAb. Furthermore, the reduced IFN-gamma production by T cells from UVB-irradiated mice in response to antigen plus APC could be restored by adding IL-12 to the culture. Our results thus indicate that UVB-induced systemic immunosuppression involves impaired Th1-type responses of T lymphocytes through CD28 stimulation, and that IL-12 compensates for the impaired CD28 costimulatory signaling in T cells resulting in the restoration of Th1-type responses.

Effect of interleukin-18 on viral myocarditis: enhancement of interferon- gamma and natural killer cell activity

Encephalomyocarditis virus causes viral myocarditis with myocyte necrosis and inflammatory cell infiltration in mice. Because previous studies have shown that some cytokines prevent the sequelae of myocarditis, we assessed the effect of a newly identified cytokine, interleukin-18 (IL-18), in preventing the sequelae of myocarditis. Murine IL-18 (10 microg/day/mouse) was given peritoneally for 10 days in C3H mice infected with EMC virus. Mice were divided into group IL-18 (infected-treated), saline group (infected-untreated), group IL-18-2 (treatment started on day 2), group IL-18-5 (treatment started on day 5). Although the 14-day survival rate in saline group was 20%, that in the group IL-18 increased to 80% (P<0.05). Either mice in group IL-18-2 or in group IL-18-5 did not survive longer than saline group. The viral titer of the heart on day 3 was lower in group IL-18 compared to the saline group (1.00+/-0.20 log(10)tissue culture infected dose (TCID)(50)/mg wet weight v 1.42+/-0.12 log(10)TCID(50)/mg, n=3 of each). Mice in group IL-18 had less myocardial necrosis and cellular infiltration than the saline group. The myocardial expression of interferon- gamma (IFN- gamma) mRNA in group IL-18 was significantly (P<0.05) greater than the saline group on days 1 and 3 after viral inoculation. Circulating IFN- gamma was significantly elevated on days 1, 5, and 7, but significantly reduced on day 3. The natural killer cell activities in the spleen on days 1, 3, and 5 were significantly (P<0.05) greater in group IL-18 than in the saline group (41+/-9%v 10+/-6% on day 3, 4 of each). We conclude that IL-18 reduces the severity of EMC viral myocarditis by inducing cardiac expression of IFN- gamma mRNA and increasing splenic natural killer cell activity.

Lipopolysaccharide/endotoxin induces IL-18 via CD14 in human peripheral blood mononuclear cells in vitro

IL-18 shares activities with IL-12 in generating T-helper 1 cells and cytokine response. It mediates LPS/endotoxin lethality by IL-12 independent interferon-gamma synthesis and it induces bacteria-related organ failure. As peripheral blood mononuclear cells (PBMC) are potent producers of IL-18, we studied the regulation of IL-18 upon exposure to LPS and Staphylococcus aureus (SAC) in vitro. Freshly isolated PBMC constitutively expressed IL-18 mRNA. After unstimulated preincubation for 48 h, however, IL-18 transcripts were nearly not detectable by RT-PCR, but inducible by LPS or SAC (P<0.01). Both LPS and SAC were potent stimuli of IL-18 protein secretion (P<0.01). LPS-mediated IL-18 gene expression and secretion was CD14-dependent and significantly inhibited by co-incubation of PBMC with neutralizing CD14 antibody (P<0.01). We conclude that LPS-driven IL-18 is dependent on the expression of costimulatory factors and that IL-18 inhibition might attenuate IL-18-related toxic effects.

Interleukin 18 is a potent proliferative factor for intestinal mucosal lymphocytes in Crohn's disease

BACKGROUND & AIMS

Crohn's disease (CD) is characterized by a marked accumulation of activated Th1 type CD4(+) T cells and macrophages in inflamed intestinal mucosa. Interleukin (IL)-18 is a recently described cytokine that mainly exists in activated macrophages and shares biological activities with IL-12 in driving the development of Th1 type CD4(+) T cells by inducing interferon gamma. To clarify the role of IL-18 in intestinal inflammation in CD, we assessed the functional role of IL-18 in regulating intestinal mucosal lymphocytes.

METHODS

Serum IL-18 concentration was measured by enzyme-linked immunosorbent assay. Expression of IL-18 and IL-18 receptor in human intestinal mucosa was determined using immunohistochemistry and flow cytometry. The functional activity of IL-18 was assessed by the use of recombinant IL-18 to stimulate both the growth of intestinal mucosal lymphocytes and IL-2 receptor induction activity.

RESULTS

The serum IL-18 concentration was significantly higher in patients with CD than normal controls. In the inflamed colonic mucosa of CD, many IL-18(+)CD68(+) macrophages had infiltrated the lamina propria. Intestinal mucosal lymphocytes from CD expressed functional IL-18 receptors. Recombinant IL-18 induced significant proliferative responses in freshly isolated mucosal lymphocytes from CD patients, but not from normal controls. IL-18 up-regulated IL-2 receptor expression in mucosal lymphocytes from patients with CD, but not from normal controls.

CONCLUSIONS

These findings suggest that infiltrated macrophages in the inflamed intestinal mucosa in CD produce IL-18, and that macrophage-derived IL-18 may serve as a potent regulatory factor for intestinal mucosal lymphocytes, thereby contributing to chronic intestinal inflammation in CD.

Clinical features in patients requiring reoperation after failed endoscopic procedures for hydrocephalus

The aim of this study was to clarify the clinical features of patients at risk of secondary obstruction following endoscopic fenestration. Clinical notes and endoscopic findings for 15 patients treated with endoscopic procedures were retrospectively reviewed. Endoscopic third ventriculostomy (ETV) was performed as initial treatment in 4 patients with non-communicating hydrocephalus, including a neonate with myelomeningocele, and as an alternative to shunt revision in 4 patients. Two patients with non-communicating hydrocephalus caused by tumor or arachnoid cyst were also managed with third ventriculostomy. Four patients with loculated hydrocephalus underwent endoscopic septostomy. A child with an isolated fourth ventricle was treated with endoscopic aqueductoplasty. Of the 15 patients undergoing endoscopic procedure, 4 required reoperation. Of the 10 patients treated with ETV, only the neonate with myelomeningocele required a ventriculoperitoneal shunt because of failure of the initial procedure. Of the 4 patients treated with endoscopic septostomy, 2 children with loculated hydrocephalus following intraventricular hemorrhage (IVH) underwent a second septostomy. In a patient with an isolated fourth ventricle following posthemorrhagic hydrocephalus, recurrence was noted 8 months after the initial procedure. He underwent a second procedure using a stent implanted into the aqueduct to maintain CSF circulation. Sufficient stomal size or implantation of a stent may be required in the under-2-year age group with hydrocephalus accompanied by IVH and associated with myelomeningocele, in whom the risk of secondary obstruction may be high.

Serum interferon-gamma-inducing factor/IL-18 levels in primary biliary cirrhosis

Primary biliary cirrhosis is an autoimmune disease of the liver in which T helper 1 cytokines predominate over those of T helper 2 in the pathogenesis. Interleukin- 18 (IL-18), for which the gene was recently cloned, is a novel T helper 1 cytokine, which augments interferon-gamma production. We designed this study to clarify the role of IL-18 in primary biliary cirrhosis and to examine whether serum IL-18 level can be a prognostic indicator for the disease. Serum IL-18 levels were measured using an enzyme linked immuno sorbent assay with mouse monoclonal antibodies. Twenty-two healthy volunteers, 31 patients with primary biliary cirrhosis (Scheuer's stage I, 13; II, 10; and IV, 8), 20 patients with autoimmune hepatitis, 11 patients with virus-related liver cirrhosis and six patients with obstructive jaundice were enrolled. Significant differences of serum IL-18 levels were observed between patients with Scheuer's stage IV and those with stage I, or II, virus-related liver cirrhosis and obstructive jaundice (P < 0.05). The IL-18 levels in primary biliary cirrhosis increased according to the disease progression, and fell promptly after living-related liver transplantation. Moreover, serum IL-18 levels in primary biliary cirrhosis were correlated with serum bilirubin concentrations and the Risk scores of the Mayo Clinic prognostic model for the disease. The IL-18 levels observed in patients with autoimmune hepatitis were also elevated, and correlated with the activity of the disease. These results indicate that serum interleukin-18 levels reflect the severity of primary biliary cirrhosis, the activity of autoimmune hepatitis, and may be an additive prognostic indicator in primary biliary cirrhosis.