Novel thermal hysteresis proteins from low temperature basidiomycete, Coprinus psychromorbidus

The low temperature basidiomycete, Coprinus psychromorbidus, produced three kinds of thermal hysteresis proteins (THPs) in the extracellular space. Molecular mass of purified fungal THPs were approximately 23 kDa, respectively, however those fungal THPs had different N-terminal amino acid sequences. Those fungal THPs formed ice crystals resembling "stone Age arrow head". These observations indicate that fungal THPs did not form hexagonal ice crystals to inhibit its growth.

Chilling resistances of isolates of Pythium ultimum var. ultimum from the Arctic and Temperate Zones

Chilling resistances in moss pathogenic fungi, Pythium ultimum var. ultimum, from Longyearbyen, Svalbard (78 degree N, 15 degree E), located in the Arctic Zone and in the same isolates from Temperate Zone, were determined. Both strains had similar optimum growth temperatures. However, the strains from Svalbard could grow and survive at 0 - 5 degrees C. In addition, chilling treatment induced irregular mycelial morphology in the Arctic isolates. On the other hand, the isolates from Japan did not grow at temperatures below 5C and were destroyed after chilling stress (0 degree C for 3 days or at 4 degrees C for 1 week). The results suggested that isolates from Svalbard highly adapted to the severe spring condition in Polar environments.

Expression of angiogenic factors predicts response to chemoradiotherapy and prognosis of oesophageal squamous cell carcinoma

The ability to predict patients' responses to chemoradiotherapy by analyzing pre-treatment biopsy specimens would be valuable for managing oesophageal squamous-cell cancer. To this end, the expression of p53, thymidine phosphorylase and vascular endothelial cell growth factor was analyzed by immunohistochemistry in 52 patients with oesophageal squamous-cell cancer prior to chemoradiotherapy. Treatment consisted of radiotherapy (40 Gy) and 5 day-infusion of 5-Fluorouracil (500 mg m(-2) per day) combined with cisplatin (10 mg m(-2) per day). Following treatment, imaging and endoscopic reassessment was performed to establish treatment response. Thirty-one patients underwent radical surgery and 21 patients were treated with an additional 20 Gy of radiotherapy. Of the tumours studied, 58% were p53-positive, 40% thymidine phosphorylase-positive and 44% vascular endothelial cell growth factor-positive. A clinical response was observed in 36 patients (69%) and was negatively associated with thymidine phosphorylase expression (P=0.02) and vascular endothelial cell growth factor expression (P<0.001). However, the 5-year survival rate was significantly lower only in patients with vascular endothelial cell growth factor-positive tumours (P=0.037). Multivariate analysis identified vascular endothelial cell growth factor as a significant independent prognostic factor (P=0.0147). These results suggest that expression of angiogenic factors has predictive value for the treatment response and outcome of patients with oesophageal cancer.

Differential and quantitative analyses of mRNA expression of glucosyltransferases from Streptococcus mutans MT8148

Streptococcus mutans produces three glucosyltransferases, coded by gtfB, gtfC, and gtfD, whose cooperative action is essential for sucrose-dependent cellular adhesion. This cellular adhesion plays an important role in the formation of dental plaque and the initiation of dental caries. Since they bear genetic similarities and are large in size, differentiation of their gene expression has been difficult, and little is known about the dynamic process of gtf expression. Using a real-time reverse-transcription/polymerase chain-reaction, we determined the expression of each gtf. Under various conditions, the relative levels of transcription were gtfB > gtfD > gtfC. Sucrose enhanced gtfD expression, whereas it reduced that of gtfB and gtfC, suggesting the presence of independent promoters. Quantitative analyses demonstrated coincidence between the ratio of expression of each gtf and the ratio previously identified as optimal for sucrose-dependent adhesion in vitro, suggesting that S. mutans produces GTF at an optimal ratio to adhere to the tooth surface.

Increased insufflation pressure enhances the development of liver metastasis in a mouse laparoscopy model: possible mechanisms

BACKGROUND

The effect of different insufflation pressures and durations of CO2 pneumoperitoneum on the growth of liver metastasis was investigated in a mouse model. The possible mechanisms involved in the pressure-related enhancement of liver metastasis were also examined.

METHODS

Mice inoculated intraportally with colon 26 cells underwent CO2 pneumoperitoneum at different pressures (5,10, or 15 mmHg) for 30 or 60 min, or received no treatment other than tumor cell inoculation (control). The subsequent growth of liver metastases was examined. Mice injected intraportally with 111In-oxine-labeled colon 26 cells underwent pneumoperitoneum at three different pressures or served as controls. The radioactivity of the liver was determined to evaluate tumor accumulation in the liver. Mice received pneumoperitoneum at three different pressures or received trocar placement alone. Changes in plasma interleukin-6 levels were determined.

RESULTS

The growth of liver metastases on day 14 was influenced by increased insufflation pressures (p < 0.05) rather than the prolonged duration of pneumoperitoneum without significant interaction. The 15-mmHg pneumoperitoneum group showed a higher (p < 0.05) accumulation of radioactivity in the liver compared with the 5-mmHg pneumoperitoneum group and controls. Pneumoperitoneum groups with 5 and 10 mmHg showed higher (p < 0.05) peak levels of IL-6 compared with controls.

CONCLUSIONS

An elevated insufflation pressure plays an important role in the enhancement of liver metastases, and this pressure-related adverse effect may be partly relevant to facilitating accumulation of tumor cells in the liver.

Liver metastases are less established after gasless laparoscopy than after carbon dioxide pneumoperitoneum and laparotomy in a mouse model

BACKGROUND

Although the liver is the most frequent site of cancer recurrence after conventional open surgery for colorectal cancer, the effect of laparoscopic procedures with or without gas insufflation on the development of liver metastases is largely unknown.

METHODS

Male BALB/C mice inoculated intraportally with colon 26 cells were randomized to undergo carbon dioxide pneumoperitoneum (n = 14), abdominal wall lifting (n = 14), or full laparotomy (n = 12), or to serve as control subjects without any procedures other than tumor inoculation (n = 13).

RESULTS

The growth of liver metastases 14 days after surgery was enhanced after full laparotomy (p < 0.01) and pneumoperitoneum (p = 0.02), as compared with that in the control subjects, whereas there was no difference in the growth of liver metastases between abdominal wall lifting and the control condition (p = 0.99).

CONCLUSIONS

These results suggest that the defense against liver metastasis is better preserved after the gasless procedure than after laparotomy and carbon dioxide pneumoperitoneum in the reported animal model.

The Accuracy and Usefulness of 3D-DSA and 3D-CT Angiography for Cerebral Aneurysms

SUMMARY

For evaluation of intracranial cerebral aneurysms, three-dimensional (3D) digital subtraction angiography (DSA) and 3D-computed tomographic angiography (CTA) were demonstrated in fifteen patients. The diagnostic accuracy of preoperative 3D-CTA is equal to that of 3D-DSA except for the case with a dissecting aneurysm. The virtual images of 3D-CTA were well correlated with surgical findings. In endovascular treatment of intracranial aneurysms, 3D-DSA had an obvious advantage in obtaining the best working angle of the C-arm. The major branches originating from the dome were depicted on 3D-DSA in two cases that could not be judged on 3D-CTA. The aim of the present study was to verify the difference between 3D-DSA and 3D-CTA for evaluation of intracranial aneurysms.

Sustained-release microcapsules of a bone formation stimulant, TAK-778, for local injection into a fracture site

The benzothiepin derivative (2R,4S)-(-)-N-(4-diethoxyphosphorylmethylphenyl)-1,2,4,5-tetrahydro-4-methyl-7,8-methylenedioxy-5-oxo-3-benzothiepin-2-carboxamide (TAK-778) is a potent bone formation stimulant. A sustained release formulation was prepared by encapsulating the drug into biodegradable microcapsules for local application to fracture repair in rats. The microcapsules consisted of TAK-778 (10% w/w) and a biodegradable polymer, copoly (d,l-lactic/glycolic acid), with a copolymer ratio of 85:15 (mol/mol) and an average molecular weight of 15 k. The TAK-778 amount at the injection site progressively diminished for 4 weeks after administration, and the serum level of TAK-778 was sustained over the same period. The local concentration of TAK-778 after administration of the microcapsules was simulated by a two-compartment open model. In the model, a first-order release rate constant and a transfer rate constant were obtained from the release profile of the microcapsules and the serum level of TAK-778 after administration of the TAK-778 solution, respectively. Localization at the injection site was examined by radiography using microcapsules in which iodoform was encapsulated as a contrast agent. The microcapsules formed a clot at the injection site, and their spread was narrowly restricted. The local concentration was calculated to be maintained within the range 10(-3)-10(-6) M over 4 weeks on the assumption that the dose and spread volume were 5 mg of TAK-778/site and 3 mL, respectively.

[A study of serum mitochondrial enzymes(mCK, mAST, mMDH) in rotavirus and adenovirus gastroenteritis in pediatric patients]

Rotavirus and adenovirus antigens in feces from 77 cases of gastroenteritis in pediatric patients were examined. Mitochondrial enzymes, mitochondrial creatine kinase(mCK), mitochondrial aspartate amino-transferase(mAST) and mitochondrial malate dehydrogenase(mMDH) activities in their sera were also measured and compared with the results of rotavirus and adenovirus antigens in the feces. Thirty-one cases were rotavirus antigen-negative(rota-negative)/adenovirus antigen-negative(adeno-negative), 5 were rota-negative/adenovirus antigen-positive(adeno-positive), 40 were rotavirus antigen-positive(rota-positive)/adeno-negative, and only one case showed positive for both antigens. The mean activities of these three enzymes were compared among 3 groups except one both positive case mentioned above and control group(n = 105) by Mann-Whitney U-test. The serum mCK activity was significantly higher in rota-positive/adeno-negative patients than in other groups(p < 0.01). On the other hand, no significant differences were observed for mAST and mMDH activities among any groups. It is suggested that these phenomena are caused by the differences of localization of these enzymes in mitochondria, that mCK is located the outer surface of inner membrane of mitochondria, and mAST and mMDH are located on the inner surface. The difference of serum mCK activity between rotavirus infection and adenovirus infection suggests that intestinal epithelial cell injury by rotavirus is stronger than that by adenovirus.

Theoretical studies of the ATP hydrolysis mechanism of myosin

The ATP hydrolysis mechanism of myosin was studied using quantum chemical (QM) and molecular dynamics calculations. The initial model compound for QM calculations was constructed on the basis of the energy-minimized structure of the myosin(S1dc)-ATP complex, which was determined by molecular mechanics calculations. The result of QM calculations suggested that the ATP hydrolysis mechanism of myosin consists of a single elementary reaction in which a water molecule nucleophilically attacked gamma-phosphorus of ATP. In addition, we performed molecular dynamics simulations of the initial and final states of the ATP hydrolysis reaction, that is, the myosin-ATP and myosin-ADP.Pi complexes. These calculations revealed roles of several amino acid residues (Lys185, Thr186, Ser237, Arg238, and Glu459) in the ATPase pocket. Lys185 maintains the conformation of beta- and gamma-phosphate groups of ATP by forming the hydrogen bonds. Thr186 and Ser237 are coordinated to a Mg(2+) ion, which interacts with the phosphates of ATP and therefore contributes to the stabilization of the ATP structure. Arg238 and Glu459, which consisted of the gate of the ATPase pocket, retain the water molecule acting on the hydrolysis at the appropriate position for initiating the hydrolysis.

Direct detection by in situ PCR of the amoA gene in biofilm resulting from a nitrogen removal process

Ammonia oxidation is a rate-limiting step in the biological removal of nitrogen from wastewater. Analysis of microbial communities possessing the amoA gene, which is a small subunit of the gene encoding ammonia monooxygenase, is important for controlling nitrogen removal. In this study, the amoA gene present in Nitrosomonas europaea cells in a pure culture and biofilms in a nitrifying reactor was amplified by in situ PCR. In this procedure, fixed cells were permeabilized with lysozyme and subjected to seminested PCR with a digoxigenin-labeled primer. Then, the amplicon was detected with an alkaline phosphatase-labeled antidigoxigenin antibody and HNPP (2-hydroxy-3-naphthoic acid-2'-phenylanilide phosphate), which was combined with Fast Red TR, and with an Alexa Fluor 488-labeled antidigoxigenin antibody. The amoA gene in the biofilms was detected with an unavoidable nonspecific signal when the former method was used for detection. On the other hand, the amoA gene in the biofilms was detected without a nonspecific signal, and the cells possessing the amoA gene were clearly observed near the surface of the biofilm when Alexa Fluor 488-labeled antidigoxigenin antibody was used for detection. Although functional gene expression was not detected in this study, detection of cells in a biofilm based on their function was demonstrated.

[A pediatric case of intractable complex partial seizures associated with mesial temporal lobe astrocytoma: usefulness of interictal epileptiform discharges in the present case]

The patient was a 10-year-old male with normal developmental milestones. He had medically intractable complex partial seizures since the age of 7 years. At the age of 10 years, he had focal motor seizures of the right face, and a head CT scan showed a calcified lesion in the left mesial temporal region. The tumor exhibited low intensity on T 1-weighted and high intensity on T 2-weighted MR images, and was not enhanced by gadolinium-diethylenetriamine pentaacetic acid. Interictal SPECT showed hypoperfusion in the left temporal region. One-day video/EEG monitoring revealed very frequent epileptiform discharges which occurred only during sleep period exclusively in the left anterior-to-middle temporal region. The patient underwent lesionectomy with the guidance of electrocorticography. The histological study of the resected tissue showed astrocytoma. After surgery he has had no seizures for 10 months. It was concluded that very frequent interictal epileptiform discharges strictly localized to the temporal lobe at which MRI-identified tumor was present could be predictive of epileptogenic zone in the present patient in whom clinical symptoms and the results of other studies were also concordant.

[Pseudocholinesterase (ChE)]

In order to establish a recommendation for the measurement of serum pseudocholinesterase (ChE), the Japan Society of Clinical Chemistry has been deribesating for several years. However, they have not yet reached a conclusion. A decrease in serum ChE is clinically meaningful and serum ChE sensitively reflects a degree of chronic diffuse liver damage. ChE isozyme is analyzed not for the estimation of origin of the enzyme, but for the evaluation of familial ChE variants. Electrophoresis or blocking by dibucaine or fluoride are employed for the detection of ChE isozyme. Familial ChE variants are related to succinylcholine apnea in cases of very low serum ChE activities.

[Histological evaluation of liver metastasis of colorectal cancer following hepatic arterial infusion with degradable starch microspheres and adriamycin/mitomycin C]

Little is known about the histological effect of hepatic arterial infusion with degradable starch microspheres (DSM), adriamycin (ADM), and mitomycin C (MMC) on liver metastasis of colorectal cancer. We histologically examined hepatic metastases resected following this therapy and investigated their relation to macroscopic changes in size. Neither a histological nor macroscopic effect was found in 2 patients receiving this therapy only one time. A 57-year-old woman with a solitary liver metastasis who received this therapy repeatedly (five times every 3 to 4 weeks) subsequently showed a partial response. She underwent hepatic metastasectomy 5 months after the end of the therapy. Histological examination showed that the greater part of the metastatic lesion was composed of fibrous tissues without any viable cancer cells. In conclusion, it should be noted that repeated infusions of DSM.ADM.MMC for liver metastases of colorectal cancer can have a marked histological effect even though the lesion does not show a complete response.

Catalytic function of the residues of phenylalanine and tyrosine conserved in squalene-hopene cyclases

Site-directed mutagenesis experiments on all the conserved residues of Phe and Tyr in all the known squalene-hopene cyclases (SHCs) were carried out to identify the active site residues of thermophilic Alicyclobacillus acidocaldarius SHC. The following functions are proposed on the basis of kinetic data and trapping of the prematurely cyclized products: (1) The Y495 residue probably amplifies the D376 acidity, which is assumed to work as a proton donor for initiating the polycyclization cascade, but its role is moderate. (2) Y609 possibly assists the function of F365, which has previously been assigned to exclusively stabilize the C-8 carbocation intermediate through cation-pi interaction. The Y609A mutant produced a partially cyclized bicyclic triterpene. (3) Y612 works to stabilize both the C10 and C8 carbocations, this being verified by the finding that mono- and bicyclic products were formed with the Y612A mutant. (4) F129 was first identified to play a crucial role in catalysis. (5) The three residues, Y372, Y474 and Y540, are responsible for reinforcing the protein structure against thermal denaturation, Y474 being located inside QW motif 3.

[Effect of peroral doxifluridine plus hepatic arterial infusion for synchronous liver metastasis of colorectal cancer--correlation with the expression of thymidine phosphorylase and dihydropyrimidine dehydrogenase in primary colorectal cancer lesions]

We investigated whether the efficacy of peroral doxifluridine and hepatic arterial 5-FU infusion on synchronous liver metastasis of colorectal cancer could be predicted based on the expression of thymidine phosphorylase (TP) and dihydropyrimidine dehydrogenase (DPD) in the primary colorectal lesions. Ten patients with synchronous liver metastasis of colorectal cancer were given doxifluridine (600-800 mg/body/day) orally and 5-FU (500 mg/body, once or twice a week) through the hepatic artery following resection of the primary lesions between June 1996 and July 2001. The levels of TP and DPD in the primary lesions were determined by an enzyme-linked immunosorbent assay. The level of TP, DPD, and the ratio of TP/DPD in patients with partial response (n = 4) were 89.8 +/- 30.0 U/mg protein, 23.5 +/- 25.7 U/mg protein, and 3.8 +/- 1.4, respectively, while those in patients with no response or progressive disease (n = 6) were 41.8 +/- 9.7 U/mg protein, 25.8 +/- 15.8 U/mg protein, and 2.2 +/- 1.6, showing significant difference (p < 0.01) in the level of TP between the groups. These results indicate that determining the level of TS in primary colorectal lesions may be useful for predicting the efficacy of this regimen for patients with synchronous liver metastasis of colorectal cancer.

Cold-stimulated increase in a regulatory subunit of cAMP-dependent protein kinase in human hepatoblastoma cells

Although cold-stress responses in bacteria and plants have been well studied and hypothermic conditions are used in clinical treatments, there has been little investigation of cold-stress responses in human cells, and there has been no report on the involvement of signal transduction modulators in the cold-stress response in human cells. We therefore investigated alterations in the expression of genes involved in the signal transduction system and the mechanisms of cold-stimulated increases in the expression of genes in human hepatoblastoma (HepG2) cells. Using a cDNA expression array method, we found that a transcript encoding a regulatory subunit Ibeta (RIbeta) of cyclic AMP-dependent protein kinase (PKA) was increased in cold-stressed cells. Western blot analysis revealed that the amount of PKA RIbeta protein was increased by cold treatment, while that of a PKA catalytic subunit (C) was unchanged. The protein level of PKA RIbeta was increased in cells treated with low concentrations of actinomycin D, whereas that of PKA C was not, implying that the increase was caused by the suppression of transcription at low temperatures. In addition, degradation of the PKA RIbeta protein was not stimulated by cold treatment, unlike that of the PKA C protein. The results suggest that signal transduction through PKA also participates in cold-stress responses in human cells and that multiple mechanisms are involved in the increase in the level of the PKA RIbeta protein.

Relationships of glucose concentrations in capillary whole blood, venous whole blood and venous plasma

We studied the difference in glucose levels between capillary and venous whole blood during 75-g oral glucose tolerance test (OGTT) in 75 healthy subjects. Capillary and venous whole blood glucose values were measured by HK-G6PD method after deproteinization. The post-loaded glucose levels in capillary blood were significantly higher than those in venous blood, and the mean values of capillary and venous difference at 30, 60, 90, 120 and 180 min were 1.37, 1.40, 1.07, 0.95 and 0.52 mmol/l, respectively, with the maximum difference at 60 min. No correlation was found in the magnitude of the differences in glucose between capillary and venous blood specimens. We determined the inaccuracy of six self-monitoring blood glucose devices relative to the reference method using venous plasma, venous whole blood and capillary whole blood from 31 diabetic patients. The differences of mean values of venous whole blood and capillary whole blood, and venous whole blood and venous plasma, and capillary whole blood and venous plasma were 9.6%, 11.3% and -3.2%, respectively. The range of bias and Sy/x were 0.31-1.06 mmol/l and 0.71-1.07 mmol/l, respectively, compared to the reference method using venous plasma.

Monooxygenation mechanism by cytochrome p-450

The substrate oxygenation mechanism by an ultimate species in monooxygenation by cytochrome P-450 (compound I) was investigated by the density functional theory method. An initial model compound was constructed from a structure obtained by 300-ps molecular dynamics simulation of compound I-formed P-450cam under physiologic conditions, and it consisted of porphine for protoporphyrin IX, S(-)-CH(3) for the side chain of Cys357 of the fifth ligand of heme, a methane molecule for the substrate, a heme iron, and an oxygen atom of the sixth ligand of heme. The results of the calculation revealed that the substrate oxygenation mechanism had four elementary processes, i.e., (1) formation of [FeOH](3+) and a substrate radical by hydrogen atom abstraction from the substrate caused by [FeO](3+), (2) rotation of the OH group of the sixth ligand of [FeOH](3+) produced by process 1, (3) substrate radical binding with the [FeOH](3+), and (4) elimination of the oxygenated substrate formed at the sixth ligand binding site. The rate-determining step is process 1, hydrogen atom abstraction from the substrate, and the activation energy was determined to be about 15 kcal/mol. For this reason, it is thought that this reaction occurs in vivo.

Contributions of three glycosyltransferases to sucrose-dependent adherence of Streptococcus mutans

Streptococcus mutans produces 3 types of glucosyltransferase (GTF), whose cooperative action is considered to be essential for its cellular adherence to the tooth surface. However, the precise mechanisms for synthesizing adhesive glucans and the specific roles of each GTF in cellular adherence to smooth surfaces have not been elucidated. In the present study, seven types of isogenic mutants of S. mutans MT8148 lacking GTFB, GTFC, and/or GTFD activities were constructed by inactivation of the genes encoding GTFB, GTFC, and/or GTFD. Furthermore, recombinant GTFB, GTFC, and GTFD were prepared from Escherichia coli cells harboring recombinant plasmids containing each of the gtf genes. Using these GTF-deficient mutants and rGTFs, we reconstituted sucrose-dependent adherence of S. mutans resting cells and examined the role of each GTF in vitro. The highest level of sucrose-dependent adherence was found at the ratio of 20 rGTFB:1 rGTFC:4 rGTFD in both the resting cells of GTF-deficient mutants and insoluble glucan synthesized by rGTFs. Moreover, when rGTFC and rGTFD were both present at concentrations of 1.5 mU and 6 mU, respectively, the insoluble glucan synthesized from sucrose by the rGTFs showed a high level of adhesiveness to smooth surfaces, even without rGTFB. These results suggest that the presence of all three GTFs at the optimum ratio is necessary for sucrose-dependent adherence of S. mutans, and that GTFC and GTFD may play significant roles in the synthesis of adhesive and insoluble glucan from sucrose.

Both E6 and E7 oncoproteins of human papillomavirus 16 inhibit IL-18-induced IFN-gamma production in human peripheral blood mononuclear and NK cells

Cervical carcinoma is the predominant cancer among malignancies in women throughout the world, and human papillomavirus (HPV) 16 is the most common agent linked to human cervical carcinoma. The present study was performed to investigate the mechanisms of immune escape in HPV-induced cervical cancer cells. The presence of HPV oncoproteins E6 and E7 in the extracellular fluids of HPV-containing cervical cancer cell lines SiHa and CaSki was demonstrated by ELISA. The effect of HPV 16 oncoproteins E6 and E7 on the production of IFN-gamma by IL-18 was assessed. E6 and E7 proteins reduced IL-18-induced IFN-gamma production in both primary PBMCs and the NK0 cell line. FACS analysis revealed that the viral oncoproteins reduced the binding of IL-18 to its cellular surface receptors on NK0 cells, whereas there was no effect of oncoproteins on IL-1 binding to its surface IL-1 receptors on D10S, a subclone of the murine Th cell D10.G4.1. In vitro pull-down assays also revealed that the viral oncoproteins and IL-18 bound to IL-18R alpha-chain competitively. These results suggest that the extracellular HPV 16 E6 and E7 proteins may inhibit IL-18-induced IFN-gamma production locally in HPV lesions through inhibition of IL-18 binding to its alpha-chain receptor. Down-modulation of IL-18-induced immune responses by HPV oncoproteins may contribute to viral pathogenesis or carcinogenesis.

Cutting edge: IL-18-transgenic mice: in vivo evidence of a broad role for IL-18 in modulating immune function

IL-18 has been shown to be a strong cofactor for Th1 T cell development. However, we previously demonstrated that when IL-18 was combined with IL-2, there was a synergistic induction of a Th2 cytokine, IL-13, in both T and NK cells. More recently, we and other groups have reported that IL-18 can potentially induce IgE, IgG1, and Th2 cytokine production in murine experimental models. Here, we report on the generation of IL-18-transgenic (Tg) mice in which mature mouse IL-18 cDNA was expressed. CD8+CD44high T cells and macrophages were increased, but B cells were decreased in these mice while serum IgE, IgG1, IL-4, and IFN-gamma levels were significantly increased. Splenic T cells in IL-18 Tg mice produced higher levels of IFN-gamma, IL-4, IL-5, and IL-13 than control wild-type mice. Thus, aberrant expression of IL-18 in vivo results in the increased production of both Th1 and Th2 cytokines.