Biomedical subjects

S Shimura

Publications and source records attributed to S Shimura.

At least 19 recordsLinked to original sources

PubMed2001

Megastigmane glycosides and an acylated triterpenoid from Eriobotrya japonica.

Two new megastigmane glycosides, eriojaposides A (1) and B (2), and a new acylated triterpenoid (3) were isolated along with nine known compounds from a leaf extract of Eriobotrya japonica. The structures of 1--3 were characterized as (6R,9R)-3-oxo-alpha-ionyl-9-O-beta-xylopyranosyl-(1' '-->6')-beta-glucopyranoside, (6R,9R)-3-oxo-alpha-ionyl-9-O-alpha-rhamnopyranosyl-(1' '-->6')-beta-glucopyranoside, and 3 alpha-trans-feruloyloxy-2 alpha-hydroxyurs-12-en-28-oic acid, respectively, on the basis of spectral and chemical evidence.

Asia↗

PubMed2001

Toxicity and health-related quality of life during and after high dose rate brachytherapy followed by external beam radiotherapy for prostate cancer.

BACKGROUND: The optimal protocol for combining high dose rate brachytherapy and external beam irradiation as treatment for localized prostate cancer is unknown. Toxicity rates and clinical and biochemical outcomes should be evaluated to validate the current treatment protocol. METHODS: Fifty-eight patients were treated for prostate cancer with high dose rate brachytherapy followed by 30 Gy of external beam radiation therapy. Toxicity during treatment and for 12-18 months thereafter, and treatment-related morbidity, were evaluated. Physician-assessed treatment-related toxicity was graded at the time of occurrence using the Radiation Therapy Oncology Group morbidity criteria. Four separate self-administered questionnaires were used to collect longitudinally demographic data and general and prostate disease-related measures of quality of life. RESULTS: Various degrees of rectal bleeding due to radiation proctitis were experienced by 13 patients (22%) at a median time of 11 months. Two of these patients needed hospitalization to undergo laser coagulation of the rectal mucosa. Study patients had statistically significant decreases in five SF-36 domains during the first month of treatment. All measures recovered by 12 months. Sexual function was not affected by irradiation. Lower urinary tract symptoms assessed by IPSS/QOL scores worsened significantly during the first month of treatment but later recovered to baseline levels. Physician-assessed RTOG scores failed to detect these changes. CONCLUSIONS: Morbidity associated with combined radiation therapy was greatest during the first month of treatment and affected quality of life significantly. Most measures recovered to baseline levels by 12 months following radiation therapy. Although the current protocol appears acceptable, measures should be taken to decrease treatment-related morbidity further.

Adult↗

PubMed2001

Secretion and gene expression of secretory leukocyte protease inhibitor by human airway submucosal glands.

Submucosal glands were isolated within 4 h of death from tracheae and bronchi obtained from autopsied lungs, and the secretory response of secretory leukocyte protease inhibitor (SLPI) was examined with ELISA and a secretory index. Although human neutrophil elastase (HNE) at low concentrations increased SLPI secretion above the control level (i.e., 149% of control level at 10(-11) M), HNE at high concentrations significantly decreased it below the control level (i.e., 16% of control level at 10(-7) M). The decrease in SLPI concentration was shown to result from the degradation of SLPI by excessive HNE. Methacholine induced significant secretion (i.e., 363% of control level at 10(-5) M) that was abolished by both M(1) and M(3) receptor antagonists. A semiquantitative analysis of SLPI mRNA by RT-PCR and Southern blot showed that compared with the superficial epithelium, submucosal glands had a 30-fold or higher level of SLPI mRNA. Both HNE and methacholine significantly increased the level of SLPI mRNA in submucosal glands in a dose-dependent manner (i.e., 357% of control level at 10(-7) M and 175% of control level at 10(-5) M, respectively). These findings indicate that human airway submucosal glands can transcribe 30-fold or more SLPI mRNA than the superficial epithelium and that SLPI mRNA transcription and secretion are regulated by both HNE and muscarinic receptors.

Adult↗

PubMed2001

Identification of cariostatic substances in the cacao bean husk: their anti-glucosyltransferase and antibacterial activities.

The cacao bean husk has been shown to possess two types of cariostatic substances, one showing anti-glucosyltransferase (GTF) activity and the other antibacterial activity, and to inhibit experimental dental caries in rats infected with mutans streptococci. In the present study, chromatographic purification revealed high-molecular-weight polyphenolic compounds and unsaturated fatty acids as active components. The former, which showed strong anti-GTF activity, were polymeric epicatechins with C-4beta and C-8 intermolecular bonds estimated to be 4636 in molecular weight in an acetylated form. The latter, which showed bactericidal activity against Streptococcus mutans, were determined to be oleic and linoleic acids, and demonstrated a high level of activity at a concentration of 30 microgram/mL. The cariostatic activity of the cacao bean husk is likely caused by these biologically active constituents.

Anti-Infective Agents, Local↗

PubMed2001

In situ prostate cancer gene therapy using a novel adenoviral vector regulated by the caveolin-1 promoter.

Caveolin-1, a structural component of caveolae, is overexpressed in metastatic and androgen-resistant prostate cancer and highly expressed in tumor-associated endothelial cells. The mouse cav-1 promoter was cloned and placed upstream of the HSV-tk gene in an adenoviral vector (Adcav-1tk) and compared with a cytomegalovirus (CMV) or Rous sarcoma virus (RSV) promoter-driven HSV-tk, AdCMVtk and AdRSVtk vectors, respectively. Mouse and human prostate cancer cells and mouse endothelial cells were infected with Adcav-1tk, AdCMVtk or control vectors without the HSV-tk gene (Adcav-1 and AdCMV) and subsequently treated with ganciclovir (GCV). GCV-mediated in vitro cytotoxicity induced by the Adcav-1tk vector was comparable to that for AdCMVtk in multiple mouse and human prostate cancer cell lines. To evaluate the activity of Adcav-1tk in vivo, orthotopic mouse prostate cancer tumors were generated with RM-9 cells and injected in situ with Adcav-1tk, AdCMVtk, AdRSVtk, or AdCMVbetagal (control) and treated with GCV. All three HSV-tk transducing vectors produced statistically significant reductions in wet weight and increased apoptotic indices compared with the control vector. However, only Adcav-1tk produced significant necrosis, and only Adcav-1tk and AdRSVtk caused significant decreases in microvessel density. In conclusion, Adcav-1tk demonstrated efficacy in vitro and in vivo in preclinical models of prostate cancer. Our results suggest that the cav-1 promoter may have unique benefits in targeting gene therapy to prostate cancer and its associated vasculature.

Adenoviridae↗

PubMed2000

Reduced infiltration of tumor-associated macrophages in human prostate cancer: association with cancer progression.

Tumor-associated macrophages (TAMs) are highly active immune effector cells that may either positively or negatively regulate the growth of various malignant cells, depending on the biological context. However, the role of TAMs in human prostate cancer progression is unclear. TAMs were immunohistochemically labeled using a monoclonal (CD68) antibody in radical prostatectomy specimens derived from 81 prostate cancer patients. CD68-positive cells were counted with the aid of a microscope and expressed as macrophage index (MphiI), including TAMs/mm2 total tumor tissue (MphiItotal), TAMs/mm2 tumor stroma (MphiIstroma), and TAMs/mm2 cancer cell area (MphiIcancer). MphiIs were analyzed in association with patients' clinical and pathological stage, recurrence status, and histological grade of the cancer. There were significant inverse relationships between MphiItotal and MphiIstroma and clinical stage (P = 0.016 and P = 0.006, respectively). Reduced MphiItotal was also associated with the presence of positive lymph nodes (P = 0.010). Interestingly, although all of the MphiIs differed between Gleason score groups, only MphiIcancer was positively associated with Gleason score. Univariate analysis of MphiItotal and multivariate analysis of MphiItotal with specific pathological markers revealed that MphiItotal was an independent predictor for disease-free survival after surgery (Cox proportional hazard model, P = 0.044 and P = 0.007, respectively). For patients with high MphiItotal (> or = 185.8, the mean MphiItotal value), the disease-free probability 5 years after surgery was 0.75, which was significantly higher than for those with low MphiItotal (0.31, P = 0.0008). Additional immunohistochemical studies that evaluated cytotoxicity-related biomarkers in stroma-associated mononuclear cells suggested reduced functional activities in highly aggressive prostate cancer compared with less aggressive disease. Our results indicate that reduced MphiItotal is a novel prognostic marker for prostate cancer.

Aged↗

PubMed2000

The mouse L-histidine decarboxylase gene: structure and transcriptional regulation by CpG methylation in the promoter region.

To investigate the regulation of mouse L-histidine decarboxylase (HDC) gene expression, we isolated genomic DNA clones encoding HDC. Structural analysis revealed that the mouse HDC gene was composed of 12 exons, spanning approximately 24 kb. Northern blotting analysis indicated that, among the cell lines examined, a high level of HDC gene expression was restricted to mature mast cell lines and an erythroblastic cell line. The gene was induced strongly in the mouse immature mast cell line P815 after incubation in the peritoneal cavity of BDF1 mice. We observed that the promoter region was demethylated in the HDC-expressing cell lines and in induced P815 cells. Interestingly, forced demethylation by 5-azacytidine (5-azaC) treatment induced high expression of HDC mRNA in P815 cells. The activity of a mouse HDC promoter-reporter construct stably transfected in P815 cells was repressed by in vitro patch-methylation. This low promoter activity of the patch-methylated reporter construct was restored after 5-azaC treatment, which demethylated the patch-methylated promoter. These results indicate that DNA methylation state of the promoter region controls HDC gene expression.

3T3 Cells↗

PubMed2000

Structural evidence of genomic exon-deletion mediated by Alu-Alu recombination in a human case with heme oxygenase-1 deficiency.

We previously reported a family affected by heme oxygenase-1 (HO-1) deficiency [Yachie et al., 1999]. The proband was a compound heterozygote for a complete loss of exon 2 (the maternal allele) and a two-nucleotide deletion within exon 3 (the paternal allele). In this report, we describe a large genomic deletion (1730 bp) including entire exon 2 in this family as a specific mechanism generating exon-2 absence observed in the HO-1 mRNA. Analysis of the deletion junction demonstrated fusion of a 5' portion of Alu-Sx element with a 3' portion of Alu-Sq element. The junction contained sequences with high homology to the recombinogenic Alu "core" sequence. These structural features of the HO-1 gene suggest homologous recombination associated with Alu element. This study presents the initial characterization of the HO-1 gene defect causing a human case of HO-1 deficiency and provides the molecular basis for understanding this genetic disease.

Alleles↗

PubMed2000

Signal transduction of mucous secretion by bronchial gland cells.

Bronchial glands, which consist of mucous and serous cells, are abundant in human airways, playing a major role in the airway secretion. Cl(-) secretion is accompanied by water transport to the lumen in the acinar cells of bronchial glands. Agonists that increase [Ca(2+)]i induce the Cl(-) secretion in bronchial glands. Ca(2+) release from a IP(3)-sensitive Ca(2+) pool at the apical portion stimulates and opens Ca(2+)-sensitive Cl(-) channels at the apical membrane, producing Cl(-) secretion in bronchial glands. K(+) channels at the basolateral membranes are Ca(2+)-sensitive and activated by Ca(2+) release from a cADPribose-sensitive Ca(2+) pool, maintaining the Cl(-) secretion in bronchial glands. Further, cADP ribose in concert with IP(3) induce [Ca(2+)]i oscillation, inducing Cl(-) secretion in bronchial glands. Some tyrosine kinases are involved in the Cl(-) secretion in bronchial glands. Mucous and serous cells in bronchial glands take part in mucin secretion and the secretion of defensive substances (glycoconjugates), respectively. [Ca(2+)]i oscillations are shown to play a central role in the exocytosis of secretory granules in serous cells of bronchial glands. Other signal transductions of mucin and glycoconjugates in airway gland cells remain to be studied, although agonists which increase [cAMP]i are also well known to induce mucin and glycoconjugate secretion from airway glands.

Bronchi↗

PubMed2000

Anti-obesity effects of lipase inhibitor CT-II, an extract from edible herbs, Nomame Herba, on rats fed a high-fat diet.

OBJECTIVE: To investigate the inhibitory effects of CT-II, extract of Nomame Herba, on lipase activity in vitro and on obesity in rats fed a high-fat diet in vivo. DESIGN: The assay for the inhibitory effect of CT-II on lipase activity was performed by measuring released free fatty acids after the incubation of the medium with CT-II, porcine pancreatic lipase and triolein (experiment 1). In vivo experiments, lean rats or obese rats (570-718 g) were fed a high-fat diet containing 60% fat with or without CT-II for 8 weeks (experiment 2), for 14 days (experiment 3) or for 12 weeks (experiment 4), respectively. MEASUREMENT: The time course of body weight, food intake, organ weight (parametrial fat, liver, heart and kidney) and plasma parameters (triglyceride, total cholesterol, glucose, AST, ALT and insulin), fecal output of total fat and total cholesterol were measured. Hepatic histological examinations were also performed. RESULTS: CT-II inhibited the porcine lipase activity dose-dependently in vitro (experiment 1). Body and liver weight were reduced and hepatic histological examination showed an amelioration of fatty liver in CT II treated animals (experiment 2). CT-II significantly inhibited body weight gain and plasma triglyceride elevation in a dose-dependent manner, without affecting food intake in lean rats fed the high-fat diet. Elevated plasma AST and ALT were also decreased (experiment 3). When obese rats fed the high-fat diet were treated with CT-II for up to 6 months, body weight was initially reduced and thereafter weight gain was significantly suppressed. Total body fat was also significantly reduced and significant reduction of plasma AST and ALT was observed (experiment 4). CONCLUSIONS: These results demonstrated that the lipase inhibitor CT-II is effective in preventing and ameliorating obesity, fatty liver and hypertriglyceridemia in rats fed a high-fat diet.

Alanine Transaminase↗

PubMed2000

Characterization of platelet-activating factor-induced cytosolic calcium mobilization in human eosinophils.

BACKGROUND: Activated eosinophils play an important role in the pathogenesis of bronchial asthma and other allergic diseases, and platelet-activating factor (PAF) is a potent activator of eosinophils. OBJECTIVE: To characterize the cytosolic Ca2+ ([Ca2+]i) mobilization in human eosinophils in response to PAF. METHODS: [Ca2+]i responses to PAF were examined in human eosinophils using a microscopic fura-2 fluorescence-ratio imaging system. RESULTS: PAF caused a significant and dose-dependent increase in (Ca2+)i, which consisted of an initial rapid rise followed by a sustained elevation. This PAF-induced (Ca2+)i rise was inhibited by WEB 2086, a specific PAF receptor antagonist. The addition of 5 mM EGTA or 1 mM Ni2+ to a nominally Ca2+-free solution did not appreciably reduce the initial rise but significantly inhibited the sustained rise. The application of a protein kinase C inhibitor, Ro31-8220, augmented the sustained increase by PAF. Thapsigargin, a microsomal Ca2+ ATPase inhibitor, induced no appreciable change in a nominally Ca2+-free solution but induced a marked increase in (Ca2+)i when changed to a Ca2+-containing solution. CONCLUSIONS: The initial rapid rise and the following sustained rise in (Ca2+)i by PAF depends on Ca2+ release from the intracellular Ca2+ stores and Ca2+ influx, respectively, which are regulated by protein kinase C in human eosinophils. Furthermore, the so called Ca2+-capacitative entry is possibly involved in the Ca2+ influx from the extracellular solution in human eosinophils.

Calcium Signaling↗

PubMed2000

Characterization of immune function and analysis of RAG gene mutations in Omenn syndrome and related disorders.

Omenn syndrome was recently found to be caused by missense mutations in RAG1 or RAG2 gene that result in partial V(D)J recombination activity. Although the clinical hallmarks of the disease are well defined, there have been several cases with clinical findings similar to, but distinct from Omenn syndrome. The data on immune functions and RAG gene mutations of such cases are limited. We described five Japanese infants from four unrelated families, including two cases of Omenn syndrome and three cases of related disorders. Sibling cases with typical Omenn phenotype were found to be compound heterozygotes of R396C and L885R mutations in RAG1. The former has been reported in European cases and may constitute a hot spot. The latter is a novel missense mutation. Infants with related disorders exhibited erythroderma, eosinophilia, hypogammaglobulinaemia, decreased number of B cells and skewing to Th2, and their lymph node specimens showed architectural effacement, lymphocyte depletion and histiocytic hyperplasia, each of which is seen characteristically in Omenn syndrome. However, in these cases serum IgE levels were low or undetectable. We found no mutation in RAG genes except for a K820R substitution in RAG1, which was regarded to be a functional polymorphism, in two of these cases. Our study suggests that RAG missense mutation may be a genetic abnormality unique to Omenn syndrome with characteristic clinical and laboratory findings. Variations of Omenn syndrome, or related disorders, may represent a different type of immunodeficiency, distinct from abnormalities in lymphoid-specific recombinase activity.

Apoptosis↗

PubMed2000

Antisense oligonucleotides to NF-kappaB improve survival in bleomycin-induced pneumopathy of the mouse.

We examined the effect of antisense oligonucleotides to the p65 subunit of NF-kappaB on the survival of bleomycin (BLM)-induced pneumonitis in C57BL/6 mice (female, 8 wk of age, 17 to 20 g body weight). Fifty-three percent and all control mice died within 6 to 9 d after intravenous administration of 150 and 300 mg/kg BLM alone, respectively. The intravenous administration of the antisense oligonucleotides (900 microgram/animal dissolved in 200 microliter saline, 6 h before and 5 d after BLM administration) significantly improved the survival rate to 100 and 40% in 150- and 300-mg/kg-treated animals, respectively. The antisense oligonucleotides also significantly improved the loss of body weight, the increase in lung hydroxyproline, and histologic changes by BLM, whereas the antisense oligonucleotides themselves did not produce any significant changes in the behavior or lung histology. Both peripheral blood monocytes and alveolar macrophages were confirmed to contain large amounts of intracellular antisense oligonucleotides after BLM injection by FITC-labeled fluorescent microscopy. Further, Western blotting confirmed the inhibition of NF-kappaB in macrophages by the antisense oligonucleotides. These findings suggest that the antisense oligonucleotides are incorporated into activated alveolar macrophages and ameleriorate the lung injury and pneumonitis/fibrosis, thereby improving the survival of BLM-induced pneumopathy in mice.

Animals↗

PubMed2000

Suppression of maxi-K channel and membrane depolarization by synthetic polycations in single tracheal myocytes.

Polycationic proteins, e.g., major basic protein from eosinophils or cathepsin G from neutrophils, have been shown to increase nonspecific airway responsiveness. Along with several indirect manners of action, polycations were reported to contract smooth-muscle strips and to raise the cellular Ca(2+) concentration as a direct action on airway smooth muscle. However, the mechanistic basis for the direct behavior remains to be elucidated. To address this issue, we examined the effects of synthetic cationic polypeptides poly-L-arginine and poly-L-lysine on fresh single smooth-muscle cells from bovine trachea using a patch-clamp technique. Both of the polycations significantly depolarized the membrane from a baseline of about -40 to -20 mV in a dose-dependent manner. The polycations also suppressed whole-cell spontaneous transient outward currents as well as both the conductance (from a baseline of about 130 to 70 pS) and open-state probability (about 25% of control values) of large-conductance Ca(2+)-dependent K(+) channel (maxi-K channel) on excised outside-out patch membranes. The polycations were without effect on the whole-cell Ca(2+) currents induced by depolarizing voltage pulses. We concluded that the synthetic polycations had at least two sites of action; one is the delayed rectifier K(+) channel that is responsible for the membrane depolarization that increases Ca(2+) influx, and the other is the maxi-K channel the suppression of which inhibits muscle relaxation. These results may explain the direct contractile action and, therefore, one of the mechanisms underlying the airway hyperresponsiveness induced by various polycationic proteins.

Animals↗

PubMed2000

A novel function of thyrotropin as a potentiator of electrolyte secretion from the tracheal gland.

Accumulating evidence suggests that thyrotropin (thyroid-stimulating hormone [TSH]) plays some roles in immunoregulation by an extrathyroidal action. Because airway submucosal glands are responsible for nonspecific and specific airway defense, we tested the effect of TSH on feline tracheal submucosal gland using a whole-cell patch-clamp technique, immunohistochemistry, and reverse transcription/polymerase chain reaction (RT-PCR). TSH potentiated neurotransmitter-induced ionic currents significantly in a dose-dependent manner. Acetylcholine (10(-)(8) M)- and norepinephrine (10(-)(7) M)-induced inward current (I(i)), which we previously showed to be a Cl(-) current, were increased to about 3-fold the pre-TSH control responses, respectively, by 2.0 ng/ml TSH; and to 6- and 23-fold the control values by 20.0 ng/ml TSH, respectively. TSH alone was without effect up to 20.0 ng/ml. Follicular stimulating hormone only slightly affected the I(i) (1. 5-fold the control). Analyses with immunohistochemistry and RT-PCR failed to identify TSH receptors on the glandular tissue. Maneuvers to raise the cellular adenosine 3',5'-cyclic monophosphate also failed to mimic the TSH-mediated potentiation. The TSH effect appeared to be mediated by a signaling pathway involving tyrosine kinase because its inhibitors (genistein and herbimycin A) abolished the augmentation completely, and interferon-gamma, a tyrosine kinase activator, imitated the TSH action on submucosal gland. Thus, TSH may be an important regulator of airway fluid secretion.

1-Methyl-3-isobutylxanthine↗

PubMed2000

Polyphenols from Eriobotrya japonica and their cytotoxicity against human oral tumor cell lines.

Three new flavonoid glycosides, together with 15 known flavonoids, have been isolated from the leaves of Eriobotrya japonica, and characterized as (2S)- and (2R)-naringenin 8-C-alpha-L-rhamnopyranosyl-(1-->2)-beta-D-glucopyranosides, and cinchonain Id 7-O-beta-D-glucopyranoside, respectively, based on spectral analyses including two dimensional (2D) NMR techniques. Higher proanthocyanidin fraction in the water-soluble portion of the extract was characterized as a procyanidin oligomer mixture mainly composed of undecameric procyanidin. These polyphenols have also been assessed for cytotoxic activity against two human oral tumor (human squamous cell carcinoma and human salivary gland tumor) cell lines. Selective cytotoxicity of the procyanidin oligomer between tumor and normal gingival fibroblast cells, and its possible mechanism, were also described.

Antibodies, Monoclonal↗

PubMed2000

Prostate cancer gene therapy: comparison of adenovirus-mediated expression of interleukin 12 with interleukin 12 plus B7-1 for in situ gene therapy and gene-modified, cell-based vaccines.

We have documented previously that adenovirus-mediated interleukin 12 (IL-12) gene therapy is effective for orthotopic tumor control and suppression of pre-established metastases in a preclinical prostate cancer model (Y. Nasu et al., Gene Ther., 6: 338-349, 1999). In this report, we directly compare the effectiveness of an adenovirus that expresses both IL-12 and the costimulatory molecule B7-1 (AdmIL12/B7) with one that expresses IL-12 alone (AdmIL-12) using the poorly immunogenic RM-9 orthotopic murine model of prostate cancer. We document AdmIL-12/B7-mediated secretion of IL-12 and increased surface expression of B7-1 in infected RM-9 tumor cells. A significant reduction in orthotopic tumor size and increased survival was demonstrated in mice treated with a single orthotopic injection of AdmIL-12/B7 compared with AdmIL-12 or controls. Six of 19 animals treated with AdmIL-12/B7 survived long term with apparent eradication of the primary tumor in contrast to one of 38 animals in the AdmIL-12-treated group. Orthotopic treatment of tumors with both vectors led to an infiltration of both CD4+ and CD8+ immunoreactive cells, with AdmIL-12/B7 treatment having a more prolonged infiltration of CD8+ cells. AdmIL-12/B7 was also more effective than AdmIL-12 or controls at suppression of pre-established metastases. We further developed a vaccine model based on s.c. injection of infected, irradiated RM-9 cells and found that both AdmIL-12 and AdmIL-12/B7 are effective at suppressing the development and growth of challenge orthotopic tumors using this protocol.

Adenoviridae↗

PubMed1999

Adenovirus-mediated interleukin-12 gene therapy for prostate cancer: suppression of orthotopic tumor growth and pre-established lung metastases in an orthotopic model.

Interleukin-12 (IL-12) can elicit potent antitumoral effects that involve the recruitment of specific immune effector cells. We investigated the efficacy of a single injection of a recombinant adenovirus expressing murine IL-12 (AdmIL-12) directly into orthotopic mouse prostate carcinomas generated from a poorly immunogenic cell line (RM-9) derived from the mouse prostate reconstitution system. Significant growth suppression (> 50% reduction of tumor weight) and increased mean survival time (23.4 to 28.9 days) were observed compared with controls. Suppression of pre-established lung metastases was also observed following the injection of AdmIL-12 into the orthotopic tumor. Cytolytic natural killer cell activity was markedly enhanced 1-2 days after virus injection. Immunohistochemical analysis showed significantly elevated intratumoral infiltration of CD4+ and CD8+ T cells 7 days after virus injection. However, splenocyte-derived cytotoxic T lymphocytes were not detected during the 14 days following treatment. Increased numbers of nitric oxide synthase-positive macrophages were seen in the AdmIL-12 treated group 7 days following injection. Systemic inhibition of natural killer cells with antiasialo-GM1 serum led to increased numbers of lung metastases in AdmIL-12-treated orthotopic tumors but did not affect local tumor growth. In this model system the antitumor effects of a single injection of adenovirus-mediated IL-12 appears to be based to a large extent on the activation of nitric oxide synthase in macrophages and possibly T cell activities, whereas the relatively early cytolytic activity of natural killer cells are largely but not exclusively responsible for the antimetastatic effects.

Adenoviridae↗