The potent antitumor effects of combined p16 gene and GM-CSF gene therapy through efficient induction of antitumor immunity

PURPOSE

Tumor suppressor gene therapy and cytokine gene therapy have limited antitumor effects when used alone. Thus, in the present study, we investigated the antitumor potentials of the combined transfer of the p16 tumor suppressor gene and the murine granulocyte-macrophage colony-stimulating factor (GM-CSF) gene.

METHODS

The adenovirus-harboring p16 gene (Adp16) and adenovirus-harboring GM-CSF (AdGMCSF) gene were utilized for the treatment of established tumors in vivo. The mice were inoculated s.c. with Renca renal carcinoma cells and 3 days later received an intratumoral injection of Adp16 in combination with AdGMCSF.

RESULTS

The results demonstrated that tumor-bearing mice treated with Adp16 and Ad-GMCSF showed more potent inhibition of tumor growth and a prolonged survival period than mice treated with Adp16. AdGMCSF, adenovirus-expressing beta-galactosidase or PBS (P<0.01). Treatments of the mice with Adp16 alone or AdGMCSF alone also showed obvious antitumor effects as compared with those mice treated with PBS (P<0.05). After combined p16 and AdGMCSF gene therapy, the expression of H2Kd and Fas molecules on freshly isolated tumor cells increased markedly, and more CD(4)+ T cells and CD(8)+ T cells infiltrated in the tumor sites. The cytotoxicity of natural killer cells and specific cytotoxic T lymphocytes increased more significantly after the combined therapy.

CONCLUSIONS

Our results demonstrated that combination p16 gene and GM-CSF gene therapy could inhibit the growth of established tumors in mice more significantly through efficient induction of antitumor immunity.

Characterization of Epstein-Barr virus-infected B cells in patients with posttransplantation lymphoproliferative disease: disappearance after rituximab therapy does not predict clinical response

Post-transplantation lymphoproliferative disease (PTLD) is associated with Epstein-Barr virus (EBV). Quantitative and qualitative differences in EBV in peripheral blood mononuclear cells (PBMCs) of PTLD patients and healthy controls were characterized. A quantitative competitive polymerase chain reaction (QC-PCR) technique confirmed previous reports that EBV load in PBMCs is increased in patients with PTLD in comparison with healthy seropositive controls (18 539 vs 335 per 10(6) PBMCs, P =.0002). The average frequency of EBV-infected cells was also increased (271 vs 9 per 10(6) PBMCs, P =.008). The distribution in numbers of viral genome copies per cell was assessed by means of QC-PCR at dilutions of PBMCs. There was no difference between PTLD patients and healthy controls. Similarly, no differences in the patterns of viral gene expression were detected between patients and controls. Finally, the impact of therapy on viral load was analyzed. Patients with a past history of PTLD who were disease-free (after chemotherapy or withdrawal of immunosuppression) at the time of testing showed viral loads that overlapped with those of healthy seropositive controls. Patients treated with rituximab showed an almost immediate and dramatic decline in viral loads. This decline occurred even in patients whose PTLD progressed during therapy. These results suggest that the increased EBV load in PBMCs of PTLD patients can be accounted for by an increase in the number of infected B cells in the blood. However, in terms of viral copy number per cell and pattern of viral gene expression, these B cells are similar to those found in healthy controls. Disappearance of viral load with rituximab therapy confirms the localization of viral genomes in PBMCs to B cells. However, the lack of relationship between the change in viral load and clinical response highlights the difference between EBV-infected PBMCs and neoplastic cells in PTLD.

Levels, metabolism, and pharmacological activity of anandamide in CB(1) cannabinoid receptor knockout mice: evidence for non-CB(1), non-CB(2) receptor-mediated actions of anandamide in mouse brain

Anandamide [arachidonylethanolamide (AEA)] appears to be an endogenous agonist of brain cannabinoid receptors (CB(1)), yet some of the neurobehavioral effects of this compound in mice are unaffected by a selective CB(1) antagonist. We studied the levels, pharmacological actions, and degradation of AEA in transgenic mice lacking the CB(1) gene. We quantified AEA and the other endocannabinoid, 2-arachidonoyl glycerol, in six brain regions and the spinal cord by isotope-dilution liquid chromatography-mass spectrometry. The distribution of endocannabinoids and their inactivating enzyme, fatty acid amide hydrolase, were found to overlap with CB(1) distribution only in part. In CB(1) knockout homozygotes (CB(1)-/-), the hippocampus and, to a lesser extent, the striatum exhibited lower AEA levels as compared with wild-type (CB(1)+/+) controls. These data suggest a ligand/receptor relationship between AEA and CB(1) in these two brain regions, where tonic activation of the receptor may tightly regulate the biosynthesis of its endogenous ligand. 2-Arachidonoyl glycerol levels and fatty acid amide hydrolase activity were unchanged in CB(1)-/- with respect to CB(1)+/+ mice in all regions. AEA and Delta(9)-tetrahydrocannabinol (THC) were tested in CB(1)-/- mice for their capability of inducing analgesia and catalepsy and decreasing spontaneous activity. The effects of AEA, unlike THC, were not decreased in CB(1)-/- mice. AEA, but not THC, stimulated GTPgammaS binding in brain membranes from CB(1)-/- mice, and this stimulation was insensitive to CB(1) and CB(2) antagonists. We suggest that non-CB(1), non-CB(2) G protein-coupled receptors might mediate in mice some of the neuro-behavioral actions of AEA.

Neurobehavioral activity in mice of N-vanillyl-arachidonyl-amide

We studied the cannabimimetic properties of N-vanillyl-arachidonoyl-amide (arvanil), a potential agonist of cannabinoid CB(1) and capsaicin VR(1) receptors, and an inhibitor of the facilitated transport of the endocannabinoid anandamide. Arvanil and anandamide exhibited similar affinities for the cannabinoid CB(1) receptor, but arvanil was less efficacious in inducing cannabinoid CB(1) receptor-mediated GTPgammaS binding. The K(i) of arvanil for the vanilloid VR(1) receptor was 0.28 microM. Administered i.v. to mice, arvanil was 100 times more potent than anandamide in producing hypothermia, analgesia, catalepsy and inhibiting spontaneous activity. These effects were not attenuated by the cannabinoid CB(1) receptor antagonist N-(piperidin-1-yl)-5-(4-chloro-phenyl)-1-(2, 4-dichlorophenyl)-4-methyl-1H-pyrazole-3-carboxamide.HCl (SR141716A). Arvanil (i.t. administration) induced analgesia in the tail-flick test that was not blocked by either SR141716A or the vanilloid VR(1) antagonist capsazepine. Conversely, capsaicin was less potent as an analgesic (ED(50) 180 ng/mouse, i.t.) and its effects attenuated by capsazepine. The analgesic effect of anandamide (i.t.) was also unaffected by SR141716A but was 750-fold less potent (ED(50) 20.5 microg/mouse) than capsaicin. These data indicate that the neurobehavioral effects exerted by arvanil are not due to activation of cannabinoid CB(1) or vanilloid VR(1) receptors.

Interleukin-18 gene transfer increases antitumor effects of suicide gene therapy through efficient induction of antitumor immunity

To increase the antitumor effects of cytosine deaminase (AdCD) gene therapy and induce more potent antitumor immunity, Th1 cytokine interleukin-18 encoded adenovirus (AdIL18) was combined with adenovirus encoding CD (AdCD) for the therapy of established murine B16 melanoma. Combination therapy of the tumor-bearing mice with AdIL 18 and AdCD/5FC inhibited the growth of the subcutaneous B16 tumors more significantly, compared with AdIL 18 or AdCD/5FC alone. In vivo depletion analysis with anti-CD4, anti-CD8 or anti-NK 1.1 McAb illustrated that both CD8+ T cells and CD4+ T cells played key roles in the augmented antitumor response of the combined therapy. Peptide/MHC tetramer represents a powerful and general tool for rapid, highly sensitive, and direct analysis of antigen-specific T cells. In this study, we prepared H-2Kb/TRP-2180-188 tetramer, which was demonstrated to bind H-2Kb-restricted, B16 melanoma-specific CD8+ T cells. B16 specific H-2Kb/TRP2180-188 tetramer was used to stain the tumor-specific CD8+ T cells and the results showed that CD8+ tetramer+ T cells were about 3-5% of the splenic CD8+ T cells derived from tumor-bearing mice after combined therapy. The CTL cytotoxicity was markedly induced in mice after combined therapy, suggesting efficient induction of tumor-specific CD8+ T cells after combined gene therapy with AdCD/5FC/AdIL18. IL-18 gene transfer could significantly augment the cytotoxicity of NK cells and macrophages, and increase the production of interleukin-2 and interferon-gamma, as compared with treatments with AdCD/5FC, AdlacZ/5FC or PBS. These data suggested that in vivo IL-18 gene transfer could augment the antitumor effects of CD suicide gene therapy through efficient induction of antitumor immunity.

[Studies on the toxicity of polymer of glycolide and lactide(PLGA) and the anti-fertility effect of levonorgestrel(LNG)]

PLGA(9:1), a chemical degraded from biomaterials, has been subjected to the tests of acute toxicity, irritations on conjunctiva and muscle, haemolysis in vitro and allergic reaction of mice and rats. The anti-fertility effect of PLGA-LNG microphere composite on the same animals also has been tested. The studies demonstrated that PLGA had fine biological compatibility without side effects such as toxicity, irritations on conjunctiva and muscle, pyrogenicity, haemolysis in vitro and allergic reaction. The contraception period of mice lasted 11.5, 34.6 and 81.2 days respectively after the subcutaneous (s.c.) injection of PLGA-LNG microphere which contains LNG 5, 10 and 20 mg/kg separately. The intramuscular(i.m.) injection of PLGA-LNG microphere containing LNG 13.6, 19.8 and 30 mg/kg respectively could keep the estrus of rats supressed for 76.3, 104.1 and 131.8 days. The injections of PLGA-LNG microphere through s.c. or i.m. showed more significant effects than the same dosages of PLGA-LNG micro-crystal. These results suggest that PLGA-LNG microphere injection has long-term anti-fertility effect.

Induction of potent antitumor response by vaccination with tumor lysate-pulsed macrophages engineered to secrete macrophage colony-stimulating factor and interferon-gamma

Adoptive transfer of activated macrophages, being both effector cells and antigen-presenting cells, represents a promising approach to immunotherapy of cancer. In order to get activated macrophages with increased antitumor potential, in the present study, murine peritoneal macrophages were transduced with human macrophage colony-stimulating factor (M-CSF) and murine interferon-gamma (IFNgamma) by recombinant adenovirus infection. The results demonstrate that M-CSF and IFNgamma gene-modified macrophages exhibited higher expression of MHC-II, B7.1 and ICAM-1, increased antigen-presenting activity and cytotoxicity. It was also shown that they secreted more tumor necrosis factor, interleukin-1 and nitric oxide. In vivo experiments showed that in previously initiated murine pulmonary metastatic melanoma, tumor lysate-pulsed, M-CSF and IFNgamma gene-modified macrophages elicited more potent antitumor effects than tumor lysate pulsed M-CSF or IFNgamma gene-modified macrophages. Cytotoxic T lymphocyte (CTL) activity, IFNgamma and tumor-necrosis factor production of the splenocytes increased significantly in mice after intravenous injection of the gene-modified macrophages. M-CSF and IFNgamma gene-modified macrophages may act as activated effector and antigen-presenting cells, thus eliciting a more potent antitumor response.

Coinfection of multiple strains of Epstein-Barr virus in immunocompetent normal individuals: reassessment of the viral carrier state

This study reassesses the occurrence of Epstein-Barr virus (EBV) diversity and coinfection versus dominance of a single viral strain within immunocompetent normal carriers. Polymerase chain reaction analysis of several different polymorphic loci of the EBV genome was performed on collections of peripheral blood mononuclear cells and multiple lymphoid and epithelial tissues of the same individuals. Autopsy specimens from 15 individuals who died of causes unrelated to EBV infection served as normal viral carriers. Unexpectedly, coinfection of multiple distinct strains of EBV of the same type (usually type 1) and less frequently of both types 1 and 2 was found to be very high within individual viral carriers. These data indicate that coinfection with multiple EBV strains is much more prevalent in normal carriers than previously appreciated, which in turn has direct implications on EBV persistence, host-viral interaction and pathogenesis.

Abnormal expression of hepatoma specific gamma-glutamyl transferase and alteration of gamma-glutamyl transferase gene methylation status in patients with hepatocellular carcinoma

BACKGROUND

Hepatoma specific gamma-glutamyl transferase (HS-GGT) bands were expressed in the development of hepatocellular carcinoma (HCC) and were associated with a high incidence of HCC diagnosis. The objectives of this study were to determine the levels of HS-GGT quantitatively in the sera of patients with different liver diseases. The methylational status of GGT gene CCGG sites was analyzed in hepatoma tissues.

METHODS

The HS-GGT concentrations were quantitatively analyzed in the sera of 156 HCC patients and others with liver diseases or extrahepatic tumors. In 20 hepatoma tissues, the GGT enzyme proteins were purified, the activities of GGTs of different molecular form were examined, total RNAs were extracted and amplified by using a nested polymerase chain reaction (PCR) assay, and the methylational status of CCGG site (M3) in the 5'-noncoding region of GGT genes was investigated with the restriction enzyme Hpa II.

RESULTS

Total GGT activities in patients with liver diseases and extrahepatic tumors were abnormally increased. The levels of serum HS-GGT were significantly elevated (P < 0.001) in the HCC group; the incidence of HS-GGT over 5.5 IU/L was 86% in HCC patients and less than 3% in patients with other diseases. From liver cancer to distal noncancerous tissues, an increasing tendency (P < 0.05) of total RNA concentrations was found; the frequencies of amplified fragment and hypomethylated M3 site of GGT genes were 100% and 75% in HCC, 85% and 55% in paracancerous tissues, and 75% and 50% in noncancerous tissues, respectively. An inverse correlation was found between methylational degrees of GGT genes and expression levels of GGT.

CONCLUSIONS

The abnormal alteration of serum HS-GGT level is a sensitive tumor marker for HCC diagnosis or differentiation, and the overexpression of GGT in HCC may be related to the hypomethylational status of CCGG sites of GGT genes.

Abnormal expression of hepatoma specific gamma-glutamyl transferase and alteration of gamma-glutamyl transferase gene methylation status in patients with hepatocellular carcinoma

BACKGROUND

Hepatoma specific gamma-glutamyl transferase (HS-GGT) bands were expressed in the development of hepatocellular carcinoma (HCC) and were associated with a high incidence of HCC diagnosis. The objectives of this study were to determine the levels of HS-GGT quantitatively in the sera of patients with different liver diseases. The methylational status of GGT gene CCGG sites was analyzed in hepatoma tissues.

METHODS

The HS-GGT concentrations were quantitatively analyzed in the sera of 156 HCC patients and others with liver diseases or extrahepatic tumors. In 20 hepatoma tissues, the GGT enzyme proteins were purified, the activities of GGTs of different molecular form were examined, total RNAs were extracted and amplified by using a nested polymerase chain reaction (PCR) assay, and the methylational status of CCGG site (M3) in the 5'-noncoding region of GGT genes was investigated with the restriction enzyme Hpa II.

RESULTS

Total GGT activities in patients with liver diseases and extrahepatic tumors were abnormally increased. The levels of serum HS-GGT were significantly elevated (P < 0.001) in the HCC group; the incidence of HS-GGT over 5.5 IU/L was 86% in HCC patients and less than 3% in patients with other diseases. From liver cancer to distal noncancerous tissues, an increasing tendency (P < 0.05) of total RNA concentrations was found; the frequencies of amplified fragment and hypomethylated M3 site of GGT genes were 100% and 75% in HCC, 85% and 55% in paracancerous tissues, and 75% and 50% in noncancerous tissues, respectively. An inverse correlation was found between methylational degrees of GGT genes and expression levels of GGT.

CONCLUSIONS

The abnormal alteration of serum HS-GGT level is a sensitive tumor marker for HCC diagnosis or differentiation, and the overexpression of GGT in HCC may be related to the hypomethylational status of CCGG sites of GGT genes.

Abnormal expression of hepatoma specific gamma-glutamyl transferase and alteration of gamma-glutamyl transferase gene methylation status in patients with hepatocellular carcinoma

BACKGROUND

Hepatoma specific gamma-glutamyl transferase (HS-GGT) bands were expressed in the development of hepatocellular carcinoma (HCC) and were associated with a high incidence of HCC diagnosis. The objectives of this study were to determine the levels of HS-GGT quantitatively in the sera of patients with different liver diseases. The methylational status of GGT gene CCGG sites was analyzed in hepatoma tissues.

METHODS

The HS-GGT concentrations were quantitatively analyzed in the sera of 156 HCC patients and others with liver diseases or extrahepatic tumors. In 20 hepatoma tissues, the GGT enzyme proteins were purified, the activities of GGTs of different molecular form were examined, total RNAs were extracted and amplified by using a nested polymerase chain reaction (PCR) assay, and the methylational status of CCGG site (M3) in the 5'-noncoding region of GGT genes was investigated with the restriction enzyme Hpa II.

RESULTS

Total GGT activities in patients with liver diseases and extrahepatic tumors were abnormally increased. The levels of serum HS-GGT were significantly elevated (P < 0.001) in the HCC group; the incidence of HS-GGT over 5.5 IU/L was 86% in HCC patients and less than 3% in patients with other diseases. From liver cancer to distal noncancerous tissues, an increasing tendency (P < 0.05) of total RNA concentrations was found; the frequencies of amplified fragment and hypomethylated M3 site of GGT genes were 100% and 75% in HCC, 85% and 55% in paracancerous tissues, and 75% and 50% in noncancerous tissues, respectively. An inverse correlation was found between methylational degrees of GGT genes and expression levels of GGT.

CONCLUSIONS

The abnormal alteration of serum HS-GGT level is a sensitive tumor marker for HCC diagnosis or differentiation, and the overexpression of GGT in HCC may be related to the hypomethylational status of CCGG sites of GGT genes.

Macrophage activation of lymphoma-bearing mice by liposome-mediated intraperitoneal IL-2 and IL-6 gene therapy

OBJECTIVE

To investigate the antitumor mechanism of interleukin-2 (IL-2) and interleukin-6 (IL-6) gene therapy.

METHODS

Liposome encapsulated IL-2 DNA and IL-6 DNA were intraperitoneally (i.p.) injected into mouse lymphoma cell line (EL-4) lymphoma-bearing mice. Macrophage function (M phi) from the mice was assessed.

RESULTS

Cytotoxicity, major histocompatibility (MHC) II expression and IL-1 and TNF secretion of the macrophages all augmented after i.p. injection of liposome encapsulated IL-2 DNA or IL-6 DNA. More efficient activation of macrophages was observed in mice treated with liposome encapsulated IL-2 DNA than IL-6 DNA. IL-2 gene therapy combined with IL-6 gene therapy showed the maximal activation of macrophages in the lymphoma-bearing mice.

CONCLUSION

IL-2 and IL-6 gene therapy can relieve the suppression of macrophages of the lymphoma-bearing mice, and efficiently activate the antitumor immune responses.

Cloning and pharmacological characterization of the rat CB(2) cannabinoid receptor

Many of the pharmacological effects of Delta(9)-tetrahydrocannabinol are mediated through CB(1) and CB(2) cannabinoid receptors. However, with the discovery of endogenous cannabinoids, some discrepancies have arisen. Furthermore, unlike the CB(1) receptor, the sequences of the mouse and human CB(2) receptor are divergent, raising the possibility of species specificity. The gene for the rat CB(2) receptor was cloned, expressed, and its properties compared with those of mouse and human CB(2) receptors. Sequence analysis of the coding region of the rat CB(2) genomic clone indicates 90% nucleic acid identity (93% amino acid identity) between rat and mouse and 81% nucleic acid identity (81% amino acid identity) between rat and human. The rat CB(2) receptor was stably expressed in human embryonic kidney-293 cells to examine its pharmacology. The rat CB(2) showed low affinity for anandamide, an endogenous ligand shown to act at the CB(1) receptor. In contrast, high-affinity binding for SR144528 (CB(2)-selective antagonist) as well as several cannabinoid receptor agonists was observed. Coupling to adenylate cyclase was observed. Aspects of the pharmacology of palmitoylethanolamide were also examined. It bound to CB(1) and CB(2) receptors with low affinity and stimulated GTPgammaS binding in the cerebellum and CB(2)-expressing cell lines with low potency. The data in this study suggest that the discrepancies in affinities between rat and human may represent species differences. The rat CB(2) receptor genomic clone will be a useful tool for studying the function and regulation of CB(2) in rats.

Abnormal expression of hepatoma specific gamma-glutamyl transferase and alteration of gamma-glutamyl transferase gene methylation status in patients with hepatocellular carcinoma

BACKGROUND

Hepatoma specific gamma-glutamyl transferase (HS-GGT) bands were expressed in the development of hepatocellular carcinoma (HCC) and were associated with a high incidence of HCC diagnosis. The objectives of this study were to determine the levels of HS-GGT quantitatively in the sera of patients with different liver diseases. The methylational status of GGT gene CCGG sites was analyzed in hepatoma tissues.

METHODS

The HS-GGT concentrations were quantitatively analyzed in the sera of 156 HCC patients and others with liver diseases or extrahepatic tumors. In 20 hepatoma tissues, the GGT enzyme proteins were purified, the activities of GGTs of different molecular form were examined, total RNAs were extracted and amplified by using a nested polymerase chain reaction (PCR) assay, and the methylational status of CCGG site (M3) in the 5'-noncoding region of GGT genes was investigated with the restriction enzyme Hpa II.

RESULTS

Total GGT activities in patients with liver diseases and extrahepatic tumors were abnormally increased. The levels of serum HS-GGT were significantly elevated (P < 0.001) in the HCC group; the incidence of HS-GGT over 5.5 IU/L was 86% in HCC patients and less than 3% in patients with other diseases. From liver cancer to distal noncancerous tissues, an increasing tendency (P < 0.05) of total RNA concentrations was found; the frequencies of amplified fragment and hypomethylated M3 site of GGT genes were 100% and 75% in HCC, 85% and 55% in paracancerous tissues, and 75% and 50% in noncancerous tissues, respectively. An inverse correlation was found between methylational degrees of GGT genes and expression levels of GGT.

CONCLUSIONS

The abnormal alteration of serum HS-GGT level is a sensitive tumor marker for HCC diagnosis or differentiation, and the overexpression of GGT in HCC may be related to the hypomethylational status of CCGG sites of GGT genes.

Establishment of labeling primer reverse transcription in situ polymerase chain reaction and detection of hepatitis C virus in liver tissues

OBJECTIVE

To establish bio-11-photosoralen (BP) labeling primer reverse transcription in situ polymerase chain reaction (PCR), and to detect the location and distribution of hepatitis C virus in 30 cases liver tissues embedded with paraffin.

METHODS

BPs were labeled in tymidine (T) position under ultraviolet lamp. The method was compared with indirect RT-in situ PCR and in situ hybridization for detecting hepatitis C virus (HCV) RNA.

RESULTS

Serum HCV PCR and southern blot showed that BP labeling psimer PCR was possible, and had a good specificity. The HCV positive rate was 53% (16/30) by indirect in situ PCR, 50% (15/30) positive specimens were found by BP labeling primer in situ PCR. Statistical analysis revealed P > or = 0.05 and the two methods had no dominant differences. Meanwhile, only 23% (7/30) positive signals were seen by in situ hybridization, which was lower than two in situ PCR(P < or = 0.05). HCV was mainly located in hepatic-plasmas, and positive signals were found in monocytes and cholangiolar epithelia.

CONCLUSIONS

Both indirect in situ PCR and BP labeling in situ PCR have good sensitivity and specificity for detecting HCV RNA of liver tissues. HCV RNA is located in hepatocytes, monocytes and cholangiolar epithelia.

Adenovirus-mediated lymphotactin gene transfer improves therapeutic efficacy of cytosine deaminase suicide gene therapy in established murine colon carcinoma

Lymphotactin (Ltn) is the sole member of C chemokines which attracts T cells and NK cells specially. Ltn gene was transferred in vivo to improve the antitumor efficacy of cytosine deaminase (CD) gene therapy. Upregulation of CD80 and CD54 on murine CT26 colon carcinoma cells was observed after combined transfection with adenovirus encoding CD (AdCD) and adenovirus encoding murine Ltn (AdLtn) followed by administration of 5-fluorocytosine (5FC) in vitro. AdCD/5FC treatment also increased the expression of CD95 and induced obvious apoptosis of CT26 cells. After combined treatment with AdLtn and AdCD/5FC, the pre-established murine model with subcutaneous CT26 colon carcinoma exhibited most significant tumor growth inhibition, and four of eight tumor-bearing mice were tumor free, while tumors in other mice grew more progressively. Examination of lymphocyte infiltration and cytokine gene expression in tumor tissue revealed that tumors from AdLtn/AdCD/5FC-or AdLtn-treated mice were heavily infiltrated with CD4+, CD8+ T cells and NK cells, and IL-2 and IFN-gamma mRNA expression were present in parallel with T cell and NK cell infiltration. Splenic NK and CTL activities increased significantly after the combination therapy. In vivo depletion analysis showed that NK cells, CD4+ T cells and CD8+T cells participated in the antitumor effect of the host with CD8+T cells being the main T cell subset responsible for the enhanced antitumor immune response. These findings suggested that increased immunogenicity and induction of apoptosis of the tumor cells, and efficient induction of local and systemic antitumor immunity of the host might contribute to the enhanced antitumor effects of the combined Ltn and CD suicide therapy. Gene Therapy (2000) 7, 329-338.

A binary vector-based large insert library for Brassica napus and identification of clones linked to a fertility restorer locus for Ogura cytoplasmic male sterility (CMS)

We constructed and characterized a large DNA insert library for Brassica napus that would facilitate genome-related research and map-based cloning efforts in Brassica species. This library, consisting of 92,160 clones arrayed in 384-well microtiter dishes, was based on a conventional plant transformation vector (binary vector), and was constructed using a single ligation with transformation efficiency of over 5000 recombinants per microliter of ligation mixture. Every clone in this library contains an insert in the size range of 30-190 kb, facilitating both chromosome walking and plant transformation. Screening this library with three DNA markers (C2, F10, and CabR) that are linked to a fertility restorer locus for Ogura cytoplasmic male sterility (CMS) identified at least 17 positive clones for each probe. Among the 17 positive clones identified by C2, nine are linked to the restorer locus. Marker F10 identified 21 clones, of which only two are linked to the restorer locus. None of 68 clones identified by CabR is linked to the restorer locus. A stability test using two clones identified by the C2 marker indicated that large DNA inserts are stable in this conventional vector in both Escherichia coli and Agrobacterium.

[Expression of glycoprotein hepatitis C virus in mammalian cell and application of purified protein for detection of antibody against E2 in hepatitis C patients]

OBJECTIVE

E2 glycoprotein of hepatitis C virus was expressed in mammalian cell and purified for detection of antibody against E2 in hepatitis C patients.

METHODS

E2/NS1 gene derived from HCV was inserted into expression vector containing six His tag. The recombinant plasmid was transfected into mammalian cells to express E2 glycoprotein expression. E2 glycoprotein was purified by affinity chromophotography. The purified protein was used to establish EIA method for detection of antibodies against E2 in hepatitis C patients.

RESULT

Expressed E2 glycoprotein was 7.0 x 10(4). Purification of the purified E2 protein was 90.2%. Twenty-nine patients were anti-E2 antibody positive(82.9%).

CONCLUSION

It was the first time to establish EIA method for detection of anti-E2 antibody by purified E2 glycoprotein in China. E2 glycoprotein expressed in mammalian cells had good immunogenity and could increase the sensibility of anti-HCV detection. It suggests that E2 glycoprotein may be useful for development of new anti-HCV reagents.

DNA methylation and the Epstein-Barr virus

EBV is a ubiquitous herpesvirus associated with a variety of lymphoid and epithelial tumors. In healthy lymphocytes and in tumors immune surveillance is evaded by suppression of a family of immunodominant viral antigens. Methylation of a viral promoter plays a crucial role in this suppression. Methylation of the viral genome in the latent state over evolutionary time is believed to account for CpG suppression that distinguishes this virus from most other large DNA viruses. Pharmacologic manipulation of methylation may offer an opportunity to unmask viral antigens and expose tumors to immune surveillance.

Prevention and therapy of hepatitis B

PURPOSE

To review the achievements of the prevention and therapy of hepatitis B (HB) in China during the thirty years after the discovery of hepatitis B virus (HBV) in 1967.

DATA SOURCE

Data come from an English language literature search using MEDLINE 1966-1999, especially 1982-1999, and Chinese language literature, published and unpublished, from the Chinese Health Administration.

STUDY SELECTION

After reviewing of the literature we select 14 articles to address our statement.

DATA EXTRACTION

Two observers independently evaluated the quality of the data materials obtaining from these articles.

RESULTS

Investigation of HBV vaccine development in China was almost simultaneously with the same kind of work in the international. At least 200 million people have accepted the vaccination of HBV vaccine. The vaccination of the HBV vaccine in China has decreased the prevalence of HBV infection no matter in urban cities or in rural area. The protection against HBV infection can be maintained at least for 9-11 years.

CONCLUSIONS

Vaccination of HBV vaccine in China is successful and has obtained great achievements in the prevention and therapy of HB.

Methylation status of the Epstein-Barr virus major latent promoter C in iatrogenic B cell lymphoproliferative disease. Application of PCR-based analysis

The Epstein-Barr virus (EBV) major latent promoter C drives the expression of viral nuclear proteins important in lymphocyte immortalization and as targets for immune surveillance by cytotoxic T cells. Hypermethylation of the C promoter silences its transcription. This promoter is methylated and silent in Burkitt's lymphoma, Hodgkin's disease, nasopharyngeal carcinoma, and nasal lymphoma. However, it is never methylated in the EBV-immortalized lymphoblastoid cell lines that serve as a model for EBV-associated lymphoproliferative disease. We have analyzed C promoter methylation in iatrogenic EBV-associated B-cell lymphoproliferative disease, mainly posttransplant lymphoma, using a sensitive polymerase chain reaction-based C promoter methylation assay. Our results showed heterogeneity in lymphoproliferative disease with methylation of viral DNA in specimens from 3 of 13 patients. In specimens from two of these patients, only methylated viral DNA was detected and viral nuclear antigen expression was correspondingly restricted. Heterogeneity in C promoter methylation and expression of associated transcripts may be an important determinant of the growth properties of lymphoproliferative lesions and may provide an explanation for the failure of some tumors to respond to withdrawal or reduction of immunosuppressive therapy.

Evaluation of the cannabinoid CB2 receptor-selective antagonist, SR144528: further evidence for cannabinoid CB2 receptor absence in the rat central nervous system

The aim of this study was to characterize the activity of the cannabinoid CB2 receptor selective antagonist, N-[(1S)-endo-1,3,3-trimethyl bicyclo[2.2.1] heptan-2-yl]-5-(4-chloro-3-methylphenyl)-1-(4-methylbenzyl)-pyrazo le-3-carboxamide] (SR144528) in a number of biochemical assays and to look for evidence of cannabinoid CB2 receptors in the rat central nervous system. SR144528 displaced [3H]CP 55,940 ((-)-3-[2-hydroxyl-4-(1,1-dimethylheptyl)-phenyl]-4-[3-hydroxyprop yl]cyclohexan-1-ol) from binding sites in CB2- and CB1-transfected cells (Ki = 0.67+/-0.30 and 33.0+/-5.09 nM) and from rat cerebellum and whole brain membrane homogenates (Ki = 54.7+/-9.70 and 54.8+/-7.86 nM). In the GTPgammaS binding assay, SR144528 antagonized a number of cannabinoid receptor agonists (K(B) values ranging from 26.3 to 76.6 nM) in rat cerebellar membranes and in rat whole brain membranes (K(B) = 50.8 nM). SR144528 also antagonized CP 55,940-stimulated GTPgammaS binding in a CB2-expressing cell line (K(B) = 6.34 nM). In Xenopus oocytes co-expressing the CB1 receptor and G-protein coupled inwardly rectifying K+ channels (GIRK 1/4), SR144528 antagonized WIN 55212-2((R)-(+)-[2,3-dihydro-5-methyl-3-[(4-morpholinyl)methyl]pyrolo [1,2,3-de]-1,4-benzoxazin-6-yl](1-naphthalenyl)methanone) -stimulated K+ currents (K(B) = 558 nM). In summary, this report characterizes the cannabinoid CB2 receptor-selective cannabinoid antagonist, SR144528, and additionally suggests an absence of cannabinoid CB2 receptors in the rat central nervous system, an observation confirmed by Northern blot.

Efficient inducation of local and systemic antitumor immune response by liposome-mediated intratumoral co-transfer of interleukin-2 gene and interleukin-6 gene

Interleukin 2 (IL-2) expressing plasmid and interleukin 6 (IL-6)-expressing plasmid were encapsulated in liposome and administrated intratumoraly into tumor-bearing mice 4 days after subcutaneous inoculation of B16F10 melanoma cells. The results showed that treatment of tumor-bearing mice with IL-2 gene or IL-6 gene transfer inhibited the growth of subcutaneous tumor and prolonged the survival of tumor-bearing mice significantly when compared with the treatment of PBS or control gene transfer mediated by liposome (P < 0.01). Combined transfer of IL-2 gene and IL-6 gene was found to elicit inhibitory effects on the growth of B16F10 tumor more significantly and prolonged the survival period of tumor-bearing mice more obviously. We investigated the local immunity in tumor microenvironment and found that IL-2 and IL-6 gene transfer could significantly increase the expression of lymphocyte function-associated antigen-1 on tumor infiltrating lymphocytes (TIL) and MHC-I molecule on tumor cells freshly isolated from the tumor mass. The NK and CTL activity of TIL increased markedly after the combined transfer of these two cytokine genes. We also observed the systemic antitumor immune response in the tumor-bearing mice and demonstrated that NK and CTL activity of splenocytes and the production of IL-2, tumor necrosis factor and interferon-gamma from splenocytes increased obviously in mice after the combined transfer of IL-2 and IL-6 gene. In conclusion, local and systemic antitumor immunity of the tumor-bearing host could be induced efficiently after the combined gene transfer. The enhanced specific and non-specific antitumor immunity might be responsible for the more potent antitumor effects of the combined gene therapy.

Enhanced antitumor immune responses of IL-2 gene-modified tumor vaccine by combination with IL-1 and low dose cyclophosphamide

To enhance the antitumor immunity induced by IL-2 gene-modified tumor vaccine, we proposed a combined protocol to treat tumor-bearing mice using IL-2 gene-modified tumor vaccine in combination with IL-1 and low-dose Cyclophosphamide(Cy). After treatment with IL-2 gene-modified B16 melanoma cell vaccine alone, the pulmonary metastases of tumor-bearing mice were reduced and their survival time was prolonged. The anti-metastases effect was improved when the vaccine was used in combination with IL-1 or low-dose Cy. The best therapeutic effect was achieved when the IL-2 gene-modified vaccine was combined with IL-1 and low-dose Cy. The cytotoxicity of the splenic CTL, NK, and the levels of IL-2, TNF secreted by splenocytes increased after tumor-bearing mice were treated with the IL-2 gene-modified tumor vaccine. The above antitumor immune functions were augmented more significantly when IL-1, low-dose Cy were used in combination with IL-2 genemodified tumor vaccine. These results demonstrated that the IL-2 gene modified vaccine could exert more potent anti-metastases effects when it is combined with IL-1 or/and low-dose Cy by activating the specific and non-specific antitumor immune responses more effectively.