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J R Wands

Publications and source records attributed to J R Wands.

At least 73 records · Page 4Linked to original sources
PubMed1998

Ethanol inhibits hepatocyte proliferation in insulin receptor substrate 1 transgenic mice.

BACKGROUND & AIMS: Long-term ethanol consumption is known to impair the ability of the liver to regenerate, but the molecular mechanisms are poorly understood. Multiple growth factors promote hepatocyte proliferation, some of which involve the insulin receptor substrate 1 (IRS-1)-mediated signal transduction pathway. To explore effects of ethanol on the IRS-1 signal liver growth in vivo, studies in transgenic mice overexpressing IRS-1 in the liver were performed because these mice show constitutive activation of the downstream signal transduction pathways leading to enhanced hepatocyte proliferation. METHODS: Tyrosyl phosphorylation of IRS-1 and subsequent protein-protein interactions were examined in liver lysates from animals fed ethanol or control diet. Activity of phosphatidylinositol-3 kinase (PI3K) and mitogen-activated protein kinase (MAPK) was assessed by specific enzymatic assays. Hepatocyte proliferation was measured by incorporation of [3H]thymidine into liver DNA. RESULTS: Tyrosyl phosphorylation of IRS-1, association of IRS-1 with PI3K, and activation of downstream PI3K and MAPK pathways were greatly reduced as a result of long-term ethanol consumption. Ethanol virtually abolished the enhanced hepatocyte DNA synthesis induced by expression of the IRS-1 transgene. CONCLUSIONS: Altered transmission of growth signals through the IRS-1-mediated signal transduction cascade may represent a molecular mechanism of how ethanol inhibits hepatocyte proliferation.

Animals↗
PubMed1998

Antisense RNA complementary to hepatitis B virus specifically inhibits viral replication.

BACKGROUND & AIMS: Chronic infection with the hepatitis B virus (HBV) is a major public health problem, and currently available therapies have limited efficacy. Gene therapy strategies for HBV infection are under active investigation. We evaluated the potential of antisense RNA transcribed from antisense genes to interfere with HBV replication. METHODS: Subgenomic fragments of the HBV genome were studied with respect to the property of inhibiting HBV replication when intracellularly expressed in the antisense orientation. RESULTS: Antisense RNAs derived from the HBV genome specifically inhibited HBV replication and antigen expression in human hepatocellular carcinoma cells by 60%-75%. DNA sequences corresponding to the identified RNAs had no effect on HBV replication, indicating that inhibitory effects are mediated by RNA. Transcripts corresponding to the inhibitory subgenomic fragments were present at high levels. One antisense RNA was found to reduce the amount of pregenomic RNA encapsidated into core particles as a molecular mechanism of antiviral effects. CONCLUSIONS: Certain antisense RNA molecules will have substantial antiviral effects against HBV. Antisense RNAs derived from the HBV genome are promising candidates as antiviral agents and may serve as novel tools to identify functionally important regions of HBV transcripts.

Base Sequence↗
PubMed1998

Total chemical synthesis of the 3' untranslated region of the hepatitis C virus with long oligodeoxynucleotides.

Hepatitis C Virus (HCV) is the major causative agent of chronic hepatitis. Since it has been difficult to obtain full-length cDNA clones of HCV including the 3' untranslated region (UTR) that give rise to replication competent virus, we generated the 3'UTR by a modified protocol of total chemical synthesis (TCS) with overlap-extension-PCR using four long oligodeoxynucleotides. A synthetic cDNA fragment of about 340 nucleotides (nt) in length was generated, subcloned and sequenced. This approach represents a rapid and easy alternative to RT-PCR from infectious serum and may be a highly valuable method to generate partial cDNA clones of HCV and other viruses including defined variants.

3' Untranslated Regions↗
PubMed1998

Differential cellular and humoral immune responses to HCV core and HBV envelope proteins after genetic immunizations using chimeric constructs.

Development of a broad based cellular and humoral immune response to hepatitis C virus (HCV) structural proteins may be important for eradication of viral infection. In previous studies in mice we demonstrated that facilitated DNA-based immunization with an HCV core DNA-expression construct stimulated the generation of weak cytotoxic T lymphocyte (CTL), helper T cell (Th), and humoral immune responses against HCV core related epitopes. To enhance the immunogenicity of this non-secreted viral structural protein at both the B- and T-cell level, several chimeric HBV-HCV constructs were prepared which were designed to express and secrete HCV core protein along with various regions of the hepatitis B envelope protein. No secretion of the chimeric proteins into the culture supernatant was detected using sensitive radioimmunoassays. However, such chimeric proteins were capable of generating CD4+ inflammatory T cell and CD8+ CTL activity against both HBV and HCV components of the fusion proteins. It was determined that the proliferative activity of T cells as well as the humoral immune responses to HCV core protein were substantially enhanced by some chimeric fusion proteins as compared to the HCV core protein alone. The strength of the immune responses appeared directly related to the level of Th1 cytokines produced by CD4+ T cells obtained from immunized animals. Further characterization of the immune responses stimulated by these DNA constructs studied helped to define some of the most immunogenic regions of the chimeric proteins that they encode.

Animals↗
PubMed1998

Cloning and characterization of a novel hepatitis B virus x binding protein that inhibits viral replication.

The hepatitis B virus and the mammalian hepadnavirus genomes encode for a short open reading frame called x. Expression of the protein product (HBx) appears necessary for establishment of natural infection. However, in vitro studies have suggested a multifunctional role for HBx as an indirect transcriptional transactivator of a variety of different viral and cellular promoters. Indeed, HBx has no known direct DNA binding properties but may interact with transcription factors as well as activate intracellular signaling pathways associated with cell growth. To further address the possible functional role of HBx in the life cycle of hepatitis B virus, we performed an analysis using the yeast two-hybrid system to screen a cDNA library derived from a hepatocellular carcinoma cell line with a HBx fusion bait in an attempt to identify cellular partners that may bind to and alter the biologic properties of HBx. A HBx-interacting protein that specifically complexes with the carboxy terminus of wild-type HBx was identified and designated XIP. This 9.6-kDa protein is capable of binding to HBx in vitro, and transient and stable expression in hepatocellular carcinoma cells abolishes the transactivation properties of HBx on luciferase constructs driven by AP-1 and endogenous hepatitis B virus enhancer/promoter elements. Investigation of the role of XIP in hepatitis B virus replication in differentiated hepatocellular carcinoma cells revealed that XIP expression reduces wild-type hepatitis B virus replication to levels observed following transfection with an HBx-minus virus. In contrast, the replication levels of the duck hepatitis B virus, a hepadnavirus that lacks the x open reading frame, were unchanged in the context of XIP expression. We propose that one of the physiologic functions of the cellular protein XIP is to negatively regulate HBx activity and thus to alter the replication life cycle of the virus.

Adaptor Proteins, Signal Transducing↗
PubMed1998

The native form and maturation process of hepatitis C virus core protein.

The maturation and subcellular localization of hepatitis C virus (HCV) core protein were investigated with both a vaccinia virus expression system and CHO cell lines stably transformed with HCV cDNA. Two HCV core proteins, with molecular sizes of 21 kDa (p21) and 23 kDa (p23), were identified. The C-terminal end of p23 is amino acid 191 of the HCV polyprotein, and p21 is produced as a result of processing between amino acids 174 and 191. The subcellular localization of the HCV core protein was examined by confocal laser scanning microscopy. Although HCV core protein resided predominantly in the cytoplasm, it was also found in the nucleus and had the same molecular size as p21 in both locations, as determined by subcellular fractionation. The HCV core proteins had different immunoreactivities to a panel of monoclonal antibodies. Antibody 5E3 stained core protein in both the cytoplasm and the nucleus, C7-50 stained core protein only in the cytoplasm, and 499S stained core protein only in the nucleus. These results clearly indicate that the p23 form of HCV core protein is processed to p21 in the cytoplasm and that the core protein in the nucleus has a higher-order structure different from that of p21 in the cytoplasm. HCV core protein in sera of patients with HCV infection was analyzed in order to determine the molecular size of genuinely processed HCV core protein. HCV core protein in sera was found to have exactly the same molecular weight as the p21 protein. These results suggest that p21 core protein is a component of native viral particles.

Animals↗
PubMed1998

P53- and CD95-associated apoptosis in neurodegenerative diseases.

Apoptosis is likely to be an important mechanism of cell loss in neurodegenerative diseases, but the signaling cascades activated before DNA fragmentation have not yet been determined. p53 or CD95 gene up-regulation precedes apoptosis in many cell types, and a potential role for these molecules in apoptosis of neurons and glial cells has already been demonstrated in Alzheimer's disease (AD). To determine whether apoptosis in other neurodegenerative diseases is mediated by similar mechanisms, p53 and CD95 expression were examined in postmortem central nervous system tissues from patients with diffuse Lewy body disease (DLBD), Pick's disease (PkD), progressive supranuclear palsy (PSP), multiple system atrophy (MSA), Parkinson's disease (PD), amyotrophic lateral sclerosis (ALS), and Down's syndrome plus Alzheimer's disease (DN+AD). Quantitative immunoblot analysis demonstrated higher temporal lobe levels of p53 and CD95 proteins in DLBD, PkD, and DN+AD, and higher temporal lobe levels of CD95 only in MSA and PSP relative to PD and aged controls (for all, p < 0.01). In histologic sections, increased p53 immunoreactivity was localized in neuronal and glial cell nuclei, neuronal perikarya, and dystrophic neuritic and glial cell processes in the frontal (Area 1 1) and temporal (Area 21) lobes in DLBD, PkD, and DN+AD, the motor cortex and spinal ventral horns in ALS, and the striatum and midbrain in DLBD, MSA, PD, and PSP. Increased CD95 expression and nuclear DNA fragmentation were present in the same cell types and structures that manifested increased nuclear p53 immunoreactivity. The results suggest that p53- or CD95-associated apoptosis may be a common mechanism of cell loss in several important neurodegenerative diseases. In addition, the presence of abundant p53-immunoreactive neurites and glial cell processes appears to be a novel feature of neurodegeneration shared by these distinct diseases.

Adult↗
PubMed1998

Ethanol inhibition of insulin signaling in hepatocellular carcinoma cells.

Chronic ethanol toxicity impairs liver regeneration, inhibits DNA synthesis, and mutes cellular responses to growth factor stimulation. Previous studies demonstrated that the adverse effects of ethanol are mediated by inhibition of tyrosyl phosphorylation of the insulin receptor and the insulin receptor substrate-type 1 (IRS-1). However, overexpression of IRS-1 leads to increased DNA synthesis and cellular transformation due to constitutive activation of mitogen-activated protein (MAP) kinase. The present study examines the effects of ethanol on insulin signaling through IRS-1 in FOCUS hepatocellular carcinoma cells, which overexpress IRS-1, to determine whether such cells were resistant to the inhibitory effects of ethanol. The results demonstrated that ethanol treatment (100 mM) caused 30 to 50% reductions in the levels of insulin-stimulated tyrosyl phosphorylation of the insulin receptor beta-subunit, tyrosyl phosphorylation of IRS-1, phosphorylation of Erk2, association of phosphatidylinositol-3 kinase with tyrosyl-phosphorylated IRS-1, and MAP kinase and phosphatidylinositol-3 kinase activities. In contrast, ethanol treatment had no effect on epidermal growth factor-stimulated tyrosyl phosphorylation of Shc. Corresponding with the pronounced inhibition of MAP kinase, ethanol treatment resulted in 30 to 50% reductions in the expression levels of two important insulin-responsive genes: glyceraldehyde-3-phosphate dehydrogenase (GAPDH) and proliferating cell nuclear antigen (PCNA). The findings suggest that, in FOCUS hepatocellular carcinoma cells, which overexpress IRS-1, ethanol treatment substantially inhibits IRS-1 and MAP kinase signaling and growth-associated gene expression, but has no effect on Shc phosphorylation, which activates p21ras through an IRS-1 independent pathway.

Carcinoma, Hepatocellular↗
PubMed1997

Characterization of the AD7C-NTP cDNA expression in Alzheimer's disease and measurement of a 41-kD protein in cerebrospinal fluid.

We have isolated a novel Alu sequence-containing cDNA, designated AD7c-NTP, that is expressed in neurons, and overexpressed in brains with Alzheimer's disease (AD). The 1,442-nucleotide AD7c-NTP cDNA encodes an approximately 41-kD protein. Expression of AD7c-NTP was confirmed by nucleic acid sequencing of reverse transcriptase PCR products isolated from brain. AD7c-NTP cDNA probes hybridized with 1. 4 kB mRNA transcripts by Northern blot analysis, and monoclonal antibodies generated with the recombinant protein were immunoreactive with approximately 41-45-kD and approximately 18-21-kD molecules by Western blot analysis. In situ hybridization and immunostaining studies localized AD7c-NTP gene expression in neurons. Using a quantitative enzyme-linked sandwich immunoassay (Ghanbari, K., I. Beheshti, and H. Ghanbari, manuscript submitted for publication) constructed with antibodies to the recombinant protein, AD7c-NTP levels were measured under code in 323 clinical and postmortem cerebrospinal fluid (CSF) samples from AD, age-matched control, Parkinson's disease, and neurological disease control patients. The molecular mass of the AD7c-NTP detected in CSF was approximately 41 kD. In postmortem CSF, the mean concentration of AD7c-NTP in cases of definite AD (9.2+/-8.2 ng/ml) was higher than in the aged control group (1.6+/-0.9; P < 0.0001). In CSF samples from individuals with early possible or probable AD, the mean concentration of AD7c-NTP (4.6+/-3.4) was also elevated relative to the levels in CSF from age-matched (1.2+/-0.7) and neurological disease (1.0+/-0.9) controls, and ambulatory patients with Parkinson's disease (1.8+/-1.1) (all P < 0.001). CSF levels of AD7c-NTP were correlated with Blessed dementia scale scores (r = 0. 66; P = 0.0001) rather than age (r = -0.06; P > 0.1). In vitro studies demonstrated that overexpression of AD7c-NTP in transfected neuronal cells promotes neuritic sprouting and cell death, the two principal neuroanatomical lesions correlated with dementia in AD. The results suggest that abnormal AD7c-NTP expression is associated with AD neurodegeneration, and during the early stages of disease, CSF levels correlate with the severity of dementia.

Aged↗
PubMed1997

Inhibitory effects of chronic ethanol consumption on cellular immune responses to hepatitis C virus core protein are reversed by genetic immunizations augmented with cytokine-expressing plasmids.

Chronic hepatitis C viral (HCV) infection is a major clinical problem in alcoholics with liver disease and may result from ethanol effects on the host immune response. To experimentally assess such effects, the DNA-based immunization approach was used to produce humoral and cellular immune responses against the HCV core protein in mice. Mice were fed an ethanol or isocaloric pair-fed control liquid diet followed by immunizations with HCV core DNA-expressing constructs. Chronic ethanol feeding was found to inhibit Th cell and CTL activities and substantially reduced cytokine secretion as well. In addition, a switch from Th1 to Th0 subtype was observed in proliferating CD4+ T cells derived from chronic ethanol-fed mice. These immunosuppressive effects were directly due to ethanol since crossover experiments to an isocaloric control diet restored the defects in cellular immunity. Furthermore, we determined if coadministration of an IL-2 or GM-CSF DNA expression plasmid with a plasmid expressing the HCV core protein (pHCV2-2) would reverse the inhibitory effects of chronic ethanol feeding on cellular immune responses. Coimmunization of chronic ethanol-fed mice with either IL-2 or GM-CSF expression plasmids restored cellular immunity and induced CD4+ inflammatory T cell and CD8+ CTL responses comparable with control mice immunized with pHCV2-2 alone. These studies provide evidence of how chronic ethanol feeding may effect cellular immune responses to a viral structural protein in the context of genetic immunization.

Adjuvants, Immunologic↗
PubMed1997

Correlates of p53- and Fas (CD95)-mediated apoptosis in Alzheimer's disease.

Apoptosis may be an important mechanism of cell loss in Alzheimer's disease (AD). Experimentally, apoptosis is preceded by nuclear accumulation of p53, and increased expression of Fas (CD95) antigen. In the present study, quantitative Western blot analysis of postmortem frontal and temporal lobe tissue demonstrated significantly higher mean levels of p53 and Fas in AD relative to age-matched controls. Immunohistochemical staining and in situ apoptosis assays demonstrated increased p53 and Fas expression and DNA fragmentation in overlapping populations of cortical neurons, and cortical and white matter glial cells distributed in regions damaged by neurodegeneration. Double-label immunohistochemical staining studies revealed p53 immunoreactivity in: 1) cortical neurons without tau-immunoreactive neurofibrillary tangles; 2) numerous, but not all tau-immunoreactive neuropil neurites and white matter axons; 3) dystrophic fibrils surrounding amyloid-beta-immunoreactive plaques; and 4) glial cells characterized as A2B5+ protoplasmic astrocytes or oligodendrocytes. The prominent distribution of dystrophic p53-immunoreactive processes around amyloid-beta-containing plaques suggests that amyloid deposits are associated with local neuritic degeneration. In addition, the results suggest that many tau-immunoreactive neuritic processes originate from degenerating (p53) as well as regenerating neurons. Finally, apoptosis of glial cells (A2B5+) required to maintain the functional integrity of axons and dendrites may represent an important pathogenic mechanism of axonal loss and synaptic disconnection in AD.

Aged↗
PubMed1997

Biologic properties of hepatitis B viral genomes with mutations in the precore promoter and precore open reading frame.

It is now well recognized that mutations in the hepatitis B virus (HBV) genome occur during the natural course of chronic viral infection. Regions of the viral genome that are frequently affected by such mutations, rearrangements, and/or deletions generally involve the precore promoter, precore, and core as well as the preS gene regions. However, little is known regarding the biologic consequences of these mutations on the functional properties of the variant viral strains with respect to effects on viral replication. In this study, we investigated the functional significance of precore promoter and precore gene mutations that reduce or abolish the synthesis of hepatitis B e antigen (HBeAg). We found that precore promoter mutations diminished the expression of HBeAg but did not affect the synthesis of pregenomic RNA. However, these precore mutations were associated with a modest increase in HBV replication. In contrast, a naturally occurring mutant that carries a termination codon in position 28 of the precore open reading frame demonstrated increased encapsidation of pregenomic mRNA into nucleocapsid particles. Consequently, this variant viral strain demonstrated a substantial increase in the level of viral replication compared to "wild-type" HBV and other precore promoter mutant viral strains. These studies suggest that substitutions in the precore promoter and precore gene not only alter the synthesis of HBeAg but also affect the level of viral replication.

Codon, Terminator↗
PubMed1997

Enhancement of cellular and humoral immune responses to hepatitis C virus core protein using DNA-based vaccines augmented with cytokine-expressing plasmids.

Development of a broad based cellular and humoral immune response to hepatitis C virus (HCV) structural proteins may be important for irradication of infection. DNA-based immunization is a promising approach to generate HCV-specific immune responses. Previous studies of DNA-based immunizations in mice using an HCV core DNA expression plasmid (pHCV2-2) demonstrated an efficient CTL response against HCV core epitopes; however, the humoral and Th cell proliferative responses were found to be weak. To enhance the immunogenicity of this nonsecreted viral structural protein at the B and T cell level, we coimmunized mice with pHCV2-2 and DNA expression constructs encoding for mouse IL-2, IL-4, and granulocyte-macrophage CSF proteins. Under these experimental conditions, a seroconversion frequency to anti-HCV core increased from 40 to 80% in immunized mice. The CD4+ inflammatory T cell proliferative responses as well as CD8+ CTL activity to HCV core protein were enhanced substantially after coimmunization with the IL-2 and granulocyte-macrophage CSF DNA expression constructs. In contrast, coimmunization with an IL-4-producing construct induced differentiation of Th cells toward a Th0 subtype and suppressed HCV core-specific CTL activity. Taken together, these studies emphasize that generation of antiviral immune responses using DNA-based immunization may be modified by local cytokine production at the site of Ag presentation.

Adjuvants, Immunologic↗
PubMed1997

Coexpression of Grb7 with epidermal growth factor receptor or Her2/erbB2 in human advanced esophageal carcinoma.

Growth factor receptors transmit intracellular signals that may be important in carcinogenesis. The Grb7 protein was recently identified as a substrate of the epidermal growth factor receptor and related Her2/ erbB2 receptor-linked tyrosine kinase activity. The Grb7 gene has been found to be coamplified with Her2/erbB2 in breast carcinomas. In this study, Grb7 expression was studied in 32 human esophageal cancers. A human Grb7 cDNA encoding for N-terminal amino acids was isolated and found to be 90% homologous to the murine counterpart. Although there was no amplification of the Grb7 gene in esophageal cancers, Grb7 mRNA was found to be overexpressed in 14 cancers (43.8%) but not in adjacent normal esophageal mucosa. It is noteworthy that coexpression of Grb7 with epidermal growth factor receptor or Her2/erbB2 was detected in 10 esophageal carcinomas (31.3%) and was significantly related to extramucosal tumor invasion (P = 0.02), whereas such a relationship was not shown by each sole expression. These findings suggest a possible relationship of Grb7 signaling in association with expression of tyrosine kinase receptors in aggressive human esophageal cancer.

Amino Acid Sequence↗
PubMed1997

Biological effects of human insulin receptor substrate-1 overexpression in hepatocytes.

The human insulin receptor substrate-1 (hIRS-1) is a key intracellular protein involved in various cytokine signaling pathways associated with cell growth. We have previously demonstrated that stable transfection and overexpression of hIRS-1 in human hepatoblastoma cells in vitro leads to the constitutive activation of the mitogen-activated protein kinase (MAPK) cascade. In this setting, hIRS-1 acts as a dominant oncogene and will induce neoplastic transformation of NIH 3T3 cells. In the present study, the biologic effects of hIRS-1 overexpression in the liver was analyzed using both clinical tumor samples and a newly developed transgenic mouse model. We have found that approximately 40% of 22 human hepatocellular carcinoma (HCC) tumors had enhanced (>200%) hIRS-1 gene expression compared with adjacent non-involved liver tissue. There was a significant relationship between the level of hIRS-1 overexpression and the tumor size; this finding suggests a possible role for hIRS-1 in tumor progression. To determine if downstream signal transduction cascades were activated by overexpression of hIRS-1 in hepatocytes, we established a transgenic mouse model using an hIRS-1 construct driven by an albumin promoter/enhancer element to direct liver specific expression. The overexpressed hIRS-1 protein was found to be tyrosyl phosphorylated and interacted with downstream SH2-containing molecules such as the p85 subunit of phosphatidylinositol-3 kinase (PI3K), Grb2 adaptor, and SHP2 phosphatase proteins. The functional consequences of hIRS-1 overexpression were reflected by constitutive activation of both the MAPK and PI3K signal transduction cascades. More important, overexpression of hIRS-1 in the transgenic liver led to increased hepatocyte DNA synthesis. Our findings indicate that hIRS-1 overexpression induces downstream signaling molecules associated with hepatocyte growth and may potentially enhance tumor progression of HCC.

3T3 Cells↗
PubMed1997

Chronic ethanol effects on cellular immune responses to hepatitis B virus envelope protein: an immunologic mechanism for induction of persistent viral infection in alcoholics.

Hepatitis B virus (HBV) is common in alcoholics and may result in chronic infection. Persistence of HBV infection could be partially caused by the effects of ethanol on the cellular and humoral immune response to viral structural proteins. The DNA-based immunization approach was used to experimentally assess the effects of chronic ethanol feeding on immune responses directed against the middle envelope protein (MHBs) of HBV. Mice were fed an ethanol or isocaloric, pair-fed control liquid diet for 8 weeks, followed by immunization with a plasmid construct containing the pre-S2/S gene that encodes for MHBs. Chronic ethanol consumption marginally reduced the levels of the antibody to hepatitis B surface proteins (anti-HBs) generated by the DNA-based immunization approach. Initially, cytotoxic lymphocyte (CTL) activity was higher in ethanol-fed mice but progressively declined following the second and third immunizations as compared with control mice. In addition, CTL and CD4+ T helper (TH) cells responded poorly to increasing concentrations of envelope protein and peptides in vitro with respect to generation of CTL activity and proliferative responses. Finally, proliferating CD4+ T cells derived from ethanol-fed animals had substantial changes in the levels of cytokines secreted into the culture supernatants as compared with control mice. These studies show that chronic ethanol consumption substantially alters the cellular immune responses to a human viral structural protein, and that these effects may contribute to the persistence of viral infection.

Alcoholism↗
PubMed1997

Cellular and humoral immune response to hepatitis B virus structural proteins in mice after DNA-based immunization.

BACKGROUND & AIMS: Development of a broad-based cellular immune response to hepatitis B viral structural proteins may be important for recovery from infection, and lack of such responses may lead to persistent viral infection and chronic liver disease. Strategies designed to enhance the hepatitis B virus (HBV)-specific immune response may be able to reduce persistent viral infection of the liver. The aim of this study was to induce HBV-specific cellular and humoral immune responses in mice using DNA-based immunizations with the large and middle envelope and nucleocapsid proteins. METHODS: Antibodies to HBV structural proteins, T-helper-cell proliferation, and cytokine release and generation of cytotoxic T lymphocyte (CTL) activity were measured in vaccinated mice. RESULTS: Immunized mice developed high-titer antibodies against envelope and core proteins in serum. More importantly, 93% of the immunized mice produced strong inflammatory CD4+ T-cell and CD8+ CTL responses to viral proteins. CONCLUSIONS: This study shows that DNA-based vaccination will generate broad-based CTL activity as well as strong T-helper cell responses with the production of TH1-type cytokines to HBV structural proteins. Such constructs are promising candidates as antiviral agents, and these studies have defined some of the most immunogenic antigens for an immunotherapeutic approach of chronic HBV infection.

Animals↗