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David B Weiner

Publications and source records attributed to David B Weiner.

At least 19 recordsLinked to original sources
PubMed2006

Long-lasting decrease in viremia in macaques chronically infected with simian immunodeficiency virus SIVmac251 after therapeutic DNA immunization.

Rhesus macaques chronically infected with highly pathogenic simian immunodeficiency virus (SIV) SIVmac251 were treated with antiretroviral drugs and vaccinated with combinations of DNA vectors expressing SIV antigens. Vaccination during therapy increased cellular immune responses. After the animals were released from therapy, the virus levels of 12 immunized animals were significantly lower (P = 0.001) compared to those of 11 animals treated with only antiretroviral drugs. Vaccinated animals showed a persistent increase in immune responses, thus indicating both a virological and an immunological benefit following DNA therapeutic vaccination. Several animals show a long-lasting decrease in viremia, suggesting that therapeutic vaccination may provide an additional benefit to antiretroviral therapy.

Animals↗
PubMed2006

Cytokine-adjuvanted HIV-DNA vaccination strategies.

This review highlights some of the most common cytokines currently being tested as adjuvants in HIV-1-DNA vaccine regimens. We discuss their use in both the prophylactic and therapeutic setting. Finally, we describe a novel dendritic cell-targeted vaccine candidate for HIV-1 treatment and prevention called DermaVir and explore the combination of the DermaVir technology with the cytokine adjuvants interleukin-7 and interleukin-15.

AIDS Vaccines↗
PubMed2006

DNA vaccines for HIV: challenges and opportunities.

In December 2005, the UNAIDS and WHO reported that the global epidemic known as acquired immunodeficiency syndrome (AIDS) has claimed the lives of more than 25 million adults and children over the past 26 years. These figures included an estimated 3.1 million AIDS-related deaths in 2005. Despite enormous efforts to control the spread of human immunodeficiency virus (HIV) new infection rates are on the rise. An estimated 40.3 million people are now living with HIV, including 4.9 million new infections this past year. Nearly half of new HIV infections are in young people between the ages of 15 and 24. While drug therapies have helped sustain the lives of infected individuals in wealthy regions, they are relatively unavailable to the poorest global regions. This includes sub-Saharan Africa which has approximately 25.8 million infected individuals, more than triple the number of infections of any other region in the world. It is widely believed that the greatest hope for controlling this devastating pandemic is a vaccine. In this review, we will discuss the current state of DNA-based vaccines and how they compare to other vaccination methods currently under investigation. We will also discuss innovative ideas for enhancing DNA vaccine efficacy and the progress being made toward developing an effective vaccine.

AIDS Vaccines↗
PubMed2006

Complete regression of established subcutaneous B16 murine melanoma tumors after delivery of an HIV-1 Vpr-expressing plasmid by in vivo electroporation.

Novel therapies and delivery methods directed against malignancies such as melanoma, and particularly metastatic melanoma, are needed. The HIV-1 accessory protein Vpr (viral protein R) has previously been demonstrated to induce G2 cell cycle arrest as well as in vitro growth inhibition/killing of a number of tumor cells by apoptosis. In vivo electroporation has been utilized as an effective delivery method for pharmacologic agents and DNA plasmids that express "therapeutic" proteins and has been targeted to various tissues, including malignant tumors. For the study reported here, we hypothesized that intratumoral delivery of a Vpr expression plasmid through in vivo electroporation would induce apoptosis and growth attenuation or regression of melanoma tumors. Established subcutaneous B16.F10 melanoma tumors were injected intratumorally with a Vpr-expressing (either 25 or 100 microg) plasmid, followed by electroporation, on day 0 (i.e., when tumors had attained an appropriate size) and day 4. Treatment with 25 or 100 microg of the Vpr-expressing plasmid resulted in complete tumor regression with long-term survival in 14.3 and 7.1% of the mice, respectively. In addition, electroporative delivery of the Vpr-expressing plasmid was shown to induce apoptosis in tumors after intratumoral injection. This is the first report demonstrating the ability of Vpr, when delivered as a DNA expression plasmid with in vivo electroporation, to attenuate melanoma lesion growth and induce complete tumor regression coupled with long-term survival of mice in a highly aggressive and metastatic solid tumor model.

Animals↗
PubMed2006

Independence of granzyme B secretion and interferon- gamma production during acute simian immunodeficiency virus infection.

BACKGROUND: Quantification of interferon (IFN)-gamma by enzyme-linked immunospot (ELISPOT) assay is currently used as a surrogate measurement of cytotoxic T lymphocyte (CTL) activity in nonhuman primates, particularly in simian immunodeficiency virus (SIV) models. Given that noncytotoxic cells and natural killer cells can also release IFN-gamma, quantification of granzyme B (GrB), a molecule secreted predominantly by activated CD8+ T cells, may represent an additional surrogate measurement of CTL activity. METHODS: We evaluated, by ELISPOT assay, GrB activity in response to 3 overlapping SIV Gag peptide pools in 18 rhesus macaques with acute SIVmac251 infection and analyzed its correlation with IFN-gamma ELISPOT responses and plasma viral load. RESULTS: SIV Gag-specific GrB activity increased from 3.9- to 14.4-fold after infection, compared with that observed before infection. GrB secretion did not correlate directly with IFN-gamma production. Importantly, SIV Gag-specific IFN- gamma production was negatively correlated with plasma viral load, whereas GrB activity was not. However, the peak of GrB activity coincided with the lowest plasma viral load detected after infection, whereas the magnitude of IFN-gamma production was 1.8-fold lower than the GrB response; these results illustrate that the responses differ. CONCLUSION: Our data support the concept that the GrB and IFN-gamma ELISPOT assays measure immune responses in different immune-cell populations with unique specificities.

Animals↗
PubMed2006

The HIV-1 Vpr and glucocorticoid receptor complex is a gain-of-function interaction that prevents the nuclear localization of PARP-1.

The Vpr protein of HIV-1 functions as a vital accessory gene by regulating various cellular functions, including cell differentiation, apoptosis, nuclear factor of kappaB (NF-kappaB) suppression and cell-cycle arrest of the host cell. Several reports have indicated that Vpr complexes with the glucocorticoid receptor (GR), but it remains unclear whether the GR pathway is required for Vpr to function. Here, we report that Vpr uses the GR pathway as a recruitment vehicle for the NF-kappaB co-activating protein, poly(ADP-ribose) polymerase-1 (PARP-1). The GR interaction with Vpr is both necessary and sufficient to facilitate this interaction by potentiating the formation of a Vpr-GR-PARP-1 complex. The recruitment of PARP-1 by the Vpr-GR complex prevents its nuclear localization, which is necessary for Vpr to suppress NF-kappaB. The association of GR with PARP-1 is not observed with steroid (glucocorticoid) treatment, indicating that the GR association with PARP-1 is a gain of function that is solely attributed to HIV-1 Vpr. These data provide important insights into Vpr biology and its role in HIV pathogenesis.

Active Transport, Cell Nucleus↗
PubMed2006

Immunogenicity testing of a novel engineered HIV-1 envelope gp140 DNA vaccine construct.

DNA vaccines expressing the envelope (env) of the human immunodeficiency virus type 1 (HIV-1) have been relatively ineffective at generating strong immune responses. In this study, we described the development of a recombinant plasmid DNA (pEK2P-B) expressing an engineered codon-optimized envelope gp140 gene of primary (nonrecombinant) HIV-1 subtype B isolate 6101. Codon usage and RNA optimization of HIV-1 structural genes has been shown to increase protein expression in vitro as well as in the context of DNA vaccines in vivo. To further increase the expression, a synthetic IgE leader with kozak sequences were fused into the env gene. The cytoplasmic tail of the gene was also truncated to prevent recycling. The expression of env by the recombinant pEK2P-B was evaluated using T7 coupled transcription/translation. The construct demonstrated high expression of the HIV-1 env gene in eukaryotic cells as demonstrated in transfected 293-T and RD cells. Immunogenicity of pEK2P-B was evaluated in mice using IFN-gamma ELISpot assay, and the construct was found to be highly immunogenic and crossreactive with HIV-1 clade C env peptides. Three immunodominant peptides were also mapped out. Furthermore, by performing a CFSE flow cytometry-based proliferation assay, 2.4 and 1.5% proliferation was observed in CD4+, CD8+, and CCR+ memory T cells, respectively. Therefore, this engineered synthetic optimized env DNA vaccine may be useful in DNA vaccine and other studies of HIV-1 immunogenicity.

AIDS Vaccines↗
PubMed2006

Initiation of antiretroviral therapy during chronic SIV infection leads to rapid reduction in viral loads and the level of T-cell immune response.

In the present era of increasing resistance of human immunodeficiency virus (HIV) to antiviral drugs, exploration of adjunct therapies directed at immune responses in combination with antiretroviral drugs may be of value for the treatment of acquired immunodeficiency syndrome. In this study, we designed a model for immune therapy using SIVmac251 infection in rhesus macaques. We explored the outcomes of primary infection on viral loads and the resulting T-cell immune responses in primates. The SIV-infected rhesus macaque model exhibited features similar to those observed in HIV-1 infection of humans. Major histocompatibility complex (MHC) segregation with viral loads were found to associate with viral containment and hence the duration of the disease-free latency period. Thus a better understanding of the relative roles of MHC class I allele in control of viral replication may provide important information for prophylactic or therapeutic vaccine designs. Mamu-A01 is significantly associated with higher immune response and control of viral replication. This allele is frequent in rhesus macaques of Indian origin (22%). Interestingly, Mamu-B01 (26% animals) was associated with lower immune responses and higher viral loads. Another allele, A08 was also predominantly present in 37% of the animals in this study. We observed higher viral replication in individual SIV-infected rhesus monkeys that did not demonstrate strong cellular immune responses. The results are important for understanding SIV disease progression in different MHC Mamu alleles and also for improving the interpretation and quality of pre-clinical studies in rhesus monkeys.

Alleles↗
PubMed2005

A dose sparing effect by plasmid encoded IL-12 adjuvant on a SIVgag-plasmid DNA vaccine in rhesus macaques.

An experimental pDNA vaccine adjuvant expressing IL-12 was evaluated for its ability to augment the humoral and cellular immune responses elicited by a SIVmac239 gag p39 expressing pDNA vaccine. To determine the effect of vaccine dose on the immune response, rhesus macaques were immunized with 1.5 mg or 5.0 mg of SIVmac239 gag pDNA, with or without co-immunization of IL-12 pDNA at 1.5 mg and 5.0 mg, respectively. Serum antibody responses to simian immunodeficiency virus (SIV) gag were increased 10-fold (p=0.044, 0.002) in macaques receiving IL-12 pDNA. Cellular immune responses, monitored by SIV gag-specific IFN-gamma ELISpot assay, were also significantly higher (p=0.007, 0.019) when the pDNA vaccine was co-immunized with IL-12 pDNA at high and low doses. There was no statistical difference between the immune responses elicited by the high and low dose of IL-12 pDNA (p=0.221, 0.917), a finding which could allow a dose reduction of vaccine without the concomitant loss of imunogenicity. Furthermore, analysis of the breadth of the T-cell response during the vaccination schedule, using overlapping peptides to SIV gag, demonstrated a significant correlation (p=0.0002) between the magnitude and breadth of the immune responses in the vaccines. These results have important implications for the continuing development of an effective, safe low dose pDNA vaccine adjuvant suitable for human use.

Adjuvants, Immunologic↗
PubMed2005

Host cell killing by the West Nile Virus NS2B-NS3 proteolytic complex: NS3 alone is sufficient to recruit caspase-8-based apoptotic pathway.

The West Nile Virus (WNV) non-structural proteins 2B and 3 (NS2B-NS3) constitute the proteolytic complex that mediates the cleavage and processing of the viral polyprotein. NS3 recruits NS2B and NS5 proteins to direct protease and replication activities. In an effort to investigate the biology of the viral protease, we cloned cDNA encoding the NS2B-NS3 proteolytic complex from brain tissue of a WNV-infected dead crow, collected from the Lower Merion area (Merion strain). Expression of the NS2B-NS3 gene cassette induced apoptosis within 48 h of transfection. Electron microscopic analysis of NS2B-NS3-transfected cells revealed ultra-structural changes that are typical of apoptotic cells including membrane blebbing, nuclear disintegration and cytoplasmic vacuolations. The role of NS3 or NS2B in contributing to host cell apoptosis was examined. NS3 alone triggers the apoptotic pathways involving caspases-8 and -3. Experimental results from the use of caspase-specific inhibitors and caspase-8 siRNA demonstrated that the activation of caspase-8 was essential to initiate apoptotic signaling in NS3-expressing cells. Downstream of caspase-3 activation, we observed nuclear membrane ruptures and cleavage of the DNA-repair enzyme, PARP in NS3-expressing cells. Nuclear herniations due to NS3 expression were absent in the cells treated with a caspase-3 inhibitor. Expression of protease and helicase domains themselves was sufficient to trigger apoptosis generating insight into the apoptotic pathways triggered by NS3 from WNV.

Amino Acid Sequence↗
PubMed2005

Anti-T-cell Ig and mucin domain-containing protein 1 antibody decreases TH2 airway inflammation in a mouse model of asthma.

BACKGROUND: The T-cell Ig and mucin domain-containing (TIM) gene locus has been linked to differences in T(H)2 responsiveness and asthma susceptibility in mice. The homologous locus in human subjects harbors the gene for TIM-1, which encodes a receptor for hepatitis A virus and has been linked with decreased susceptibility to atopic disease in hepatitis A virus-seropositive individuals. OBJECTIVE: We investigated the effects of administering antibodies against TIM-1 in a mouse model of allergic asthma to determine whether the treatment could downregulate T(H)2 cytokines and reduce pulmonary inflammation. METHODS: BALB/c mice were sensitized and challenged with ovalbumin to induce airway inflammation. Before the ovalbumin challenge, mice were treated with anti-TIM-1 mAb or a control antibody. RESULTS: Administration of anti-TIM-1 antibody to mice after ovalbumin sensitization and before ovalbumin challenge results in a significant decrease in inflammatory cells in bronchoalveolar lavage fluid compared with administration of a control antibody. The decrease is accompanied by significantly lower antigen-specific production of the T(H)2 cytokines IL-10 and IL-13 by cells from the draining lymph nodes. The T(H)1 cytokine IFN-gamma appears to be unaffected. Analysis of the lungs shows that goblet cell hyperplasia and mucus production and the expression of IL-10 are markedly decreased in anti-TIM-1-treated mice. CONCLUSION: The results indicate that anti-TIM-1 might offer a novel approach to treating asthma.

Animals↗
PubMed2005

Mapping of immune responses following wild-type and mutant ABeta42 plasmid or peptide vaccination in different mouse haplotypes and HLA Class II transgenic mice.

Although the recent clinical trial of the ABeta42 peptide vaccine against Alzheimer's Disease (AD) has been halted due to adverse events, the apparent clinical utility of this approach underscores the need to further improve the safety of the vaccine, as well as to understand the potential immunological basis for complications. In this study, we examine both humoral and cellular immune responses elicited by immunization with peptide or DNA encoding wild-type and the Flemish and Dutch mutations of ABeta42 (i.e. the beta amyloid peptide spanning amino acids 1-42) in mice of different immune haplotypes as well as HLA Class II transgenic mice. The Flemish and Dutch mutations have been associated with cerebrovascular hemorrhages in affected individuals. These data allow determination of potential immunological responses that could mediate pathology observed with mutant forms of amyloid beta, as well as lead to the generation of safer vaccine preparations. Following peptide or plasmid immunization, antibody responses were measured against the different ABeta42 peptides in an ELISA assay, while T cell epitopes were analyzed through interferon gamma ELISPOT and lymphocyte proliferation assays. B cell mapping studies indicated that sera from all of the haplotype mice vaccinated with any of the ABeta42 peptides reacted specifically to the first 10 amino acids of ABeta42 with the ABeta42 mutants eliciting higher immune responses. ELISPOT analysis, which accessed cellular immune responses indicated that mice expressed differences in Class I epitopes dependent on the different immune haplotypes. These results may have implications for the design of future ABeta42 based vaccines against Alzheimer's Disease.

Amino Acid Sequence↗
PubMed2005

Rational design of a plasmid DNA vaccine capable of eliciting cell-mediated immune responses to multiple HIV antigens in mice.

Given the importance of the HIV-specific cell-mediated immune response in the early control and resolution of HIV infection and the observed correlation between pre-challenge vaccine elicited CTL responses and post challenge outcome in SHIV/rhesus macaque experiments, we sought to identify several candidate plasmid DNA (pDNA) vaccine designs capable of eliciting robust and balanced cell-mediated immune responses to multiple HIV-1 derived antigens in mice for further vaccine development. To rationally construct candidate vaccines for immunogenicity testing, we determined the relative immunogenicity of the individual HIV-derived vaccine antigens (env, gag, pol, nef, tat and vif) and the relative strength of various transcriptional control elements (HCMV, SCMV, HSV Lap1) in Balb/c mice. Next, a number of 1-, 2-, 3- and 4-vector pDNA vaccine designs were tested for their ability to elicit HIV-1 antigen-specific CMI responses. For these studies, Balb/c mice were immunized with a fixed total pDNA vaccine dose of 100 mcg in combination with 25 mcg plasmid-based murine IL-12 and tested for the induction of HIV-1 antigen-specific CMI responses by IFN-gamma ELISpot analysis. The results of this study indicate that all pDNA vaccine designs were capable of eliciting CMI responses to multiple HIV-1 antigens. As a result of this iterative comparative analysis, we have identified a number of pDNA vaccine candidates capable of eliciting potent, balanced CMI responses to multiple HIV-1 derived antigens. These results have important implications for the design and development of an efficacious vaccine for the prevention of HIV-1 infection.

Animals↗
PubMed2005

Efficacy of novel plasmid DNA encoding vaccinia antigens in improving current smallpox vaccination strategy.

We tested a DNA vaccine strategy in order to improve the efficacy and safety of the current live smallpox vaccine involving priming with DNA vaccines and boosting with live vaccinia virus (VacV). We generated DNA plasmids encoding the A4L, A27L and H5R VacV genes. A considerable increase in antigen-specific IFN-gamma responses, high proliferative and humoral antigen-specific responses were detected in experimental primed Balb/C mice compared to controls after VacV boost. The VacV-DNA plasmids elicited IFN-gamma production in HLA-A2.1 transgenic mice in response to predicted HLA-A2.1 restricted peptide epitopes, providing valuable data for further vaccine development.

Animals↗
PubMed2005

Rhesus macaques with high levels of vaccine induced IFN-gamma producing cells better control viral set-point following challenge with SIV239.

HIV-1 specific cellular immune responses play a significant part in controlling HIV-1 viral replication and are an important component of an HIV-1 vaccine induced immune response. We reported earlier that recombinant DNA vaccine delivered intramuscularly, and recombinant Listeria monocytogenes, delivered orally induced CD8+ and CD4+ T cell immune responses in rhesus macaques and that this vaccine protocol showed partial protection against an SIV239 challenge. In this paper, we have analyzed the SIV antigen-specific immune responses at the time of challenge and during the subsequent infection course. We find that the immune status of the animals, as measured by the frequency of antigen-specific IFN-gamma secreting peripheral blood mononuclear cells, at the time of challenge correlates more strongly with viral loads at set point than peak viral loads. The correlation between the immune response and viral load was strongest early, as viral set-point was just being established and disintegrates overtime. This study demonstrates the cellular immune response to SIV at the time of challenge of a nonhuman primate is able to impact on viral set-point following SIV239 challenge. Further, this study demonstrates that as virus replicates the T cell immune response to SIV antigens induced by the vaccine is modulated by antigen encountered by immune cells during viral replication.

Animals↗
PubMed2005

HIV-1 Viral protein-r (Vpr) protects against lethal superantigen challenge while maintaining homeostatic T cell levels in vivo.

The HIV-1 accessory protein Vpr exhibits many interesting features related to macrophage and T cell biology. As a viral protein or as a soluble molecule it can suppress immune cell activation and cytokine production in vitro in part by targeted inhibition of NF-kappaB. In this regard we sought to test its effects in vivo on an NF-kappaB-dependent immune pathway. We examined the activity of Vpr in a lethal toxin-mediated challenge model in mice. Intravenous delivery of Vpr was sufficient to protect mice from lethal challenge with staphylococcal endotoxin B (SEB). Furthermore, Vpr protected host CD4+ T cells from in vivo depletion likely by preventing induction of AICD of SEB-exposed cells in a post-toxin-binding fashion. Understanding the biology of Vpr's activities in this model may allow for new insight into potential mechanisms of hyperinflammatory disease and into Vpr pathobiology in the context of HIV infection.

Animals↗