Interleukin-Encoding Adenoviral Vectors as Genetic Adjuvant for Vaccination against Retroviral Infection

Interleukins (IL) are cytokines with stimulatory and modulatory functions in the immune system. In this study, we have chosen interleukins which are involved in the enhancement of T_H2 responses and B cell functions to analyze their potential to improve a prophylactic adenovirus-based anti-retroviral vaccine with regard to antibody and virus-specific CD4⁺ T cell responses. Mice were vaccinated with an adenoviral vector which encodes and displays the Friend Virus (FV) surface envelope protein gp70 (Ad.pIXgp70) in combination with adenoviral vectors encoding the interleukins IL4, IL5, IL6, IL7 or IL23. Co-application of Ad.pIXgp70 with Ad.IL5, Ad.IL6 or Ad.IL23 resulted in improved protection with high control over FV-induced splenomegaly and reduced viral loads. Mice co-immunized with adenoviral vectors encoding IL5 or IL23 showed increased neutralizing antibody responses while mice co-immunized with Ad.IL6 or Ad.IL23 showed improved FV-specific CD4⁺ T cell responses compared to mice immunized with Ad.pIXgp70 alone. We show that the co-application of adenoviral vectors encoding specific interleukins is suitable to improve the vaccination efficacy of an anti-retroviral vaccine. Improved protection correlated with improved CD4⁺ T cell responses and especially with higher neutralizing antibody titers. The co-application of selected interleukin-encoding adenoviral vectors is a valuable tool for vaccination with regard to enhancement of antibody mediated immunity.     

Vascular Gene Transfer from Metallic Stent Surfaces Using Adenoviral Vectors Tethered through Hydrolysable Cross-linkers

In-stent restenosis presents a major complication of stent-based revascularization procedures widely used to re-establish blood flow through critically narrowed segments of coronary and peripheral arteries. Endovascular stents capable of tunable release of genes with anti-restenotic activity may present an alternative strategy to presently used drug-eluting stents. In order to attain clinical translation, gene-eluting stents must exhibit predictable kinetics of stent-immobilized gene vector release and site-specific transduction of vasculature, while avoiding an excessive inflammatory response typically associated with the polymer coatings used for physical entrapment of the vector. This paper describes a detailed methodology for coatless tethering of adenoviral gene vectors to stents based on a reversible binding of the adenoviral particles to polyallylamine bisphosphonate (PABT)-modified stainless steel surface via hydrolysable cross-linkers (HC). A family of bifunctional (amine- and thiol-reactive) HC with an average t_1/2 of the in-chain ester hydrolysis ranging between 5 and 50 days were used to link the vector with the stent. The vector immobilization procedure is typically carried out within 9 hr and consists of several steps: 1) incubation of the metal samples in an aqueous solution of PABT (4 hr); 2) deprotection of thiol groups installed in PABT with tris(2-carboxyethyl) phosphine (20 min); 3) expansion of thiol reactive capacity of the metal surface by reacting the samples with polyethyleneimine derivatized with pyridyldithio (PDT) groups (2 hr); 4) conversion of PDT groups to thiols with dithiothreitol (10 min); 5) modification of adenoviruses with HC (1 hr); 6) purification of modified adenoviral particles by size-exclusion column chromatography (15 min) and 7) immobilization of thiol-reactive adenoviral particles on the thiolated steel surface (1 hr). This technique has wide potential applicability beyond stents, by facilitating surface engineering of bioprosthetic devices to enhance their biocompatibility through the substrate-mediated gene delivery to the cells interfacing the implanted foreign material.     

人Sef基因重组腺病毒载体的构建与鉴定

构建人Sef-L和Sef-S基因的复制缺陷型重组腺病毒表达载体, 为研究Sef的功能和作用机制以及Sef的基因治疗奠定基础。通过PCR方法以hSef的表达质粒为模板扩增得到hSef的编码序列, 亚克隆到穿梭载体pAdTrack-CMV中, 经测序验证之后, 将穿梭载体使用Pme I酶切线性化, 然后与腺病毒基因组质粒pAdEasy-1共转化大肠杆菌BJ5183, 得到重组的Ad-hSef-L和Ad-hSef-S质粒, 最后将Ad-hSef-L和Ad-hSef-S质粒使用Pac I线性化, 转染到HEK293细胞中, 包装收获病毒颗粒, 免疫印迹实验鉴定表达, 荧光素酶报告实验验证其功能。成功构建了人Sef基因的复制缺陷型重组腺病毒表达载体, 获得了有功能的Ad-hSef-L和Ad-hSef-S病毒重组子。     

人Sef基因重组腺病毒载体的构建与鉴定

构建人Sef-L和Sef-S基因的复制缺陷型重组腺病毒表达载体, 为研究Sef的功能和作用机制以及Sef的基因治疗奠定基础。通过PCR方法以hSef的表达质粒为模板扩增得到hSef的编码序列, 亚克隆到穿梭载体pAdTrack-CMV中, 经测序验证之后, 将穿梭载体使用Pme I酶切线性化, 然后与腺病毒基因组质粒pAdEasy-1共转化大肠杆菌BJ5183, 得到重组的Ad-hSef-L和Ad-hSef-S质粒, 最后将Ad-hSef-L和Ad-hSef-S质粒使用Pac I线性化, 转染到HEK293细胞中, 包装收获病毒颗粒, 免疫印迹实验鉴定表达, 荧光素酶报告实验验证其功能。成功构建了人Sef基因的复制缺陷型重组腺病毒表达载体, 获得了有功能的Ad-hSef-L和Ad-hSef-S病毒重组子。     

腺病毒载体在肿瘤靶向性基因治疗中的应用

近年来,腺病毒载体广泛应用于恶性肿瘤的靶向性基因治疗。对传统腺病毒载体的改造主要有以下策略：(1)通过改变腺病毒的嗜性(tropism),使之具有感染宿主细胞的靶向性;(2)在转录水平控制外源性基因的表达;(3)可选择性裂解肿瘤细胞的有复制能力的腺病毒(replication-competent adenovirus,RCA)。更多安全、高效的靶向性腺病毒载体将应用于肿瘤基因治疗中。     

Multivalent Human Papillomavirus L1 DNA Vaccination Utilizing Electroporation

Objectives

Naked DNA vaccines can be manufactured simply and are stable at ambient temperature, but require improved delivery technologies to boost immunogenicity. Here we explore in vivo electroporation for multivalent codon-optimized human papillomavirus (HPV) L1 and L2 DNA vaccination.

Methods

Balb/c mice were vaccinated three times at two week intervals with a fusion protein comprising L2 residues ∼11−88 of 8 different HPV types (11−88×8) or its DNA expression vector, DNA constructs expressing L1 only or L1+L2 of a single HPV type, or as a mixture of several high-risk HPV types and administered utilizing electroporation, i.m. injection or gene gun. Serum was collected two weeks and 3 months after the last vaccination. Sera from immunized mice were tested for in-vitro neutralization titer, and protective efficacy upon passive transfer to naive mice and vaginal HPV challenge. Heterotypic interactions between L1 proteins of HPV6, HPV16 and HPV18 in 293TT cells were tested by co-precipitation using type-specific monoclonal antibodies.

Results

Electroporation with L2 multimer DNA did not elicit detectable antibody titer, whereas DNA expressing L1 or L1+L2 induced L1-specific, type-restricted neutralizing antibodies, with titers approaching those induced by Gardasil. Co-expression of L2 neither augmented L1-specific responses nor induced L2-specific antibodies. Delivery of HPV L1 DNA via in vivo electroporation produces a stronger antibody response compared to i.m. injection or i.d. ballistic delivery via gene gun. Reduced neutralizing antibody titers were observed for certain types when vaccinating with a mixture of L1 (or L1+L2) vectors of multiple HPV types, likely resulting from heterotypic L1 interactions observed in co-immunoprecipitation studies. High titers were restored by vaccinating with individual constructs at different sites, or partially recovered by co-expression of L2, such that durable protective antibody titers were achieved for each type.

Discussion

Multivalent vaccination via in vivo electroporation requires spatial separation of individual type L1 DNA vaccines.     

Targeting Adenoviral Vectors by Using the Extracellular Domain of the Coxsackie-Adenovirus Receptor: Improved Potency via Trimerization

Adenovirus binds to mammalian cells via interaction of fiber with the coxsackie-adenovirus receptor (CAR). Redirecting adenoviral vectors to enter target cells via new receptors has the advantage of increasing the efficiency of gene delivery and reducing nonspecific transduction of untargeted tissues. In an attempt to reach this goal, we have produced bifunctional molecules with soluble CAR (sCAR), which is the extracellular domain of CAR fused to peptide-targeting ligands. Two peptide-targeting ligands have been evaluated: a cyclic RGD peptide (cRGD) and the receptor-binding domain of apolipoprotein E (ApoE). Human diploid fibroblasts (HDF) are poorly transduced by adenovirus due to a lack of CAR on the surface. Addition of the sCAR-cRGD or sCAR-ApoE targeting protein to adenovirus redirected binding to the appropriate receptor on HDF. However, a large excess of the monomeric protein was needed for maximal transduction, indicating a suboptimal interaction. To improve interaction of sCAR with the fiber knob, an isoleucine GCN4 trimerization domain was introduced, and trimerization was verified by cross-linking analysis. Trimerized sCAR proteins were significantly better at interacting with fiber and inhibiting binding to HeLa cells. Trimeric sCAR proteins containing cRGD and ApoE were more efficient at transducing HDF in vitro than the monomeric proteins. In addition, the trimerized sCAR protein without targeting ligands efficiently blocked liver gene transfer in normal C57BL/6 mice. However, addition of either ligand failed to retarget the liver in vivo. One explanation may be the large complex size, which serves to decrease the bioavailability of the trimeric sCAR-adenovirus complexes. In summary, we have demonstrated that trimerization of sCAR proteins can significantly improve the potency of this targeting approach in altering vector tropism in vitro and allow the efficient blocking of liver gene transfer in vivo.     

丙型肝炎病毒重要编码蛋白重组腺病毒载体的构建

旨在构建含HCV core、E1、E2、F、NS3、NS5a和NS5b基因的重组腺病毒载体。运用PCR技术扩增目的基因片段,通过酶切连接方法将上述7种基因片段克隆至穿梭质粒pAdTrack-TO4中,然后将重组质粒用PmeⅠ线性化后与骨架质粒pAdEasy-1在BJ5183细菌中同源重组。用PacⅠ酶把重组腺病毒载体线性化后转染HEK293细胞后产生重组腺病毒颗粒。利用穿梭质粒中带有绿色荧光蛋白GFP对其感染效率进行监测。结果显示,酶切鉴定和测序结果均证实含core、E1、E2、F、NS3、NS5a和NS5b基因的重组腺病毒构建成功,在感染的Huh7细胞中观察到绿色荧光蛋白GFP。成功制备了高滴度的腺病毒Ad-core、Ad-E1、Ad-E2、Ad-F、Ad-NS3、Ad-NS5a和Ad-NS5b,为后续研究奠定了基础。     

Pulse HIV Vaccination: Feasibility for Virus Eradication and Optimal Vaccination Schedule

We modify the classical virus dynamics model by incorporating an immune response with fixed or fluctuating vaccination frequencies and dosages to obtain a system of impulsive differential equations for the virus dynamics of both the wild-type and mutant strains. This model framework permits us to obtain precise conditions for the virus elimination, which are much more feasible compared with existing results, which require frequent vaccine administration with large dosage. We also consider the corresponding impulsive optimal control problem to describe when and how much of the vaccine should be administered in order to maximize levels of healthy CD4⁺ T cells and immune response cells. A gradient-based optimization method is applied to obtain the optimal schedule numerically. For a case study when the CTL vaccine is administered in a period of one year, our numerical studies support the optimal vaccination schedule consisting of vaccine administration three times, with the first dosage strong (to boost the immune system), followed by a second dosage shortly after (to strengthen the immune response) and then the third and final dosage long after (to ensure the immune system can handle viruses rebound).     

A Novel and Simple Method for Rapid Generation of Recombinant Porcine Adenoviral Vectors for Transgene Expression

Many human (different serotypes) and nonhuman adenovirus vectors are being used for gene delivery. However, the current system for isolating recombinant adenoviral vectors is either time-consuming or expensive, especially for the generation of recombinant non-human adenoviral vectors. We herein report a new and simple cloning approach for the rapid generation of a porcine adenovirus (PAdV-3) vector which shows promise for gene transfer to human cells and evasion of human adenovirus type 5 (HAdV-5) immunity. Based on the final cloning plasmid, pFPAV3-CcdB-Cm, and our modified SLiCE strategy (SLiCE cloning and lethal CcdB screening), the process for generating recombinant PAdV-3 plasmids required only one step in 3 days, with a cloning efficiency as high as 620±49.56 clones/ng and zero background (100% accuracy). The recombinant PAdV-3 plasmids could be successfully rescued in porcine retinal pigment epithelium cells (VR1BL), which constitutively express the HAdV-5 E1 and PAdV-3 E1B 55k genes, and the foreign genes were highly expressed at 24 h after transduction into swine testicle (ST) cells. In conclusion, this strategy for generating recombinant PAdV-3 vectors based on our modified SLiCE cloning system was rapid and cost-efficient, which could be used as universal cloning method for modification the other regions of PAdV-3 genome as well as other adenoviral genomes.     

Transduction of Brain Dopamine Neurons by Adenoviral Vectors Is Modulated by CAR Expression: Rationale for Tropism Modified Vectors in PD Gene Therapy

Background

Gene-based therapy is a new paradigm for the treatment of Parkinson disease (PD) and offers considerable promise for precise targeting and flexibility to impact multiple pathobiological processes for which small molecule agents are not available. Some success has been achieved utilizing adeno-associated virus for this approach, but it is likely that the characteristics of this vector system will ultimately create barriers to progress in clinical therapy. Adenovirus (Ad) vector overcomes limitations in payload size and targeting. The cellular tropism of Ad serotype 5 (Ad5)–based vectors is regulated by the Ad attachment protein binding to its primary cellular receptor, the coxsackie and adenovirus receptor (CAR). Many clinically relevant tissues are refractory to Ad5 infection due to negligible CAR levels but can be targeted by tropism-modified, CAR-independent forms of Ad. Our objective was to evaluate the role of CAR protein in transduction of dopamine (DA) neurons in vivo.

Methodology/Principal Findings

Ad5 was delivered to the substantia nigra (SN) in wild type (wt) and CAR transgenic animals. Cellular tropism was assessed by immunohistochemistry (IHC) in the SN and striatal terminals. CAR expression was assessed by western blot and IHC. We found in wt animals, Ad5 results in robust transgene expression in astrocytes and other non-neuronal cells but poor infection of DA neurons. In contrast, in transgenic animals, Ad5 infects SNc neurons resulting in expression of transduced protein in their striatal terminals. Western blot showed low CAR expression in the ventral midbrain of wt animals compared to transgenic animals. Interestingly, hCAR protein localizes with markers of post-synaptic structures, suggesting synapses are the point of entry into dopaminergic neurons in transgenic animals.

Conclusions/Significance

These findings demonstrate that CAR deficiency limits infection of wild type DA neurons by Ad5 and provide a rationale for the development of tropism-modified, CAR-independent Ad-vectors for use in gene therapy of human PD.     

Adenoviral Vectors Stimulate Glucagon Transcription in Human Mesenchymal Stem Cells Expressing Pancreatic Transcription Factors

Viral gene carriers are being widely used as gene transfer systems in (trans)differentiation and reprogramming strategies. Forced expression of key regulators of pancreatic differentiation in stem cells, liver cells, pancreatic duct cells, or cells from the exocrine pancreas, can lead to the initiation of endocrine pancreatic differentiation. While several viral vector systems have been employed in such studies, the results reported with adenovirus vectors have been the most promising in vitro and in vivo. In this study, we examined whether the viral vector system itself could impact the differentiation capacity of human bone-marrow derived mesenchymal stem cells (hMSCs) toward the endocrine lineage. Lentivirus-mediated expression of Pdx-1, Ngn-3, and Maf-A alone or in combination does not lead to robust expression of any of the endocrine hormones (i.e. insulin, glucagon and somatostatin) in hMSCs. Remarkably, subsequent transduction of these genetically modified cells with an irrelevant early region 1 (E1)-deleted adenoviral vector potentiates the differentiation stimulus and promotes glucagon gene expression in hMSCs by affecting the chromatin structure. This adenovirus stimulation was observed upon infection with an E1-deleted adenovirus vector, but not after exposure to helper-dependent adenovirus vectors, pointing at the involvement of genes retained in the E1-deleted adenovirus vector in this phenomenon. Lentivirus mediated expression of the adenovirus E4-ORF3 mimics the adenovirus effect. From these data we conclude that E1-deleted adenoviral vectors are not inert gene-transfer vectors and contribute to the modulation of the cellular differentiation pathways.     

Lineage Analysis Using Retroviral Vectors

Knowledge of the genealogical relationships of cells during development can allow one to gain insight into when and where developmental decisions are being made. Genealogical relationships can be revealed by a variety of methods, all of which involve marking a progenitor cell and/or a group of cells and then following the progeny. The use of replication-incompetent retroviral vectors for the analysis of lineal relationships in developing vertebrate tissues is described. An overview of the relevant aspects of the retroviral life cycle is given, and the strategies and current methods in use in our laboratory are described.     

克服腺病毒载体介导免疫应答的新策略:关闭淋巴细胞反应

近年来随着分子免疫学的迅速发展,人们对于自身免疫耐受机制以及病毒逃逸免疫应答的策略有了较多的认识。基于这些研究,多种抵抗腺病毒载体介导免疫反应的新策略正在被探讨之中。这些策略包括:1口服或胸腺内应用腺病毒载体或其抽提物;2应用CTLA4Ig可溶性分子或其表达载体;3开发修饰腺病毒载体。所有这些策略其最终机制都在于特异性地阻止或中断针对腺病毒载体的T淋巴细胞反应。     

Priming Immunization with DNA Augments Immunogenicity of Recombinant Adenoviral Vectors for Both HIV-1 Specific Antibody and T-Cell Responses

Background

Induction of HIV-1-specific T-cell responses relevant to diverse subtypes is a major goal of HIV vaccine development. Prime-boost regimens using heterologous gene-based vaccine vectors have induced potent, polyfunctional T cell responses in preclinical studies.

Methods

The first opportunity to evaluate the immunogenicity of DNA priming followed by recombinant adenovirus serotype 5 (rAd5) boosting was as open-label rollover trials in subjects who had been enrolled in prior studies of HIV-1 specific DNA vaccines. All subjects underwent apheresis before and after rAd5 boosting to characterize in depth the T cell and antibody response induced by the heterologous DNA/rAd5 prime-boost combination.

Results

rAd5 boosting was well-tolerated with no serious adverse events. Compared to DNA or rAd5 vaccine alone, sequential DNA/rAd5 administration induced 7-fold higher magnitude Env-biased HIV-1-specific CD8⁺ T-cell responses and 100-fold greater antibody titers measured by ELISA. There was no significant neutralizing antibody activity against primary isolates. Vaccine-elicited CD4⁺ and CD8⁺ T-cells expressed multiple functions and were predominantly long-term (CD127⁺) central or effector memory T cells and that persisted in blood for >6 months. Epitopes mapped in Gag and Env demonstrated partial cross-clade recognition.

Conclusion

Heterologous prime-boost using vector-based gene delivery of vaccine antigens is a potent immunization strategy for inducing both antibody and T-cell responses.

Trial Registration

ClinicalTrails.gov {"type":"clinical-trial","attrs":{"text":"NCT00102089","term_id":"NCT00102089"}}NCT00102089, {"type":"clinical-trial","attrs":{"text":"NCT00108654","term_id":"NCT00108654"}}NCT00108654     

Effective Gene Transfer into Regenerating Sciatic Nerves by Adenoviral Vectors: Potentials for Gene Therapy of Peripheral Nerve Injury

Replication defective adenoviral vectors have been demonstrated as an effective method for delivering genes into a variety of cell types and tissues both in vivo and in vitro. Transfecting genes into neuronal cells has proven to be difficult because of their lack of cell division. Since the major problem in neurological disease is the degeneration of the terminally differentiated neuronal cells, the adenoviral vectors ability to transfer genes into differentiated post-mitotic cells makes them advantageous for a gene delivery system for the nervous system. Here we showed that a replication defective recombinant adenovirus carrying the lacZ gene could infect the neuronal stem cells and even the differentiated neuronal cells derived from the central nervous system. The lacZ gene delivered into the neuronal cells was expressed efficiently. In addition, the recombinant virus also infected Schwann cells in intact and injured nerves in vivo. The expression of the lacZ gene lasted for 5 weeks, within which nerve regeneration is accomplished in the rat. Adenoviral vectors might thus be used to modulate Schwann cell gene expression for treating peripheral nerve injury or peripheral neuropathy.