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At least 793 records · Page 44Linked to original sources
PubMed2005

Effect of posttranscriptional regulatory elements on transgene expression and virus production in the context of retrovirus vectors.

Ineffective transgene expression in a sufficient amount of target cells is still a limitation in retroviral vector mediated gene therapy. Thus, we systematically evaluated four genetic modulators, (i) the woodchuck posttranscriptional regulatory element (WPRE), (ii) the mouse RNA transport element (RTE), (iii) the constitutive transport element (CTE) of the simian retrovirus type 1 (SRV-1), and (iv) the 5' untranslated region of the human heat shock protein 70 (Hsp70 5'UTR), all of them involved in the posttranscriptional control of mRNA nucleo/cytoplasmatic transport, RNA stability, and translation efficiency, in an MLV-based retrovirus vector context. Insertion of the WPRE into the retrovirus vector resulted in enhancement of transgene expression (EGFP) both in transfected virus producing cells as well as in infected recipient cells irrespective of the location in the vector. The best effect was observed with two copies of the WPRE, 3' of the transgene and in the 3' untranslated region of the vector backbone. However, oligomerization of this element does not further increase transgene expression. Presence of the WPRE resulted also in an increase in virus production. Introduction of the CTE and/or RTE in the retroviral vector did not alter transgene expression and infectious particle production. Positive effects were observed only in vectors harboring the CTE and/or RTE in combination with the WPRE. The activity of the Hsp70 5'UTR as a translational enhancer was found to be negligible in the context of the retroviral vector. However, interference of the Hsp70 5'UTR strong secondary structure with the packaging sequence of the viral RNA was experimentally excluded as being the cause of this. These data suggest that only the WPRE is a suitable element for the improvement of transgene expression and oncoretroviral vector production.

5' Untranslated Regions↗
PubMed2003

The effect of sequestration by nontarget tissues on anti-tumor efficacy of systemically applied, conditionally replicating adenovirus vectors.

Avoiding transduction of normal tissue after intravenous application of oncolytic adenoviruses (Ad) is an important strategy to improve the safety and efficacy of these vectors in gene therapy. As a model for a targeted vector, we used Ad vectors with type 35 fibers (Ad5/35), which efficiently transduce human cervical carcinoma cells but not liver cells. In an in vitro model of liver metastases, in which small nests of HeLa cells were surrounded by mouse hepatocytes, we showed that an Ad5/35-based conditionally replicating vector regulated by DNA replication-dependent recombination conferred increased gene transfer to tumor cells and enhanced viral replication and tumor cell lysis compared to the nontargeted Ad5 vector. Intravenous injection of Ad5/35 vectors into mice bearing liver metastases derived from HeLa cells caused markedly less hepatotoxicity than Ad5 vectors; however, it did not result in enhanced tumor cell transduction, viral replication, or oncolysis. Apparently, other factors, including the stability of virus in the blood, trapping within the liver sinusoids, transendothelial transfer, and/or vector diffusion of viral particles to tumor cells, limit tumor transduction, even if the vector is not taken up by liver cells.

Adenoviridae↗
PubMed2004

Ablating CAR and integrin binding in adenovirus vectors reduces nontarget organ transduction and permits sustained bloodstream persistence following intraperitoneal administration.

To create tumor-targeted Ad vectors, ablation of native CAR and integrin receptor binding is crucial to enhance the specificity of tumor transduction. Toward this aim, we have previously created base vectors in which binding to CAR (single-ablated) or to both CAR and integrins (double-ablated) has been ablated. In this study, the biodistribution of the conventional (CAR and integrin binding intact), single-ablated, and double-ablated vectors was evaluated following intraperitoneal administration. The mesothelial lining of the peritoneal organs was the principle site of CAR-dependent gene transfer by the conventional vector. Surprisingly, the single-ablated vector strongly transduced the liver parenchyma rather than the mesothelium, while the double-ablated vector did not significantly transduce the parenchyma or mesothelium. The high level of parenchymal transduction by the single-ablated vector suggested that it efficiently entered the bloodstream from the peritoneal cavity. Consistent with this hypothesis, a large proportion of active particles distributed and persisted in the bloodstream following intraperitoneal administration of either the single- or the double-ablated vector. The above results suggest that the double-ablated vector backbone may not only significantly improve targeting to cancers located in the peritoneal cavity, but may also significantly improve targeting to metastatic tumors located throughout the body by virtue of its enhanced bloodstream persistence.

Adenoviridae↗
PubMed2004

Sustained muscle expression of dystrophin from a high-capacity adenoviral vector with systemic gene transfer of T cell costimulatory blockade.

Adenoviral vector (Ad)-mediated gene delivery of normal, full-length dystrophin to skeletal muscle provides a promising strategy for the treatment of Duchenne muscular dystrophy (DMD). However, cellular and humoral immune responses induced by vector gene transfer limit the application of this approach. Blockade of the costimulatory interaction between naïve T cells and antigen-presenting cells has proven to be a successful means to diminish immunity induced by gene transfer. In this study we explore the potential of supplementing dystrophin gene delivery to dystrophin-deficient Dmd mouse skeletal muscle with systemic gene delivery of CTLA4Ig and CD40Ig molecules to effect costimulatory blockade. We found that systemic administration of a high-capacity Ad (HC-Ad) vector carrying murine CTLA4Ig (AdmCTLA4Ig) either alone or codelivered with an HC-Ad vector carrying murine CD40Ig (AdmCD40Ig) provided sustained expression of recombinant full-length murine dystrophin from an HC-Ad vector carrying the dystrophin cDNA (AdmDys). The level of AdmDys vector genomes remained stable in animals cotreated with systemic delivery of vectors carrying molecules to block costimulation. In addition, muscle CD4(+) and CD8(+) T cell infiltrates and Th1 cytokine production by splenocytes were reduced. The production of neutralizing antibody against Ad vector was significantly inhibited in mice receiving systemic codelivery of both AdmCTLA4Ig and AdmCD40Ig, but not in the mice treated with AdmCTLA4Ig alone. The results suggested that coblockade of both CD28/B7 and CD40L/CD40 costimulatory pathways is required for effective inhibition of the Ad vector-induced humoral immune response in Dmd mice, whereas blockade of CD28/B7 alone by murine CTLA4Ig would be sufficient for prolonged dystrophin expression in treated muscle.

Abatacept↗
PubMed2005

Evaluation of polyethylene glycol modification of first-generation and helper-dependent adenoviral vectors to reduce innate immune responses.

Adenoviruses are robust gene delivery vectors in vivo, but are limited by their propensity to provoke strong innate and adaptive responses. Previous work has demonstrated that polyethylene glycol (PEG) modification of adenovirus can protect the vectors from preexisting and adaptive immune responses by reducing protein-protein interactions. To test whether PEGylation can reduce innate immune responses to adenovirus by reducing their interactions with immune cells, first-generation (FG-Ad) and helper-dependent (HD-Ad) Ad5 vectors were PEGylated with SPA-PEG and tested in vitro and in vivo. We demonstrate that increasing PEGylation ablated in vitro transduction, but surprisingly had no negative effect on the level or distribution of in vivo gene delivery. This poor in vitro transduction could be rescued in part by physically forcing the PEGylated vectors onto cells, suggesting that physiological forces in vivo may enable transduction via heparin sulfate proteoglycan and integrin interactions. While transduction remained the same as for unmodified vectors, the PEGylated vectors reduced innate IL-6 responses by 70 and 50% in vivo for FG-Ad and HD-Ad. These reduced innate responses paralleled similar reductions in vector uptake by macrophages in vitro and Kupffer cells in vivo. These data suggest that PEGylation of Ad vectors can reduce innate immune responses without reducing transduction in vivo. These data also suggest that nonspecific vector uptake by macrophages and Kupffer cells may be critically involved in the initial activation of innate immune responses.

Adenoviridae↗
PubMed2005

Efficacy of an adeno-associated virus 8-pseudotyped vector in glycogen storage disease type II.

Glycogen storage disease type II (GSD-II; Pompe disease) causes death in infancy from cardiorespiratory failure. The underlying deficiency of acid alpha-glucosidase (GAA; acid maltase) can be corrected by liver-targeted gene therapy in GSD-II, if secretion of GAA is accompanied by receptor-mediated uptake in cardiac and skeletal muscle. An adeno-associated virus (AAV) vector encoding human (h) GAA was pseudotyped as AAV8 (AAV2/8) and injected intravenously into immunodeficient GSD-II mice. High levels of hGAA were maintained in plasma for 24 weeks following AAV2/8 vector administration. A marked increase in vector copy number in the liver was demonstrated for the AAV2/8 vector compared to the analogous AAV2/2 vector. GAA deficiency in the heart and skeletal muscle was corrected with the AAV2/8 vector in male GSD-II mice, consistent with receptor-mediated uptake of hGAA. Male GSD-II mice demonstrated complete correction of glycogen storage in heart and diaphragm with the AAV2/8 vector, while female GSD-II mice had correction only in the heart. A biomarker for GSD-II was reduced in both sexes following AAV2/8 vector administration. Therefore, GAA production with an AAV2/8 vector in a depot organ, the liver, generated evidence for efficacious gene therapy in a mouse model for GSD-II.

Animals↗
PubMed2006

A trans-lentiviral packaging cell line for high-titer conditional self-inactivating HIV-1 vectors.

Lentiviral vector safety has been the impetus underlying the progress in packaging cell line development. The prospects of generating replication-competent lentiviruses (RCLs) and the potential for vector mobilization continue to be the driving force for the advancement of packaging cell lines. We have exploited the trans-lentiviral packaging system to develop the SODk3 packaging cell line for the generation of conditional self-inactivating (cSIN) vectors. Separating the gag-pol genome into two distinct expression cassettes (gag-pro and vpr-RT-IN) may reduce the potential for RCL formation, while concurrently employing cSIN vectors supports retention of the SIN phenotype in target cells and alleviates technical constraints associated with generating producer cell lines. Through development of the SODk3 packaging cell line we determined that the ratio of Gag/Pol in vector particles may be used as an indicator for packaging cell clones that yield high vector titers. Conditional SIN vector titers (1 x 10(7) TU/ml) were augmented through clonal selection. Distinct producer cell clones revealed a parallel between vector titer and transgene expression levels. We exploited this observation to demonstrate that incorporation of an internal ribosome entry site between the GFP marker and a relevant transgene affords efficient selection of high-titer producer cell lines. Furthermore, cSIN vectors generated from SODk3 packaging cells imparted efficient transduction of primary human fibroblasts, an indication of the future applicability of the SODk3 packaging cell line.

Cell Line↗
PubMed2006

Analysis of tumors arising in male B6C3F1 mice with and without AAV vector delivery to liver.

The present study reports on the frequency of liver tumors observed in a gene therapy study with AAV vectors in male mice of the B6C3F1 hybrid background, which are known to have a high frequency of spontaneous liver tumors. Male mice with mutations in their Otc gene and their wild-type siblings received AAV vectors expressing either the murine Otc or the LacZ gene. Untreated control animals were included in the study. All experimental groups, including wild-type and OTC-deficient animals not treated with vector, developed liver nodules, which in some cases were due to hepatocellular carcinoma. Vector DNA was lower in tumors than in adjacent normal liver. A statistical analysis of the data did not show an association between treatment with Otc vectors and formation of tumors in OTC-deficient mice. However, mice treated with LacZ vectors showed increased risks of tumor formation and hepatocellular carcinoma relative to untreated animals or animals that had received vectors with Otc as the transgene. It appears that AAV vectors alone do not contribute to the formation of tumors in these strains of mice although the expression of LacZ alone or in combination with vector may be problematic.

Animals↗
PubMed2000

Retroviral vectors.

Retroviral vectors are widely used for preclinical and clinical applications. Unlike many of the other types of vectors currently being developed for gene therapy, retroviral vectors are able to genetically modify cells stably without perturbing cell growth. Retroviral vectors based on murine retroviruses are well suited for ex vivo applications where the cells are rapidly dividing. In particular, retroviral viral vectors have been used for a variety of ex vivo gene therapy approaches for treating genetic diseases such as Gaucher and severe combined immunodeficiency (SCID) and for acquired diseases such as cancer and arthritis. However, recent advances in the production of retroviral vectors have allowed for their use in vivo such as for the treatment of cancer and human immunodeficiency virus. The ability to target retroviral vectors to specific cell types will also increase the utility of high titer retroviral vectors for in vivo applications. Clearly retroviral vectors have been extremely useful for both preclinical and clinical gene therapy studies, and it is likely that they will continue to be utilized for ex vivo and in vivo strategies in the future.

Animals↗
PubMed2001

Preferential gene transfer to BBN-induced rat bladder tumor by simple instillation of adenoviral vector.

OBJECTIVES: We examined the efficacy and safety of intravesical instillation of adenoviral vectors to develop gene therapy protocols for bladder cancer. In this study, an adenoviral vector containing the beta-galactosidase gene was instilled into the rat bladder with N-butyl-N-(4-hydroxybutyl) nitrosamine-induced tumors. We evaluated the effect of the glycosaminoglycan (GAG) layer on adenoviral transduction of bladder urothelium. In addition, we determined the systemic distribution of the adenoviral vector after instillation. METHODS: An adenoviral vector containing either the beta-galactosidase or the herpes simplex virus thymidine kinase gene was transurethrally instilled into the bladder, after which efficacy of gene transfer was evaluated by staining with 5-bromo-4-chloro-3-indolyl-beta-D-galactopyraminoside, and the distribution of the gene was examined by reverse transcriptase-polymerase chain reaction. To determine the extent to which the GAG layer may have inhibited gene transfer by the adenoviral vector, prior to instillation of adenoviral vector, normal bladders were pretreated with either phosphate-buffered saline or HCl, which would destroy the mucosal GAG layer. RESULTS: We found that intravesical instillation of an adenoviral vector caused preferential gene transfer to the tumor cells and that expression of the transferred gene occurred exclusively in the bladder. Removing the GAG layer rendered the normal bladder highly susceptible to adenoviral gene transfer, indicating that GAG on normal mucosa prevented adenoviral gene transfer. CONCLUSIONS: BBN-induced bladder tumors were preferentially transduced by instillation of adenoviral vectors probably due to the lack of GAG layers on their surface. Intravesical instillation of adenoviral vectors does not result in systemic infection. These results encourage the consideration of gene therapy in the treatment of human bladder cancer.

Adenoviridae↗
PubMed1998

Novel synthesis and release of GABA in cerebellar granule cell cultures after infection with defective herpes simplex virus vectors expressing glutamic acid decarboxylase.

The inhibitory amino acid neurotransmitter gamma-aminobutyric acid (GABA) is synthesized from glutamate in a single step by the enzyme glutamatic acid decarboxylase (GAD). We sought to determine whether viral vectors containing GAD cDNA could be used to enhance synthesis and stimulation-evoked release of GABA in cultures of CNS neurons. For this purpose, we generated double-cassette defective herpes simplex virus (HSV) vectors that expressed one of the two GAD isoforms (GAD65 or GAD67), and Escherichia coli LacZ. Infection of cerebellar granule cell (CGC) cultures with vectors containing GAD cDNA resulted in a significant increase in isoform-specific expression of GAD, synthesis of GABA, and stimulation-evoked GABA release. GAD65 and GAD67 vector-infected neurons exhibited a comparable profile of GABA levels, synthesis and release, as well as GAD protein distribution. In CGCs cultured for 6 days in vitro (DIV), GABA synthesized after vector-derived GAD expression was released by treatment with glutamate or veratridine, but only in a Ca2+-independent fashion. In more mature (10 DIV) cultures, both Ca2+-dependent, K+ depolarization-induced, as well as Ca2+-independent, veratridine-induced, GABA release was significantly enhanced by GAD vector infection. Treatment of CGCs with kainic acid, which destroys most of the GABAergic neurons (<1% remaining), did not prevent vector-derived expression of GAD nor synthesis of GABA. This suggests that defective HSV vector-derived GAD expression can be used to increase GABA synthesis and release in CNS tissue, even in the relative absence of GABAergic neurons. The use of such GAD vectors in the CNS has potential therapeutic value in neurologic disorders such as epilepsy, chronic pain, Parkinson's and Huntington's disease.

Animals↗
PubMed2002

Autonomous parvovirus vectors.

Parvoviruses are small, icosahedral viruses (approximately 25 nm) containing a single-strand DNA genome (approximately 5 kb) with hairpin termini. Autonomous parvoviruses (APVs) are found in many species; they do not require a helper virus for replication but they do require proliferating cells (S-phase functions) and, in some cases, tissue-specific factors. APVs can protect animals from spontaneous or experimental tumors, leading to consideration of these viruses, and vectors derived from them, as anticancer agents. Vector development has focused on three rodent APVs that can infect human cells, namely, LuIII, MVM, and H1. LuIII-based vectors with complete replacement of the viral coding sequences can direct transient or persistent expression of transgenes in cell culture. MVM-based and H1-based vectors with substitution of transgenes for the viral capsid sequences retain viral nonstructural (NS) coding sequences and express the NS1 protein. The latter serves to amplify the vector genome in target cells, potentially contributing to antitumor activity. APV vectors have packaging capacity for foreign DNA of approximately 4.8 kb, a limit that probably cannot be exceeded by more than a few percent. LuIII vectors can be pseudotyped with capsid proteins from related APVs, a promising strategy for controlling tissue tropism and circumventing immune responses to repeated administration. Initial success has been achieved in targeting such a pseudotyped vector by genetic modification of the capsid. Subject to advances in production and purification methods, APV vectors have potential as gene transfer agents for experimental and therapeutic use, particularly for cancer therapy.

Animals↗
PubMed2003

Analysis of gene transfer and expression in skeletal muscle using enhanced EIAV lentivirus vectors.

Skeletal muscle is an attractive target tissue for gene therapy involving both muscle and nonmuscle disorders. HIV-1-based vectors transduce mature skeletal muscle; however, the use of these vectors for human gene therapy may be limited by biosafety concerns. In this study, we investigated gene transfer using lentivirus vectors based on the equine infectious anemia virus (EIAV) in skeletal muscle in vitro and in vivo. EIAV vectors transduce proliferating and differentiating C2C12 mouse muscle cells; furthermore, the addition of the woodchuck hepatitis posttranscriptional element to EIAV vectors markedly increases gene expression in these cells. A single injection of EIAV vectors into skeletal muscle of adult mice led to detectable gene marking and gene expression for the duration of the 3-month study. Use of a second-generation EIAV self-inactivating vector (E-SIN) increased transduction in muscle cells in vitro, and injection of E-SIN vectors into skeletal muscle resulted in increased gene marking and gene expression compared to first-generation EIAV vectors.

Animals↗
PubMed2003

Metabolically biotinylated adenovirus for cell targeting, ligand screening, and vector purification.

Development of cell-targeting vectors is an important focus for gene therapy. While some ligands can be genetically inserted into virus capsid proteins for cell targeting, for many ligands, this approach can disrupt either ligand function or vector function. To address this problem for adenovirus type 5 vectors, the fiber capsid protein was genetically fused to a biotin acceptor peptide (BAP). Adenovirus particles bearing this BAP were metabolically biotinylated during vector production by the endogenous biotin ligase in 293 cells to produce covalently biotinylated virions. The resulting biotinylated vector could be retargeted to new receptors by conjugation to biotinylated antibodies using tetrameric avidin (K(d) = 10(-15) M). The biotinylated vector could also be purified by biotin-reversible binding on monomeric avidin (K(d) = 10(-7) M). Finally, this vector was used as a ligand screening platform for dendritic cells in which a variety of structurally diverse protein, carbohydrate, and nucleic acid ligands were easily added to the vector using the biotin-avidin interaction. This work demonstrates the utility of metabolically biotinylated viruses for ligand screening, vector targeting, and virus purification applications.

Adenoviridae↗
PubMed2001

Prospects for gene therapy using HIV-based vectors.

Recombinant vectors derived from murine leukemia virus (MLV) have been widely used to introduce genes in human gene therapy clinical trials and have shown the potential for medical applications and the promise of significantly improving medical therapies. Yet, the demonstrated limitations of these vectors support the need for continued development of improved vectors. The intrinsic properties associated with the MLV genome and its life cycle do not favor the successful application of this vector system in certain human gene transfer applications. Since MLV integrates randomly into the host genome, transgene expression is frequently affected by the flanking host chromatin. MLV insertions can often result in silencing or position effect variation of gene expression either immediately after insertion or following cell expansion in culture or in vivo. Migration of the MLV pre-integration complex from the cytoplasm into the nucleus of infected cells requires mitosis for nuclear membrane breakdown. Since a majority of human cells exist in a quiescent state in vivo, it is unlikely that direct in vivo gene delivery into target tissues can be achieved with the MLV vector system. Finally, insertion of tissue-specific cis-regulatory sequences to direct transgene expression frequently results in either the rearrangement of the vector sequence or disruption of the cis-regulatory sequence functions. The long terminal repeat (LTR) of MLV, which contains a ubiquitously active enhancer/promoter element, may partially account for this problem. Together, these problems pose a major obstacle for the use of MLV vectors in the treatment of human diseases. This Chapter discusses some of the potential targets to which HIV vectors might be applied in clinical settings and some of the issues surrounding use of HIV vectors in gene transfer clinical trials.

Animals↗
PubMed2002

Gene transfer mediated by different viral vectors following direct cannulation of mouse submandibular salivary glands.

The salivary gland has been suggested as an accessible organ for gene transfer to express recombinant proteins locally in the saliva, as well as for secretion to the blood circulation. The aim of this study was to evaluate the efficiency of gene transfer to salivary glands using different viral vectors: adenovirus, vaccinia, herpes simplex type 1 (HSV), and two retroviral vectors (murine leukemia virus (MuLV) and lentivirus). We show, by in situ staining and beta-galactosidase reporter activity assay, that the adenoviral and vaccinia vectors were able to deliver the reporter gene efficiently to acinar and duct cells. The HSV vector was less efficient and infected only the acinar cells. The lentiviral vector infected acinar and duct cells, but at a relatively low efficiency. The MuLV vector did not infect the salivary gland unless cell proliferation was induced. Host immune responses to viral infection, inflammation, apoptosis and lymphocyte infiltration, in the transduced glands, were assessed. The DNA viral vectors induced local lymphocyte infiltration and apoptosis. In contrast, the retroviral vectors did not induce an immune response. Our results describe the outcome of salivary gland infection with each of the five different viral vectors and indicate their advantages and limitations for transferring genes to the salivary glands.

Adenoviridae↗
PubMed1998

Efficient transduction of nondividing human cells by feline immunodeficiency virus lentiviral vectors.

The molecular bases for species barriers to lentiviral replication are not well understood, but are of interest for explaining lentiviral pathogenesis, devising therapeutic strategies, and adapting lentiviruses to gene therapy. HIV-1-based lentiviral vectors efficiently transduce nondividing cells, but present complex safety concerns. Nonprimate (ungulate or feline) lentiviruses might provide safer alternatives, but these viruses display highly restricted tropisms, and their potential for adaptation as replication-defective vectors capable of transducing human cells is unknown. Feline immunodeficiency virus (FIV) does not infect humans or other non-Felidae despite prevalent natural exposure. Although long terminal repeat (LTR)-directed FIV expression was found to be negligible in human cells, promoter substitution enabled an env-deleted, three-plasmid, human cell-FIV lentiviral vector system to express high levels of FIV proteins and FIV vectors in human cells, thus bypassing the hazards of feline vector producer cells. Pseudotyped FIV vectors efficiently transduced dividing, growth-arrested, and postmitotic human targets. The experiments delineate mechanisms involved in species-restricted replication of this lentivirus and show that human cells support both productive- and infective-phase mechanisms of the FIV life cycle needed for efficient lentiviral vector transduction. Nonprimate lentiviral vectors may offer safety advantages, and FIV vectors provide unique experimental opportunities.

Animals↗
PubMed2000

Efficient cotransduction of tumors by multiple herpes simplex vectors: implications for tumor vaccine production.

Many gene therapy strategies would be enhanced by efficient transfer of multiple genes into the same cell. Herpes simplex viral amplicon (HSV) vectors are good vehicles for gene transfer because they accommodate large pieces of foreign DNA and transfer genes rapidly and efficiently. The current studies examine whether efficient cotransduction of tumor cells can be accomplished using multiple HSV vectors in a manner useful for clinical gene therapy. Interleukin-12 (IL-12) exists as a heterodimer, with components (m35 and m40) coded for by genes on two separate chromosomes. We constructed HSV vectors carrying either IL12m35 (HSVm35) or IL12m40 (HSVm40) or both genes (HSVm75) separated by an internal ribosome entry site to assess whether gene transfer using a single HSV vector constructed to carry multiple genes has any advantage over gene transfer using multiple vectors that are each carrying single genes. Because IL-12 and IL-2 have been found to have synergistic antitumoral activity, we further analyzed the biologic activity of tumor cells cotransduced by separate HSV vectors carrying genes coding for these two cytokines. The results demonstrate that multiple genes can be inserted into the same cell efficiently using multiple HSV vectors, and that these vectors allow rapid production of tumor vaccines expressing multiple cytokine genes. Thus, gene transfer using HSV may not be limited by the size of the DNA that each vector can accommodate. Immunizations with tumors cotransduced with HSVm35 and HSVm40 were equally effective in eliciting a cytolytic T-lymphocyte response and in protecting against tumor growth in vivo as immunization with tumors treated with HSVm75. Immunization with tumors cotransduced with HSVm75 and HSVil2 was superior to immunization with tumors transduced with either alone. The combination of IL-2- and IL-12-secreting tumor cells may be used as an effective immunization strategy against solid tumors.

Animals↗