Abstract: The present invention relates to methods and compositions for increasing the production of high titre stocks of recombinant AAV (rAAV) through regulation of expression of the AAV REP and CAP proteins. The methods and compositions of the invention are based on the observation that the low level expression of the AAV REP 78/68 protein increases the production of AAV viral capsid protein and efficiency of packaging resulting in production of higher titre recombinant viral stocks. The invention encompasses recombinant AAV vectors that direct the expression of AAV REP and CAP proteins and the use of such vectors for the production of novel stable cell lines capable of generating high titre rAAV vectors. The invention provides methods for regulating the expression of the AAV REP 78/68, REP 40/52 and CAP gene at the transcriptional and post-translational level.

Abstract: Expression of mammalian target genes is achieved by employing chromosomal target DNA, either native primary cells or YACs in a yeast host, where the YACs include a fragment of a mammalian chromosome, the fragment comprising the target gene. Employing homologous recombination, an amplifiable gene is integrated into the mammalian fragment at a site to allow for amplification. In the same step, or one or more steps, as desired, the mammalian gene and/or the transcriptional system may be modified by in vivo mutagenesis. The resulting construct from homologous recombination may then be transformed into a mammalian expression host and integrated into the host genome, either randomly or by homologous recombination. The amplifiable gene may then be amplified by an appropriate agent providing for multiple copies of the target gene and the expression host grown to provide for high yields of the desired wild-type or modified protein.

Abstract: Lentiviral vectors modified at the 5' LTR or both the 5' and 3' LTR's are useful in the production of recombinant lentivirus vectors. Such vectors can be produced in the absence of a functional tat gene. Multiple transformation of the host cell with the vector carrying the transgene enhances virus production.

Abstract: Methods and compositions are provided for expression of mammalian genes in culture. An amplifiable gene is introduced by homologous recombination in juxtaposition to a target gene, the resulting combination of amplifiable gene and target gene transferred to a convenient host and the target gene amplified by means of the amplifiable gene. The resulting expression host may then be grown in culture with enhanced expression of the target gene.

Abstract: The present invention is directed to novel replication-deficient adenoviral vectors characterized in that they harbor at least two lethal early region gene deletions (E1 and E4) that normally transcribe adenoviral early proteins. These novel recombinant vectors find particular use in human gene therapy treatment whereby the vectors additionally carry a transgene or therapeutic gene that replaces the E1 or E4 regions. The present invention is further directed to novel packaging cell lines that are transformed at a minimum with the adenoviral E1 and E4 gene regions and function to propagate the above novel replication-deficient adenoviral vectors.

Abstract: The invention provides a novel retroviral packaging system, in which retroviral packaging constructs and packagable vector transcripts are produced from high expression plasmids by transfection in human cells. High titers of recombinant retrovirus are produced in infected cells. The methods of the invention include the use of the novel retroviral constructs to transduce primary human cells, including T cells and human hematopoietic stem cells, with foreign genes by cocultivation at high efficiencies. The invention is useful for the rapid production of high viral supernatants, and to transduce with high efficiency cells that are refractory to transduction by conventional means.

Abstract: The present invention is directed to novel chimeric proliferation receptor proteins and DNA sequences encoding these proteins where the chimeric proteins are characterized in three general categories. In one category, the novel chimeric proteins comprise at least three domains, namely, an extracellular inducer-responsive clustering domain capable of binding an extracellular inducer that transmits a signal to a proliferation signaling domain, a transmembrane domain and a proliferation signaling domain that signals a host cell to divide. In the second category, the novel chimeric proteins comprise at least two domains, namely, an intracellular inducer-responsive clustering domain capable of binding an intracellular inducer and a proliferation signaling domain that signals the cell to divide.

Abstract: The invention provides a novel retroviral packaging system, in which retroviral packaging constructs and packagable vector transcripts are produced from high expression plasmids by transfection in human cells. High titers of recombinant retrovirus are produced in infected cells. The methods of the invention include the use of the novel retroviral constructs to transduce primary human cells, including T cells and bone marrow stem cells, with foreign genes by cocultivation at high efficiencies. The invention is useful for the rapid production of high viral supernatants, and to transduce with high efficiency cells that are refractory to transduction by conventional means.

Abstract: The present invention is directed to novel chimeric proliferation receptor proteins and DNA sequences encoding these proteins where the chimeric proteins are characterized in three general categories. In one category, the novel chimeric proteins comprise at least three domains, namely, an extracellular inducer-responsive clustering domain capable of binding an extracellular inducer that transmits a signal to a proliferation signaling domain, a transmembrane domain and a proliferation signaling domain that signals a host cell to divide. In the second category, the novel chimeric proteins comprise at least two domains, namely, an intracellular inducer-responsive clustering domain capable of binding an intracellular inducer and a proliferation signaling domain that signals the cell to divide.

Abstract: The present invention is directed to novel chimeric co-stimulatory receptor proteins and DNA sequences encoding these proteins. The chimeric receptors comprise at least three domains in a single chain molecule: an extracellular ligand binding domain, a transmembrane domain and a cytoplasmic co-stimulatory effector function signaling domain that acts synergistically with an effector function signal in the host cell. Novel hybrid co-stimulatory receptor proteins include a second cytoplasmic effector function signaling domain. The invention further relates to expression cassettes containing the nucleic acids encoding the novel chimeric receptors, to host cells expressing the novel chimeric receptors and to methods of using the receptors to co-stimulate effector functions in the cells and for using cells expressing the receptors for treatment of cancer, disease and viral infections.

Abstract: The present invention is directed to novel chimeric co-stimulatory receptor proteins and DNA sequences encoding these proteins. The chimeric receptors comprise at least three domains in a single chain molecule: an extracellular ligand binding domain, a transmembrane domain and a cytoplasmic co-stimulatory effector function signaling domain that acts synergistically with an effector function signal in the host cell. Novel hybrid co-stimulatory receptor proteins include a second cytoplasmic effector function signaling domain. The invention further relates to expression cassettes containing the nucleic acids encoding the novel chimeric receptors, to host cells expressing the novel chimeric receptors and to methods of using the receptors to co-stimulate effector functions in the cells and for using cells expressing the receptors for treatment of cancer, disease and viral infections.

Abstract: The invention provides a novel retroviral packaging system, in which retroviral packaging constructs and packagable vector transcripts are produced from high expression plasmids by transfection in human cells. High titers of recombinant retrovirus are produced in infected cells. The methods of the invention include the use of the novel retroviral constructs to transduce primary human cells, including T cells and human hematopoietic stem cells, with foreign genes by cocultivation at high efficiencies. The invention is useful for the rapid production of high viral supernatants, and to transduce with high efficiency cells that are refractory to transduction by conventional means.

Abstract: Novel regimens are provided for administering foreign genetically modified allogeneic cells to a host by combining the administration of the cells with a reduced regimen of an immunosuppressive agent. Particularly, cells having a reduced level of Class I MHC antigens may be employed in a variety of cellular therapy situations, where foreign cells are engrafted to treat diseased states.

Abstract: Homozygotic cells are obtained by employing homologous recombination with a construct comprising a marker gene. The marker gene allows for selection without amplification and by employing elevated levels of the antibiotic to which the marker gene imparts resistance, gene conversion can occur, where in a diploid host, both copies of the target locus will be the same. In this manner, knock-outs of genes can be readily achieved without requiring two steps of homologous recombination.

Abstract: Expression of mammalian target genes is achieved by employing chromosomal target DNA, either native primary cells or YACs in a yeast host, where the YACs include a fragment of a mammalian chromosome, the fragment comprising the target gene. Employing homologous recombination, an amplifiable gene is integrated into the mammalian fragment at a site to allow for amplification. In the same step, or one or more steps, as desired, the mammalian gene and/or the transcriptional system may be modified by in vivo mutagenesis. The resulting construct from homologous recombination may then be transformed into a mammalian expression host and integrated into the host genome, either randomly or by homologous recombination. The amplifiable gene may then be amplified by an appropriate agent providing for multiple copies of the target gene and the expression host grown to provide for high yields of the desired wild-type or modified protein.

Abstract: Homologous recombination is employed to inactivate genes, particularly genes associated with MHC antigens. Particularly, the .beta..sub.2 -microglobulin gene is inactivated for reducing or eliminating Class I MHC antigens. The resulting cells may be used as universal donors. In addition, embryonic stem cells may be modified by homologous recombination for use in producing chimeric or transgenic mammalian hosts, which may be used as source of universal donor organs, or as models for drug and transplantation therapies.

Abstract: Chimeric proteins and DNA sequence encoding chimeric proteins are provided, where the chimeric proteins are characterized by an extracellular domain capable of binding to a ligand in a non-MHC restricted manner, a transmembrane domain and a cytoplasmic domain capable of activating a signaling pathway. The extracellular domain and cytoplasmic domain are not naturally found together. Binding of ligand to the extracellular domain results in transduction of a signal and activation of a signaling pathway in the cell, whereby the cell may be induced to carry out various functions relating to the signalling pathway. A wide variety of extracellular domains may be employed as receptors, where such domains may be naturally occurring or synthetic. The chimeric DNA sequences may be used to modify lymphocytes as well as hematopoietic stem cells as precursors to a number of important cell types.