Abstract: The present invention involves methods and compositions for increasing the susceptibility of target cells to transduction by gene transfer vectors. Specifically, it is proposed that increasing intracellular permeability in epithelial tissue increases the percentage of input vector that will transduce that target tissue. Specific examples show that receptors for retrovirus are preferentially accessible on the basolateral surface of airway epithelia, and permeabilizing such tissues results in greater infection with retrovirus. This has important implications in gene therapy, for example, to treat cystic fibrosis with the CFTR gene.

Abstract: Retroviral vector particle producing cells are provided, wherein the cell (a) has greater than 5 stably integrated copies of a retroviral vector construct; (b) produces greater than 10 infectious recombinant retroviral vector particles per cell per day; and (c) produces replication incompetent retroviral vector particles.

Abstract: Retroviral vector constructs are described which have a 5′ LTR, a tRNA binding site, a packaging signal, one or more heterologous sequences, an origin of second strand synthesis and a 3′ LTR, wherein the vector construct lacks retroviral gag/pol or env coding sequences. In addition, gag/pol, and env expression cassettes are described wherein the expression cassettes lack a consecutive sequence of more than 8 nucleotides in common. The above-described retroviral vector constructs, gag/pol and env expression cassettes may be utilized to construct producer cell lines which preclude the formation of replication competent virus.

Abstract: Retroviral vector constructs are described which have a 5' LTR, a tRNA binding site, a packaging signal, one or more heterologous sequences, an origin of second strand synthesis and a 3' LTR, wherein the vector construct lacks retroviral gag/pol or env coding sequences. In addition, gag/pol, and env expression-cassettes are described wherein the expression cassettes lack a consecutive sequence of more than 8 nucleotides in common. The above-described retroviral vector constructs, gag/pol and env expression cassettes may be utilized to construct producer cell lines which preclude the formation of replication competent virus.

Abstract: The present invention provides a method of destroying selected tumor cells comprising administering to a warm-blooded animal a vector construct which directs the expression of at least one immunogenic, non-tumorigenic form of an altered cellular component normally associated with the selected tumor cells. Also provided are vector constructs which direct the expression of altered cellular components. Representative altered cellular components include ras.sup.*, p53.sup.*, Rb.sup.*, alter protein encoded by the Wilms' tumor gene, ubiquitin.sup.*, mucin.sup.*, DCC, APC, MCC, neu, an altered receptor, and bcr/abl. Also provided are recombinant viruses carrying a vector construct, target cells infected with the recombinant virus, and pharmaceutical compositions comprising the recombinant virus and a pharmaceutically acceptable carrier or diluent.

Abstract: Retroviral vectors for directing expression of full length factor VIII in transduced host cells, plasmids encoding the same, and host cells transformed, transfected, or transduced therewith are disclosed. Also disclosed are retroviral particles comprising such retrovital vectors, as are methods for making such particles in suitable packaging cells. Retroviral particles so produced may be amphotropic, ecotropic, polytropic, or xenotropic; alternatively, they may comprise chimeric or hybrid envelope proteins to alter host range. Also described are retrovital particles comprising retroviral vectors for directing full length factor VIII expression which are complement resistant. Pharmaceutical compositions comprising retrovital particles of the invention are also disclosed, as are methods of treating mammals, particularly humans, afflicted with hemophilia.