The present disclosure relates to a method for constructing a producer cell and the producer cell obtained by the method, wherein the producer cell is for producing a retroviral vector carrying a nucleic acid fragment of interest.

Conditionally replicating recombinant cells, compositions and vaccines having the cells, and methods of using the cells, are provided.

In alternative embodiments, the invention provides methods for treating, ameliorating or protecting (preventing) an individual or a patient against a disease, an infection or a condition responsive to an increased paracrine polypeptide level in vivo comprising: providing a paracrine polypeptide-encoding nucleic acid or gene operatively linked to a transcriptional regulatory sequence; or an expression vehicle, a vector, a recombinant virus, or equivalent, having contained therein a paracrine-encoding nucleic acid or gene, and the expression vehicle, vector, recombinant virus, or equivalent can express the paracrine-encoding nucleic acid or gene in a cell or in vivo; and administering or delivering the paracrine polypeptide-encoding nucleic acid or gene operatively linked to a transcriptional regulatory sequence, or the expression vehicle, vector, recombinant virus, or equivalent, to an individual or a patient in need thereof, thereby treating, ameliorating or protecting (preventing) the individual or patient against the disease, infection or condition responsive to an increased paracrine polypeptide level.

Provided is an rtTA and single chain rtTA variants and uses thereof for inducible expression of a nucleic acid of interest. Nucleic acid molecules comprising an improved rtTA and/or sc rtTA sequence according to the invention are also provided, as well as vectors, replicons and cells comprising such nucleic acid molecules.

Recombinant adenovirus genomes that include a synthetic transcriptional circuit are described. Synthetic adenoviruses positively regulated using two-step transcriptional amplification (TSTA) are further described. Selection of the heterologous promoter is based on the desired replication characteristics of the synthetic virus. For example, the heterologous promoter can be a constitutive promoter, a tumor-specific promoter or a tissue-specific promoter.

The present invention relates to a stable method for introducing at least one inducible cassette into a cell, and permitting controllable transcription from within that inducible cassette. The method may be used for any cell type, from any eukaryotic organism, but has a particular application in the introduction of inducible cassettes into pluripotent stem cells, such as animal or human pluripotent stem cells (hPSCs). The inducible cassette is controllably inserted in such a way to ensure that the genetic material it contains is not silenced or subject to negative influences from the insertion site, and transcription of the genetic material is controlled.

The present invention relates to the preparation of mesenchymal stem cells, which are for the proliferation of viral vectors and viruses, and enable virus production and release timing control such that tumor targeting can be improved and viruses can be mass-produced. In addition, the tumorigenesis of mesenchymal stem cells of the present invention can be fundamentally blocked, safety is secured by enabling virus production and release to be controlled at desired time points, and antitumor effects can be maximized.

Recombinant expression vectors are disclosed that include a control sequence for recombinant expression of proteins of interest; the control sequence combines a mCMV enhancer sequence with a rat EF-1alpha intron sequence. Some of the vectors are useful for tetracycline-inducible expression. Some of the vectors contain a 5′ PiggyBac ITR and a 3′ PiggyBac ITR to promote genomic integration into a host cell chromosome. A method of selecting a stable production cell line for manufacturing a protein of interest is also disclosed. Also disclosed are mammalian host cells comprising the inventive recombinant expression vectors and a method of producing a protein of interest, in vitro, involving the mammalian host cell.

The invention provides methods for reprogramming somatic cells to generate multipotent or pluripotent cells. Such methods are useful for a variety of purposes, including treating or preventing a medical condition in an individual. The invention further provides methods for identifying an agent that reprograms somatic cells to a less differentiated state.

The present disclosure provides dual viruses capable of producing a primary virus and a secondary virus, and dual oncolytic viruses capable of producing a primary oncolytic virus and a secondary oncolytic virus.