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.

The present disclosure provides methods and compositions for genetically modifying lymphocytes, for example T cells and/or NK cells. In some embodiments, the methods include reaction mixtures, and resulting cell formulations, that are created using whole blood, or a component thereof that is not a PBMC, and additionally comprise T cells and recombinant retroviral particles having polynucleotides that encode a CAR. In some embodiments, modified lymphocytes are reintroduced into a subject subcutaneously. In some embodiments, polynucleotides that provide T cells the ability to regulate cell survival and proliferation in response to binding to a CAR, are provided.

The present invention provides new stable packaging cell lines and producer cell lines as well as methods to obtain them, and a new method to produce lentiviral vectors using such cell lines. New methods and packaging cell lines of the invention are generated using a baculo-AAV hybrid system for stable expression of structural and regulatory lentiviral proteins, such system comprising a baculoviral backbone containing an integration cassette flanked by AAV ITR, in combination with a plasmid encoding rep protein. This system allows to obtain a stable integration of the structural and regulatory HIV-1 proteins gag/pol and rev. The system allows to obtain a first intermediate including only the structural and regulatory HIV proteins gag/pol and rev, to be used as starting point to obtain stable packaging cell lines as well as producer cell lines.

The present disclosure relates to methods for producing lentiviral vectors using mammalian cells. Specifically, the methods utilize three plasmids, rather than four, to provide the required packaging elements and transfer vector to a cell, allowing for the production of a large number of lentiviral vectors in mammalian cells, including suspension-based cells. These methods allow for the production of lentiviral vectors that can be tailored to include a specific gene of interest.

The present invention provides a retroviral or lentiviral vector having a viral envelope which comprises a mitogenic T-cell activating transmembrane protein which comprises: (i) a mitogenic domain which binds a mitogenic tetraspanin, and (ii) a transmembrane domain; wherein the mitogenic T-cell activating transmembrane protein is not part of a viral envelope glycoprotein. When cells such as T-cells or Natural Killer cells are transduced by such a viral vector, they are activated by the mitogenic T-cell activating transmembrane protein.

A modified U1 snRNA, wherein said modified U1 snRNA has been modified to bind to a nucleotide sequence within the packaging region of a lentiviral vector genome sequence.

Provided is a lentivirus packaging system, which comprises: a transfer plasmid comprising a nucleotide sequence of TAR-reserved-chimeric 5′ long terminal repeat (LTR); at least one packaging plasmid comprising a nucleotide sequence encoding TAR RNA binding protein, a nucleotide sequence of rev gene, a nucleotide sequence of gag gene, and a nucleotide sequence of pol gene; and an envelope plasmid. Due to the expression of gene of TAR RNA binding protein by the packaging plasmids, the produced lentivirus has higher virus titer and can improve the transduction rate and the gene delivery efficiency during cell transduction. The present invention further provides a method of improving lentivirus production in a host cell, which comprises using the lentivirus packaging system to transfect the host cell. The present invention further provides a cell transduced by the lentivirus and a method of using the cell for treating cancer.

Provided herein are non-cell particles, e.g. virus particles or virus-like particles, such as pseudotyped lentiviral-like particles, containing an exogenous CD24 or a biologically active portion of CD24. In some embodiments, the non-cell particles, e.g. virus particles or virus-like particles, such as pseudotyped lentiviral-like particles, can further contain an exogenous CD47 or a biologically active portion of CD47. Also provided herein are compositions containing such non-cell particles and methods of making and using the non-cell particles.

The present invention relates to a method for obtaining stable pseudotyped lentiviral particles including a heterologous gene of interest, comprising the following steps: a) transfecting at least one plasmid in appropriate cell lines, wherein said at least one plasmid comprises the gene of interest, the rev, gag and pol genes, and a sequence coding for an ERV syncytin, wherein the rev, gag and pol genes are retroviral genes; b) incubating the transfected cells obtained in a), so that they produce the stable pseudotyped lentiviral particles in the supernatant; and c) harvesting and concentrating the stable lentiviral particles obtained in b).

The present invention also relates to a method to transduce immune cells using lentiviral vectors pseudotyped with an ERV syncytin glycoprotein. The method can be performed on non-stimulated blood cells or on cells stimulated briefly with IL7, and the cells can be expanded.

The stable pseudotyped lentiviral particles obtained are particularly useful in gene therapy.

The present disclosure provides methods for genetically modifying lymphocytes and methods for performing adoptive cellular therapy that include transducing T cells and/or NK cells. The methods can include inhibitory RNA molecule(s) and/or engineered signaling polypeptides that can include a lymphoproliferative element, and/or a chimeric antigen receptor (CAR), for example a microenvironment restricted biologic CAR (MRB-CAR). Additional elements of such engineered signaling polypeptides are provided herein, such as those that drive proliferation and regulatory elements therefor, as well as replication incompetent recombinant retroviral particles and packaging cell lines and methods of making the same. Numerous elements and methods for regulating transduced and/or genetically modified T cells and/or NK cells are provided, such as, for example, those including riboswitches, MRB-CARs, recognition domains, and/or pH-modulating agents.