Provided herein are novel therapeutic compositions and methods that keep cellular immunotherapies in the circulation or at the site of injection for extended periods of time without resorting to the use of cytotoxic preconditioning. More specifically the compositions and methods herein lymphodeplete and reduce or ablate sites in the secondary lymphatics where the cellular immunotherapy is bound and sequestered, without the use of cytotoxic preconditioning.

Disclosed herein are recombinant meganucleases engineered to recognize and cleave a recognition sequence present in the human T cell receptor alpha constant region gene. The present disclosure further relates to the use of such recombinant meganucleases in methods for producing genetically-modified eukaryotic cells.

The present invention relates to methods for developing engineered immune cells such as T-cells for immunotherapy that have a higher potential of persistence and/or engraftment in host organism. IN particular, this method involves an inactivation of at least one gene involved in self/non self recognition, combined with a step of contact with at least one non-endogenous immunosuppressive polypeptide. The invention allows the possibility for a standard and affordable adoptive immunotherapy, whereby the risk of GvH is reduced.

Graft-versus-host disease (GVHD) is a lethal complication of allograft transplantation. The current strategy of using immunosuppressive agents to control GVHD may cause general immune suppression and limit the effectiveness of allograft transplantation. Adoptive transfer of regulatory T cells (Treg) can prevent GVHD in rodents, indicating the therapeutic potential of Treg for GVHD in humans. However, the clinical application of Treg-based therapy is hampered by the low frequency of human Treg and the lack of a reliable model to test their therapeutic effects in vivo. Human alloantigen-specific Treg are generated from antigenically-na?ve precursors in a large scale ex vivo using allogeneic activated B cells as stimulators. Here, a human allogeneic GVHD model is established in humanized mice to mimic GVHD after allograft transplantation in humans. The ex vivo-induced CD8.sup.hi Treg can control GVHD in an allo-specific manner by reduction of alloreactive T-cell proliferation, and inflammatory cytokine and chemokine secretion within target organs through a CTLA-4-dependent mechanism in humanized mice. Importantly, the Tregs can induce long-term tolerance effectively without compromising general immunity and graft-versus-tumor (GVT) activity.

Graft-versus-host disease (GVHD) is a lethal complication of allograft transplantation. The current strategy of using immunosuppressive agents to control GVHD may cause general immune suppression and limit the effectiveness of allograft transplantation. Adoptive transfer of regulatory T cells (Treg) can prevent GVHD in rodents, indicating the therapeutic potential of Treg for GVHD in humans. However, the clinical application of Treg-based therapy is hampered by the low frequency of human Treg and the lack of a reliable model to test their therapeutic effects in vivo. Human alloantigen-specific Treg are generated from antigenically-na?ve precursors in a large scale ex vivo using allogeneic activated B cells as stimulators. Here, a human allogeneic GVHD model is established in humanized mice to mimic GVHD after allograft transplantation in humans. The ex vivo-induced CD8.sup.hi Treg can control GVHD in an allo-specific manner by reduction of alloreactive T-cell proliferation, and inflammatory cytokine and chemokine secretion within target organs through a CTLA-4-dependent mechanism in humanized mice. Importantly, the Tregs can induce long-term tolerance effectively without compromising general immunity and graft-versus-tumor (GVT) activity.

The invention provides methods and compositions for administration of allogeneic lymphocytes as an exogenous source of CD4+ T cell help for endogenous, tumor-reactive CD8+ T cells. Depletion of CD8+ T cells from the donor lymphocyte infusion reduces the risk of sustained engraftment and graft-versus-host disease. Removal of regulatory T cells from the infused population may augment the ability of non-regulatory T cells to provide help for endogenous effectors of anti-tumor immunity. Allogeneic T cell therapy is typically given in the context of allogeneic stem cell transplantation, in which the patient receives highly immunosuppressive conditioning followed by an infusion of a stem cell graft containing unselected populations of mature T cells. In the treatment described here, the graft is engineered to minimize the possibility of sustained donor cell engraftment, and the anti-tumor effector T cells derive from the host.

The present invention provides improved and/or shortened methods for expanding TILs and producing therapeutic populations of TILs, including novel methods for expanding TIL populations in a closed system that lead to improved efficacy, improved phenotype, and increased metabolic health of the TILs in a shorter time period, while allowing for reduced microbial contamination as well as decreased costs. Such TILs find use in therapeutic treatment regimens.

The present invention provides improved and/or shortened methods for expanding TILs and producing therapeutic populations of TILs, including novel methods for expanding TIL populations in a closed system that lead to improved efficacy, improved phenotype, and increased metabolic health of the TILs in a shorter time period, while allowing for reduced microbial contamination as well as decreased costs. Such TILs find use in therapeutic treatment regimens.

Disclosed herein are engineered cells and/or hypoimmunogenic cells including engineered cells and/or hypoimmunogenic stem cells, engineered cells and/or hypoimmunogenic cells differentiated therefrom, and engineered cells and/or hypoimmunogenic CAR-T cells (primary or differentiated from engineered and/or hypoimmunogenic stem cells) and related methods of their use and generation comprising reduced expression of one or more Y chromosome genes and reduced expression of MHC I and/or MHC II human leukocyte antigen molecules and overexpression of CD47. Provided herein are cells further exhibiting reduced expression of T-cell receptors.

Provided are engineered primary blood and monocyte-derived dendritic cells, wherein the dendritic cell expresses a functional Tax protein from a T cell leukemia virus, and methods of making and using the same.