Abstract: Provided herein are anti-idiotype antibodies that specifically recognize anti-CD19 antibody moieties, in particular, anti-CD19 antibody moieties present in recombinant receptors, including chimeric antigen receptors (CARs). The disclosure further relates to uses of anti-idiotype antibodies for specifically identifying and/or selecting cells expressing such recombinant receptors, such as anti-CD19 CART cells. The disclosure further relates to uses of anti-idiotype antibodies for specifically activating such cells.

Abstract: Provided herein are BCMA-binding molecules, including anti-BCMA antibodies and antigen-binding fragments thereof such as heavy chain variable (VH) regions and single-chain antibody fragments, and chimeric receptors comprising the anti-BCMA binding molecules such as chimeric antigen receptors (CARs). In some embodiments, the anti-BCMA antibodies or antigen-binding fragments thereof specifically bind to BCMA-1. Among the anti-BCMA antibodies are human antibodies, including those that compete for binding to BCMA with reference antibodies, such as a non-human reference antibody. Also provided are genetically engineered cells expressing the CARs or BCMA-binding molecules and uses thereof such as in adoptive cell therapy.

Abstract: Provided are anti-idiotype antibodies that specifically recognize anti-ROR1 antibody moieties, in particular, anti-ROR1 antibody moieties present in recombinant receptors, including chimeric antigen receptors (CARs). The disclosure further relates to uses of anti-idiotype antibodies for specifically identifying and/or selecting cells expressing such recombinant receptors, such as anti-ROR1 CAR T cells. The disclosure further relates to uses of anti-idiotype antibodies for specifically blocking or activating such cells.

Abstract: The present disclosure provides compositions and methods for stimulating, enriching, expanding, and/or activating engineered cells that express a recombinant receptor, e.g., a chimeric antigen receptor. In some embodiments, the provided methods include ex vivo or in vitro stimulation, enrichment, expansion, and/or activation of cells by incubation with a particle, e.g., a bead particle, attached to a binding molecule, such as a polypeptide antigen or anti-idiotype antibody, that recognizes or binds to the recombinant receptor. Also provided herein are methods for transfecting or transducing cells that have not been previously incubated with an activating or stimulating agent, such as have not been incubated with anti-CD3/anti-CD28 antibodies and/or one or more recombinant cytokines, by transducing or transfecting the cells in the presence of the particles with attached binding molecules. In some embodiments, the provided compositions can be used in methods to prepare cells, e.g.

Abstract: Provided are anti-idiotype antibodies that specifically recognize anti-GPRC5D antibody moieties, in particular, anti-GPRC5D antibody moieties present in recombinant receptors, including chimeric antigen receptors (CARs). The disclosure further relates to uses of antiidiotype antibodies for specifically identifying and/or selecting cells expressing such recombinant receptors, such as anti-GPRC5D CAR T cells. The disclosure further relates to uses of anti-idiotype antibodies for specifically activating such cells.

Abstract: Provided herein are BCMA-binding molecules, including anti-BCMA antibodies and antigen-binding fragments thereof such as heavy chain variable (VH) regions and single-chain antibody fragments, and chimeric receptors comprising the anti-BCMA binding molecules such as chimeric antigen receptors (CARs). In some embodiments, the anti-BCMA antibodies or antigen-binding fragments thereof specifically bind to BCMA-1. Among the anti-BCMA antibodies are human antibodies, including those that compete for binding to BCMA with reference antibodies, such as a non-human reference antibody. Also provided are genetically engineered cells expressing the CARs or BCMA-binding molecules and uses thereof such as in adoptive cell therapy.

Abstract: Provided are anti-idiotype antibodies that specifically recognize anti-BCMA antibody moieties, in particular, anti-BC-MA antibody moieties present in recombinant receptors, including chimeric antigen receptors (CARs). The disclosure further relates to uses of antiidiotype antibodies for specifically identifying and/or selecting cells expressing such recombinant receptors, such as anti-BCMA CAR T cells. The disclosure further relates to uses of anti-idiotype antibodies for specifically activating such cells.

Abstract: Provided are receptor tyrosine kinase-like orphan receptor 1 (ROR1)-binding molecules, in particular, to human antibodies specific for ROR1, including antibody fragments. The present disclosure further relates to recombinant receptors, including chimeric antigen receptors (CARs) that contain such antibodies or fragments, and polynucleotides that encode the antibodies, antigen-binding fragments or receptors specific for ROR1. The disclosure further relates to genetically engineered cells, containing such ROR1-binding proteins and receptors, and related methods and uses thereof in adoptive cell therapy.

Abstract: Provided herein are chimeric receptors, such as chimeric antigen receptors (CARs), comprising BCMA-binding molecules, such as anti-BCMA antibodies and antigen-binding fragments thereof, such as heavy chain variable (VH) regions and single-chain antibody fragments, and encoding polynucleotides. In some embodiments, the anti-BCMA chimeric receptors specifically bind to BCMA. Among the anti-BCMA-binding molecules are human antibodies, including those that compete for binding to BCMA with reference antibodies, such as a non-human reference antibody. Also provided are genetically engineered cells expressing the CARs and uses thereof such as in adoptive cell therapy.

Abstract: Provided herein are chimeric receptors, such as chimeric antigen receptors (CARs), comprising BCMA-binding molecules, such as anti-BCMA antibodies and antigen-binding fragments thereof, such as heavy chain variable (VH) regions and single-chain antibody fragments, and encoding polynucleotides. In some embodiments, the anti-BCMA chimeric receptors specifically bind to BCMA. Among the anti-BCMA-binding molecules are human antibodies, including those that compete for binding to BCMA with reference antibodies, such as a non-human reference antibody. Also provided are genetically engineered cells expressing the CARs and uses thereof such as in adoptive cell therapy.

Abstract: Provided herein are BCMA-binding molecules, including anti-BCMA antibodies and antigen-binding fragments thereof such as heavy chain variable (VH) regions and single-chain antibody fragments, and chimeric receptors comprising the anti-BCMA binding molecules such as chimeric antigen receptors (CARs). In some embodiments, the anti-BCMA antibodies or antigen-binding fragments thereof specifically bind to BCMA-1. Among the anti-BCMA antibodies are human antibodies, including those that compete for binding to BCMA with reference antibodies, such as a non-human reference antibody. Also provided are genetically engineered cells expressing the CARs or BCMA-binding molecules and uses thereof such as in adoptive cell therapy.

Abstract: Provided herein are immunomodulatory polypeptides containing first and second submits of a cytokine or a chemokine connected by a joining region containing a targeting moiety that binds to a target molecule. In some aspects, the disclosure further relates to engineered cells and compositions comprising the immunomodulatory polypeptides and methods for their administration to subjects. In some embodiments, the cells engineered to contain the immunomodulatory polypeptide, such as T cells, further contain a genetically engineered antigen receptor that specifically binds to antigens, such as a chimeric antigen receptor (CAR). In some embodiments, features of the polypeptides, engineered cells, and methods provide for improved treatment of diseases or disorders, such as by reducing adverse effects of cytokine or chemokine therapy, or increasing activity, efficacy and/or persistence or decreasing immunogenicity of adoptive cell therapy.