Molecules that bind to CS1 polypeptides

Abstract

This document provides methods and materials involved in binding a molecule (e.g., an antibody domain, an antigen binding fragment, an antibody, a chimeric antigen receptor (CAR), a cell engager, or an antibody-drug conjugate (ADC)) to a CS1 polypeptide. For example, this document provides binders (e.g., antibody domains, antigen binding fragments, antibodies, CARs, cell engagers, and ADCs) that bind to a CS1 polypeptide and methods and materials for using such binders (or cells expressing such binder such as a cell expressing a CAR) to treat cancer (e.g., multiple myeloma).

Description

Attorney Docket No.07039-2338WO1 / 2024-299 MOLECULES THAT BIND TO CS1 POLYPEPTIDES CROSS-REFERENCE TO RELATED APPLICATIONS This application claims the benefit of U.S. Patent Application Serial No. 63 / 672,543, filed on July 17, 2024. The disclosure of the prior application is considered part of, and is incorporated by reference in, the disclosure of this application. SEQUENCE LISTING This application contains a Sequence Listing that has been submitted electronically as an XML file named “07039-2338WO1_SL.xml.” The XML file, created on July 7, 2025, is 343,829 bytes in size. The material in the XML file is hereby incorporated by reference in its entirety. TECHNICAL FIELD This document relates to methods and materials involved in binding a molecule (e.g., an antibody domain, an antigen binding fragment, an antibody, a chimeric antigen receptor (CAR), a cell engager, or an antibody-drug conjugate (ADC)) to a CS1 polypeptide. For example, this document provides binders (e.g., antibody domains, antigen binding fragments, antibodies, CARs, cell engagers, and ADCs) that bind to a CS1 polypeptide. This document also provides methods and materials for using such binders to treat cancer (e.g., multiple myeloma). BACKGROUND Multiple myeloma accounts for over 10% of all hematological malignancies and is responsible for approximately 13,000 deaths each year in the US (Rajkumar, Am. J. Hematol., 97(8):1086-1107 (2022)). Multiple myeloma is largely incurable; the only curative option to date is allogeneic hematopoietic stem cell transplantation, which has a high rate of nonrelapse mortality (including from graft-vs-host disease, infections, and conditioning regimens) and is not a viable option for many patients (Liberatore et al., Front. Oncol., 14:1402106 (2024)). New treatment strategies resulting in durable remission are urgently needed.Attorney Docket No.07039-2338WO1 / 2024-299 SUMMARY This document provides methods and materials involved in binding a molecule (e.g., an antibody domain, an antigen binding fragment, an antibody, a CAR, a cell engager, or an ADC) to a CS1 polypeptide (also known as CD319, CRACC, or SLAMF7). For example, this document provides binders (e.g., antibody domains, antigen binding fragments, antibodies, CARs, cell engagers, and ADCs) that bind to a CS1 polypeptide and methods and materials for using one or more such binders to treat a mammal (e.g., a human) having cancer (e.g., multiple myeloma). As described herein, binders (e.g., antibody domains, antigen binding fragments, antibodies, CARs, cell engagers, and / or ADCs) can be designed to have the ability to bind to a CS1 polypeptide. For example, a binder (e.g., an antibody domain, an antigen binding fragment, an antibody, a CAR, a cell engager, or an ADC) provided herein can include an antigen binding domain having the ability to bind to a polypeptide comprising, consisting essentially of, or consisting of the amino acid sequence of a human CS1 polypeptide as set forth in any one of SEQ ID NOs:65-66 (see, e.g., Example 2). In some cases, at least one set of three CDRs of an antigen binding domain provided herein (e.g., SEQ ID NOs:1-3, SEQ ID NOs:9-11, SEQ ID NOs:17-19, SEQ ID NOs:25-27, SEQ ID NOs:33-35, SEQ ID NOs:41-43, SEQ ID NOs:49-51, or SEQ ID NOs:57-59) can be engineered into a CAR to create CAR+cells (e.g., CAR+T cells, CAR+stem cells such as CAR+induced pluripotent stem cells, or CAR+natural killer (NK) cells) having the ability to target CS1+cells (e.g., CS1+cells such as CS1+cancer cells and CS1+cancer-associated fibroblasts (CAFs)), can be engineered into an antibody structure that includes an Fc region to create antibodies having the ability to target CS1+cells (e.g., CS1+cells such as CS1+cancer cells and CS1+CAFs) and induce antibody- dependent cell-mediated cytotoxicity (ADCC) against the targeted CS1+cells, and / or can be engineered into a cell engager such as a bi-specific T cell engager (e.g., a BiTE), a bi- specific killer engager (e.g., a BiKE), and / or a tri-specific killer engager (e.g., a TriKE) to create cell engagers having the ability to target CS1+cells (e.g., CS1+cells such as CS1+cancer cells and CS1+CAFs) and induce one or more immune responses (e.g., T cell immune responses and / or ADCC using a cell engager in the absence of an Fc-containing antibody) against the targeted CS1+cells. It is noted that BiKE- and TriKE-mediated killing can be referred to ADCC even though it is not initiated by an Fc domain.Attorney Docket No.07039-2338WO1 / 2024-299 In addition, as described herein, binders (e.g., antibody domains, antigen binding fragments, and antibodies) provided herein can be used to create conjugates that include the binder and a drug (e.g., ADCs). For example, ADCs such as full antibody-drug conjugates, Fab-drug conjugates, and / or antibody domain-drug conjugates can be designed to include an appropriate binder provided herein to create the conjugate. Such conjugates can be used to deliver the drug payload to target cells such as cancer cells (e.g., CS1+cancer cells). As also described herein, cells (e.g., host cells) can be designed to express one or more binders (e.g., antibody domains, antigen binding fragments, antibodies, CARs, and / or cell engagers) having the ability to bind to a CS1 polypeptide. For example, cells such as T cells (e.g., CTLs), stem cells (e.g., induced pluripotent stem cells), or NK cells can be engineered to express one or more CARs having the ability to bind to a CS1 polypeptide. Such cells (e.g., CS1-specific CAR+T cells or NK cells) can be used to treat cancer (e.g., multiple myeloma). This document also provides methods for using binders (e.g., antibody domains, antigen binding fragments, antibodies, cell engagers, and / or ADCs) having the ability to bind to a CS1 polypeptide or cells expressing one or more binders (e.g., antibody domains, antigen binding fragments, antibodies, CARs, and / or cell engagers) having the ability to bind to a CS1 polypeptide to treat cancer (e.g., multiple myeloma). As described herein, binders (e.g., antibody domains, antigen binding fragments, antibodies, cell engagers, and / or ADCs) provided herein can be used to treat a mammal (e.g., a human) having cancer (e.g., multiple myeloma). For example, a mammal (e.g., a human) having cancer (e.g., a CS1+cancer) can be administered a composition comprising one or more binders (e.g., one or more antibody domains, one or more antigen binding fragments, one or more antibodies, one or more cell engagers, and / or one or more ADCs) provided herein (or a nucleic acid, a vector, or a host cell (e.g., CAR+cells) provided herein) to reduce the number of cancer cells within the mammal, to induce ADCC against cancer cells within the mammal, and / or to increase the survival duration of the mammal from cancer. In some cases, a binder (e.g., an antibody domain, an antigen binding fragment, an antibody, a cell engager, or an ADC) provided herein can be used to detect the presence or absence of a CS1 polypeptide. For example, a binder (e.g., an antibody domain, an antigen binding fragment, an antibody, a cell engager, or an ADC) provided herein can beAttorney Docket No.07039-2338WO1 / 2024-299 used to determine whether or not a sample (e.g., a biological sample such tumor biopsy) obtained from a mammal (e.g., a human) contains CS1+cells (e.g., CS1+cells such as CS1+cancer cells and CS1+CAFs). Having the ability to detect the presence or absence of a CS1 polypeptide (e.g., CS1+cancer cells) can allow clinicians, health professionals, and patients to make better decisions about possible treatment options. For example, detection of CS1+cancer cells within a mammal can allow clinicians, health professionals, and patients to select an appropriate anti-cancer treatment that targets the CS1+cancer cells. Such treatments that target the CS1+cancer cells can include administration of an anti-CS1 antibody such as elotuzumab (e.g., EMPLICITI®) and / or one or more of the binders described herein having the ability to bind to a CS1 polypeptide and / or administration of one or more cells (e.g., CS1-specific CAR+T cells or NK cells) designed to express a binder described herein. In general, one aspect of this document features binding molecules that can include: (i) a heavy chain variable domain or region comprising the amino acid sequences set forth in SEQ ID NO:1 (or SEQ ID NO:1 with one, two, or three amino acid additions, deletions, or substitutions), SEQ ID NO:2 (or SEQ ID NO:2 with one, two, or three amino acid additions, deletions, or substitutions), and SEQ ID NO:3 (or SEQ ID NO:3 with one, two, or three amino acid additions, deletions, or substitutions), and a light chain variable domain or region comprising the amino acid sequences set forth in SEQ ID NO:9 (or SEQ ID NO:9 with one, two, or three amino acid additions, deletions, or substitutions), SEQ ID NO:10 (or SEQ ID NO:10 with one, two, or three amino acid additions, deletions, or substitutions), and SEQ ID NO:11 (or SEQ ID NO:11 with one, two, or three amino acid additions, deletions, or substitutions); (ii) a heavy chain variable domain or region comprising the amino acid sequences set forth in SEQ ID NO:17 (or SEQ ID NO:17 with one, two, or three amino acid additions, deletions, or substitutions), SEQ ID NO:18 (or SEQ ID NO:18 with one, two, or three amino acid additions, deletions, or substitutions), and SEQ ID NO:19 (or SEQ ID NO:19 with one, two, or three amino acid additions, deletions, or substitutions), and a light chain variable domain or region comprising the amino acid sequences set forth in SEQ ID NO:25 (or SEQ ID NO:25 with one, two, or three amino acid additions, deletions, or substitutions), SEQ ID NO:26 (or SEQ ID NO:26 with one, two, or three amino acid additions, deletions, or substitutions), and SEQ ID NO:27 (or SEQ ID NO:27 with one, two, or three amino acidAttorney Docket No.07039-2338WO1 / 2024-299 additions, deletions, or substitutions); (iii) a heavy chain variable domain or region comprising the amino acid sequences set forth in SEQ ID NO:33 (or SEQ ID NO:33 with one, two, or three amino acid additions, deletions, or substitutions), SEQ ID NO:34 (or SEQ ID NO:34 with one, two, or three amino acid additions, deletions, or substitutions), and SEQ ID NO:35 (or SEQ ID NO:35 with one, two, or three amino acid additions, deletions, or substitutions), and a light chain variable domain or region comprising the amino acid sequences set forth in SEQ ID NO:41 (or SEQ ID NO:41 with one, two, or three amino acid additions, deletions, or substitutions), SEQ ID NO:42 (or SEQ ID NO:42 with one, two, or three amino acid additions, deletions, or substitutions), and SEQ ID NO:43 (or SEQ ID NO:43 with one, two, or three amino acid additions, deletions, or substitutions); or (iv) a heavy chain variable domain or region comprising the amino acid sequences set forth in SEQ ID NO:49 (or SEQ ID NO:49 with one, two, or three amino acid additions, deletions, or substitutions), SEQ ID NO:50 (or SEQ ID NO:50 with one, two, or three amino acid additions, deletions, or substitutions), and SEQ ID NO:51 (or SEQ ID NO:51 with one, two, or three amino acid additions, deletions, or substitutions), and a light chain variable domain or region comprising the amino acid sequences set forth in SEQ ID NO:57 (or SEQ ID NO:57 with one, two, or three amino acid additions, deletions, or substitutions), SEQ ID NO:58 (or SEQ ID NO:58 with one, two, or three amino acid additions, deletions, or substitutions), and SEQ ID NO:59 (or SEQ ID NO:59 with one, two, or three amino acid additions, deletions, or substitutions). The binding molecule can have the ability to bind to a polypeptide sequence set forth in any one of SEQ ID NOs:65-66. The binding molecule can include (i). For example, the binding molecule can include (i) where said heavy chain variable domain comprises an amino acid sequence having at least 90 percent identity to the amino acid sequence set forth in SEQ ID NO:8, and wherein said light chain variable region comprises an amino acid sequence having at least 90 percent identify to the amino acid sequence set forth in SEQ ID NO:16. The binding molecule can include (ii). For example, the binding molecule can include (ii) wherein said heavy chain variable domain comprises an amino acid sequence having at least 90 percent identity to the amino acid sequence set forth in SEQ ID NO:24, and wherein said light chain variable region comprises an amino acid sequence having at least 90 percent identify to the amino acid sequence set forth in SEQ ID NO:32. The binding molecule can include (iii). For example, the binding molecule can include (iii)Attorney Docket No.07039-2338WO1 / 2024-299 wherein said heavy chain variable domain comprises an amino acid sequence having at least 90 percent identity to the amino acid sequence set forth in SEQ ID NO:40, and wherein said light chain variable region comprises an amino acid sequence having at least 90 percent identify to the amino acid sequence set forth in SEQ ID NO:48. The binding can include (iv). For example, the binding molecule can include (iv) wherein said heavy chain variable domain comprises an amino acid sequence having at least 90 percent identity to the amino acid sequence set forth in SEQ ID NO:56, and wherein said light chain variable region comprises an amino acid sequence having at least 90 percent identify to the amino acid sequence set forth in SEQ ID NO:64. The binding molecule can be a monoclonal antibody. The binding molecule can be an scFv antibody. In another aspect, this document features compositions including such binding molecules. In another aspect, this document features nucleic acids including a nucleic acid sequence encoding at least part of a binding molecule that includes: (i) a heavy chain variable domain or region comprising the amino acid sequences set forth in SEQ ID NO:1 (or SEQ ID NO:1 with one, two, or three amino acid additions, deletions, or substitutions), SEQ ID NO:2 (or SEQ ID NO:2 with one, two, or three amino acid additions, deletions, or substitutions), and SEQ ID NO:3 (or SEQ ID NO:3 with one, two, or three amino acid additions, deletions, or substitutions), and a light chain variable domain or region comprising the amino acid sequences set forth in SEQ ID NO:9 (or SEQ ID NO:9 with one, two, or three amino acid additions, deletions, or substitutions), SEQ ID NO:10 (or SEQ ID NO:10 with one, two, or three amino acid additions, deletions, or substitutions), and SEQ ID NO:11 (or SEQ ID NO:11 with one, two, or three amino acid additions, deletions, or substitutions); (ii) a heavy chain variable domain or region comprising the amino acid sequences set forth in SEQ ID NO:17 (or SEQ ID NO:17 with one, two, or three amino acid additions, deletions, or substitutions), SEQ ID NO:18 (or SEQ ID NO:18 with one, two, or three amino acid additions, deletions, or substitutions), and SEQ ID NO:19 (or SEQ ID NO:19 with one, two, or three amino acid additions, deletions, or substitutions), and a light chain variable domain or region comprising the amino acid sequences set forth in SEQ ID NO:25 (or SEQ ID NO:25 with one, two, or three amino acid additions, deletions, or substitutions), SEQ ID NO:26 (or SEQ ID NO:26 with one, two, or three amino acid additions, deletions, or substitutions), and SEQ ID NO:27 (or SEQ ID NO:27 with one, two, or three amino acid additions,Attorney Docket No.07039-2338WO1 / 2024-299 deletions, or substitutions); (iii) a heavy chain variable domain or region comprising the amino acid sequences set forth in SEQ ID NO:33 (or SEQ ID NO:33 with one, two, or three amino acid additions, deletions, or substitutions), SEQ ID NO:34 (or SEQ ID NO:34 with one, two, or three amino acid additions, deletions, or substitutions), and SEQ ID NO:35 (or SEQ ID NO:35 with one, two, or three amino acid additions, deletions, or substitutions), and a light chain variable domain or region comprising the amino acid sequences set forth in SEQ ID NO:41 (or SEQ ID NO:41 with one, two, or three amino acid additions, deletions, or substitutions), SEQ ID NO:42 (or SEQ ID NO:42 with one, two, or three amino acid additions, deletions, or substitutions), and SEQ ID NO:43 (or SEQ ID NO:43 with one, two, or three amino acid additions, deletions, or substitutions); or (iv) a heavy chain variable domain or region comprising the amino acid sequences set forth in SEQ ID NO:49 (or SEQ ID NO:49 with one, two, or three amino acid additions, deletions, or substitutions), SEQ ID NO:50 (or SEQ ID NO:50 with one, two, or three amino acid additions, deletions, or substitutions), and SEQ ID NO:51 (or SEQ ID NO:51 with one, two, or three amino acid additions, deletions, or substitutions), and a light chain variable domain or region comprising the amino acid sequences set forth in SEQ ID NO:57 (or SEQ ID NO:57 with one, two, or three amino acid additions, deletions, or substitutions), SEQ ID NO:58 (or SEQ ID NO:58 with one, two, or three amino acid additions, deletions, or substitutions), and SEQ ID NO:59 (or SEQ ID NO:59 with one, two, or three amino acid additions, deletions, or substitutions). The nucleic acid sequence can encode said heavy chain variable domain or region of (i). The nucleic acid sequence can encode said light chain variable domain or region of (i). The nucleic acid sequence can encode said heavy chain variable domain or region of (ii). The nucleic acid sequence can encode said light chain variable domain or region of (ii). The nucleic acid sequence can encode said heavy chain variable domain or region of (iii). The nucleic acid sequence can encode said light chain variable domain or region of (iii). The nucleic acid sequence can encode said heavy chain variable domain or region of (iv). The nucleic acid sequence can encode said light chain variable domain or region of (iv). The nucleic acid can be a viral vector. In another aspect, this document features host cells including such nucleic acids. In another aspect, this document features compositions including such host cells including such nucleic acids.Attorney Docket No.07039-2338WO1 / 2024-299 In another aspect, this document features CARs including an antigen binding domain, a hinge, a transmembrane domain, and one or more signaling domains, wherein said antigen binding domain comprises a binding molecule that includes: (i) a heavy chain variable domain or region comprising the amino acid sequences set forth in SEQ ID NO:1 (or SEQ ID NO:1 with one, two, or three amino acid additions, deletions, or substitutions), SEQ ID NO:2 (or SEQ ID NO:2 with one, two, or three amino acid additions, deletions, or substitutions), and SEQ ID NO:3 (or SEQ ID NO:3 with one, two, or three amino acid additions, deletions, or substitutions), and a light chain variable domain or region comprising the amino acid sequences set forth in SEQ ID NO:9 (or SEQ ID NO:9 with one, two, or three amino acid additions, deletions, or substitutions), SEQ ID NO:10 (or SEQ ID NO:10 with one, two, or three amino acid additions, deletions, or substitutions), and SEQ ID NO:11 (or SEQ ID NO:11 with one, two, or three amino acid additions, deletions, or substitutions); (ii) a heavy chain variable domain or region comprising the amino acid sequences set forth in SEQ ID NO:17 (or SEQ ID NO:17 with one, two, or three amino acid additions, deletions, or substitutions), SEQ ID NO:18 (or SEQ ID NO:18 with one, two, or three amino acid additions, deletions, or substitutions), and SEQ ID NO:19 (or SEQ ID NO:19 with one, two, or three amino acid additions, deletions, or substitutions), and a light chain variable domain or region comprising the amino acid sequences set forth in SEQ ID NO:25 (or SEQ ID NO:25 with one, two, or three amino acid additions, deletions, or substitutions), SEQ ID NO:26 (or SEQ ID NO:26 with one, two, or three amino acid additions, deletions, or substitutions), and SEQ ID NO:27 (or SEQ ID NO:27 with one, two, or three amino acid additions, deletions, or substitutions); (iii) a heavy chain variable domain or region comprising the amino acid sequences set forth in SEQ ID NO:33 (or SEQ ID NO:33 with one, two, or three amino acid additions, deletions, or substitutions), SEQ ID NO:34 (or SEQ ID NO:34 with one, two, or three amino acid additions, deletions, or substitutions), and SEQ ID NO:35 (or SEQ ID NO:35 with one, two, or three amino acid additions, deletions, or substitutions), and a light chain variable domain or region comprising the amino acid sequences set forth in SEQ ID NO:41 (or SEQ ID NO:41 with one, two, or three amino acid additions, deletions, or substitutions), SEQ ID NO:42 (or SEQ ID NO:42 with one, two, or three amino acid additions, deletions, or substitutions), and SEQ ID NO:43 (or SEQ ID NO:43 with one, two, or three amino acid additions, deletions, or substitutions);Attorney Docket No.07039-2338WO1 / 2024-299 or (iv) a heavy chain variable domain or region comprising the amino acid sequences set forth in SEQ ID NO:49 (or SEQ ID NO:49 with one, two, or three amino acid additions, deletions, or substitutions), SEQ ID NO:50 (or SEQ ID NO:50 with one, two, or three amino acid additions, deletions, or substitutions), and SEQ ID NO:51 (or SEQ ID NO:51 with one, two, or three amino acid additions, deletions, or substitutions), and a light chain variable domain or region comprising the amino acid sequences set forth in SEQ ID NO:57 (or SEQ ID NO:57 with one, two, or three amino acid additions, deletions, or substitutions), SEQ ID NO:58 (or SEQ ID NO:58 with one, two, or three amino acid additions, deletions, or substitutions), and SEQ ID NO:59 (or SEQ ID NO:59 with one, two, or three amino acid additions, deletions, or substitutions). The antigen binding domain can include a scFv having the ability to bind to a CS1 polypeptide. The hinge canbe a hinge set forth in any one of SEQ ID NOs:110-117. The hinge can be a CD8 hinge.The transmembrane domain can be a transmembrane domain set forth in any one of SEQID NOs:119-126. The transmembrane domain can be a CD8 transmembrane domain.The CAR can include one or more signaling domains set forth in any one of SEQ IDNOs:128-137. The CAR can include a 4-1BB intracellular signaling domain and a CD3intracellular signaling domain. In another aspect, this document features compositions including such CARs In another aspect, this document features cells that include such a CAR. The cell can be a T cell, a stem cell, or an NK cell. In another aspect, this document features compositions including such cells. In another aspect, this document features nucleic acids including a nucleic acid sequence that can encode such CARs. The nucleic acid can be a viral vector. In another aspect, this document features host cells including nucleic acid including a nucleic acid sequence that can encode such CARs. In another aspect, this document features host cells that express such CARs. The host cell can be a T cell, stem cell, or NK cell. In another aspect, this document features compositions including such host cells. In some cases, host cells including such CARs also can include a second CAR. The second CAR can include an antigen binding domain, a hinge, a transmembrane domain, and one or more signaling domains, where the antigen binding domain includes a scFv having the ability to bind to a B-cell maturation antigen (BCMA) polypeptide. The scFv can include a heavy chain variable domain comprising the amino acid sequences set forth in SEQ ID NO:67, SEQ ID NO:68, and SEQ ID NO:69, and a light chain variable domain or region comprising the amino acid sequences set forth inAttorney Docket No.07039-2338WO1 / 2024-299 SEQ ID NO:70, SEQ ID NO:71, and SEQ ID NO:72. The second CAR can be an activation-inducible CAR. The second CAR can be an expression-inducible CAR In another aspect, this document features cell engagers including a first antigen binding domain, a linker, and a second antigen binding domain, wherein said first antigen binding domain comprises a binding molecule that includes: (i) a heavy chain variable domain or region comprising the amino acid sequences set forth in SEQ ID NO:1 (or SEQ ID NO:1 with one, two, or three amino acid additions, deletions, or substitutions), SEQ ID NO:2 (or SEQ ID NO:2 with one, two, or three amino acid additions, deletions, or substitutions), and SEQ ID NO:3 (or SEQ ID NO:3 with one, two, or three amino acid additions, deletions, or substitutions), and a light chain variable domain or region comprising the amino acid sequences set forth in SEQ ID NO:9 (or SEQ ID NO:9 with one, two, or three amino acid additions, deletions, or substitutions), SEQ ID NO:10 (or SEQ ID NO:10 with one, two, or three amino acid additions, deletions, or substitutions), and SEQ ID NO:11 (or SEQ ID NO:11 with one, two, or three amino acid additions, deletions, or substitutions); (ii) a heavy chain variable domain or region comprising the amino acid sequences set forth in SEQ ID NO:17 (or SEQ ID NO:17 with one, two, or three amino acid additions, deletions, or substitutions), SEQ ID NO:18 (or SEQ ID NO:18 with one, two, or three amino acid additions, deletions, or substitutions), and SEQ ID NO:19 (or SEQ ID NO:19 with one, two, or three amino acid additions, deletions, or substitutions), and a light chain variable domain or region comprising the amino acid sequences set forth in SEQ ID NO:25 (or SEQ ID NO:25 with one, two, or three amino acid additions, deletions, or substitutions), SEQ ID NO:26 (or SEQ ID NO:26 with one, two, or three amino acid additions, deletions, or substitutions), and SEQ ID NO:27 (or SEQ ID NO:27 with one, two, or three amino acid additions, deletions, or substitutions); (iii) a heavy chain variable domain or region comprising the amino acid sequences set forth in SEQ ID NO:33 (or SEQ ID NO:33 with one, two, or three amino acid additions, deletions, or substitutions), SEQ ID NO:34 (or SEQ ID NO:34 with one, two, or three amino acid additions, deletions, or substitutions), and SEQ ID NO:35 (or SEQ ID NO:35 with one, two, or three amino acid additions, deletions, or substitutions), and a light chain variable domain or region comprising the amino acid sequences set forth in SEQ ID NO:41 (or SEQ ID NO:41 with one, two, or three amino acid additions, deletions, or substitutions), SEQ ID NO:42 (or SEQ ID NO:42 with one, two, or three amino acidAttorney Docket No.07039-2338WO1 / 2024-299 additions, deletions, or substitutions), and SEQ ID NO:43 (or SEQ ID NO:43 with one, two, or three amino acid additions, deletions, or substitutions); or (iv) a heavy chain variable domain or region comprising the amino acid sequences set forth in SEQ ID NO:49 (or SEQ ID NO:49 with one, two, or three amino acid additions, deletions, or substitutions), SEQ ID NO:50 (or SEQ ID NO:50 with one, two, or three amino acid additions, deletions, or substitutions), and SEQ ID NO:51 (or SEQ ID NO:51 with one, two, or three amino acid additions, deletions, or substitutions), and a light chain variable domain or region comprising the amino acid sequences set forth in SEQ ID NO:57 (or SEQ ID NO:57 with one, two, or three amino acid additions, deletions, or substitutions), SEQ ID NO:58 (or SEQ ID NO:58 with one, two, or three amino acid additions, deletions, or substitutions), and SEQ ID NO:59 (or SEQ ID NO:59 with one, two, or three amino acid additions, deletions, or substitutions). The first antigen binding domain can be a scFv having the ability to bind to a CS1 polypeptide. The linker can be a linker set forth in any one of SEQ ID NOs:75-79 or SEQ ID NOs:110-117. In some cases, the second antigen binding domain can bind to a polypeptide expressed on the surface of T cells. The polypeptide expressed on the surface of T cells can be a CD3 polypeptide. The second antigen binding domain can be an antigen binding domain set forth in Example 16. In some cases, the second antigen binding domain binds to a polypeptide expressed on the surface of NK cells. The polypeptide expressed on the surface of NK cells can be a CD16a, NKG2A, NKG2D, NKp30, NKp44, or NKp46 polypeptide. The second antigen binding domain can be an antigen binding domain set forth in Example 17. In another aspect, this document features compositions including such cell engagers. In another aspect, this document features nucleic acids including a nucleic acid sequence that can encode such cell engagers. The nucleic acid can be a viral vector. In another aspect, this document features host cells including a nucleic acid including a nucleic acid that can encode such cell engagers. In another aspect, this document features host cells that express such cell engagers. The host cell can be a T cell, stem cell, or NK cell. In another aspect, this document features compositions including such host cells. In another aspect, this document features ADCs including an antigen binding domain covalently linked to a drug, wherein said antigen binding domain comprises a binding molecule that includes: (i) a heavy chain variable domain or region comprising the amino acid sequences set forth in SEQ ID NO:1 (or SEQ ID NO:1 with one, two, orAttorney Docket No.07039-2338WO1 / 2024-299 three amino acid additions, deletions, or substitutions), SEQ ID NO:2 (or SEQ ID NO:2 with one, two, or three amino acid additions, deletions, or substitutions), and SEQ ID NO:3 (or SEQ ID NO:3 with one, two, or three amino acid additions, deletions, or substitutions), and a light chain variable domain or region comprising the amino acid sequences set forth in SEQ ID NO:9 (or SEQ ID NO:9 with one, two, or three amino acid additions, deletions, or substitutions), SEQ ID NO:10 (or SEQ ID NO:10 with one, two, or three amino acid additions, deletions, or substitutions), and SEQ ID NO:11 (or SEQ ID NO:11 with one, two, or three amino acid additions, deletions, or substitutions); (ii) a heavy chain variable domain or region comprising the amino acid sequences set forth in SEQ ID NO:17 (or SEQ ID NO:17 with one, two, or three amino acid additions, deletions, or substitutions), SEQ ID NO:18 (or SEQ ID NO:18 with one, two, or three amino acid additions, deletions, or substitutions), and SEQ ID NO:19 (or SEQ ID NO:19 with one, two, or three amino acid additions, deletions, or substitutions), and a light chain variable domain or region comprising the amino acid sequences set forth in SEQ ID NO:25 (or SEQ ID NO:25 with one, two, or three amino acid additions, deletions, or substitutions), SEQ ID NO:26 (or SEQ ID NO:26 with one, two, or three amino acid additions, deletions, or substitutions), and SEQ ID NO:27 (or SEQ ID NO:27 with one, two, or three amino acid additions, deletions, or substitutions); (iii) a heavy chain variable domain or region comprising the amino acid sequences set forth in SEQ ID NO:33 (or SEQ ID NO:33 with one, two, or three amino acid additions, deletions, or substitutions), SEQ ID NO:34 (or SEQ ID NO:34 with one, two, or three amino acid additions, deletions, or substitutions), and SEQ ID NO:35 (or SEQ ID NO:35 with one, two, or three amino acid additions, deletions, or substitutions), and a light chain variable domain or region comprising the amino acid sequences set forth in SEQ ID NO:41 (or SEQ ID NO:41 with one, two, or three amino acid additions, deletions, or substitutions), SEQ ID NO:42 (or SEQ ID NO:42 with one, two, or three amino acid additions, deletions, or substitutions), and SEQ ID NO:43 (or SEQ ID NO:43 with one, two, or three amino acid additions, deletions, or substitutions); or (iv) a heavy chain variable domain or region comprising the amino acid sequences set forth in SEQ ID NO:49 (or SEQ ID NO:49 with one, two, or three amino acid additions, deletions, or substitutions), SEQ ID NO:50 (or SEQ ID NO:50 with one, two, or three amino acid additions, deletions, or substitutions), and SEQ ID NO:51 (or SEQ ID NO:51 with one, two, or three amino acid additions,Attorney Docket No.07039-2338WO1 / 2024-299 deletions, or substitutions), and a light chain variable domain or region comprising the amino acid sequences set forth in SEQ ID NO:57 (or SEQ ID NO:57 with one, two, or three amino acid additions, deletions, or substitutions), SEQ ID NO:58 (or SEQ ID NO:58 with one, two, or three amino acid additions, deletions, or substitutions), and SEQ ID NO:59 (or SEQ ID NO:59 with one, two, or three amino acid additions, deletions, or substitutions). The binding molecule can have the ability to bind to a CS1 polypeptide. The drug can be an auristatin (e.g., monomethyl auristatin E (MMAE), a mertansine, a pyrrolobenzodiazepine (PBD) dimer, ozogamicin, calicheamicin, deruxtecan, vedotin, or tesirine. In another aspect, this document features compositions including such ADCs. In another aspect, this document features methods for treating a mammal having cancer. The methods can include, or consist essentially of, administering, to a mammal having cancer, a composition including: (a) a binding molecule that includes: (i) a heavy chain variable domain or region comprising the amino acid sequences set forth in SEQ ID NO:1 (or SEQ ID NO:1 with one, two, or three amino acid additions, deletions, or substitutions), SEQ ID NO:2 (or SEQ ID NO:2 with one, two, or three amino acid additions, deletions, or substitutions), and SEQ ID NO:3 (or SEQ ID NO:3 with one, two, or three amino acid additions, deletions, or substitutions), and a light chain variable domain or region comprising the amino acid sequences set forth in SEQ ID NO:9 (or SEQ ID NO:9 with one, two, or three amino acid additions, deletions, or substitutions), SEQ ID NO:10 (or SEQ ID NO:10 with one, two, or three amino acid additions, deletions, or substitutions), and SEQ ID NO:11 (or SEQ ID NO:11 with one, two, or three amino acid additions, deletions, or substitutions); (ii) a heavy chain variable domain or region comprising the amino acid sequences set forth in SEQ ID NO:17 (or SEQ ID NO:17 with one, two, or three amino acid additions, deletions, or substitutions), SEQ ID NO:18 (or SEQ ID NO:18 with one, two, or three amino acid additions, deletions, or substitutions), and SEQ ID NO:19 (or SEQ ID NO:19 with one, two, or three amino acid additions, deletions, or substitutions), and a light chain variable domain or region comprising the amino acid sequences set forth in SEQ ID NO:25 (or SEQ ID NO:25 with one, two, or three amino acid additions, deletions, or substitutions), SEQ ID NO:26 (or SEQ ID NO:26 with one, two, or three amino acid additions, deletions, or substitutions), and SEQ ID NO:27 (or SEQ ID NO:27 with one, two, or three amino acid additions, deletions, or substitutions); (iii) a heavy chain variable domain or region comprising theAttorney Docket No.07039-2338WO1 / 2024-299 amino acid sequences set forth in SEQ ID NO:33 (or SEQ ID NO:33 with one, two, or three amino acid additions, deletions, or substitutions), SEQ ID NO:34 (or SEQ ID NO:34 with one, two, or three amino acid additions, deletions, or substitutions), and SEQ ID NO:35 (or SEQ ID NO:35 with one, two, or three amino acid additions, deletions, or substitutions), and a light chain variable domain or region comprising the amino acid sequences set forth in SEQ ID NO:41 (or SEQ ID NO:41 with one, two, or three amino acid additions, deletions, or substitutions), SEQ ID NO:42 (or SEQ ID NO:42 with one, two, or three amino acid additions, deletions, or substitutions), and SEQ ID NO:43 (or SEQ ID NO:43 with one, two, or three amino acid additions, deletions, or substitutions); or (iv) a heavy chain variable domain or region comprising the amino acid sequences set forth in SEQ ID NO:49 (or SEQ ID NO:49 with one, two, or three amino acid additions, deletions, or substitutions), SEQ ID NO:50 (or SEQ ID NO:50 with one, two, or three amino acid additions, deletions, or substitutions), and SEQ ID NO:51 (or SEQ ID NO:51 with one, two, or three amino acid additions, deletions, or substitutions), and a light chain variable domain or region comprising the amino acid sequences set forth in SEQ ID NO:57 (or SEQ ID NO:57 with one, two, or three amino acid additions, deletions, or substitutions), SEQ ID NO:58 (or SEQ ID NO:58 with one, two, or three amino acid additions, deletions, or substitutions), and SEQ ID NO:59 (or SEQ ID NO:59 with one, two, or three amino acid additions, deletions, or substitutions); (b) a cell engager including such a binding molecule; (c) a cell expressing a CAR including such a binding molecule; and / or (d) an ADC of any including such a binding molecule. The mammal can be a human. The cancer can be a CS1+cancer. The cancer can be a multiple myeloma or a myelofibrosis. The number of cancer cells within said mammal can be reduced following said administering step. In another aspect, this document features methods for binding a binding molecule to a CS1 polypeptide. The methods can include, or consist essentially of, contacting a CS1 polypeptide with a binding molecule that includes: (i) a heavy chain variable domain or region comprising the amino acid sequences set forth in SEQ ID NO:1 (or SEQ ID NO:1 with one, two, or three amino acid additions, deletions, or substitutions), SEQ ID NO:2 (or SEQ ID NO:2 with one, two, or three amino acid additions, deletions, or substitutions), and SEQ ID NO:3 (or SEQ ID NO:3 with one, two, or three amino acid additions, deletions, or substitutions), and a light chain variable domain or regionAttorney Docket No.07039-2338WO1 / 2024-299 comprising the amino acid sequences set forth in SEQ ID NO:9 (or SEQ ID NO:9 with one, two, or three amino acid additions, deletions, or substitutions), SEQ ID NO:10 (or SEQ ID NO:10 with one, two, or three amino acid additions, deletions, or substitutions), and SEQ ID NO:11 (or SEQ ID NO:11 with one, two, or three amino acid additions, deletions, or substitutions); (ii) a heavy chain variable domain or region comprising the amino acid sequences set forth in SEQ ID NO:17 (or SEQ ID NO:17 with one, two, or three amino acid additions, deletions, or substitutions), SEQ ID NO:18 (or SEQ ID NO:18 with one, two, or three amino acid additions, deletions, or substitutions), and SEQ ID NO:19 (or SEQ ID NO:19 with one, two, or three amino acid additions, deletions, or substitutions), and a light chain variable domain or region comprising the amino acid sequences set forth in SEQ ID NO:25 (or SEQ ID NO:25 with one, two, or three amino acid additions, deletions, or substitutions), SEQ ID NO:26 (or SEQ ID NO:26 with one, two, or three amino acid additions, deletions, or substitutions), and SEQ ID NO:27 (or SEQ ID NO:27 with one, two, or three amino acid additions, deletions, or substitutions); (iii) a heavy chain variable domain or region comprising the amino acid sequences set forth in SEQ ID NO:33 (or SEQ ID NO:33 with one, two, or three amino acid additions, deletions, or substitutions), SEQ ID NO:34 (or SEQ ID NO:34 with one, two, or three amino acid additions, deletions, or substitutions), and SEQ ID NO:35 (or SEQ ID NO:35 with one, two, or three amino acid additions, deletions, or substitutions), and a light chain variable domain or region comprising the amino acid sequences set forth in SEQ ID NO:41 (or SEQ ID NO:41 with one, two, or three amino acid additions, deletions, or substitutions), SEQ ID NO:42 (or SEQ ID NO:42 with one, two, or three amino acid additions, deletions, or substitutions), and SEQ ID NO:43 (or SEQ ID NO:43 with one, two, or three amino acid additions, deletions, or substitutions); or (iv) a heavy chain variable domain or region comprising the amino acid sequences set forth in SEQ ID NO:49 (or SEQ ID NO:49 with one, two, or three amino acid additions, deletions, or substitutions), SEQ ID NO:50 (or SEQ ID NO:50 with one, two, or three amino acid additions, deletions, or substitutions), and SEQ ID NO:51 (or SEQ ID NO:51 with one, two, or three amino acid additions, deletions, or substitutions), and a light chain variable domain or region comprising the amino acid sequences set forth in SEQ ID NO:57 (or SEQ ID NO:57 with one, two, or three amino acid additions, deletions, or substitutions), SEQ ID NO:58 (or SEQ ID NO:58 with one, two, or three amino acid additions,Attorney Docket No.07039-2338WO1 / 2024-299 deletions, or substitutions), and SEQ ID NO:59 (or SEQ ID NO:59 with one, two, or three amino acid additions, deletions, or substitutions). The contacting can be performed in vitro. The contacting can be performed in vivo. For example, the contacting can be performed within a mammal by administering said binding molecule to said mammal. The mammal can be a human. Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. Although methods and materials similar or equivalent to those described herein can be used to practice the invention, suitable methods and materials are described below. All publications, patent applications, patents, and other references mentioned herein are incorporated by reference in their entirety. In case of conflict, the present specification, including definitions, will control. In addition, the materials, methods, and examples are illustrative only and not intended to be limiting. The details of one or more embodiments of the invention are set forth in the accompanying drawings and the description below. Other features, objects, and advantages of the invention will be apparent from the description and drawings, and from the claims. BRIEF DESCRIPTION OF THE DRAWINGS Figure 1. CS1 CAR successfully transduced to human T cells. Bulk T cells were isolated from healthy donor-derived peripheral blood mononuclear cells, and T cells were stimulated with CD3 / CD28 Dynabeads at 1:3 T cell-to-bead ratio.24 hours post- stimulation, T cells were transduced with a lentivirus that encodes a CS1 CAR (K271- K276) at a MOI of 3. Six days post-T-cell stimulation, cells were debeaded, and CAR expression was assessed with flow cytometry. Figure 2. CS1 CAR T-cell expansion assay. Bulk T cells were isolated from healthy donor-derived peripheral blood mononuclear cells, and T cells were stimulated with CD3 / CD28 Dynabeads at 1:3 T cell-to-bead ratio.24 hours post-stimulation, T cells were transduced with a lentivirus that encodes a CS1 CAR (K271-K276) at a MOI of 3. Cells were fed with medium at days 3, 4, 5, and 6 to keep a concentration of one million cells per mL. On day 8 post-stimulation, cells were cryopreserved.Attorney Docket No.07039-2338WO1 / 2024-299 Figure 3. CS1 CAR T-cell killing assay. Cryopreserved CAR T cells were thawed and rested overnight before use in CAR T-cell function assays. CS1-CAR T cells were cocultured with luciferase+human CS1+OPM-2 cells or luciferase+murine CS1+A20 cells. At 24 hours, cytotoxicity was assessed by luminescence relative to controls (mean and SEM; **P = .01, ****P < .0001, two-way analysis). CD19 CAR T cells were served as a negative control. Figure 4. CS1 CAR T-cell proliferation assay upon stimulation. Cryopreserved CAR T cells were thawed and rested overnight before use in CAR T-cell function assays. CS1-CAR T cells were cocultured with human CS1+OPM-2 cells at a 1:1 effector-to- target ratio. At day 5, the absolute number of CAR T cells was assessed by flow cytometry. Figure 5. Schematics of an exemplary CS1 nanobody-based cell engager (top) and an exemplary CS1 scFv-based cell engager (bottom). DETAILED DESCRIPTION This document provides binders (e.g., antibody domains, antigen binding fragments, antibodies, CARs, cell engagers, and ADCs) that bind (e.g., specifically bind) to a CS1 polypeptide (e.g., a human CS1 polypeptide). A binder provided herein can be any appropriate binder including an antigen binding domain having the ability to bind to a CS1 polypeptide. For example, this document provides antibody domains, antigen binding fragments, antibodies, CARs, cell engagers, and ADCs that bind (e.g., specifically bind) to a polypeptide comprising, consisting essentially of, or consisting of the amino acid set forth in any one of SEQ ID NOs:65-66 (see, e.g., Example 2). The term “antibody domain” as used herein refers to a domain of an antibody such as a heavy chain variable domain (VH domain) or a light chain variable domain (VL domain) in the absence of one or more other domains of an antibody. In some cases, an antibody domain can be a single antibody domain (e.g., a VH domain or a VL domain) having the ability to bind to an antigen. An antibody domain provided herein can include the CDRs as described herein (e.g., as described in Table 25) and can be a human antibody domain (e.g., a human VH domain), a humanized antibody domain (e.g., a humanized VH domain), or a chimeric antibody domain (e.g., a chimeric VH domain). In some cases, an antibody domain provided herein can include the CDRs as describedAttorney Docket No.07039-2338WO1 / 2024-299 herein (e.g., as described in Table 25) and can be a monoclonal antibody domain. In some cases, an antibody domain provided herein can include the CDRs as described herein (e.g., as described in Table 25) and can be engineered as a single VH domain or a single VL domain. The term “antigen binding fragment” as used herein refers to a fragment of an antibody (e.g., a fragment of a humanized antibody, a fragment of a human antibody, or a fragment of a chimeric antibody) having the ability to bind to an antigen. Examples of antigen binding fragments include, without limitation, Fab, Fab’, or F(ab’)2 antigen binding fragments. An antigen binding fragment provided herein can include the CDRs as described herein (e.g., as described in Table 25) and can be configured to be a human antigen binding fragment, a humanized antigen binding fragment, or a chimeric antigen binding fragment. In some cases, an antigen binding fragment provided herein can include the CDRs as described herein (e.g., as described in Table 25) and can be a monoclonal antigen binding fragment. In some cases, an antigen binding fragment provided herein can include the CDRs as described herein (e.g., as described in Table 25) and can be configured as an Fab antibody. In some cases, a Fab antibody can include a hinge sequence to allow for disulfide bonding between heavy and light chains of the Fab. The term “antibody” as used herein includes polyclonal antibodies, monoclonal antibodies, recombinant antibodies, humanized antibodies, human antibodies, chimeric antibodies, single-domain antibodies (sdAbs; also referred to as nanobodies or VHHs), multi-specific antibodies (e.g., bispecific antibodies) formed from at least two antibodies, diabodies, single-chain variable fragment antibodies (e.g., scFv antibodies), and tandem single-chain variable fragments antibody (e.g., taFv). A diabody can include two chains, each having a heavy chain variable domain and a light chain variable domain, either from the same or from different antibodies (see, e.g., Hornig and Färber-Schwarz, Methods Mol. Biol., 907:713-27 (2012); and Brinkmann and Kontermann, MAbs., 9(2):182-212 (2017)). The two variable domains can be directly connected or can be connected using any appropriate linker sequence (e.g., a polypeptide linker such as a polypeptide linker having five to ten residues in length). For example, a heavy chain variable domain can be directly connected to a light chain variable domain, or a heavy chain variable domain can be connected to a light chain variable domain via a linker sequence. In some cases, a linker can be a flexible linker (e.g., such that the linker can function as a hinge).Attorney Docket No.07039-2338WO1 / 2024-299 Examples of linker sequences that can be used to connect a heavy chain variable domain and a light chain variable domain (e.g., to create a scFv) include, without limitation, those linkers set forth in Example 7. In some cases, an interdomain disulfide bond can be present in one or both of the heavy chain variable domain and light chain variable domain pairs of the diabody. A scFv is a single-chain polypeptide antibody in which the heavy chain variable domain and the light chain variable domain are directly connected or connected via a polypeptide linker (e.g., a polypeptide linker having eight to 18 residues in length or a polypeptide linker as set forth in Example 7). See, also, Chen et al., Adv. Drug Deliv. Rev., 65(10):1357-1369 (2013). A scFv can be designed to have an orientation with the heavy chain variable domain being followed by the light chain variable domain or can be designed to have an orientation with the light chain variable domain being followed by the heavy chain variable domain. In both cases, the optional linker can be located between the two domains. Examples of scFv structures of scFv’s provided herein include, without limitation, those structures set forth in Example 5. An antibody provided herein can include the CDRs as described herein (e.g., as described in Table 25) and can be configured to be a human antibody, a humanized antibody, or a chimeric antibody. In some cases, an antibody provided herein can include the CDRs as described herein (e.g., as described in Table 25) and can be a monoclonal antibody. In some cases, an antibody provided herein can include the CDRs as described herein (e.g., as described in Table 25) and can be configured as a scFv antibody. An anti-CS1 antibody domain, anti-CS1 antigen binding fragment, or anti-CS1 antibody provided herein can be of the IgA-, IgD-, IgE-, IgG-, or IgM-type, including IgG- or IgM-types such as, without limitation, IgG1-, IgG2-, IgG3-, IgG4-, IgM1-, and IgM2-types. In some cases, an antibody domain provided herein (e.g., an anti-CS1 antibody domain) can be a VH domain. In some cases, an antibody domain provided herein (e.g., an anti-CS1 antibody domain) can be a sdAb. In some cases, an antigen binding fragment provided herein (e.g., an anti-CS1 antibody fragment) can be a Fab. In some cases, an antibody provided herein (e.g., an anti-CS1 antibody) can be a scFv antibody. In some cases, an antibody provided herein (e.g., an anti-CS1 antibody) can be a fully intact antibody. The term “chimeric antigen receptor” as used herein refers to a chimeric polypeptide that is designed to include an optional signal peptide, an antigen bindingAttorney Docket No.07039-2338WO1 / 2024-299 domain, an optional hinge, a transmembrane domain, and one or more intracellular signaling domains. As described herein, the antigen binding domain of a CAR provided herein can be designed to bind to a CS1 polypeptide (e.g., a human CS1 polypeptide). For example, a CAR provided herein can be designed to include the components of an antibody domain, antigen binding fragment, and / or antibody described herein (e.g., a combination of CDRs) as an antigen binding domain provided that that antigen binding domain has the ability to bind to a CS1 polypeptide (e.g., a human CS1 polypeptide). In some cases, a CAR provided herein can be designed to include an antigen binding domain that includes at least one set of three CDRs (e.g., CDR1, CDR2, and CDR3) of an antigen binding domain provided herein (e.g., SEQ ID NOs:1-3, SEQ ID NOs:9-11, SEQ ID NOs:17-19, SEQ ID NOs:25-27, SEQ ID NOs:33-35, SEQ ID NOs:41-43, SEQ ID NOs:49-51, or SEQ ID NOs:57-59). For example, an antigen binding domain of a CAR targeting a CS1 polypeptide can be designed to include a VH domain and / or a VL domain described herein. In some cases, a CAR provided herein can be designed to include an antigen binding domain that includes two sets of three CDRs (e.g., CDR1, CDR2, and CDR3 of a heavy chain and CDR1, CDR2, and CDR3 of a light chain) of an antigen binding fragment provided herein (e.g., SEQ ID NOs:1-3 and 9-11, SEQ ID NOs:17-19 and 25-27, SEQ ID NOs:33-35 and 44-46, or SEQ ID NOs:49-51 and 57-59). For example, an antigen binding domain of a CAR targeting a CS1 polypeptide can be designed to include a scFv antibody described herein. In some cases, a CAR provided herein can be designed to have a structure set forth in Example 9. In some cases, a CAR provided herein can be designed to include a signal peptide. Any appropriate signal peptide can be used to design a CAR described herein. Examples of signal peptides that can be used to make a CAR described herein include withoutlimitation, human CD8 -derived signal peptides, Kozak sequences, and GM-CSF leadersequences. In some cases, a CAR provided herein can be designed to include a signal peptide that comprises, consists essentially of, or consists of one of the amino acid sequences set forth in Example 10 (e.g., a signal peptide that comprises, consists of, or consisting of the amino acid set forth in SEQ ID NO:99). In some cases, a CAR provided herein can be designed to include a signal peptide that comprises, consists essentially of, or consists of one of the amino acid sequences set forth in Example 10 with one, two,Attorney Docket No.07039-2338WO1 / 2024-299 three, four, five, six, seven, eight, nine, or ten amino acid deletions, additions, substitutions, or combinations thereof. In some cases, a CAR provided herein can be designed to include a signal peptide that comprises, consists essentially of, or consists of one of the amino acid sequences set forth in Example 10 with two or less, three or less, four or less, five or less, six or less, seven or less, eight or less, nine or less, or ten or less amino acid deletions, additions, substitutions, or combinations thereof. In some cases, a CAR provided herein can be designed to include a hinge. Any appropriate hinge can be used to design a CAR described herein. Examples of hinges thatcan be used to make a CAR described herein include, without limitation, CD8 -derivedhinges, CD28 hinges, and IgG4 hinges. A CAR provided herein can be designed to include a hinge of any appropriate length. For example, a CAR provided herein can be designed to include a hinge that is from about 4 to about 230 (e.g., from about 4 to about 200, from about 4 to about 175, from about 4 to about 150, from about 4 to about 125, from about 4 to about 100, from about 4 to about 75, from about 4 to about 50, from about 4 to about 25, from about 4 to about 10, from about 25 to about 230, from about 50 to about 230, from about 75 to about 230, from about 100 to about 230, from about 125 to about 230, from about 150 to about 230, from about 175 to about 230, from about 200 to about 230, from about 25 to about 200, from about 50 to about 175, from about 75 to about 150, from about 100 to about 125, from about 10 to about 25, from about 25 to about 50, from about 50 to about 75, from about 75 to about 100, from about 125 to about 150, from about 150 to about 175, from about 175 to about 200, or from about 200 to about 225) amino acid residues in length. In some cases, a linker sequence can be used as a hinge to make a CAR described herein. For example, any one of the linker sequences set forth in Example 7 can be used as a hinge of a CAR described herein. In some cases, a CAR provided herein can be designed to include a hinge that comprises, consists essentially of, or consists of one of the amino acid sequences set forth in Example 6 or Example 11. In some cases, a CAR provided herein can be designed to include a hinge that comprises, consists essentially of, or consists of one of the amino acid sequences set forth in Example 6 or Example 11 with one, two, three, four, five, six, seven, eight, nine, or ten amino acid deletions, additions, substitutions, or combinations thereof. In some cases, a CAR provided herein can be designed to include a hinge that comprises, consists essentially of, or consists of one of the amino acid sequences set forth in Example 6 orAttorney Docket No.07039-2338WO1 / 2024-299 Example 11 with two or less, three or less, four or less, five or less, six or less, seven or less, eight or less, nine or less, or ten or less amino acid deletions, additions, substitutions, or combinations thereof. In some cases, a hinge region of a CAR can be as described elsewhere (see, e.g., U.S. Patent Application Publication No.2018 / 0000914 such as U.S. Patent Application Publication No.2018 / 0000914 at paragraph

[0168] , and Table 1; U.S. Patent Application Publication No.2017 / 0183418 such as U.S. Patent Application Publication No. 2017 / 0183418 at paragraphs

[0034] ,

[0037] ,

[0040] , and Table 2; U.S. Patent Application Publication No.2017 / 0183413 such as U.S. Patent Application Publication No. 2017 / 0183413 at paragraph

[0116] ; and U.S. Patent Application Publication No. 2017 / 0145094 such as U.S. Patent Application Publication No.2017 / 0145094 at paragraph

[0104] . A CAR provided herein can be designed to include any appropriate transmembrane domain. Examples of transmembrane domains that can be used to make aCAR described herein include, without limitation, CD3 transmembrane domains, CD4transmembrane domains, CD8 transmembrane domains, CD28 transmembrane domains,and 4-1BB transmembrane domains. In some cases, a CAR provided herein can be designed to include a transmembrane domain that comprises, consists essentially of, or consists of one of the amino acid sequences set forth in Example 12. In some cases, a CAR provided herein can be designed to include a transmembrane domain that comprises, consists essentially of, or consists of one of the amino acid sequences set forth in Example 12 with one, two, three, four, five, six, seven, eight, nine, or ten amino acid deletions, additions, substitutions, or combinations thereof. In some cases, a CAR provided herein can be designed to include a transmembrane domain that comprises, consists essentially of, or consists of one of the amino acid sequences set forth in Example 12 with two or less, three or less, four or less, five or less, six or less, seven or less, eight or less, nine or less, or ten or less amino acid deletions, additions, substitutions, or combinations thereof. In some cases, a transmembrane domain of a CAR can be as described elsewhere (see, e.g., U.S. Patent Application Publication No.2016 / 0120906 such as U.S. Patent Application Publication No.2016 / 0120906 at paragraphs

[0155] ,

[0161] ,

[0269] , Figure 4, and Figure 11; U.S. Patent Application Publication No.2019 / 0209616 such as U.S.Attorney Docket No.07039-2338WO1 / 2024-299 Patent Application Publication No.2019 / 0209616 at paragraph

[0026] ; U.S. Patent Application Publication No.2018 / 0000914 such as U.S. Patent Application Publication No.2018 / 0000914 at paragraphs

[0168] –

[0171] ; U.S. Patent Application Publication No.2017 / 0183418 such as U.S. Patent Application Publication No.2017 / 0183418 at paragraphs

[0116] –

[0118] ; U.S. Patent Application Publication No.2017 / 0183413 such as U.S. Patent Application Publication No.2017 / 0183413 at paragraphs

[0116] –

[0118] ; and U.S. Patent Application Publication No.2017 / 0145094 such as U.S. Patent Application Publication No.2017 / 0145094 at paragraphs

[0104] –

[0107] . A CAR provided herein can be designed to include one or more intracellular signaling domains. For example, a CAR provided herein can be designed to include one, two, three, or four intracellular signaling domains. Any appropriate intracellular signaling domain or combination of intracellular signaling domains can be used to make a CAR described herein. Examples of intracellular signaling domains that can be used to make aCAR described herein include, without limitation, CD3 intracellular signaling domains,CD27 intracellular signaling domains, CD28 intracellular signaling domains, OX40 (CD134) intracellular signaling domains, 4-1BB (CD137) intracellular signaling domains, CD278 intracellular signaling domains, DAP10 intracellular signaling domains, and DAP12 intracellular signaling domains. In some cases, a CAR described herein can bedesigned to be a first-generation CAR having a CD3 intracellular signaling domain. Insome cases, a CAR described herein can be designed to be a second-generation CARhaving a CD28 intracellular signaling domain followed by a CD3 intracellular signalingdomain. In some cases, a CAR described herein can be designed to be a third generation CAR having (a) a CD28 intracellular signaling domain followed by (b) a CD27 intracellular signaling domain, an OX40 intracellular signaling domains, or a 4-1BBintracellular signaling domain followed by (c) a CD3 intracellular signaling domain. Insome cases, a CAR provided herein can be designed to include at least one intracellular signaling domain that comprises, consists essentially of, or consists of one of the amino acid sequences set forth in Example 13. In some cases, a CAR provided herein can be designed to include at least one intracellular signaling domain that comprises, consists essentially of, or consists of one of the amino acid sequences set forth in Example 13 with one, two, three, four, five, six, seven, eight, nine, or ten amino acid deletions, additions, substitutions, or combinations thereof, provided that that intracellular signaling domainAttorney Docket No.07039-2338WO1 / 2024-299 has at least some activity to activate intracellular signaling. In some cases, a CAR provided herein can be designed to include at least one intracellular signaling domain that comprises, consists essentially of, or consists of one of the amino acid sequences set forth in Example 13 with two or less, three or less, four or less, five or less, six or less, seven or less, eight or less, nine or less, or ten or less amino acid deletions, additions, substitutions, or combinations thereof, provided that that intracellular signaling domain has at least some activity to activate intracellular signaling. In some cases, the intracellular signaling domain(s) of a CAR can be as described elsewhere (see, e.g., U.S. Patent Application Publication No.2018 / 0000914 such as U.S. Patent Application Publication No.2018 / 0000914 at paragraphs

[0164] –

[0167] ; and U.S. Patent Application Publication No.2017 / 0183413 such as U.S. Patent Application Publication No.2017 / 0183413 at paragraphs

[0112] –

[0115] . In some cases, a CAR targeting a CS1 polypeptide can be designed to include an antigen binding domain including (a) a heavy chain variable domain comprising SEQ ID NO:1, SEQ ID NO:2, and SEQ ID NO:3 and / or (b) a light chain variable domain comprising SEQ ID NO:9, SEQ ID NO:10, and SEQ ID NO:11, followed by a hinge suchas a hinge / linker set forth in Example 6 or Example 11 (e.g., a CD8 hinge such as aCD8 hinge that comprises, consists of, or consisting of the amino acid set forth in SEQID NO:110), followed by a transmembrane domain such as a transmembrane domain setforth in Example 12 (e.g., a CD8 transmembrane domain such as a CD8transmembrane domain that comprises, consists of, or consisting of the amino acid set forth in SEQ ID NO:119), followed by one or more intracellular signaling domains such as one or more intracellular signaling domain set forth in Example 13 (e.g., a human 4-1BB intracellular signaling domain followed by a human CD3 intracellular signalingdomain). For example, a CAR targeting a CS1 polypeptide can be designed to include a heavy chain variable domain comprising SEQ ID NO:1, SEQ ID NO:2, and SEQ ID NO:3, followed by SEQ ID NO:110, followed by SEQ ID NO:119, followed by SEQ ID NO:128, followed by SEQ ID NO:130. In some cases, a CAR targeting a CS1 polypeptide can be designed to include an antigen binding domain including (a) a heavy chain variable domain comprising SEQ ID NO:17, SEQ ID NO:18, and SEQ ID NO:19 and / or (b) a light chain variable domain comprising SEQ ID NO:25, SEQ ID NO:26, and SEQ ID NO:27, followed by a hingeAttorney Docket No.07039-2338WO1 / 2024-299such as a hinge / linker set forth in Example 6 or Example 11 (e.g., a CD8 hinge such as aCD8 hinge that comprises, consists of, or consisting of the amino acid set forth in SEQID NO:110), followed by a transmembrane domain such as a transmembrane domain setforth in Example 12 (e.g., a CD8 transmembrane domain such as a CD8transmembrane domain that comprises, consists of, or consisting of the amino acid set forth in SEQ ID NO:119), followed by one or more intracellular signaling domains such as one or more intracellular signaling domain set forth in Example 13 (e.g., a human 4-1BB intracellular signaling domain followed by a human CD3 intracellular signalingdomain). For example, a CAR targeting a CS1 polypeptide can be designed to include a heavy chain variable domain comprising SEQ ID NO:9, SEQ ID NO:10, and SEQ ID NO:11, followed by SEQ ID NO:110, followed by SEQ ID NO:119, followed by SEQ ID NO:128, followed by SEQ ID NO:130. In some cases, a CAR targeting a CS1 polypeptide can be designed to include an antigen binding domain including (a) a heavy chain variable domain comprising SEQ ID NO:33, SEQ ID NO:34, and SEQ ID NO:35 and / or (b) a light chain variable domain comprising SEQ ID NO:41, SEQ ID NO:42, and SEQ ID NO:43, followed by a hingesuch as a hinge / linker set forth in Example 6 or Example 11 (e.g., a CD8 hinge such as aCD8 hinge that comprises, consists of, or consisting of the amino acid set forth in SEQID NO:110), followed by a transmembrane domain such as a transmembrane domain setforth in Example 12 (e.g., a CD8 transmembrane such as a CD8 transmembranedomain that comprises, consists of, or consisting of the amino acid set forth in SEQ ID NO:119), followed by one or more intracellular signaling domains such as one or more intracellular signaling domain set forth in Example 13 (e.g., a human 4-1BB intracellularsignaling domain followed by a human CD3 intracellular signaling domain). Forexample, a CAR targeting a CS1 polypeptide can be designed to include a heavy chain variable domain comprising SEQ ID NO:17, SEQ ID NO:18, and SEQ ID NO:19, followed by SEQ ID NO:110, followed by SEQ ID NO:119, followed by SEQ ID NO:128, followed by SEQ ID NO:130. In some cases, a CAR targeting a CS1 polypeptide can be designed to include an antigen binding domain including (a) a heavy chain variable domain comprising SEQ ID NO:49, SEQ ID NO:50, and SEQ ID NO:51 and / or (b) a light chain variable domain comprising SEQ ID NO:57, SEQ ID NO:58, and SEQ ID NO:59, followed by a hingeAttorney Docket No.07039-2338WO1 / 2024-299such as a hinge / linker set forth in Example 6 or Example 11 (e.g., a CD8 hinge such as aCD8 hinge that comprises, consists of, or consisting of the amino acid set forth in SEQID NO:110), followed by a transmembrane domain such as a transmembrane domain setforth in Example 12 (e.g., a CD8 transmembrane such as a CD8 transmembranedomain that comprises, consists of, or consisting of the amino acid set forth in SEQ ID NO:119), followed by one or more intracellular signaling domains such as one or more intracellular signaling domain set forth in Example 13 (e.g., a human 4-1BB intracellularsignaling domain followed by a human CD3 intracellular signaling domain). Forexample, a CAR targeting a CS1 polypeptide can be designed to include a heavy chain variable domain comprising SEQ ID NO:17, SEQ ID NO:18, and SEQ ID NO:19, followed by SEQ ID NO:110, followed by SEQ ID NO:119, followed by SEQ ID NO:128, followed by SEQ ID NO:130. The term “cell engager” as used herein refers to a polypeptide that includes two or more antigen binding domains (e.g., two, three, or four antigen binding domains) and has the ability to link two cells together. Examples of cell engagers include, without limitation, BiTEs, BiKEs, and TriKEs. In general, a cell engager provided herein can be designed to include at least one antigen binding domain having the ability to bind to a CS1 polypeptide (e.g., a human CS1 polypeptide) and at least one antigen binding domain having the ability to bind to an antigen expressed on the surface of a cell (e.g., a T cell or an NK cell). In some cases, a cell engager described herein can link a CS1+cell (e.g., a CS1+cancer cell) to another cell (e.g., a T cell or an NK cell) via the two or more antigen binding domains of the cell engager. Examples of cell engager structures of cell engagers provided herein include, without limitation, the structures set forth in Figure 5. In some cases, the anti-CD3 scFv depicted in Figure 5 can be replaced with a different antigen binding domain having the ability to bind to an antigen expressed on the surface of a cell (e.g., a T cell or an NK cell). When a cell engager includes an antigen binding domain having the ability to bind to a CS1 polypeptide (e.g., a human CS1 polypeptide) and two or more other antigen binding domains (e.g., two, three, or four other antigen binding domains), each of those other antigen binding domains can bind to different antigens expressed on the surface of different cell types or can bind to different antigens expressed on the surface of the same cell type. For example, a TriKE can be designed to have a first antigen binding domainAttorney Docket No.07039-2338WO1 / 2024-299 having the ability to bind to a CS1 polypeptide (e.g., a human CS1 polypeptide), a second antigen binding domain having the ability to bind to a first antigen expressed on the surface of an NK cell (e.g., a CD16 polypeptide such as a CD16a polypeptide), and a third antigen binding domain having the ability to bind to a second antigen expressed on the surface of an NK cell (e.g., an NKG2A polypeptide). As described herein, at least one antigen binding domain of a cell engager provided herein can be designed to bind to a CS1 polypeptide (e.g., a human CS1 polypeptide). For example, a cell engager provided herein can be designed to include the components of an antibody, antigen binding fragment, and / or antibody domain described herein (e.g., a combination of CDRs) as an antigen binding domain provided that that antigen binding domain has the ability to bind to a CS1 polypeptide (e.g., a human CS1 polypeptide). In some examples, a cell engager provided herein can be designed to include an antigen binding domain that includes at least one set of three CDRs (e.g., CDR1, CDR2, and CDR3) of an antigen binding fragment provided herein (e.g., SEQ ID NOs:1-3, SEQ ID NOs:9-11, SEQ ID NOs:17-19, SEQ ID NOs:25-27, SEQ ID NOs:33- 35, SEQ ID NOs:41-43, SEQ ID NOs:49-51, or SEQ ID NOs:57-59). In some cases, an antigen binding domain of a cell engager targeting a CS1 polypeptide can be designed to include a VH domain described herein or a scFv or Fab antibody described herein. In some cases, an antigen binding domain of a CAR described herein that has the ability to bind to a CS1 polypeptide (e.g., a human CS1 polypeptide) can be used as an antigen binding domain of a cell engager that targets CS1+cells. As described herein, a cell engager can be designed to include at least one antigen binding domain having the ability to bind to a CS1 polypeptide (e.g., a human CS1 polypeptide) and at least one other antigen binding domain. That at least one other antigen binding domain can have the ability to bind to any appropriate antigen expressed on the surface of a cell. For example, when designing a cell engager such as a BiTE to link a CS1+cell and a T cell, the cell engager can include an antigen binding domain having the ability to bind to a CS1 polypeptide (e.g., a human CS1 polypeptide) and an antigen binding domain having the ability to bind to a polypeptide expressed on the surface of a T cell. Examples example of polypeptides expressed on the surface of a T cell that can be targeted by an antigen binding domain of a cell engager provided herein include, without limitation, CD3 polypeptides. Examples of antigen binding domainsAttorney Docket No.07039-2338WO1 / 2024-299 having the ability to bind to a polypeptide expressed on the surface of a T cell that can be used to make a cell engager provided herein (e.g., a BiTE) include, without limitation, anti-CD3 scFvs, anti-CD3 VH domains, anti-CD8 scFvs, anti-CD4 scFvs, anti-CD2 scFvs, and anti-CD5 scFvs. Additional examples of amino acid sequences that can be used as antigen binding domains having the ability to bind to a polypeptide expressed on the surface of a T cell (e.g., CD3) are described in U.S. Patent No.6,750,325 (see, e.g., the sequence listing of U.S. Patent No.6,750,325). In some cases, a cell engager provided herein can be designed to include an antigen binding domain that comprises, consists essentially of, or consists of one of the amino acid sequences set forth in Example 16. In some cases, a cell engager provided herein can be designed to include an antigen binding domain that comprises, consists essentially of, or consists of one of the amino acid sequences set forth in Example 16 with one, two, three, four, five, six, seven, eight, nine, or ten amino acid deletions, additions, substitutions, or combinations thereof, provided that the antigen binding domain has the ability to bind to a polypeptide expressed on the surface of a T cell. In some cases, a cell engager provided herein can be designed to include an antigen binding domain that comprises, consists essentially of, or consists of one of the amino acid sequences set forth in Example 16 with two or less, three or less, four or less, five or less, six or less, seven or less, eight or less, nine or less, or ten or less amino acid deletions, additions, substitutions, or combinations thereof, provided that the antigen binding domain has the ability to bind to a polypeptide expressed on the surface of a T cell. When designing a cell engager such as a BiKE or a TriKE to link a CS1+cell and an NK cell, the cell engager can include an antigen binding domain having the ability to bind to a CS1 polypeptide (e.g., a human CS1 polypeptide) and one or more (e.g., one, two, or three) antigen binding domains having the ability to bind to a polypeptide expressed on the surface of an NK cell. Examples of polypeptides expressed on the surface of an NK cell that can be targeted by an antigen binding domain of a cell engager provided herein include, without limitation, CD16 polypeptides (e.g., CD16a polypeptides), NKG2A polypeptides, NKG2D polypeptides, NKp30 polypeptides, NKp44 polypeptides, and NKp46 polypeptides. Examples of antigen binding domains having the ability to bind to a polypeptide expressed on the surface of an NK cell that can be used to make a cell engager provided herein (e.g., a BiKE or TriKE) include, withoutAttorney Docket No.07039-2338WO1 / 2024-299 limitation, anti-CD16a scFvs, anti-NKG2A scFvs, anti-NKG2D scFvs, anti-NKp30 scFvs (see, e.g., BioLegend Catalog #325207), anti-NKp44 scFvs, anti-NKp46 scFvs, anti- CD16a VH domains, anti-NKG2A VH domains, anti-NKG2D VH domains, anti-NKp30 VH domains, anti-NKp44 VH domains, and anti-NKp46 VH domains. Additional examples of amino acid sequences that can be used as antigen binding domains having the ability to bind to a polypeptide expressed on the surface of an NK cell (e.g., CD16, NKG2A, NKG2D, or NKp46) are described in McCall et al. (Mol. Immunol., 36(7):433- 445 (1999); see, e.g., anti-CD16 scFv sequences); International Patent Application Publication No. PCT / US2017 / 048721 (see, e.g., the CDRs and sequence listing for anti- CD16a binding domains); U.S. Patent Application Publication No.2011 / 0052606 (see, e.g., the CDRs and the sequence listing for anti-NKG2A antibodies such as Z199); U.S. Patent Application Publication No.2011 / 0150870 (see, e.g., the CDRs and sequence listing for anti-NKG2D antibodies); U.S. Patent Application Publication No. 2018 / 0369373 (see, e.g., the CDRs and sequence listing for anti-NKp46 antibodies); and U.S. Patent Application Publication No.2017 / 0368169 (see, e.g., the CDRs and sequence listing for anti-NKp46 antibodies). In some cases, a cell engager provided herein can be designed to include an antigen binding domain (e.g., a VH or a scFv) that comprises, consists essentially of, or consists of one or more of the amino acid sequences set forth in Example 17. In some cases, a cell engager provided herein can be designed to include an antigen binding domain (e.g., a VH or a scFv) that comprises, consists essentially of, or consists of one of the amino acid sequences set forth in Example 17 with one, two, three, four, five, six, seven, eight, nine, or ten amino acid deletions, additions, substitutions, or combinations thereof, provided that the antigen binding domain has the ability to bind to a polypeptide expressed on the surface of an NK cell. In some cases, a cell engager provided herein can be designed to include an antigen binding domain (e.g., a VH or a scFv) that comprises, consists essentially of, or consists of one of the amino acid sequences set forth in Example 17 with two or less, three or less, four or less, five or less, six or less, seven or less, eight or less, nine or less, or ten or less amino acid deletions, additions, substitutions, or combinations thereof, provided that the antigen binding domain has the ability to bind to a polypeptide expressed on the surface of an NK cell.Attorney Docket No.07039-2338WO1 / 2024-299 In some cases, a cell engager provided herein can be designed to include a linker located between each antigen binding domain. Any appropriate linker can be used to design a cell engager provided herein. Examples of linkers that can be used to make a cell engager described herein include, without limitation, the linker sequences set forth in Example 6. A cell engager provided herein can be designed to include a linker of any appropriate length. For example, a cell engager provided herein can be designed to include a linker that is from about 3 to about 100 (e.g., from about 3 to about 90, from about 3 to about 80, from about 3 to about 70, from about 3 to about 60, from about 3 to about 50, from about 3 to about 40, from about 3 to about 30, from about 3 to about 20, from about 3 to about 15, from about 5 to about 100, from about 10 to about 100, from about 20 to about 100, from about 30 to about 100, from about 40 to about 100, from about 50 to about 100, from about 60 to about 100, from about 70 to about 100, from about 10 to about 50, from about 10 to about 40, from about 10 to about 30, from about 10 to about 20, or from about 12 to about 17) amino acid residues in length. In some cases, a cell engager provided herein (e.g., a BiTE) can be designed to include a GGGGSGGGGSGGGGS (SEQ ID NO:76) linker. In some cases, a hinge of a CAR described herein can be used as a linker to make a cell engager described herein. For example, any one of the sequences set forth in Example 11 can be used as a linker of a cell engager described herein. In some cases, a cell engager provided herein can be designed to include a linker that comprises, consists essentially of, or consists of one of the amino acid sequences set forth in Example 6 or Example 11. In some cases, a cell engager provided herein can be designed to include a linker that comprises, consists essentially of, or consists of one of the amino acid sequences set forth in Example 6 or Example 11 with one, two, three, four, five, six, seven, eight, nine, or ten amino acid deletions, additions, substitutions, or combinations thereof. In some cases, a cell engager provided herein can be designed to include a linker that comprises, consists essentially of, or consists of one of the amino acid sequences set forth in Example 6 or Example 11 with two or less, three or less, four or less, five or less, six or less, seven or less, eight or less, nine or less, or ten or less amino acid deletions, additions, substitutions, or combinations thereof. In some cases, a cell engager (e.g., a BiTE) targeting a CS1 polypeptide can be designed to include an antigen binding domain including (a) a heavy chain variableAttorney Docket No.07039-2338WO1 / 2024-299 domain comprising SEQ ID NO:1, SEQ ID NO:2, and SEQ ID NO:3 and / or (b) a light chain variable domain comprising SEQ ID NO:9, SEQ ID NO:10, and SEQ ID NO:11, followed by a hinge such as a hinge / linker set forth in Example 6 or Example 11, followed by an antigen binding domain having the ability to bind to a polypeptide expressed on the surface of a T cell (e.g., an anti-human CD3 scFv). In some cases, a cell engager (e.g., a BiTE) targeting a CS1 polypeptide can be designed to include an antigen binding domain including (a) a heavy chain variable domain comprising SEQ ID NO:17, SEQ ID NO:18, and SEQ ID NO:19 and / or (b) a light chain variable domain comprising SEQ ID NO:25, SEQ ID NO:26, and SEQ ID NO:27, followed by a hinge such as a hinge / linker set forth in Example 6 or Example 11, followed by an antigen binding domain having the ability to bind to a polypeptide expressed on the surface of a T cell (e.g., an anti-human CD3 scFv). In some cases, a cell engager (e.g., a BiTE) targeting a CS1 polypeptide can be designed to include an antigen binding domain including (a) a heavy chain variable domain comprising SEQ ID NO:33, SEQ ID NO:34, and SEQ ID NO:34 and / or (b) a light chain variable domain comprising SEQ ID NO:41, SEQ ID NO:42, and SEQ ID NO:42, followed by a hinge such as a hinge / linker set forth in Example 6 or Example 11, followed by an antigen binding domain having the ability to bind to a polypeptide expressed on the surface of a T cell (e.g., an anti-human CD3 scFv). In some cases, a cell engager (e.g., a BiTE) targeting a CS1 polypeptide can be designed to include an antigen binding domain including (a) a heavy chain variable domain comprising SEQ ID NO:49, SEQ ID NO:50, and SEQ ID NO:51 and / or (b) a light chain variable domain comprising SEQ ID NO:57, SEQ ID NO:58, and SEQ ID NO:59, followed by a hinge such as a hinge / linker set forth in Example 6 or Example 11, followed by an antigen binding domain having the ability to bind to a polypeptide expressed on the surface of a T cell (e.g., an anti-human CD3 scFv). In some cases, a cell engager (e.g., a BiKE or a TriKE) targeting a CS1 polypeptide can be designed to include an antigen binding domain including (a) a heavy chain variable domain comprising SEQ ID NO:1, SEQ ID NO:2, and SEQ ID NO:3 and / or (b) a light chain variable domain comprising SEQ ID NO:9, SEQ ID NO:10, and SEQ ID NO:11, followed by a linker such as a hinge / linker set forth in Example 6 or Example 11, followed by one or more antigen binding domains having the ability to bindAttorney Docket No.07039-2338WO1 / 2024-299 to a polypeptide expressed on the surface of an NK cell (e.g., an anti-human CD16a scFv for a BiKE or an anti-human CD16a scFv and an anti-human NKG2A scFv for a TriKE). In some cases, a cell engager (e.g., a BiKE or a TriKE) targeting a CS1 polypeptide can be designed to include an antigen binding domain including (a) a heavy chain variable domain comprising SEQ ID NO:17, SEQ ID NO:18, and SEQ ID NO:19 and / or (b) a light chain variable domain comprising SEQ ID NO:25, SEQ ID NO:26, and SEQ ID NO:27, followed by a linker such as a hinge / linker set forth in Example 6 or Example 11, followed by one or more antigen binding domains having the ability to bind to a polypeptide expressed on the surface of an NK cell (e.g., an anti-human CD16a scFv for a BiKE or an anti-human CD16a scFv and an anti-human NKG2A scFv for a TriKE). In some cases, a cell engager (e.g., a BiKE or a TriKE) targeting a CS1 polypeptide can be designed to include an antigen binding domain including (a) a heavy chain variable domain comprising SEQ ID NO:33, SEQ ID NO:34, and SEQ ID NO:34 and / or (b) a light chain variable domain comprising SEQ ID NO:41, SEQ ID NO:42, and SEQ ID NO:42, followed by a linker such as a hinge / linker set forth in Example 6 or Example 11, followed by one or more antigen binding domains having the ability to bind to a polypeptide expressed on the surface of an NK cell (e.g., an anti-human CD16a scFv for a BiKE or an anti-human CD16a scFv and an anti-human NKG2A scFv for a TriKE). In some cases, a cell engager (e.g., a BiKE or a TriKE) targeting a CS1 polypeptide can be designed to include an antigen binding domain including (a) a heavy chain variable domain comprising SEQ ID NO:49, SEQ ID NO:50, and SEQ ID NO:51 and / or (b) a light chain variable domain comprising SEQ ID NO:57, SEQ ID NO:58, and SEQ ID NO:59, followed by a linker such as a hinge / linker set forth in Example 6 or Example 11, followed by one or more antigen binding domains having the ability to bind to a polypeptide expressed on the surface of an NK cell (e.g., an anti-human CD16a scFv for a BiKE or an anti-human CD16a scFv and an anti-human NKG2A scFv for a TriKE). In some cases, a binder (e.g., an antibody domain, an antigen binding fragment, an antibody, a CAR, a cell engager, or an ADC) provided herein having the ability to bind to a CS1 polypeptide (e.g., a human CS1 polypeptide) can include (a) a heavy chain variable domain having a CDR1 having the amino acid sequence set forth in SEQ ID NO:1 (or a variant of SEQ ID NO:1 with one, two, three, or four amino acid modifications), a CDR2 having the amino acid sequence set forth in SEQ ID NO:2 (or a variant of SEQ ID NO:2Attorney Docket No.07039-2338WO1 / 2024-299 with one, two, three, or four amino acid modifications), and a CDR3 having the amino acid sequence set forth in SEQ ID NO:3 (or a variant of SEQ ID NO:3 with one, two, three, or four amino acid modifications) and / or (b) a light chain variable domain comprising (i) a CDR1 having the amino acid sequence set forth in SEQ ID NO:9 (or a variant of SEQ ID NO:9 with one, two, three, or four amino acid modifications), (ii) a CDR2 having the amino acid sequence set forth in SEQ ID NO:10 (or a variant of SEQ ID NO:10 with one, two, three, or four amino acid modifications), and (iii) a CDR3 having the amino acid sequence set forth in SEQ ID NO:11 (or a variant of SEQ ID NO:11 with one, two, three, or four amino acid modifications). An example of such an antigen binding domain having these CDRs and the ability to bind to a CS1 polypeptide (e.g., a human CS1 polypeptide) includes, without limitation, a binder including (a) the VH domain set forth in SEQ ID NO:8 (see, e.g., Example 3) and / or (b) the VL domain set forth in SEQ ID NO:16 (see, e.g., Example 3). In some cases, a binder (e.g., an antibody domain, an antigen binding fragment, an antibody, a CAR, a cell engager, or an ADC) provided herein having the ability to bind to a CS1 polypeptide (e.g., a human CS1 polypeptide) and a heavy chain variable domain having a CDR1 having the amino acid sequence set forth in SEQ ID NO:1 (or a variant of SEQ ID NO:1 with one, two, three, or four amino acid modifications), a CDR2 having the amino acid sequence set forth in SEQ ID NO:2 (or a variant of SEQ ID NO:2 with one, two, three, or four amino acid modifications), and a CDR3 having the amino acid sequence set forth in SEQ ID NO:3 (or a variant of SEQ ID NO:3 with one, two, three, or four amino acid modifications) can include any appropriate framework regions. For example, such a binder can include a heavy chain variable domain that includes a framework region 1 having the amino acid sequence set forth in SEQ ID NO:4 (or a variant of SEQ ID NO:4 with one, two, three, four, five, six, seven, eight, nine, ten, or more amino acid modifications), a framework region 2 having the amino acid sequence set forth in SEQ ID NO:5 (or a variant of SEQ ID NO:5 with one, two, three, four, five, six, seven, eight, nine, ten, or more amino acid modifications), a framework region 3 having the amino acid sequence set forth in SEQ ID NO:6 (or a variant of SEQ ID NO:6 with one, two, three, four, five, six, seven, eight, nine, ten, or more amino acid modifications), and a framework region 4 having the amino acid sequence set forth inAttorney Docket No.07039-2338WO1 / 2024-299 SEQ ID NO:7 (or a variant of SEQ ID NO:7 with one, two, three, four, five, six, seven, eight, nine, ten, or more amino acid modifications). In some cases, a binder (e.g., an antibody domain, an antigen binding fragment, an antibody, a CAR, a cell engager, or an ADC) provided herein having the ability to bind to a CS1 polypeptide (e.g., a human CS1 polypeptide) can include a heavy chain variable domain that includes an amino acid sequence having at least 90 percent identity to the amino acid sequence set forth in SEQ ID NO:8. For example, a binder provided herein can include a heavy chain variable domain that includes an amino acid sequence having at least 90, 91, 92, 93, 94, 95, 96, 97, 98, or 99 percent identity to the amino acid sequence set forth in SEQ ID NO:8. In some cases, a binder provided herein can include a heavy chain variable domain that includes an amino acid sequence having 100 percent identity to the amino acid sequence set forth in SEQ ID NO:8. In some cases, a binder (e.g., an antibody domain, an antigen binding fragment, an antibody, a CAR, a cell engager, or an ADC) provided herein having the ability to bind to a CS1 polypeptide (e.g., a human CS1 polypeptide) can include a heavy chain variable domain that includes an amino acid sequence having at least 90 percent identity to the amino acid sequence set forth in SEQ ID NO:8, provided that the heavy chain variable domain includes the amino acid sequences set forth in SEQ ID NOs:1, 2, and 3. For example, a binder provided herein can include a heavy chain variable domain that includes an amino acid sequence having at least 90, 91, 92, 93, 94, 95, 96, 97, 98, or 99 percent identity to the amino acid sequence set forth in SEQ ID NO:8, provided that the heavy chain variable domain includes the amino acid sequences set forth in SEQ ID NOs:1, 2, and 3. In some cases, a binder (e.g., an antibody domain, an antigen binding fragment, an antibody, a CAR, a cell engager, or an ADC) provided herein having the ability to bind to a CS1 polypeptide (e.g., a human CS1 polypeptide) and a light chain variable domain having a CDR1 having the amino acid sequence set forth in SEQ ID NO:9 (or a variant of SEQ ID NO:9 with one, two, three, or four amino acid modifications), a CDR2 having the amino acid sequence set forth in SEQ ID NO:10 (or a variant of SEQ ID NO:10 with one, two, three, or four amino acid modifications), and a CDR3 having the amino acid sequence set forth in SEQ ID NO:11 (or a variant of SEQ ID NO:11 with one, two, three, or four amino acid modifications) can include any appropriate framework regions. ForAttorney Docket No.07039-2338WO1 / 2024-299 example, such a binder can include a light chain variable domain that includes a framework region 1 having the amino acid sequence set forth in SEQ ID NO:12 (or a variant of SEQ ID NO:12 with one, two, three, four, five, six, seven, eight, nine, ten, or more amino acid modifications), a framework region 2 having the amino acid sequence set forth in SEQ ID NO:13 (or a variant of SEQ ID NO:13 with one, two, three, four, five, six, seven, eight, nine, ten, or more amino acid modifications), a framework region 3 having the amino acid sequence set forth in SEQ ID NO:14 (or a variant of SEQ ID NO:14 with one, two, three, four, five, six, seven, eight, nine, ten, or more amino acid modifications), and a framework region 4 having the amino acid sequence set forth in SEQ ID NO:15 (or a variant of SEQ ID NO:15 with one, two, three, four, five, six, seven, eight, nine, ten, or more amino acid modifications). In some cases, a binder (e.g., an antibody domain, an antigen binding fragment, an antibody, a CAR, a cell engager, or an ADC) provided herein having the ability to bind to a CS1 polypeptide (e.g., a human CS1 polypeptide) can include a light chain variable domain that includes an amino acid sequence having at least 90 percent identity to the amino acid sequence set forth in SEQ ID NO:16. For example, a binder provided herein can include a light chain variable domain that includes an amino acid sequence having at least 90, 91, 92, 93, 94, 95, 96, 97, 98, or 99 percent identity to the amino acid sequence set forth in SEQ ID NO:16. In some cases, a binder provided herein can include a light chain variable domain that includes an amino acid sequence having 100 percent identity to the amino acid sequence set forth in SEQ ID NO:16. In some cases, a binder (e.g., an antibody domain, an antigen binding fragment, an antibody, a CAR, a cell engager, or an ADC) provided herein having the ability to bind to a CS1 polypeptide (e.g., a human CS1 polypeptide) can include a light chain variable domain that includes an amino acid sequence having at least 90 percent identity to the amino acid sequence set forth in SEQ ID NO:16, provided that the light chain variable domain includes the amino acid sequences set forth in SEQ ID NOs:9, 10, and 11. For example, a binder provided herein can include a light chain variable domain that includes an amino acid sequence having at least 90, 91, 92, 93, 94, 95, 96, 97, 98, or 99 percent identity to the amino acid sequence set forth in SEQ ID NO:16, provided that the light chain variable domain includes the amino acid sequences set forth in SEQ ID NOs:9, 10, and 11.Attorney Docket No.07039-2338WO1 / 2024-299 In some cases, a binder (e.g., an antibody domain, an antigen binding fragment, an antibody, a CAR, a cell engager, or an ADC) provided herein having the ability to bind to a CS1 polypeptide (e.g., a human CS1 polypeptide) can include (a) a heavy chain variable domain having a CDR1 having the amino acid sequence set forth in SEQ ID NO:17 (or a variant of SEQ ID NO:17 with one, two, three, or four amino acid modifications), a CDR2 having the amino acid sequence set forth in SEQ ID NO:18 (or a variant of SEQ ID NO:18 with one, two, three, or four amino acid modifications), and a CDR3 having the amino acid sequence set forth in SEQ ID NO:19 (or a variant of SEQ ID NO:19 with one, two, three, or four amino acid modifications) and / or (b) a light chain variable domain comprising (i) a CDR1 having the amino acid sequence set forth in SEQ ID NO:25 (or a variant of SEQ ID NO:25 with one, two, three, or four amino acid modifications), (ii) a CDR2 having the amino acid sequence set forth in SEQ ID NO:26 (or a variant of SEQ ID NO:26 with one, two, three, or four amino acid modifications), and (iii) a CDR3 having the amino acid sequence set forth in SEQ ID NO:27 (or a variant of SEQ ID NO:27 with one, two, three, or four amino acid modifications). An example of such an antigen binding domain having these CDRs and the ability to bind to a CS1 polypeptide (e.g., a human CS1 polypeptide) includes, without limitation, a binder including (a) the VH domain set forth in SEQ ID NO:24 (see, e.g., Example 3) and / or (b) the VL domain set forth in SEQ ID NO:32 (see, e.g., Example 3). In some cases, a binder (e.g., an antibody domain, an antigen binding fragment, an antibody, a CAR, a cell engager, or an ADC) provided herein having the ability to bind to a CS1 polypeptide (e.g., a human CS1 polypeptide) and a heavy chain variable domain having a CDR1 having the amino acid sequence set forth in SEQ ID NO:17 (or a variant of SEQ ID NO:17 with one, two, three, or four amino acid modifications), a CDR2 having the amino acid sequence set forth in SEQ ID NO:18 (or a variant of SEQ ID NO:18 with one, two, three, or four amino acid modifications), and a CDR3 having the amino acid sequence set forth in SEQ ID NO:19 (or a variant of SEQ ID NO:19 with one, two, three, or four amino acid modifications) can include any appropriate framework regions. For example, such a binder can include a heavy chain variable domain that includes a framework region 1 having the amino acid sequence set forth in SEQ ID NO:20 (or a variant of SEQ ID NO:20 with one, two, three, four, five, six, seven, eight, nine, ten, or more amino acid modifications), a framework region 2 having the amino acidAttorney Docket No.07039-2338WO1 / 2024-299 sequence set forth in SEQ ID NO:21 (or a variant of SEQ ID NO:21 with one, two, three, four, five, six, seven, eight, nine, ten, or more amino acid modifications), a framework region 3 having the amino acid sequence set forth in SEQ ID NO:22 (or a variant of SEQ ID NO:22 with one, two, three, four, five, six, seven, eight, nine, ten, or more amino acid modifications), and a framework region 4 having the amino acid sequence set forth in SEQ ID NO:23 (or a variant of SEQ ID NO:23 with one, two, three, four, five, six, seven, eight, nine, ten, or more amino acid modifications). In some cases, a binder (e.g., an antibody domain, an antigen binding fragment, an antibody, a CAR, a cell engager, or an ADC) provided herein having the ability to bind to a CS1 polypeptide (e.g., a human CS1 polypeptide) can include a heavy chain variable domain that includes an amino acid sequence having at least 90 percent identity to the amino acid sequence set forth in SEQ ID NO:24. For example, a binder provided herein can include a heavy chain variable domain that includes an amino acid sequence having at least 90, 91, 92, 93, 94, 95, 96, 97, 98, or 99 percent identity to the amino acid sequence set forth in SEQ ID NO:8. In some cases, a binder provided herein can include a heavy chain variable domain that includes an amino acid sequence having 100 percent identity to the amino acid sequence set forth in SEQ ID NO:24. In some cases, a binder (e.g., an antibody domain, an antigen binding fragment, an antibody, a CAR, a cell engager, or an ADC) provided herein having the ability to bind to a CS1 polypeptide (e.g., a human CS1 polypeptide) can include a heavy chain variable domain that includes an amino acid sequence having at least 90 percent identity to the amino acid sequence set forth in SEQ ID NO:24, provided that the heavy chain variable domain includes the amino acid sequences set forth in SEQ ID NOs:17, 18, and 19. For example, a binder provided herein can include a heavy chain variable domain that includes an amino acid sequence having at least 90, 91, 92, 93, 94, 95, 96, 97, 98, or 99 percent identity to the amino acid sequence set forth in SEQ ID NO:24, provided that the heavy chain variable domain includes the amino acid sequences set forth in SEQ ID NOs:17, 18, and 19. In some cases, a binder (e.g., an antibody domain, an antigen binding fragment, an antibody, a CAR, a cell engager, or an ADC) provided herein having the ability to bind to a CS1 polypeptide (e.g., a human CS1 polypeptide) and a light chain variable domain having a CDR1 having the amino acid sequence set forth in SEQ ID NO:25 (or a variantAttorney Docket No.07039-2338WO1 / 2024-299 of SEQ ID NO:25 with one, two, three, or four amino acid modifications), a CDR2 having the amino acid sequence set forth in SEQ ID NO:26 (or a variant of SEQ ID NO:26 with one, two, three, or four amino acid modifications), and a CDR3 having the amino acid sequence set forth in SEQ ID NO:27 (or a variant of SEQ ID NO:27 with one, two, three, or four amino acid modifications) can include any appropriate framework regions. For example, such a binder can include a light chain variable domain that includes a framework region 1 having the amino acid sequence set forth in SEQ ID NO:28 (or a variant of SEQ ID NO:28 with one, two, three, four, five, six, seven, eight, nine, ten, or more amino acid modifications), a framework region 2 having the amino acid sequence set forth in SEQ ID NO:29 (or a variant of SEQ ID NO:29 with one, two, three, four, five, six, seven, eight, nine, ten, or more amino acid modifications), a framework region 3 having the amino acid sequence set forth in SEQ ID NO:30 (or a variant of SEQ ID NO:30 with one, two, three, four, five, six, seven, eight, nine, ten, or more amino acid modifications), and a framework region 4 having the amino acid sequence set forth in SEQ ID NO:31 (or a variant of SEQ ID NO:31 with one, two, three, four, five, six, seven, eight, nine, ten, or more amino acid modifications). In some cases, a binder (e.g., an antibody domain, an antigen binding fragment, an antibody, a CAR, a cell engager, or an ADC) provided herein having the ability to bind to a CS1 polypeptide (e.g., a human CS1 polypeptide) can include a light chain variable domain that includes an amino acid sequence having at least 90 percent identity to the amino acid sequence set forth in SEQ ID NO:32. For example, a binder provided herein can include a light chain variable domain that includes an amino acid sequence having at least 90, 91, 92, 93, 94, 95, 96, 97, 98, or 99 percent identity to the amino acid sequence set forth in SEQ ID NO:32. In some cases, a binder provided herein can include a light chain variable domain that includes an amino acid sequence having 100 percent identity to the amino acid sequence set forth in SEQ ID NO:32. In some cases, a binder (e.g., an antibody domain, an antigen binding fragment, an antibody, a CAR, a cell engager, or an ADC) provided herein having the ability to bind to a CS1 polypeptide (e.g., a human CS1 polypeptide) can include a light chain variable domain that includes an amino acid sequence having at least 90 percent identity to the amino acid sequence set forth in SEQ ID NO:32, provided that the light chain variable domain includes the amino acid sequences set forth in SEQ ID NOs:25, 26, and 27. ForAttorney Docket No.07039-2338WO1 / 2024-299 example, a binder provided herein can include a light chain variable domain that includes an amino acid sequence having at least 90, 91, 92, 93, 94, 95, 96, 97, 98, or 99 percent identity to the amino acid sequence set forth in SEQ ID NO:32, provided that the light chain variable domain includes the amino acid sequences set forth in SEQ ID NOs:25, 26, and 27. In some cases, a binder (e.g., an antibody domain, an antigen binding fragment, an antibody, a CAR, a cell engager, or an ADC) provided herein having the ability to bind to a CS1 polypeptide (e.g., a human CS1 polypeptide) can include (a) a heavy chain variable domain having a CDR1 having the amino acid sequence set forth in SEQ ID NO:33 (or a variant of SEQ ID NO:33 with one, two, three, or four amino acid modifications), a CDR2 having the amino acid sequence set forth in SEQ ID NO:34 (or a variant of SEQ ID NO:34 with one, two, three, or four amino acid modifications), and a CDR3 having the amino acid sequence set forth in SEQ ID NO:35 (or a variant of SEQ ID NO:35 with one, two, three, or four amino acid modifications) and / or (b) a light chain variable domain comprising (i) a CDR1 having the amino acid sequence set forth in SEQ ID NO:41 (or a variant of SEQ ID NO:41 with one, two, three, or four amino acid modifications), (ii) a CDR2 having the amino acid sequence set forth in SEQ ID NO:42 (or a variant of SEQ ID NO:42 with one, two, three, or four amino acid modifications), and (iii) a CDR3 having the amino acid sequence set forth in SEQ ID NO:43 (or a variant of SEQ ID NO:43 with one, two, three, or four amino acid modifications). An example of such an antigen binding domain having these CDRs and the ability to bind to a CS1 polypeptide (e.g., a human CS1 polypeptide) includes, without limitation, a binder including (a) the VH domain set forth in SEQ ID NO:40 (see, e.g., Example 3) and / or (b) the VL domain set forth in SEQ ID NO:48 (see, e.g., Example 3). In some cases, a binder (e.g., an antibody domain, an antigen binding fragment, an antibody, a CAR, a cell engager, or an ADC) provided herein having the ability to bind to a CS1 polypeptide (e.g., a human CS1 polypeptide) and a heavy chain variable domain having a CDR1 having the amino acid sequence set forth in SEQ ID NO:33 (or a variant of SEQ ID NO:33 with one, two, three, or four amino acid modifications), a CDR2 having the amino acid sequence set forth in SEQ ID NO:34 (or a variant of SEQ ID NO:34 with one, two, three, or four amino acid modifications), and a CDR3 having the amino acid sequence set forth in SEQ ID NO:35 (or a variant of SEQ ID NO:35 with one,Attorney Docket No.07039-2338WO1 / 2024-299 two, three, or four amino acid modifications) can include any appropriate framework regions. For example, such a binder can include a heavy chain variable domain that includes a framework region 1 having the amino acid sequence set forth in SEQ ID NO:36 (or a variant of SEQ ID NO:36 with one, two, three, four, five, six, seven, eight, nine, ten, or more amino acid modifications), a framework region 2 having the amino acid sequence set forth in SEQ ID NO:37 (or a variant of SEQ ID NO:37 with one, two, three, four, five, six, seven, eight, nine, ten, or more amino acid modifications), a framework region 3 having the amino acid sequence set forth in SEQ ID NO:38 (or a variant of SEQ ID NO:38 with one, two, three, four, five, six, seven, eight, nine, ten, or more amino acid modifications), and a framework region 4 having the amino acid sequence set forth in SEQ ID NO:39 (or a variant of SEQ ID NO:39 with one, two, three, four, five, six, seven, eight, nine, ten, or more amino acid modifications). In some cases, a binder (e.g., an antibody domain, an antigen binding fragment, an antibody, a CAR, a cell engager, or an ADC) provided herein having the ability to bind to a CS1 polypeptide (e.g., a human CS1 polypeptide) can include a heavy chain variable domain that includes an amino acid sequence having at least 90 percent identity to the amino acid sequence set forth in SEQ ID NO:40. For example, a binder provided herein can include a heavy chain variable domain that includes an amino acid sequence having at least 90, 91, 92, 93, 94, 95, 96, 97, 98, or 99 percent identity to the amino acid sequence set forth in SEQ ID NO:40. In some cases, a binder provided herein can include a heavy chain variable domain that includes an amino acid sequence having 100 percent identity to the amino acid sequence set forth in SEQ ID NO:40. In some cases, a binder (e.g., an antibody domain, an antigen binding fragment, an antibody, a CAR, a cell engager, or an ADC) provided herein having the ability to bind to a CS1 polypeptide (e.g., a human CS1 polypeptide) can include a heavy chain variable domain that includes an amino acid sequence having at least 90 percent identity to the amino acid sequence set forth in SEQ ID NO:40, provided that the heavy chain variable domain includes the amino acid sequences set forth in SEQ ID NOs:33, 34, and 35. For example, a binder provided herein can include a heavy chain variable domain that includes an amino acid sequence having at least 90, 91, 92, 93, 94, 95, 96, 97, 98, or 99 percent identity to the amino acid sequence set forth in SEQ ID NO:40, provided that theAttorney Docket No.07039-2338WO1 / 2024-299 heavy chain variable domain includes the amino acid sequences set forth in SEQ ID NOs:33, 34, and 35. In some cases, a binder (e.g., an antibody domain, an antigen binding fragment, an antibody, a CAR, a cell engager, or an ADC) provided herein having the ability to bind to a CS1 polypeptide (e.g., a human CS1 polypeptide) and a light chain variable domain having a CDR1 having the amino acid sequence set forth in SEQ ID NO:41 (or a variant of SEQ ID NO:41 with one, two, three, or four amino acid modifications), a CDR2 having the amino acid sequence set forth in SEQ ID NO:42 (or a variant of SEQ ID NO:42 with one, two, three, or four amino acid modifications), and a CDR3 having the amino acid sequence set forth in SEQ ID NO:43 (or a variant of SEQ ID NO:43 with one, two, three, or four amino acid modifications) can include any appropriate framework regions. For example, such a binder can include a light chain variable domain that includes a framework region 1 having the amino acid sequence set forth in SEQ ID NO:44 (or a variant of SEQ ID NO:44 with one, two, three, four, five, six, seven, eight, nine, ten, or more amino acid modifications), a framework region 2 having the amino acid sequence set forth in SEQ ID NO:45 (or a variant of SEQ ID NO:45 with one, two, three, four, five, six, seven, eight, nine, ten, or more amino acid modifications), a framework region 3 having the amino acid sequence set forth in SEQ ID NO:46 (or a variant of SEQ ID NO:46 with one, two, three, four, five, six, seven, eight, nine, ten, or more amino acid modifications), and a framework region 4 having the amino acid sequence set forth in SEQ ID NO:47 (or a variant of SEQ ID NO:47 with one, two, three, four, five, six, seven, eight, nine, ten, or more amino acid modifications). In some cases, a binder (e.g., an antibody domain, an antigen binding fragment, an antibody, a CAR, a cell engager, or an ADC) provided herein having the ability to bind to a CS1 polypeptide (e.g., a human CS1 polypeptide) can include a light chain variable domain that includes an amino acid sequence having at least 90 percent identity to the amino acid sequence set forth in SEQ ID NO:48. For example, a binder provided herein can include a light chain variable domain that includes an amino acid sequence having at least 90, 91, 92, 93, 94, 95, 96, 97, 98, or 99 percent identity to the amino acid sequence set forth in SEQ ID NO:48. In some cases, a binder provided herein can include a light chain variable domain that includes an amino acid sequence having 100 percent identity to the amino acid sequence set forth in SEQ ID NO:48.Attorney Docket No.07039-2338WO1 / 2024-299 In some cases, a binder (e.g., an antibody domain, an antigen binding fragment, an antibody, a CAR, a cell engager, or an ADC) provided herein having the ability to bind to a CS1 polypeptide (e.g., a human CS1 polypeptide) can include a light chain variable domain that includes an amino acid sequence having at least 90 percent identity to the amino acid sequence set forth in SEQ ID NO:48, provided that the light chain variable domain includes the amino acid sequences set forth in SEQ ID NOs:41, 42, and 43. For example, a binder provided herein can include a light chain variable domain that includes an amino acid sequence having at least 90, 91, 92, 93, 94, 95, 96, 97, 98, or 99 percent identity to the amino acid sequence set forth in SEQ ID NO:48, provided that the light chain variable domain includes the amino acid sequences set forth in SEQ ID NOs:41, 42, and 43. In some cases, a binder (e.g., an antibody domain, an antigen binding fragment, an antibody, a CAR, a cell engager, or an ADC) provided herein having the ability to bind to a CS1 polypeptide (e.g., a human CS1 polypeptide) can include (a) a heavy chain variable domain having a CDR1 having the amino acid sequence set forth in SEQ ID NO:49 (or a variant of SEQ ID NO:49 with one, two, three, or four amino acid modifications), a CDR2 having the amino acid sequence set forth in SEQ ID NO:50 (or a variant of SEQ ID NO:50 with one, two, three, or four amino acid modifications), and a CDR3 having the amino acid sequence set forth in SEQ ID NO:51 (or a variant of SEQ ID NO:51 with one, two, three, or four amino acid modifications) and / or (b) a light chain variable domain comprising (i) a CDR1 having the amino acid sequence set forth in SEQ ID NO:57 (or a variant of SEQ ID NO:57 with one, two, three, or four amino acid modifications), (ii) a CDR2 having the amino acid sequence set forth in SEQ ID NO:58 (or a variant of SEQ ID NO:58 with one, two, three, or four amino acid modifications), and (iii) a CDR3 having the amino acid sequence set forth in SEQ ID NO:59 (or a variant of SEQ ID NO:59 with one, two, three, or four amino acid modifications). An example of such an antigen binding domain having these CDRs and the ability to bind to a CS1 polypeptide (e.g., a human CS1 polypeptide) includes, without limitation, a binder including (a) the VH domain set forth in SEQ ID NO:56 (see, e.g., Example 3) and / or (b) the VL domain set forth in SEQ ID NO:64 (see, e.g., Example 3). In some cases, a binder (e.g., an antibody domain, an antigen binding fragment, an antibody, a CAR, a cell engager, or an ADC) provided herein having the ability to bind toAttorney Docket No.07039-2338WO1 / 2024-299 a CS1 polypeptide (e.g., a human CS1 polypeptide) and a heavy chain variable domain having a CDR1 having the amino acid sequence set forth in SEQ ID NO:49 (or a variant of SEQ ID NO:49 with one, two, three, or four amino acid modifications), a CDR2 having the amino acid sequence set forth in SEQ ID NO:50 (or a variant of SEQ ID NO:50 with one, two, three, or four amino acid modifications), and a CDR3 having the amino acid sequence set forth in SEQ ID NO:51 (or a variant of SEQ ID NO:51 with one, two, three, or four amino acid modifications) can include any appropriate framework regions. For example, such a binder can include a heavy chain variable domain that includes a framework region 1 having the amino acid sequence set forth in SEQ ID NO:52 (or a variant of SEQ ID NO:52 with one, two, three, four, five, six, seven, eight, nine, ten, or more amino acid modifications), a framework region 2 having the amino acid sequence set forth in SEQ ID NO:53 (or a variant of SEQ ID NO:53 with one, two, three, four, five, six, seven, eight, nine, ten, or more amino acid modifications), a framework region 3 having the amino acid sequence set forth in SEQ ID NO:54 (or a variant of SEQ ID NO:54 with one, two, three, four, five, six, seven, eight, nine, ten, or more amino acid modifications), and a framework region 4 having the amino acid sequence set forth in SEQ ID NO:55 (or a variant of SEQ ID NO:55 with one, two, three, four, five, six, seven, eight, nine, ten, or more amino acid modifications). In some cases, a binder (e.g., an antibody domain, an antigen binding fragment, an antibody, a CAR, a cell engager, or an ADC) provided herein having the ability to bind to a CS1 polypeptide (e.g., a human CS1 polypeptide) can include a heavy chain variable domain that includes an amino acid sequence having at least 90 percent identity to the amino acid sequence set forth in SEQ ID NO:56. For example, a binder provided herein can include a heavy chain variable domain that includes an amino acid sequence having at least 90, 91, 92, 93, 94, 95, 96, 97, 98, or 99 percent identity to the amino acid sequence set forth in SEQ ID NO:56. In some cases, a binder provided herein can include a heavy chain variable domain that includes an amino acid sequence having 100 percent identity to the amino acid sequence set forth in SEQ ID NO:56. In some cases, a binder (e.g., an antibody domain, an antigen binding fragment, an antibody, a CAR, a cell engager, or an ADC) provided herein having the ability to bind to a CS1 polypeptide (e.g., a human CS1 polypeptide) can include a heavy chain variable domain that includes an amino acid sequence having at least 90 percent identity to theAttorney Docket No.07039-2338WO1 / 2024-299 amino acid sequence set forth in SEQ ID NO:56, provided that the heavy chain variable domain includes the amino acid sequences set forth in SEQ ID NOs:49, 50, and 51. For example, a binder provided herein can include a heavy chain variable domain that includes an amino acid sequence having at least 90, 91, 92, 93, 94, 95, 96, 97, 98, or 99 percent identity to the amino acid sequence set forth in SEQ ID NO:56, provided that the heavy chain variable domain includes the amino acid sequences set forth in SEQ ID NOs:49, 50, and 51. In some cases, a binder (e.g., an antibody domain, an antigen binding fragment, an antibody, a CAR, a cell engager, or an ADC) provided herein having the ability to bind to a CS1 polypeptide (e.g., a human CS1 polypeptide) and a light chain variable domain having a CDR1 having the amino acid sequence set forth in SEQ ID NO:57 (or a variant of SEQ ID NO:57 with one, two, three, or four amino acid modifications), a CDR2 having the amino acid sequence set forth in SEQ ID NO:58 (or a variant of SEQ ID NO:58 with one, two, three, or four amino acid modifications), and a CDR3 having the amino acid sequence set forth in SEQ ID NO:59 (or a variant of SEQ ID NO:59 with one, two, three, or four amino acid modifications) can include any appropriate framework regions. For example, such a binder can include a light chain variable domain that includes a framework region 1 having the amino acid sequence set forth in SEQ ID NO:60 (or a variant of SEQ ID NO:60 with one, two, three, four, five, six, seven, eight, nine, ten, or more amino acid modifications), a framework region 2 having the amino acid sequence set forth in SEQ ID NO:61 (or a variant of SEQ ID NO:61 with one, two, three, four, five, six, seven, eight, nine, ten, or more amino acid modifications), a framework region 3 having the amino acid sequence set forth in SEQ ID NO:62 (or a variant of SEQ ID NO:62 with one, two, three, four, five, six, seven, eight, nine, ten, or more amino acid modifications), and a framework region 4 having the amino acid sequence set forth in SEQ ID NO:63 (or a variant of SEQ ID NO:63 with one, two, three, four, five, six, seven, eight, nine, ten, or more amino acid modifications). In some cases, a binder (e.g., an antibody domain, an antigen binding fragment, an antibody, a CAR, a cell engager, or an ADC) provided herein having the ability to bind to a CS1 polypeptide (e.g., a human CS1 polypeptide) can include a light chain variable domain that includes an amino acid sequence having at least 90 percent identity to the amino acid sequence set forth in SEQ ID NO:64. For example, a binder provided hereinAttorney Docket No.07039-2338WO1 / 2024-299 can include a light chain variable domain that includes an amino acid sequence having at least 90, 91, 92, 93, 94, 95, 96, 97, 98, or 99 percent identity to the amino acid sequence set forth in SEQ ID NO:64. In some cases, a binder provided herein can include a light chain variable domain that includes an amino acid sequence having 100 percent identity to the amino acid sequence set forth in SEQ ID NO:64. In some cases, a binder (e.g., an antibody domain, an antigen binding fragment, an antibody, a CAR, a cell engager, or an ADC) provided herein having the ability to bind to a CS1 polypeptide (e.g., a human CS1 polypeptide) can include a light chain variable domain that includes an amino acid sequence having at least 90 percent identity to the amino acid sequence set forth in SEQ ID NO:64, provided that the light chain variable domain includes the amino acid sequences set forth in SEQ ID NOs:57, 58, and 59. For example, a binder provided herein can include a light chain variable domain that includes an amino acid sequence having at least 90, 91, 92, 93, 94, 95, 96, 97, 98, or 99 percent identity to the amino acid sequence set forth in SEQ ID NO:64, provided that the light chain variable domain includes the amino acid sequences set forth in SEQ ID NOs:57, 58, and 59. In some cases, a binder (e.g., an antibody domain, an antigen binding fragment, an antibody, a CAR, a cell engager, or an ADC) provided herein having the ability to bind to a CS1 polypeptide (e.g., a human CS1 polypeptide) can include (a) a heavy chain variable domain comprising (i) a CDR1 that comprises, consists essentially of, or consists of the amino acid sequence set forth in SEQ ID NO:1, (ii) a CDR2 that comprises, consists essentially of, or consists of the amino acid sequence set forth in SEQ ID NO:2, and (iii) a CDR3 that comprises, consists essentially of, or consists of the amino acid sequence set forth in SEQ ID NO:3, and / or (b) a light chain variable domain comprising (i) a CDR1 that comprises, consists essentially of, or consists of the amino acid sequence set forth in SEQ ID NO:9, (ii) a CDR2 that comprises, consists essentially of, or consists of the amino acid sequence set forth in SEQ ID NO:10, and (iii) a CDR3 that comprises, consists essentially of, or consists of the amino acid sequence set forth in SEQ ID NO:11. As used herein, a “CDR1 that consists essentially of the amino acid sequence set forth in SEQ ID NO:1” is a CDR1 that has zero, one, or two amino acid substitutions within SEQ ID NO:1, that has zero, one, two, three, four, or five amino acid residues directly preceding SEQ ID NO:1, and / or that has zero, one, two, three, four, or five amino acidAttorney Docket No.07039-2338WO1 / 2024-299 residues directly following SEQ ID NO:1, provided that the binder maintains its basic ability to bind to a CS1 polypeptide (e.g., a human CS1 polypeptide). Examples of a CDR1 that consists essentially of the amino acid sequence set forth in SEQ ID NO:1 include, without limitation, those set forth in Table 1. Table 1. Exemplary CDR1s that consist essentially of the amino acid sequence set forth in SEQ ID NO:1.As used herein, a “CDR2 that consists essentially of the amino acid sequence set forth in SEQ ID NO:2” is a CDR2 that has zero, one, or two amino acid substitutions within SEQ ID NO:2, that has zero, one, two, three, four, or five amino acid residues directly preceding SEQ ID NO:2, and / or that has zero, one, two, three, four, or five amino acid residues directly following SEQ ID NO:2, provided that the binder (e.g., the antibody domain, the antigen binding fragment, the antibody, the CAR, the cell engager, or the ADC) maintains its basic ability to bind to a CS1 polypeptide (e.g., a human CS1 polypeptide). Examples of a CDR2 that consists essentially of the amino acid sequence set forth in SEQ ID NO:2 include, without limitation, those set forth in Table 2. Table 2. Exemplary CDR2s that consist essentially of the amino acid sequence set forth in SEQ ID NO:2.Attorney Docket No.07039-2338WO1 / 2024-299As used herein, a “CDR3 that consists essentially of the amino acid sequence set forth in SEQ ID NO:3” is a CDR3 that has zero, one, or two amino acid substitutions within SEQ ID NO:3, that has zero, one, two, three, four, or five amino acid residues directly preceding SEQ ID NO:3, and / or that has zero, one, two, three, four, or five amino acid residues directly following SEQ ID NO:3, provided that the binder (e.g., the antibody domain, the antigen binding fragment, the antibody, the CAR, the cell engager, or the ADC) maintains its basic ability to bind to a CS1 polypeptide (e.g., a human CS1 polypeptide). Examples of a CDR3 that consists essentially of the amino acid sequence set forth in SEQ ID NO:3 include, without limitation, those set forth in Table 3. Table 3. Exemplary CDR3s that consist essentially of the amino acid sequence set forth in SEQ ID NO:3.As used herein, a “CDR1 that consists essentially of the amino acid sequence set forth in SEQ ID NO:9” is a CDR1 that has zero, one, or two amino acid substitutions within SEQ ID NO:9, that has zero, one, two, three, four, or five amino acid residues directly preceding SEQ ID NO:9, and / or that has zero, one, two, three, four, or five amino acid residues directly following SEQ ID NO:9, provided that the binder maintains its basic ability to bind to a CS1 polypeptide (e.g., a human CS1 polypeptide). Examples of a CDR1 that consists essentially of the amino acid sequence set forth in SEQ ID NO:9 include, without limitation, those set forth in Table 4.Attorney Docket No.07039-2338WO1 / 2024-299 Table 4. Exemplary CDR1s that consist essentially of the amino acid sequence set forth in SEQ ID NO:9.As used herein, a “CDR2 that consists essentially of the amino acid sequence set forth in SEQ ID NO:10” is a CDR2 that has zero, one, or two amino acid substitutions within SEQ ID NO:10, that has zero, one, two, three, four, or five amino acid residues directly preceding SEQ ID NO:10, and / or that has zero, one, two, three, four, or five amino acid residues directly following SEQ ID NO:10, provided that the binder (e.g., the antibody domain, the antigen binding fragment, the antibody, the CAR, the cell engager, or the ADC) maintains its basic ability to bind to a CS1 polypeptide (e.g., a human CS1 polypeptide). Examples of a CDR2 that consists essentially of the amino acid sequence set forth in SEQ ID NO:10 include, without limitation, those set forth in Table 5. Table 5. Exemplary CDR2s that consist essentially of the amino acid sequence set forth in SEQ ID NO:10.As used herein, a “CDR3 that consists essentially of the amino acid sequence set forth in SEQ ID NO:11” is a CDR3 that has zero, one, or two amino acid substitutions within SEQ ID NO:11, that has zero, one, two, three, four, or five amino acid residuesAttorney Docket No.07039-2338WO1 / 2024-299 directly preceding SEQ ID NO:11, and / or that has zero, one, two, three, four, or five amino acid residues directly following SEQ ID NO:11, provided that the binder (e.g., the antibody domain, the antigen binding fragment, the antibody, the CAR, the cell engager, or the ADC) maintains its basic ability to bind to a CS1 polypeptide (e.g., a human CS1 polypeptide). Examples of a CDR3 that consists essentially of the amino acid sequence set forth in SEQ ID NO:11 include, without limitation, those set forth in Table 6. Table 6. Exemplary CDR3s that consist essentially of the amino acid sequence set forth in SEQ ID NO:11.In some cases, a binder (e.g., an antibody domain, an antigen binding fragment, an antibody, a CAR, a cell engager, or an ADC) provided herein having the ability to bind to a CS1 polypeptide (e.g., a human CS1 polypeptide) can include (a) a heavy chain variable domain comprising (i) a CDR1 that comprises, consists essentially of, or consists of the amino acid sequence set forth in SEQ ID NO:17, (ii) a CDR2 that comprises, consists essentially of, or consists of the amino acid sequence set forth in SEQ ID NO:18, and (iii) a CDR3 that comprises, consists essentially of, or consists of the amino acid sequence set forth in SEQ ID NO:19, and / or (b) a light chain variable domain comprising (i) a CDR1 that comprises, consists essentially of, or consists of the amino acid sequence set forth in SEQ ID NO:25, (ii) a CDR2 that comprises, consists essentially of, or consists of the amino acid sequence set forth in SEQ ID NO:26, and (iii) a CDR3 that comprises, consists essentially of, or consists of the amino acid sequence set forth in SEQ ID NO:27. As used herein, a “CDR1 that consists essentially of the amino acid sequence set forth in SEQ ID NO:17” is a CDR1 that has zero, one, or two amino acid substitutions within SEQ ID NO:17, that has zero, one, two, three, four, or five amino acid residues directly preceding SEQ ID NO:17, and / or that has zero, one, two, three, four, or five amino acid residues directly following SEQ ID NO:17, provided that the binder maintains its basicAttorney Docket No.07039-2338WO1 / 2024-299 ability to bind to a CS1 polypeptide (e.g., a human CS1 polypeptide). Examples of a CDR1 that consists essentially of the amino acid sequence set forth in SEQ ID NO:17 include, without limitation, those set forth in Table 7. Table 7. Exemplary CDR1s that consist essentially of the amino acid sequence set forth in SEQ ID NO:17.As used herein, a “CDR2 that consists essentially of the amino acid sequence set forth in SEQ ID NO:18” is a CDR2 that has zero, one, or two amino acid substitutions within SEQ ID NO:18, that has zero, one, two, three, four, or five amino acid residues directly preceding SEQ ID NO:18, and / or that has zero, one, two, three, four, or five amino acid residues directly following SEQ ID NO:18, provided that the binder (e.g., the antibody domain, the antigen binding fragment, the antibody, the CAR, the cell engager, or the ADC) maintains its basic ability to bind to a CS1 polypeptide (e.g., a human CS1 polypeptide). Examples of a CDR2 that consists essentially of the amino acid sequence set forth in SEQ ID NO:18 include, without limitation, those set forth in Table 8. Table 8. Exemplary CDR2s that consist essentially of the amino acid sequence set forth in SEQ ID NO:18.Attorney Docket No.07039-2338WO1 / 2024-299As used herein, a “CDR3 that consists essentially of the amino acid sequence set forth in SEQ ID NO:19” is a CDR3 that has zero, one, or two amino acid substitutions within SEQ ID NO:19, that has zero, one, two, three, four, or five amino acid residues directly preceding SEQ ID NO:19, and / or that has zero, one, two, three, four, or five amino acid residues directly following SEQ ID NO:19, provided that the binder (e.g., the antibody domain, the antigen binding fragment, the antibody, the CAR, the cell engager, or the ADC) maintains its basic ability to bind to a CS1 polypeptide (e.g., a human CS1 polypeptide). Examples of a CDR3 that consists essentially of the amino acid sequence set forth in SEQ ID NO:19 include, without limitation, those set forth in Table 9. Table 9. Exemplary CDR3s that consist essentially of the amino acid sequence set forth in SEQ ID NO:19.As used herein, a “CDR1 that consists essentially of the amino acid sequence set forth in SEQ ID NO:25” is a CDR1 that has zero, one, or two amino acid substitutions within SEQ ID NO:25, that has zero, one, two, three, four, or five amino acid residues directly preceding SEQ ID NO:25, and / or that has zero, one, two, three, four, or five amino acid residues directly following SEQ ID NO:25, provided that the binder maintains its basic ability to bind to a CS1 polypeptide (e.g., a human CS1 polypeptide). Examples of a CDR1 that consists essentially of the amino acid sequence set forth in SEQ ID NO:25 include, without limitation, those set forth in Table 10.Attorney Docket No.07039-2338WO1 / 2024-299 Table 10. Exemplary CDR1s that consist essentially of the amino acid sequence set forth in SEQ ID NO:25.As used herein, a “CDR2 that consists essentially of the amino acid sequence set forth in SEQ ID NO:26” is a CDR2 that has zero, one, or two amino acid substitutions within SEQ ID NO:26, that has zero, one, two, three, four, or five amino acid residues directly preceding SEQ ID NO:26, and / or that has zero, one, two, three, four, or five amino acid residues directly following SEQ ID NO:26, provided that the binder (e.g., the antibody domain, the antigen binding fragment, the antibody, the CAR, the cell engager, or the ADC) maintains its basic ability to bind to a CS1 polypeptide (e.g., a human CS1 polypeptide). Examples of a CDR2 that consists essentially of the amino acid sequence set forth in SEQ ID NO:26 include, without limitation, those set forth in Table 11. Table 11. Exemplary CDR2s that consist essentially of the amino acid sequence set forth in SEQ ID NO:26.As used herein, a “CDR3 that consists essentially of the amino acid sequence set forth in SEQ ID NO:27” is a CDR3 that has zero, one, or two amino acid substitutions within SEQ ID NO:27, that has zero, one, two, three, four, or five amino acid residuesAttorney Docket No.07039-2338WO1 / 2024-299 directly preceding SEQ ID NO:27, and / or that has zero, one, two, three, four, or five amino acid residues directly following SEQ ID NO:27, provided that the binder (e.g., the antibody domain, the antigen binding fragment, the antibody, the CAR, the cell engager, or the ADC) maintains its basic ability to bind to a CS1 polypeptide (e.g., a human CS1 polypeptide). Examples of a CDR3 that consists essentially of the amino acid sequence set forth in SEQ ID NO:27 include, without limitation, those set forth in Table 12. Table 12. Exemplary CDR3s that consist essentially of the amino acid sequence set forth in SEQ ID NO:27.In some cases, a binder (e.g., an antibody domain, an antigen binding fragment, an antibody, a CAR, a cell engager, or an ADC) provided herein having the ability to bind to a CS1 polypeptide (e.g., a human CS1 polypeptide) can include (a) a heavy chain variable domain comprising (i) a CDR1 that comprises, consists essentially of, or consists of the amino acid sequence set forth in SEQ ID NO:33, (ii) a CDR2 that comprises, consists essentially of, or consists of the amino acid sequence set forth in SEQ ID NO:34, and (iii) a CDR3 that comprises, consists essentially of, or consists of the amino acid sequence set forth in SEQ ID NO:35, and / or (b) a light chain variable domain comprising (i) a CDR1 that comprises, consists essentially of, or consists of the amino acid sequence set forth in SEQ ID NO:41, (ii) a CDR2 that comprises, consists essentially of, or consists of the amino acid sequence set forth in SEQ ID NO:42, and (iii) a CDR3 that comprises, consists essentially of, or consists of the amino acid sequence set forth in SEQ ID NO:43. As used herein, a “CDR1 that consists essentially of the amino acid sequence set forth in SEQ ID NO:33” is a CDR1 that has zero, one, or two amino acid substitutions within SEQ ID NO:33, that has zero, one, two, three, four, or five amino acid residues directly preceding SEQ ID NO:33, and / or that has zero, one, two, three, four, or five amino acidAttorney Docket No.07039-2338WO1 / 2024-299 residues directly following SEQ ID NO:33, provided that the binder maintains its basic ability to bind to a CS1 polypeptide (e.g., a human CS1 polypeptide). Examples of a CDR1 that consists essentially of the amino acid sequence set forth in SEQ ID NO:33 include, without limitation, those set forth in Table 13. Table 13. Exemplary CDR1s that consist essentially of the amino acid sequence set forth in SEQ ID NO:33.As used herein, a “CDR2 that consists essentially of the amino acid sequence set forth in SEQ ID NO:34” is a CDR2 that has zero, one, or two amino acid substitutions within SEQ ID NO:34, that has zero, one, two, three, four, or five amino acid residues directly preceding SEQ ID NO:34, and / or that has zero, one, two, three, four, or five amino acid residues directly following SEQ ID NO:34, provided that the binder (e.g., the antibody domain, the antigen binding fragment, the antibody, the CAR, the cell engager, or the ADC) maintains its basic ability to bind to a CS1 polypeptide (e.g., a human CS1 polypeptide). Examples of a CDR2 that consists essentially of the amino acid sequence set forth in SEQ ID NO:34 include, without limitation, those set forth in Table 14. Table 14. Exemplary CDR2s that consist essentially of the amino acid sequence set forth in SEQ ID NO:34.Attorney Docket No.07039-2338WO1 / 2024-299As used herein, a “CDR3 that consists essentially of the amino acid sequence set forth in SEQ ID NO:35” is a CDR3 that has zero, one, or two amino acid substitutions within SEQ ID NO:35, that has zero, one, two, three, four, or five amino acid residues directly preceding SEQ ID NO:35, and / or that has zero, one, two, three, four, or five amino acid residues directly following SEQ ID NO:35, provided that the binder (e.g., the antibody domain, the antigen binding fragment, the antibody, the CAR, the cell engager, or the ADC) maintains its basic ability to bind to a CS1 polypeptide (e.g., a human CS1 polypeptide). Examples of a CDR3 that consists essentially of the amino acid sequence set forth in SEQ ID NO:35 include, without limitation, those set forth in Table 15.As used herein, a “CDR1 that consists essentially of the amino acid sequence set forth in SEQ ID NO:41” is a CDR1 that has zero, one, or two amino acid substitutions within SEQ ID NO:41, that has zero, one, two, three, four, or five amino acid residues directly preceding SEQ ID NO:41, and / or that has zero, one, two, three, four, or five amino acid residues directly following SEQ ID NO:41, provided that the binder maintainsAttorney Docket No.07039-2338WO1 / 2024-299 its basic ability to bind to a CS1 polypeptide (e.g., a human CS1 polypeptide). Examples of a CDR1 that consists essentially of the amino acid sequence set forth in SEQ ID NO:41 include, without limitation, those set forth in Table 16. Table 16. Exemplary CDR1s that consist essentially of the amino acid sequence set forth in SEQ ID NO:41.As used herein, a “CDR2 that consists essentially of the amino acid sequence set forth in SEQ ID NO:42” is a CDR2 that has zero, one, or two amino acid substitutions within SEQ ID NO:42, that has zero, one, two, three, four, or five amino acid residues directly preceding SEQ ID NO:42, and / or that has zero, one, two, three, four, or five amino acid residues directly following SEQ ID NO:42, provided that the binder (e.g., the antibody domain, the antigen binding fragment, the antibody, the CAR, the cell engager, or the ADC) maintains its basic ability to bind to a CS1 polypeptide (e.g., a human CS1 polypeptide). Examples of a CDR2 that consists essentially of the amino acid sequence set forth in SEQ ID NO:42 include, without limitation, those set forth in Table 17. Table 17. Exemplary CDR2s that consist essentially of the amino acid sequence set forth in SEQ ID NO:42.Attorney Docket No.07039-2338WO1 / 2024-299 As used herein, a “CDR3 that consists essentially of the amino acid sequence set forth in SEQ ID NO:43” is a CDR3 that has zero, one, or two amino acid substitutions within SEQ ID NO:43, that has zero, one, two, three, four, or five amino acid residues directly preceding SEQ ID NO:43, and / or that has zero, one, two, three, four, or five amino acid residues directly following SEQ ID NO:43, provided that the binder (e.g., the antibody domain, the antigen binding fragment, the antibody, the CAR, the cell engager, or the ADC) maintains its basic ability to bind to a CS1 polypeptide (e.g., a human CS1 polypeptide). Examples of a CDR3 that consists essentially of the amino acid sequence set forth in SEQ ID NO:43 include, without limitation, those set forth in Table 18. Table 18. Exemplary CDR3s that consist essentially of the amino acid sequence set forth in SEQ ID NO:43.In some cases, a binder (e.g., an antibody domain, an antigen binding fragment, an antibody, a CAR, a cell engager, or an ADC) provided herein having the ability to bind to a CS1 polypeptide (e.g., a human CS1 polypeptide) can include (a) a heavy chain variable domain comprising (i) a CDR1 that comprises, consists essentially of, or consists of the amino acid sequence set forth in SEQ ID NO:49, (ii) a CDR2 that comprises, consists essentially of, or consists of the amino acid sequence set forth in SEQ ID NO:50, and (iii) a CDR3 that comprises, consists essentially of, or consists of the amino acid sequence set forth in SEQ ID NO:51, and / or (b) a light chain variable domain comprising (i) a CDR1 that comprises, consists essentially of, or consists of the amino acid sequence set forth in SEQ ID NO:57, (ii) a CDR2 that comprises, consists essentially of, or consists of the amino acid sequence set forth in SEQ ID NO:58, and (iii) a CDR3 that comprises,Attorney Docket No.07039-2338WO1 / 2024-299 consists essentially of, or consists of the amino acid sequence set forth in SEQ ID NO:59. As used herein, a “CDR1 that consists essentially of the amino acid sequence set forth in SEQ ID NO:49” is a CDR1 that has zero, one, or two amino acid substitutions within SEQ ID NO:49, that has zero, one, two, three, four, or five amino acid residues directly preceding SEQ ID NO:49, and / or that has zero, one, two, three, four, or five amino acid residues directly following SEQ ID NO:49, provided that the binder maintains its basic ability to bind to a CS1 polypeptide (e.g., a human CS1 polypeptide). Examples of a CDR1 that consists essentially of the amino acid sequence set forth in SEQ ID NO:49 include, without limitation, those set forth in Table 19. Table 19. Exemplary CDR1s that consist essentially of the amino acid sequence set forth in SEQ ID NO:49.As used herein, a “CDR2 that consists essentially of the amino acid sequence set forth in SEQ ID NO:50” is a CDR2 that has zero, one, or two amino acid substitutions within SEQ ID NO:50, that has zero, one, two, three, four, or five amino acid residues directly preceding SEQ ID NO:50, and / or that has zero, one, two, three, four, or five amino acid residues directly following SEQ ID NO:50, provided that the binder (e.g., the antibody domain, the antigen binding fragment, the antibody, the CAR, the cell engager, or the ADC) maintains its basic ability to bind to a CS1 polypeptide (e.g., a human CS1 polypeptide). Examples of a CDR2 that consists essentially of the amino acid sequence set forth in SEQ ID NO:50 include, without limitation, those set forth in Table 20.Attorney Docket No.07039-2338WO1 / 2024-299 Table 20. Exemplary CDR2s that consist essentially of the amino acid sequence set forth in SEQ ID NO:50.As used herein, a “CDR3 that consists essentially of the amino acid sequence set forth in SEQ ID NO:51” is a CDR3 that has zero, one, or two amino acid substitutions within SEQ ID NO:51, that has zero, one, two, three, four, or five amino acid residues directly preceding SEQ ID NO:51, and / or that has zero, one, two, three, four, or five amino acid residues directly following SEQ ID NO:51, provided that the binder (e.g., the antibody domain, the antigen binding fragment, the antibody, the CAR, the cell engager, or the ADC) maintains its basic ability to bind to a CS1 polypeptide (e.g., a human CS1 polypeptide). Examples of a CDR3 that consists essentially of the amino acid sequence set forth in SEQ ID NO:51 include, without limitation, those set forth in Table 21. Table 21. Exemplary CDR3s that consist essentially of the amino acid sequence set forth in SEQ ID NO:51.As used herein, a “CDR1 that consists essentially of the amino acid sequence set forth in SEQ ID NO:57” is a CDR1 that has zero, one, or two amino acid substitutions within SEQ ID NO:57, that has zero, one, two, three, four, or five amino acid residuesAttorney Docket No.07039-2338WO1 / 2024-299 directly preceding SEQ ID NO:57, and / or that has zero, one, two, three, four, or five amino acid residues directly following SEQ ID NO:57, provided that the binder maintains its basic ability to bind to a CS1 polypeptide (e.g., a human CS1 polypeptide). Examples of a CDR1 that consists essentially of the amino acid sequence set forth in SEQ ID NO:57 include, without limitation, those set forth in Table 22. Table 22. Exemplary CDR1s that consist essentially of the amino acid sequence set forth in SEQ ID NO:57.As used herein, a “CDR2 that consists essentially of the amino acid sequence set forth in SEQ ID NO:58” is a CDR2 that has zero, one, or two amino acid substitutions within SEQ ID NO:58, that has zero, one, two, three, four, or five amino acid residues directly preceding SEQ ID NO:58, and / or that has zero, one, two, three, four, or five amino acid residues directly following SEQ ID NO:58, provided that the binder (e.g., the antibody domain, the antigen binding fragment, the antibody, the CAR, the cell engager, or the ADC) maintains its basic ability to bind to a CS1 polypeptide (e.g., a human CS1 polypeptide). Examples of a CDR2 that consists essentially of the amino acid sequence set forth in SEQ ID NO:58 include, without limitation, those set forth in Table 23. Table 23. Exemplary CDR2s that consist essentially of the amino acid sequence set forth in SEQ ID NO:58.Attorney Docket No.07039-2338WO1 / 2024-299As used herein, a “CDR3 that consists essentially of the amino acid sequence set forth in SEQ ID NO:59” is a CDR3 that has zero, one, or two amino acid substitutions within SEQ ID NO:59, that has zero, one, two, three, four, or five amino acid residues directly preceding SEQ ID NO:59, and / or that has zero, one, two, three, four, or five amino acid residues directly following SEQ ID NO:59, provided that the binder (e.g., the antibody domain, the antigen binding fragment, the antibody, the CAR, the cell engager, or the ADC) maintains its basic ability to bind to a CS1 polypeptide (e.g., a human CS1 polypeptide). Examples of a CDR3 that consists essentially of the amino acid sequence set forth in SEQ ID NO:59 include, without limitation, those set forth in Table 24. Table 24. Exemplary CDR3s that consist essentially of the amino acid sequence set forth in SEQ ID NO:59.In some cases, a binder (e.g., an antibody domain, an antigen binding fragment, an antibody, a CAR, a cell engager, or an ADC) provided herein having the ability to bind to a CS1 polypeptide (e.g., a human CS1 polypeptide) can include (a) a heavy chain variable domain and / or (b) a light chain variable domain as described elsewhere. See, for example, Tai et al, Blood, 112(4):1329-37 (2008). As indicated herein, the amino acid sequences described herein can include amino acid modifications (e.g., the articulated number of amino acid modifications). Such amino acid modifications can include, without limitation, amino acid substitutions, amino acidAttorney Docket No.07039-2338WO1 / 2024-299 deletions, amino acid additions, and combinations. In some cases, an amino acid modification can be made to improve the binding and / or contact with an antigen and / or to improve a functional activity of a binder (e.g., an antibody domain, an antigen binding fragment, an antibody, a CAR, a cell engager, or an ADC) provided herein. In some cases, an amino acid substitution within an articulated sequence identifier can be a conservative amino acid substitution. For example, conservative amino acid substitutions can be made by substituting one amino acid residue for another amino acid residue having a similar side chain. Families of amino acid residues having similar side chains can include amino acids with basic side chains (e.g., lysine, arginine, histidine), acidic side chains (e.g., aspartic acid, glutamic acid), uncharged polar side chains (e.g., glycine, asparagine, glutamine, serine, threonine, tyrosine, cysteine), non-polar side chains (e.g., alanine, valine, leucine, isoleucine, proline, phenylalanine, methionine, tryptophan), beta- branched side chains (e.g., threonine, valine, isoleucine), and aromatic side chains (e.g., tyrosine, phenylalanine, tryptophan, histidine). In some cases, an amino acid substitution within an articulated sequence identifier can be a non-conservative amino acid substitution. Non-conservative amino acid substitutions can be made by substituting one amino acid residue for another amino acid residue having a dissimilar side chain. Examples of non-conservative substitutions include, without limitation, substituting (a) a hydrophilic residue (e.g., serine or threonine) for a hydrophobic residue (e.g., leucine, isoleucine, phenylalanine, valine, or alanine); (b) a cysteine or proline for any other residue; (c) a residue having a basic side chain (e.g., lysine, arginine, or histidine) for a residue having an acidic side chain (e.g., aspartic acid or glutamic acid); and (d) a residue having a bulky side chain (e.g., phenylalanine) for glycine or other residue having a small side chain. Methods for generating an amino acid sequence variant (e.g., an amino acid sequence that includes one or more modifications with respect to an articulated sequence identifier) can include site-specific mutagenesis or random mutagenesis (e.g., by PCR) of a nucleic acid encoding the antibody or fragment thereof. See, for example, Zoller, Curr. Opin. Biotechnol.3: 348-354 (1992). Both naturally occurring and non-naturally occurring amino acids (e.g., artificially-derivatized amino acids) can be used to generate an amino acid sequence variant provided herein.Attorney Docket No.07039-2338WO1 / 2024-299 A representative number of binders (e.g., antibody domains, antigen binding fragments, antibodies, CARs, cell engagers, and / or ADCs) having the ability to bind to a CS1 polypeptide (e.g., a human CS1 polypeptide) are further described in Table 25. Table 25. Representative binders having the ability to bind to a CS1 polypeptide.Table 26 includes an alternative designation that can be used to refer to each of Clones #1 - #7. Table 26. Alternative nomenclature for Clones #1 - #7.The binders (e.g., antibody domains, antigen binding fragments, antibodies, CARs, cell engagers, and / or ADCs) provided herein can be produced using any appropriate method. For example, the binders provided herein can be produced in recombinant host cells. For example, a nucleic acid encoding a binder provided herein can be constructed, introduced into an expression vector, and expressed in suitable host cells. Example 4 and Example 8 are sequence listings of nucleic acid sequences encodingAttorney Docket No.07039-2338WO1 / 2024-299 exemplary binders described herein. In some cases, a binder provided herein can be recombinantly produced in prokaryotic hosts such as E. coli, Bacillus brevis, Bacillus subtilis, Bacillus megaterium, Lactobacillus zeae / casei, or Lactobacillus paracasei. A binder provided herein also can be recombinantly produced in eukaryotic hosts such as yeast (e.g., Pichia pastoris, Saccharomyces cerevisiae, Hansenula polymorpha, Schizosaccharomyces pombe, Schwanniomyces occidentalis, Kluyveromyces lactis, or Yarrowia lipolytica), filamentous fungi of the genera Trichoderma (e.g., T. reesei) and Aspergillus (e.g., A. niger and A. oryzae), protozoa such as Leishmania tarentolae, insect cells, or mammalian cells (e.g., mammalian cell lines such as Chinese hamster ovary (CHO) cells, Per.C6 cells, mouse myeloma NS0 cells, baby hamster kidney (BHK) cells, or human embryonic kidney cell line HEK293). See, for example, the Frenzel et al. reference (Front Immunol., 4:217 (2013)). In some cases, an antigen binding fragment or antibody domain provided herein can be produced by proteolytic digestion of an intact antibody. For example, an antigen binding fragment can be obtained by treating an antibody with an enzyme such as papain or pepsin. Papain digestion of whole antibodies can be used to produce F(ab)2 or Fab fragments, while pepsin digestion of whole antibodies can be used to produce F(ab’)2 or Fab’ fragments. In some cases, a binder (e.g., an antibody domain, an antigen binding fragment, an antibody, a CAR, a cell engager, or an ADC) provided herein can be substantially pure. The term “substantially pure” as used herein with reference to a binder refers to the binder as being substantially free of other polypeptides, lipids, carbohydrates, and nucleic acid with which it is naturally associated. Thus, a substantially pure binder provided herein is any binder that is removed from its natural environment and is at least 60 percent pure. A substantially pure binder provided herein can be at least about 65, 70, 75, 80, 85, 90, 95, or 99 percent pure. This document also provides bispecific binders (e.g., bispecific antibody domains, bispecific antigen binding fragments, bispecific antibodies, bispecific CARs, bispecific cell engagers, and / or bispecific ADCs) that bind to two different epitopes with at least one being an epitope of a CS1 polypeptide (e.g., a human CS1 polypeptide). In some cases, a bispecific binder provided herein can be designed to bind to two different epitopes of the same CS1 polypeptide (e.g., a human CS1 polypeptide). In some cases, aAttorney Docket No.07039-2338WO1 / 2024-299 bispecific binder provided herein can bind to a CS1 polypeptide (e.g., a human CS1 polypeptide) and to an epitope on a different polypeptide (e.g., a CD3 polypeptide). Bispecific binders can be produced by chemically conjugating two different binders together. Bispecific binders also can be produced by fusing two antibody-producing cells, e.g., hybridomas, to make a hybrid cell line that produces two different heavy and two different light chains within the same cell, which can result in, for example, bispecific IgG molecules. See, Brinkmann and Kontermann, MAbs., 9(2):182-212 (2017). In some cases, a binder (e.g., an antibody domain, an antigen binding fragment, an antibody, a CAR, a cell engager, or an ADC) provided herein can be fused or conjugated (e.g., covalently or non-covalently attached) to another polypeptide or other moiety to provide a fusion protein or conjugate. For example, a binder provided herein can be conjugated (e.g., covalently or non-covalently attached) to a polymer (e.g., polyethylene glycol (PEG), polyethylenimine (PEI) modified with PEG (PEI-PEG), and / or polyglutamic acid (PGA) (N-(2-Hydroxypropyl) methacrylamide (HPMA) copolymers), hyaluronic acid, a fluorescent substance, a luminescent substance, a hapten, an enzyme, a metal chelate, a drug, a radioisotope, and / or a cytotoxic agent. Any appropriate method can be used to conjugate (e.g., covalently or non-covalently attach) another polypeptide or other moiety to a binder provided herein. For example, another polypeptide or other moiety can be conjugated to a binder provided herein using the methods described in U.S. Patent No.8,021,661. In some cases, a binder (e.g., an antibody domain, an antigen binding fragment, an antibody, a CAR, a cell engager, or an ADC) provided herein can be modified with a moiety that improves its stabilization and / or retention in circulation, for example, in blood, serum, or other tissues by, for example, at least 1.5-, 2-, 5-, 10-, or 50-fold. For example, a binder provided herein can be attached (e.g., covalently or non-covalently attached) to a polymer such as a substantially non-antigenic polymer. Examples of substantially non-antigenic polymers that can be used as described herein include, without limitation, polyalkylene oxides, polyethylene oxides, and polyethylenes. In some cases, a polymer used herein can have any appropriate molecule weight. For example, a polymer having an average molecular weight from about 200 Daltons to about 35,000 Daltons (e.g., from about 1,000 to about 15,000 Daltons or from about 2,000 to about 12,500 Daltons) can be used. In some cases, a binder provided herein can be attached (e.g.,Attorney Docket No.07039-2338WO1 / 2024-299 covalently or non-covalently) to a water-soluble polymer. Examples of water-soluble polymers that can be used as described herein include, without limitation, hydrophilic polyvinyl polymers, polyvinylalcohol, polyvinylpyrrolidone, polyalkylene oxide homopolymers, polyethylene glycol (PEG), polypropylene glycols, and polyoxyethylenated polyols and copolymers thereof and / or block copolymers thereof provided that the water solubility of the copolymer or block copolymers is maintained. In some cases, a binder (e.g., an antibody domain, an antigen binding fragment, an antibody, a CAR, a cell engager, or an ADC) provided herein can be attached (e.g., covalently or non-covalently attached) to one or more polyoxyalkylenes (e.g., polyoxyethylene, polyoxypropylene, or block copolymers of polyoxyethylene and polyoxypropylene), polymethacrylates, carbomers, branched or unbranched polysaccharides, or combinations thereof. For example, a binder provided herein can be covalently attached to polyoxyethylene. This document also provides ADCs including one or more binders (e.g., one or more antibody domains, one or more antigen binding fragments, one or more antibodies, one or more CARs) provided herein. The term “ADC” as used herein refers to a conjugate that includes (a) an antigen binding domain and (b) at least one drug covalently linked directly or indirectly to that antigen binding domain. In some cases, an ADC described herein can include (a) an antigen binding domain having the ability to bind to a CS1 polypeptide (e.g., a human CS1 polypeptide) and (b) at least one drug covalently linked directly or indirectly to that antigen binding domain. Any appropriate binder (e.g., the antibody domain, the antigen binding fragment, the antibody, the CAR, the cell engager, or the ADC) provided herein and having the ability to bind to a CS1 polypeptide (e.g., a human CS1 polypeptide) can be used as an antigen binding domain to make an ADC described herein. For example, any of the binders set forth in Table 25 can be used to make an ADC having the ability to bind to a CS1 polypeptide (e.g., a human CS1 polypeptide). Examples of drugs that can be used to make an ADC described herein include, without limitation, auristatins (e.g., MMAE), mertansine (DM-1), PBD dimers, ozogamicin, calicheamicin, deruxtecan, vedotin, and tesirine. Any appropriate ADC linker can be used to covalently attach one or more drugs to an antigen binding domain having the ability to bind to a CS1 polypeptide (e.g., a human CS1 polypeptide) to form an ADC provided herein. For example, cleavable or non-cleavable ADC linkers can be used toAttorney Docket No.07039-2338WO1 / 2024-299 covalently attach one or more drugs to an antigen binding domain having the ability to bind to a CS1 polypeptide (e.g., a human CS1 polypeptide) to form an ADC provided herein. Examples of ADC linkers can be used to covalently attach one or more drugs to an antigen binding domain having the ability to bind to a CS1 polypeptide (e.g., a human CS1 polypeptide) to form an ADC provided herein include, without limitation, ADC disulfide linkers, ADC hydrazone linkers, ADC peptide linkers, ADC thioether linkers, ADC PEG-containing linkers, and ADC beta-glucuronide linkers. This document also provides nucleic acid molecules (e.g., isolated nucleic acid molecules) having a nucleic acid sequence encoding at least part of a binder (e.g., an antibody domain, an antigen binding fragment, an antibody, a CAR, a cell engager, or an ADC) provided herein. For example, an isolated nucleic acid molecule provided herein can include a nucleic acid sequence encoding a heavy chain variable domain such as a heavy chain variable domain as set forth in Example 3. In another example, an isolated nucleic acid molecule provided herein can include a nucleic acid sequence set forth in Example 4 and / or Example 8. A nucleic acid provided herein (e.g., an isolated nucleic acid molecule) can be single stranded or double stranded nucleic acid of any appropriate type (e.g., DNA, RNA, or DNA / RNA hybrids). This document also provides vectors (e.g., plasmid vectors or viral vectors) containing one or more nucleic acids provided herein. An example of a plasmid vector that can be designed to include one or more nucleic acids having a nucleic acid sequence encoding at least part of a binder (e.g., an antibody domain, an antigen binding fragment, an antibody, a CAR, a cell engager, or an ADC) provided herein includes, without limitation, phagemids. Examples of viral vectors that can be designed to include one or more nucleic acids having a nucleic acid sequence encoding at least part of a binder provided herein include, without limitation, retroviral vectors, parvovirus-based vectors (e.g., adenoviral-based vectors and adeno-associated virus (AAV)-based vectors), lentiviral vectors (e.g., herpes simplex (HSV)-based vectors), poxviral vectors (e.g., vaccinia virus-based vectors and fowlpox virus-based vectors), and hybrid or chimeric viral vectors. For example, a viral vector having an adenoviral backbone with lentiviral components such as those described elsewhere (Zheng et al., Nat. Biotech., 18(2): 176-80 (2000); WO 98 / 22143; WO 98 / 46778; and WO 00 / 17376) or viral vectors having an adenoviral backbone with AAV components such as those described elsewhere (Fisher etAttorney Docket No.07039-2338WO1 / 2024-299 al., Hum. Gene Ther., 7:2079-2087 (1996)) can be designed to include one or more nucleic acids having a nucleic acid sequence encoding at least part of a binder provided herein. In some cases, a vector (e.g., a plasmid vector or a viral vector) provided herein can include a nucleic acid sequence encoding an antibody domain (e.g., a VH domain) provided herein. In some cases, a vector (e.g., a plasmid vector or a viral vector) provided herein can include a nucleic acid sequence encoding CAR provided herein. In some cases, a vector (e.g., a plasmid vector or a viral vector) provided herein can include a nucleic acid sequence encoding cell engager provided herein. A vector provided herein (e.g., a plasmid vector or viral vector provided herein) can include any appropriate promoter and other regulatory sequence (e.g., transcription and translation initiation and termination codons) operably linked the nucleic acid sequence encoding at least part of a binder (e.g., an antibody domain, an antigen binding fragment, an antibody, a CAR, a cell engager, or an ADC) provided herein. In some cases, a promoter used to drive expression can be a constitutive promotor or a regulatable promotor. Examples of regulatable promoters that can be used as described herein include, without limitation, inducible promotors, repressible promotors, and tissue- specific promoters. Examples of viral promotors that can be used as described herein include, without limitation, adenoviral promotors, vaccinia virus promotors, CMV promotors (e.g., immediate early CMV promotors), and AAV promoters. Any appropriate method can be used to make a nucleic acid molecule (or vector such as a plasmid vector or viral vector) having a nucleic acid sequence encoding at least part of a binder (e.g., an antibody domain, an antigen binding fragment, an antibody, a CAR, a cell engager, or an ADC) provided herein. For example, molecule cloning techniques can be used to make a nucleic acid molecule (or vector such as a plasmid vector or viral vector) having a nucleic acid sequence encoding at least part of a binder provided herein as described elsewhere (see, e.g., Sambrook et al., Molecular Cloning: A Laboratory Manual, 2nd edition, Cold Spring Harbor Laboratory, NY (1989); and Ausubel et al., Current Protocols in Molecular Biology, Green Publishing Associates and John Wiley & Sons, New York, N.Y. (1994)). This document also provides host cells that include a nucleic acid provided herein (e.g., a nucleic acid having a nucleic acid sequence encoding at least part of a binder (e.g.,Attorney Docket No.07039-2338WO1 / 2024-299 an antibody domain, an antigen binding fragment, an antibody, a CAR, a cell engager, or an ADC) provided herein). Host cells that can be designed to include one or more nucleic acids provided herein can be prokaryotic cells or eukaryotic cells. Examples of prokaryotic cells that can be designed to include a nucleic acid provided herein include,without limitation, E. coli (e.g., Tb-1, TG-1, DH5 , XL-Blue MRF (Stratagene), SA2821,or Y1090 cells), Bacillus subtilis, Salmonella typhimurium, Serratia marcescens, or Pseudomonas (e.g., P. aeruginosa) cells. Examples of eukaryotic cells that can be designed to include a nucleic acid provided herein include, without limitation, insect cells (e.g., Sf9 or Ea4 cells), yeast cells (e.g., S. cerevisiae cells), and mammalian cells (e.g., mouse, rat, hamster, monkey, or human cells). For example, VERO cells, HeLa cells, 3T3 cells, Chinese hamster ovary (CHO) cells, W138 BHK cells, COS-7 cells, and MDCK cells can be designed to include a nucleic acid provided herein. Any appropriate method can be used to introduce one or more nucleic acids provided herein (e.g., a vector such as a plasmid vector or viral vector having a nucleic acid sequence encoding at least part of a binder provided herein) into a host cell. For example, calcium chloride-mediated transformation, transduction, conjugation, triparental mating, DEAE, dextran-mediated transfection, infection, membrane fusion with liposomes, high velocity bombardment with DNA-coated microprojectiles, direct microinjection into single cells, electroporation, or combinations thereof can be used to introduce a nucleic acid provided herein into a host cell (see, e.g., Sambrook et al., Molecular Biology: A Laboratory Manual, Cold Spring Harbor Laboratory, NY (1989); Davis et al., Basic Methods in Molecular Biology (1986); and Neumann et al., EMBO J., 1:841 (1982)). In some cases, cells such as T cells, stem cells (e.g., induced pluripotent stem cells or mesenchymal stem cells), or NK cells can be designed to express one or more nucleic acids encoding a CAR described herein. For example, a population of T cells can be infected with viral vectors designed to express nucleic acid encoding a CAR described herein (e.g., a CAR having the ability to bind to a CS1 polypeptide). In some cases, cells such as T cells, stem cells (e.g., induced pluripotent stem cells or mesenchymal stem cells), or NK cells can be designed to express one or more nucleic acids encoding a cell engager described herein. For example, a population of T cells can be infected with viral vectors designed to express nucleic acid encoding a cell engager described herein (e.g., a cell engager having the ability to bind to a CS1 polypeptide).Attorney Docket No.07039-2338WO1 / 2024-299 In some cases, cells (e.g., host cells) designed to express one or more binders (e.g., one or more antibody domains, one or more antigen binding fragments, one or more antibodies, one or more CARs, one or more cell engagers, and / or one or more ADCs) having the ability to bind to a CS1 polypeptide can be dual-specific cells (e.g., can bind to two different polypeptides with at least one being a CS1 polypeptide (e.g., a human CS1 polypeptide)). For example, a dual-specific cell provided herein can include a first CAR having the ability to bind to a CS1 polypeptide and can include a second CAR having the ability to bind to a polypeptide other than a CS1 polypeptide. In some cases, cells designed to express a CAR having the ability to bind to a CS1 polypeptide also can express (e.g., can be designed to express) a CAR having the ability to bind to a polypeptide expressed by a cancer cell. In some cases, cells designed to express a CAR having the ability to bind to a CS1 polypeptide also can express (e.g., can be designed to express) a CAR having the ability to bind to a polypeptide expressed by a cancer- associated fibroblast (CAF). Such dual-specific cells can target CS1+cancers cells (e.g., to reduce or eliminate the number of cancer cells present in a mammal (e.g., a human) having cancer) and can target CAFs in an immunosuppressive tumor microenvironment (TME; e.g., to reduce or eliminate resistance to CART cell therapy). For example, a host cell that includes a nucleic acid having a nucleic acid sequence encoding a CAR having the ability to bind a CS1 polypeptide provided herein also can include a nucleic acid having a nucleic acid sequence encoding a CAR having the ability to bind to a polypeptide other than a CS1 polypeptide. For example, a CAR+T cell can be a dual- specific CAR+T cell such that the CAR+T cell expresses one or more CS1-specific CARs (e.g., such that the CAR+T cell can bind to a CS1 polypeptide) and can express one or more binders (e.g., CARs) specific for a polypeptide other than a CS1 polypeptide (e.g., such that the CAR+T cell can bind to that other polypeptide). Examples of polypeptides that can be targeted by a binder (e.g., a CAR) that can be expressed by a CAR+T cell expressing one or more CS1-specific CARs include, without limitation, BCMA polypeptides, CD38 polypeptides, GPRC5D polypeptides, CD19 polypeptides, and CD138 polypeptides. In some cases, a binder (e.g., a CAR) having the ability to bind to a BCMA polypeptide (e.g., a human BCMA polypeptide) can include (a) a heavy chain variable domain comprising (i) a CDR1 that comprises, consists essentially of, or consists of theAttorney Docket No.07039-2338WO1 / 2024-299 amino acid sequence set forth in SEQ ID NO:67, (ii) a CDR2 that comprises, consists essentially of, or consists of the amino acid sequence set forth in SEQ ID NO:68, and (iii) a CDR3 that comprises, consists essentially of, or consists of the amino acid sequence set forth in SEQ ID NO:69, and / or (b) a light chain variable domain comprising (i) a CDR1 that comprises, consists essentially of, or consists of the amino acid sequence set forth in SEQ ID NO:70, (ii) a CDR2 that comprises, consists essentially of, or consists of the amino acid sequence set forth in SEQ ID NO:71, and (iii) a CDR3 that comprises, consists essentially of, or consists of the amino acid sequence set forth in SEQ ID NO:72. In some cases, a binding agent (e.g., a CAR) having the ability to bind to a BCMA polypeptide (e.g., a human BCMA polypeptide) can include CDRs that comprise, consist essentially of, or consist of the CDR amino acid sequences set forth in Table 27. Table 27. Exemplary CDR sequences for a binder that can bind a BCMA polypeptide.A CDR that can be included in a binder (e.g., a CAR) having the ability to bind to a BCMA polypeptide (e.g., a human BCMA polypeptide) that consists essentially of a CDR amino acid sequence set forth in any one of SEQ ID NOs:67-72 is a CDR that has zero, one, or two amino acid substitutions within the articulated sequence of the sequence identifier (e.g., any one of SEQ ID NOs:67-72), has zero, one, two, three, four, or five amino acid residues preceding the articulated sequence of the sequence identifier (e.g., any one of SEQ ID NOs:67-72), and / or has zero, one, two, three, four, or five amino acid residues following the articulated sequence of the sequence identifier (e.g., any one of SEQ ID NOs:67-72), provided that the binder retains the ability to bind to a BCMA polypeptide (e.g., a human BCMA polypeptide). When a CAR+T cell is a dual specific CAR+T cell having the ability to bind to a CS1 polypeptide and also having the ability to bind to a polypeptide other than a CS1 polypeptide (e.g., a BCMA polypeptide), the CAR specific for a polypeptide other thanAttorney Docket No.07039-2338WO1 / 2024-299 the CS1 polypeptide can be an inducible CAR. In some cases, an inducible CAR can be an expression-inducible CAR. For example, a cell can include a nucleic acid sequence encoding a CAR specific for a polypeptide other than the CS1 polypeptide (e.g., a BCMA polypeptide) that is operably linked to a regulatable promotor (e.g., an activation- dependent promoter, an inducible promotor, or a tissue-specific promoters) such that the CAR specific for a polypeptide other than the CS1 polypeptide is only expressed in the cell when the regulatable promoter is activated. In some cases, an inducible CAR can be an activation-inducible CAR. For example, a cell can express one or more CS1-specific CARs, can express a CAR specific for a polypeptide other than the CS1 polypeptide (e.g., a BCMA polypeptide), and can express one or more response elements such that the CAR specific for a polypeptide other than the CS1 polypeptide is only expressed in the cell when the CS1-specific CAR(s) intracellular signaling domain(s) are activated (e.g., by binding to a CS1 polypeptide). Examples of systems that can be used to induce a CAR specific for a polypeptide other than the CS1 polypeptide (e.g., a BCMA polypeptide) upon activation of a CS1- specific CAR include, without limitation, synthetic Notch (synNotch) receptors, TET-on systems, NFAT inducible systems, and GAL4 / upstream activation sequence (UAS) systems. In some cases, a binder (e.g., an antibody domain, an antigen binding fragment, an antibody, a CAR, a cell engager, or an ADC) provided herein can be produced using a method that includes (a) introducing nucleic acid encoding the polypeptide into a host cell; (b) culturing the host cell in culture medium under conditions sufficient to express the polypeptide; (c) harvesting the polypeptide from the cell or culture medium; and (d) purifying the polypeptide (e.g., to reach at least 50, 60, 70, 80, 90, 95, 97, 98, or 99 percent purity). In some cases, a binder (e.g., an antibody domain, an antigen binding fragment, an antibody, a CAR, a cell engager, or an ADC) provided herein, a nucleic acid provided herein (e.g., nucleic acid encoding an antibody domain, an antigen binding fragment, an antibody, a CAR, a cell engager, or an ADC provided herein), a vector provided herein (e.g., a viral vector designed to express an antibody domain, an antigen binding fragment, an antibody, a CAR, a cell engager, or an ADC provided herein), and / or a host cell provided herein (e.g., a host cell designed to express an antibody domain, an antigenAttorney Docket No.07039-2338WO1 / 2024-299 binding fragment, an antibody, a CAR, a cell engager, or an ADC provided herein) can be formulated as a pharmaceutical composition for administration to a mammal (e.g., a human) having cancer (e.g., one or more sarcomas) to treat that mammal. In some cases, a binder provided herein, a nucleic acid provided herein, a vector provided herein, and / or a host cell provided herein can be formulated as a pharmaceutical composition for administration to a mammal (e.g., a human) to reduce the number of cancer cells within the mammal and / or to increase the survival of the mammal suffering from cancer. For example, a binder provided herein having the ability to bind to a CS1 polypeptide (e.g., a human CS1 polypeptide) can be formulated as a pharmaceutical composition for administration to a mammal (e.g., a human). In some cases, a pharmaceutical composition provided herein can include a pharmaceutically acceptable carrier such as a buffer, a salt, a surfactant, a sugar, a tonicity modifier, or combinations thereof as, for example, described elsewhere (Gervasi, et al., Eur. J. Pharmaceutics and Biopharmaceutics, 131:8- 24 (2018)). Examples of pharmaceutically acceptable carriers that can be used to make a pharmaceutical composition provided herein include, without limitation, water, lactic acid, citric acid, sodium chloride, sodium citrate, sodium succinate, sodium phosphate, a surfactant (e.g., polysorbate 20, polysorbate 80, or poloxamer 188), dextran 40, or a sugar (e.g., sorbitol, mannitol, sucrose, dextrose, or trehalose), or combinations thereof. For example, a pharmaceutical composition designed to include a binder provided herein (or a nucleic acid, a vector, or a host cell provided herein) can be formulated to include a buffer (e.g., an acetate, citrate, histidine, succinate, phosphate, or hydroxymethylaminomethane (Tris) buffer), a surfactant (e.g., polysorbate 20, polysorbate 80, or poloxamer 188), and a sugar such as sucrose. Other ingredients that can be included within a pharmaceutical composition provided herein include, without limitation, amino acids such as glycine or arginine, and antioxidants such as ascorbic acid, methionine, or ethylenediaminetetraacetic acid (EDTA). In some cases, when a pharmaceutical composition is formulated to include one or more binders (e.g., one or more antibody domains, one or more antigen binding fragments, one or more antibodies, one or more CARs, one or more cell engagers, and / or one or more ADCs) provided herein (or a nucleic acid, vector, or host cell (e.g., CAR+cells) provided herein), any appropriate concentration of the binder can be used. For example, a pharmaceutical composition provided herein can be formulated to be a liquidAttorney Docket No.07039-2338WO1 / 2024-299 that includes from about 50 mg to about 5000 mg (e.g., from about 50 mg to about 4500 mg, from about 50 mg to about 4000 mg, from about 50 mg to about 3500 mg, from about 50 mg to about 3000 mg, from about 50 mg to about 2500 mg, from about 50 mg to about 2000 mg, from about 50 mg to about 1500 mg, from about 50 mg to about 1000 mg, from about 50 mg to about 500 mg, from about 50 mg to about 250 mg, from about 250 mg to about 5000 mg, from about 500 mg to about 5000 mg, from about 100 mg to about 5000 mg, from about 1500 mg to about 5000 mg, from about 2000 mg to about 5000 mg, from about 2500 mg to about 5000 mg, from about 3000 mg to about 5000 mg, from about 3500 mg to about 5000 mg, from about 4000 mg to about 5000 mg, from about 4500 mg to about 5000 mg, from about 500 mg to about 4500 mg, from about 1000 mg to about 4000 mg, from about 1500 mg to about 3500 mg, from about 2000 mg to about 2500 mg, from about 500 mg to about 1500 mg, from about 1000 mg to about 2000 mg, from about 1500 mg to about 2500 mg, from about 2000 mg to about 3000 mg, from about 2500 mg to about 3500 mg, from about 3000 mg to about 4000 mg, or from about 3500 mg to about 4500 mg) of a binder provided herein per mL. In another example, a pharmaceutical composition provided herein can be formulated to be a solid or semi-solid that includes from about 50 mg to about 5000 mg (e.g., from about 50 mg to about 4500 mg, from about 50 mg to about 4000 mg, from about 50 mg to about 3500 mg, from about 50 mg to about 3000 mg, from about 50 mg to about 2500 mg, from about 50 mg to about 2000 mg, from about 50 mg to about 1500 mg, from about 50 mg to about 1000 mg, from about 50 mg to about 500 mg, from about 50 mg to about 250 mg, from about 250 mg to about 5000 mg, from about 500 mg to about 5000 mg, from about 100 mg to about 5000 mg, from about 1500 mg to about 5000 mg, from about 2000 mg to about 5000 mg, from about 2500 mg to about 5000 mg, from about 3000 mg to about 5000 mg, from about 3500 mg to about 5000 mg, from about 4000 mg to about 5000 mg, from about 4500 mg to about 5000 mg, from about 500 mg to about 4500 mg, from about 1000 mg to about 4000 mg, from about 1500 mg to about 3500 mg, from about 2000 mg to about 2500 mg, from about 500 mg to about 1500 mg, from about 1000 mg to about 2000 mg, from about 1500 mg to about 2500 mg, from about 2000 mg to about 3000 mg, from about 2500 mg to about 3500 mg, from about 3000 mg to about 4000 mg, or from about 3500 mg to about 4500 mg) of a binder provided herein. In some cases, a pharmaceutical composition containing one or more cells designed to express a CAR having the ability toAttorney Docket No.07039-2338WO1 / 2024-299 bind to a CS1 polypeptide provided herein can be formulated as a dosage form with from about 50,000 anti-CS1 CAR+cells (e.g., per kg body weight of the mammal to be treated) to about 50,000,000 anti-CS1 CAR+cells (e.g., per kg body weight of the mammal to be treated) (e.g., from about 50,000 to about 25,000,000, from about 50,000 to about 1,000,000, from about 50,000 to about 750,000, from about 50,000 to about 500,000, from about 50,000 to about 250,000, from about 50,000 to about 100,000, from about 100,000 to about 50,000,000, from about 250,000 to about 50,000,000, from about 500,000 to about 50,000,000, from about 750,000 to about 50,000,000, from about 1,000,000 to about 50,000,000, from about 25,000,000 to about 50,000,000, from about 75,000 to about 25,000,000, from about 100,000 to about 1,000,000, from about 250,000 to about 750,000, from about 100,000 to about 500,000, from about 250,000 to about 750,000, from about 500,000 to about 1,000,000, or from about 750,000 to about 25,000,000 anti-CS1 CAR+cells per kg body weight of the mammal to be treated). In some cases, when a pharmaceutical composition is formulated to include one or more nucleic acids (e.g., vectors such as viral vectors) encoding at least part of a binder provided herein, any appropriate concentration of the nucleic acid can be used. For example, a pharmaceutical composition provided herein can be formulated to be a liquid that includes from 50 mg to about 5000 mg (e.g., from about 50 mg to about 4500 mg, from about 50 mg to about 4000 mg, from about 50 mg to about 3500 mg, from about 50 mg to about 3000 mg, from about 50 mg to about 2500 mg, from about 50 mg to about 2000 mg, from about 50 mg to about 1500 mg, from about 50 mg to about 1000 mg, from about 50 mg to about 500 mg, from about 50 mg to about 250 mg, from about 250 mg to about 5000 mg, from about 500 mg to about 5000 mg, from about 100 mg to about 5000 mg, from about 1500 mg to about 5000 mg, from about 2000 mg to about 5000 mg, from about 2500 mg to about 5000 mg, from about 3000 mg to about 5000 mg, from about 3500 mg to about 5000 mg, from about 4000 mg to about 5000 mg, from about 4500 mg to about 5000 mg, from about 500 mg to about 4500 mg, from about 1000 mg to about 4000 mg, from about 1500 mg to about 3500 mg, from about 2000 mg to about 2500 mg, from about 500 mg to about 1500 mg, from about 1000 mg to about 2000 mg, from about 1500 mg to about 2500 mg, from about 2000 mg to about 3000 mg, from about 2500 mg to about 3500 mg, from about 3000 mg to about 4000 mg, or from about 3500 mg to about 4500 mg) of a nucleic acid provided herein per mL. In another example, aAttorney Docket No.07039-2338WO1 / 2024-299 pharmaceutical composition provided herein can be formulated to be a solid or semi-solid that includes from about 50 mg to about 5000 mg (e.g., from about 50 mg to about 4500 mg, from about 50 mg to about 4000 mg, from about 50 mg to about 3500 mg, from about 50 mg to about 3000 mg, from about 50 mg to about 2500 mg, from about 50 mg to about 2000 mg, from about 50 mg to about 1500 mg, from about 50 mg to about 1000 mg, from about 50 mg to about 500 mg, from about 50 mg to about 250 mg, from about 250 mg to about 5000 mg, from about 500 mg to about 5000 mg, from about 100 mg to about 5000 mg, from about 1500 mg to about 5000 mg, from about 2000 mg to about 5000 mg, from about 2500 mg to about 5000 mg, from about 3000 mg to about 5000 mg, from about 3500 mg to about 5000 mg, from about 4000 mg to about 5000 mg, from about 4500 mg to about 5000 mg, from about 500 mg to about 4500 mg, from about 1000 mg to about 4000 mg, from about 1500 mg to about 3500 mg, from about 2000 mg to about 2500 mg, from about 500 mg to about 1500 mg, from about 1000 mg to about 2000 mg, from about 1500 mg to about 2500 mg, from about 2000 mg to about 3000 mg, from about 2500 mg to about 3500 mg, from about 3000 mg to about 4000 mg, or from about 3500 mg to about 4500 mg) of a nucleic acid provided herein. In some cases, a pharmaceutical composition designed to include one or more binders (e.g., one or more antibody domains, one or more antigen binding fragments, one or more antibodies, one or more CARs, one or more cell engagers, and / or one or more ADCs) provided herein (or a nucleic acid, vector, or host cell (e.g., CAR+cells) provided herein) can be formulated to include one or more agents capable of reducing aggregation of the binder when formulated. Examples of such agents that can be used as described herein include, without limitation, methionine, arginine, lysine, aspartic acid, glycine, glutamic acid, and combinations thereof. In some cases, one or more of these amino acids can be included within the formulation at a concentration from about 0.5 mM to about 145 mM (e.g., from about 1 mM to about 145 mM, from about 10 mM to about 145 mM, from about 100 mM to about 145 mM, from about 0.5 mM to about 125 mM, from about 0.5 mM to about 100 mM, from about 0.5 mM to about 75 mM, or from about 10 mM to about 100 mM). A pharmaceutical composition provided herein can be in any appropriate form. For example, a pharmaceutical composition provided herein can designed to be a liquid, a semi-solid, or a solid. In some cases, a pharmaceutical composition provided herein canAttorney Docket No.07039-2338WO1 / 2024-299 be a liquid solution (e.g., an injectable and / or infusible solution), a dispersion, a suspension, a tablet, a pill, a powder, a microemulsion, a liposome, or a suppository. In some cases, a pharmaceutical composition provided herein can be lyophilized. In some cases, a pharmaceutical composition provided herein (e.g., a pharmaceutical composition that includes one or more binders (e.g., one or more antibody domains, one or more antigen binding fragments, one or more antibodies, one or more CARs, one or more cell engagers, and / or one or more ADCs) provided herein (or a nucleic acid, vector, or host cell (e.g., CAR+cells) provided herein)) can be formulated with a carrier or coating designed to protect against rapid release. For example, a pharmaceutical composition provided herein can be formulated as a controlled release formulation or as a regulated release formulation as described elsewhere (U.S. Patent Application Publication Nos. 2019 / 0241667; 2019 / 0233522; and 2019 / 0233498). This document also provides methods for administering a composition (e.g., a pharmaceutical composition provided herein) containing one or more binders (e.g., one or more antibody domains, one or more antigen binding fragments, one or more antibodies, one or more CARs, one or more cell engagers, and / or one or more ADCs) provided herein (or a nucleic acid, vector, or host cell (e.g., CAR+cells) provided herein) to a mammal (e.g., a human). For example, a composition (e.g., a pharmaceutical composition provided herein) containing one or more binders provided herein (or a nucleic acid, vector, and / or host cell (e.g., CAR+cells) provided herein) can be administered to a mammal (e.g., a human) having cancer (e.g., multiple myeloma) to treat that mammal. In some cases, a composition (e.g., a pharmaceutical composition provided herein) containing one or more binders provided herein (or a nucleic acid, vector, and / or host cell (e.g., CAR+cells) provided herein) can be administered to a mammal (e.g., a human) to reduce the number of cancer cells within the mammal and / or to increase the survival of the mammal. In some cases, a composition (e.g., a pharmaceutical composition provided herein) containing one or more binders (e.g., one or more antibody domains, one or more antigen binding fragments, one or more antibodies, one or more CARs, one or more cell engagers, and / or one or more ADCs) provided herein (or a nucleic acid, vector, and / or host cell (e.g., CAR+cells) provided herein) can be administered to a mammal (e.g., a human) having cancer (e.g., a CS1+cancer) to reduce or eliminate one or more symptoms of theAttorney Docket No.07039-2338WO1 / 2024-299 cancer. Examples of symptoms of a cancer (e.g., multiple myeloma) that can be reduced using a composition comprising one or more binders described herein include, without limitation, bone pain (e.g., in the spine, chest, and / or hips), nausea, constipation, loss of appetite, confusion, tiredness, infections, weight loss, weakness, thirst, needing to urinate often, anemia, neutropenia, thrombocytopenia, and dizziness. In some cases, a composition (e.g., a pharmaceutical composition provided herein) containing one or more binders (e.g., one or more antibody domains, one or more antigen binding fragments, one or more antibodies, one or more CARs, one or more cell engagers, and / or one or more ADCs) provided herein (or a nucleic acid, vector, and / or host cell (e.g., CAR+cells) provided herein) can be administered to a mammal (e.g., a human) having cancer (e.g., a CS1+cancer) to reduce the size of cancer within the mammal. For example, a mammal having cancer and in need of treatment thereof can be administered one or more binders provided herein (or a nucleic acid, vector, and / or host cell (e.g., CAR+cells) provided herein) to reduce the number of cancer cells in the mammal by, for example, 10, 20, 30, 40, 50, 60, 70, 80, 90, 95, or more percent. In another example, a mammal having cancer and in need of treatment thereof can be administered one or more binders provided herein (or a nucleic acid, vector, and / or host cell (e.g., CAR+cells) provided herein) to reduce the volume of one or more solid tumors in the mammal by, for example, 10, 20, 30, 40, 50, 60, 70, 80, 90, 95, or more percent. In some cases, a composition (e.g., a pharmaceutical composition provided herein) containing one or more binders (e.g., one or more antibody domains, one or more antigen binding fragments, one or more antibodies, one or more CARs, one or more cell engagers, and / or one or more ADCs) provided herein (or a nucleic acid, vector, and / or host cell (e.g., CAR+cells) provided herein) can be administered to a mammal (e.g., a human) having cancer (e.g., a CS1+cancer) to improve survival of the mammal. For example, a mammal having cancer and in need of treatment thereof can be administered one or more binders provided herein (or a nucleic acid, vector, and / or host cell (e.g., CAR+cells) provided herein) to improve the survival of a mammal having cancer by, for example, 10, 20, 30, 40, 50, 60, 70, 80, 90, 95, or more percent. In another example, a mammal having cancer and in need of treatment thereof can be administered one or more binders provided herein (or a nucleic acid, vector, and / or host cell (e.g., CAR+cells) provided herein) to improve the survival of a mammal having cancer by, for example, at least 6 months (e.g.,Attorney Docket No.07039-2338WO1 / 2024-299 about 6 months, about 8 months, about 10 months, about 1 year, about 1.5 years, about 2 years, about 2.5 years, about 3 years, about 4 years, about 5 years, or more). Any appropriate mammal having cancer can be treated as described herein (e.g., by administering a composition (e.g., a pharmaceutical composition provided herein) containing one or more binders (e.g., one or more antibody domains, one or more antigen binding fragments, one or more antibodies, one or more CARs, one or more cell engagers, and / or one or more ADCs) provided herein (or a nucleic acid, vector, and / or host cell (e.g., CAR+cells) provided herein)). Examples of mammals that can have cancer and can be treated as described herein include, without limitation, humans, non-human primates (e.g., monkeys), horses, bovine species, porcine species, dogs, cats, mice, and rats. In some cases, a human having cancer can be treated by administering one or more provided herein (or a nucleic acid, vector, and / or host cell (e.g., CAR+cells) provided herein) to the human. Any appropriate cancer can be treated using a composition (e.g., a pharmaceutical composition provided herein) containing one or more binders (e.g., one or more antibody domains, one or more antigen binding fragments, one or more antibodies, one or more CARs, one or more cell engagers, and / or one or more ADCs) provided herein (or a nucleic acid, vector, or host cell (e.g., CAR+cells) provided herein). For example, a mammal (e.g., a human) having cancer can be treated by administering a composition (e.g., a pharmaceutical composition) containing one or more binders provided herein to that mammal. In some cases, a cancer that can be treated as described herein can be a CS1+cancer (e.g., can include one or more CS1+cancer cells). In some cases, a cancer that can be treated as described herein can include one or more solid tumors (e.g., solid tumors having a TME including one or more CS1+CAFs). In some cases, a cancer that can be treated as described herein can be a blood cancer. Examples of cancers that can be treated as described herein include, without limitation, multiple myelomas and myelofibrosis. In some cases, a mammal (e.g., a human) having a CS1+cancer can be administered a composition (e.g., a pharmaceutical composition) containing one or more binders provided herein to treat that mammal. Any appropriate method can be used to administer a composition (e.g., a pharmaceutical composition) provided herein to a mammal (e.g., a human). For example, a composition provided herein (e.g., a pharmaceutical composition containing one orAttorney Docket No.07039-2338WO1 / 2024-299 more binders provided herein such as one or more antibody domains, one or more antigen binding fragments, one or more antibodies, one or more cells designed to express a CAR having the ability to bind a CS1 polypeptide, one or more cell engagers, and / or one or more ADCs provided herein) can be administered to a mammal (e.g., a human) intravenously (e.g., via an intravenous injection or infusion), subcutaneously (e.g., via a subcutaneous injection), intraperitoneally (e.g., via an intraperitoneal injection), orally, via inhalation, or intramuscularly (e.g., via intramuscular injection). In some cases, the route and / or mode of administration of a composition (e.g., a pharmaceutical composition provided herein) can be adjusted for the mammal being treated. In some cases, an effective amount (e.g., an effective dose) of a composition containing one or more binders (e.g., one or more antibody domains, one or more antigen binding fragments, one or more antibodies, one or more CARs, one or more cell engagers, and / or one or more ADCs) provided herein (or a nucleic acid, vector, or host cell (e.g., CAR+cells) provided herein) (e.g., a pharmaceutical composition provided herein) can be an amount that reduces the number of cancer cells within a mammal having cancer without producing significant toxicity to the mammal. In some cases, an effective amount of a composition containing one or more binders provided herein (or a nucleic acid, vector, or host cell (e.g., CAR+cells) provided herein) (e.g., a pharmaceutical composition provided herein) can be an amount that increases the survival time of a mammal having cancer as compared to a control mammal having comparable cancer and not treated with the composition. For example, an effective amount of a binder provided herein can be from about 10 mg / m2to about 500 mg / m2(e.g., from about 10 to about 450, from about 10 to about 400, from about 10 to about 350, from about 10 to about 300, from about 10 to about 250, from about 10 to about 200, from about 10 to about 150, from about 10 to about 100, from about 10 to about 50, from about 50 to about 500, from about 100 to about 500, from about 150 to about 500, from about 200 to about 500, from about 250 to about 500, from about 300 to about 500, from about 350 to about 500, from about 400 to about 500, from about 450 to about 500, from about 50 to about 450, from about 100 to about 400, from about 150 to about 350, from about 200 to about 300, from about 50 to about 150, from about 100 to about 200, from about 150 to about 250, from about 250 to about 350, from about 300 to about 400, or from about 350 to about 450 mg / m2). In another example, an effective amount of cells (e.g., T cells) expressing aAttorney Docket No.07039-2338WO1 / 2024-299 binder (e.g., CAR) provided herein can be from about 50,000 anti-CS1 CAR+cells / kg to about 10,000,000 anti-CS1 CAR+cells / kg (e.g., from about 50,000 to about 5,000,000, from about 50,000 to about 1,000,000, from about 50,000 to about 750,000, from about 50,000 to about 500,000, from about 50,000 to about 250,000, from about 50,000 to about 100,000, from about 100,000 to about 10,000,000, from about 250,000 to about 10,000,000, from about 500,000 to about 10,000,000, from about 750,000 to about 10,000,000, from about 100,000 to about 5,000,000, from about 250,000 to about 1,000,000, from about 500,000 to about 750,000, from about 100,000 to about 250,000, from about 250,000 to about 500,000, from about 500,000 to about 750,000, from about 750,000 to about 1,000,000, or from about 1,000,000 to about 5,000,000 anti-CS1 CAR+cells / kg). The effective amount can remain constant or can be adjusted as a sliding scale or variable dose depending on the mammal’s response to treatment. Various factors can influence the actual effective amount used for a particular application. For example, the severity of cancer when treating a mammal having cancer (e.g., one or more sarcomas), the route of administration, the age and general health condition of the mammal, excipient usage, the possibility of co-usage with other therapeutic or prophylactic treatments such as use of other agents (e.g., checkpoint inhibitors), and the judgment of the treating physician may require an increase or decrease in the actual effective amount of a composition provided herein (e.g., a pharmaceutical composition containing one or more binders provided herein) that is administered. In some cases, an effective frequency of administration of a composition containing one or more binders (e.g., one or more antibody domains, one or more antigen binding fragments, one or more antibodies, one or more CARs, one or more cell engagers, and / or one or more ADCs) provided herein (or a nucleic acid, vector, or host cell (e.g., CAR+cells) provided herein) (e.g., a pharmaceutical composition provided herein) can be a frequency that reduces the number of cancer cells within a mammal having cancer without producing significant toxicity to the mammal. In some cases, an effective frequency of administration of a composition containing one or more binders provided herein (or a nucleic acid, vector, or host cell (e.g., CAR+cells) provided herein) can be a frequency that increases the survival time of a mammal having cancer as compared to a control mammal having comparable cancer and not treated with the composition. For example, an effective frequency of administration of a pharmaceutical compositionAttorney Docket No.07039-2338WO1 / 2024-299 provided herein such as a pharmaceutical composition containing one or more binders provided herein can be from about twice daily to about once a year (e.g., from about twice daily to about once a month, from about twice daily to about once a week, from about once daily to about once a month, or from one once daily to about once a week). In some cases, the frequency of administration of a pharmaceutical composition provided herein such as a pharmaceutical composition containing one or more binders provided herein can be daily. The frequency of administration of a pharmaceutical composition provided herein such as a pharmaceutical composition containing one or more binders provided herein can remain constant or can be variable during the duration of treatment. Various factors can influence the actual effective frequency used for a particular application. For example, the severity of the cancer, the route of administration, the age and general health condition of the mammal, excipient usage, the possibility of co-usage with other therapeutic or prophylactic treatments such as use of other agents (e.g., checkpoint inhibitors), and the judgment of the treating physician may require an increase or decrease in the actual effective frequency of administration of a composition provided herein (e.g., a pharmaceutical composition containing one or more binders provided herein). In some cases, an effective duration of administration of a composition containing one or more binders (e.g., one or more antibody domains, one or more antigen binding fragments, one or more antibodies, one or more CARs, one or more cell engagers, and / or one or more ADCs) provided herein (or a nucleic acid, vector, or host cell (e.g., CAR+cells) provided herein) (e.g., a pharmaceutical composition provided herein) can be a duration that reduces the number of cancer cells within a mammal without producing significant toxicity to the mammal. In some cases, an effective duration of administration of a composition containing one or more binders provided herein (or a nucleic acid, vector, or host cell (e.g., CAR+cells) provided herein) can be a duration that increases the survival time of a mammal having cancer as compared to a control mammal having comparable cancer and not treated with the composition. For example, an effective duration of administration of a pharmaceutical composition provided herein such as a pharmaceutical composition containing one or more binders provided herein can vary from a single time point of administration to several weeks to several months (e.g., 4 to 12 weeks). Multiple factors can influence the actual effective duration used for aAttorney Docket No.07039-2338WO1 / 2024-299 particular application. For example, the severity of the cancer, the route of administration, the age and general health condition of the mammal, excipient usage, the possibility of co-usage with other therapeutic or prophylactic treatments such as use of other agents (e.g., checkpoint inhibitors), and the judgment of the treating physician may require an increase or decrease in the actual effective duration of administration of a composition provided herein (e.g., a pharmaceutical composition containing one or more binders provided herein). In some cases, one or more binders (e.g., one or more antibody domains, one or more antigen binding fragments, one or more antibodies, one or more CARs, one or more cell engagers, and / or one or more ADCs) provided herein (or a nucleic acid, vector, or host cell (e.g., CAR+cells) provided herein) (e.g., a pharmaceutical composition provided herein) can be administered to a mammal (e.g., a human) having cancer as the sole active agent(s) to treat the cancer. In some cases, methods for treating a mammal (e.g., a human) as described herein (e.g., by administering a composition containing one or more binders (e.g., one or more antibody domains, one or more antigen binding fragments, one or more antibodies, one or more CARs, one or more cell engagers, and / or one or more ADCs) provided herein (or a nucleic acid, vector, or host cell (e.g., CAR+cells) provided herein) (e.g., a pharmaceutical composition provided herein)) also can include administering to the mammal one or more (e.g., one, two, three, or more) additional agents used to treat cancer and / or performing one or more (e.g., one, two, three, or more) therapies used to treat cancer. For example, a combination therapy used to treat a mammal (e.g., a human) having cancer can include administering to the mammal one or more binders provided herein (or a nucleic acid, vector, or host cell (e.g., CAR+cells) provided herein) and administering to the mammal one or more (e.g., one, two, three, or more) additional agents used to treat cancer. In some cases, an additional anti-cancer agent that can be administered to a mammal can be a chemotherapeutic agent. In some cases, an additional anti-cancer agent that can be administered to a mammal can be a cytotoxic agent. In some cases, an additional anti-cancer agent that can be administered to a mammal can be an immune-checkpoint inhibitor (e.g., anti-PD-1 antibodies, PD-1 inhibitors, anti-PD-L1 antibodies, PD-L1 inhibitors and anti-CTLA-4 antibodies). Examples of additional anti- cancer agents that can be administered to a mammal (e.g., a human) having cancer (e.g., aAttorney Docket No.07039-2338WO1 / 2024-299 cancer including one or more solid tumors) to treat the mammal include, without limitation, enzalutamide, imanitib, gefitinib, erlotini, sunitinib, lapatinib, nilotinib, sorafenib, temsirolimus, everolimus, pazopanib, crizotinib, ruxolitinib, axitinib, bosutinib, cabozantinib, ponatinib, regorafenib, ibrutinib, trametinib, perifosine, bortezomib, carfilzomib, batimastat, ganetespib, obatoclax, navitoclax, taxol, paclitaxel, bevacizumab, cemiplimab, nivolumab, pembrolizumab, JTX-4014, spartalizumab, camrelizumab, sintilimab, tislelizumab, toripalimab, dostarlimab, INCMGA00012, AMP-224, AMP-514, avelumab, durvalumab, atezolizumab, KN035, CK-301, AUNP12, CA-170, BMS- 986189, ipilimumab, dubermatinib, lenzilumab, tafasitamab, and any combinations thereof. In cases where one or more binders (e.g., one or more antibody domains, one or more antigen binding fragments, one or more antibodies, one or more CARs, one or more cell engagers, and / or one or more ADCs) provided herein (or a nucleic acid, vector, or host cell (e.g., CAR+cells) provided herein) (e.g., a pharmaceutical composition provided herein) are used in combination with additional anti-cancer agents, the one or more additional anti-cancer agents can be administered at the same time (e.g., in a single composition containing one or more binders provided herein (or a nucleic acid, vector, or host cell (e.g., CAR+cells) provided herein) and containing the one or more additional agents) or independently. For example, a composition including one or more binders provided herein (or a nucleic acid, vector, or host cell (e.g., CAR+cells) provided herein) can be administered first, and the one or more additional agents administered second, or vice versa. In some cases, a combination therapy used to treat a mammal (e.g., a human) having cancer can include administering to the mammal one or more binders (e.g., one or more antibody domains, one or more antigen binding fragments, one or more antibodies, one or more CARs, one or more cell engagers, and / or one or more ADCs) provided herein (or a nucleic acid, vector, or host cell (e.g., CAR+cells) provided herein) (e.g., a pharmaceutical composition provided herein), and can include performing one or more (e.g., one, two, three, or more) therapies used to treat cancer. Examples of additional therapies that can be used to treat a mammal (e.g., a human) having cancer include, without limitation, radiation therapies, surgeries, and / or hematopoietic stem cell transplants (e.g., autologous hematopoietic stem cell transplants and allogeneicAttorney Docket No.07039-2338WO1 / 2024-299 hematopoietic stem cell transplants). In cases where one or more binders provided herein (or a nucleic acid, vector, or host cell (e.g., CAR+cells) provided herein) and containing the one or more additional agents) are used in combination with one or more therapies used to treat a mammal (e.g., a human) having cancer, the one or more additional therapies can be performed at the same time or independently of the administration of the one or more binders provided herein (or a nucleic acid, vector, or host cell (e.g., CAR+cells) provided herein) and containing the one or more additional agents). For example, one or more binders provided herein (or a nucleic acid, vector, or host cell (e.g., CAR+cells) provided herein) and containing the one or more additional agents) can be administered before, during, or after the one or more additional therapies are performed. In some cases, a binder (e.g., an antibody domain, an antigen binding fragment, an antibody, a CAR, a cell engager, or an ADC) provided herein can be used to detect the presence or absence of a CS1 polypeptide (e.g., a human CS1 polypeptide) in vitro, in situ, or in vivo (e.g., in vivo imaging within a mammal such as a human). For example, a binder provided herein can be designed to include a label (e.g., a covalently attached radioactive, enzymatic, colorimetric, or fluorescent label). The labelled binder can be used to detect the presence or absence of a CS1 polypeptide (e.g., a human CS1 polypeptide) within a biological sample in vitro. Examples of biological samples that can be assessed using a binder provided herein include, without limitation, serum samples, plasma samples, tissue samples, biopsy samples, cell line samples, and tissue culture samples. In some cases, a biological sample that can be assessed as described herein can include mammalian body tissues and / or cells such as leukocytes, ovary tissue or cells, prostate tissue or cells, heart tissue or cells, placenta tissue or cells, pancreas tissue or cells, liver tissue or cells, spleen tissue or cells, lung tissue or cells, breast tissue or cells, head and neck tissue or cells, endometrium tissue or cells, colon tissue or cells, colorectal tissue or cells, cervix tissue or cells, stomach tissue or cells, or umbilical tissue or cells that may express a CS1 polypeptide (e.g., a human CS1 polypeptide). In some cases, a binder provided herein can be immobilized, e.g., on a support, and retention of a CS1 polypeptide (e.g., a human CS1 polypeptide) from a biological sample on the support can be detected, and / or vice versa. In some cases, a binder provided herein can be used in applications such as fluorescence polarization, microscopy, ELISA, centrifugation, chromatography, and / or cell sorting (e.g., fluorescence activated cell sorting).Attorney Docket No.07039-2338WO1 / 2024-299 In some cases, a binder (e.g., an antibody domain, an antigen binding fragment, an antibody, a CAR, a cell engager, or an ADC) provided herein containing a label (e.g., a covalently attached radioactive label) can be used to detect the presence or absence of a CS1 polypeptide (e.g., a human CS1 polypeptide) within a mammal (e.g., a human). For example, a binder provided herein that is labelled (e.g., covalently labelled) with a radiolabel or an MRI detectable label can be administered to a mammal (e.g., a human), and that mammal can be assessed using a means for detecting the detectable label. In some cases, a mammal can be scanned to evaluate the location(s) of a labelled binder provided herein within the mammal. For example, the mammal can be imaged using NMR or other tomographic techniques. Examples of labels that can be attached (e.g., covalently or non-covalently attached) to a binder (e.g., an antibody domain, an antigen binding fragment, an antibody, a CAR, a cell engager, or an ADC) provided herein include, without limitation, radiolabels such as131I,111In,123I,99mTc,32P,33P,125I,3H,14C, and188Rh, fluorescent labels such as fluorescein and rhodamine, nuclear magnetic resonance active labels, positron emitting isotopes detectable by a positron emission tomography (“PET”) scanner, chemiluminescers such as luciferin, and enzymatic markers such as a peroxidase or a phosphatase. In some cases, short-range radiation emitters such as isotopes detectable by short-range detector probes can be used. The invention will be further described in the following examples, which do not limit the scope of the invention described in the claims. EXAMPLES Example 1: Design and Generation of CART Cell Therapy for CS1+Cancer This Example describes the design and characterization of molecules that can bind to a CS1 polypeptide. Methods Development of CS1-targeted CART cells A CS1-specific single chain variable fragment (scFv) was cloned into a CARconstruct containing 41BB and CD3 signaling domains in a third-generation lentiviralAttorney Docket No.07039-2338WO1 / 2024-299 backbone. This construct was transfected into 293T cells in the presence of envelope plasmids and lipofectamine. Supernatants were collected and lentiviral particles were concentrated by ultracentrifugation. T cells isolated from normal donors were stimulated with CD3 / CD28 beads at a 3:1 bead-to-cell ratio and then transduced with lentiviral particles encoding a CS1 CAR at a multiplicity of infection of 3. CART cells were expanded for 6 days, and then the beads were removed. CAR expression was measured on day 6 by flow cytometry using goat anti-mouse IgG staining to detect the CAR scFv (Figure 1). CART cells were expanded until day 8 (Figure 2) and cryopreserved for future use. CART cell cytotoxicity assay CS1+luciferase+multiple myeloma cells (human OPM-2 or murine A20) were co- cultured with untransduced T cells or CART cells at different effector:target (E:T) ratios, and CART-mediated cytotoxicity was assessed by luminescence of residual live target cells at 48 hours (Figure 3). CART cell proliferation assay CART cell proliferation was assessed by coculturing CART cells with media alone (negative control), PMA / ionomycin (positive control), or CS1+MM1S target cells at a 1:1 ratio (100K:100K cells). Cells were fed on day 3, and absolute CD3+, CD4+, or CD8+T cell counts were assessed with flow cytometry on day 5 (Figure 4). Results Development of CS1-targeted CART cells CS1-targeted CAR constructs demonstrated strong transduction efficiency of primary healthy donor-derived human T cells compared to untransduced control T cells (Figure 1). CS1 CART cells expanded in vitro during the eight-day manufacturing process (Figure 2). CART cell cytotoxicity assay CS1 CART cells demonstrated significant target cell killing of human CS1+OPM- 2 cells (left panel), and murine cross-reactive CS1 CART cells demonstrated significant target cell killing of murine CS1+A20 cells (right panel) compared to controlAttorney Docket No.07039-2338WO1 / 2024-299 untransduced T cells or control CD19-targeted CART cells (Figure 3). CART cell proliferation assay CS1 CART cells demonstrated significant proliferation (determined by CD3, CD4, and CD8 absolute counts on flow cytometry) when cocultured in the presence of CS1+target cells compared to control untransduced T cells (Figure 4). Example 2: Exemplary CS1 Polypeptides This Example provides an amino acid sequence of a human CS1 polypeptide (SEQ ID NO:65). The boxed amino acid sequence of this human CS1 polypeptide depicts the extracellular domain (SEQ ID NO:66).DPDSSMVLLCLLLVPLLLSLFVLGLFLWFLKRERQEEYIEEKKRVDICRETPNICP HSGENTEYDTIPHTNRTILKEDPANTVYSTVEIPKKMENPHSLLTMPDTPRLFAYE NVI (SEQ ID NO:65) Example 3: Exemplary CS1 Binding Molecules This Example provides the amino acid sequences of exemplary binding molecules having the ability to bind a CS1 polypeptide. The CDRs and framework sequences of each also are provided and delineated. Exemplary VH domains VH domain: EVQLLESGGGLVQPGGSLRLSCAASGFTFSSYAMSWVRQAPGKGLEHVSAISPNGAT TYYADSVKGRFTISRDNSKNTLYLQMSSLRPEDTAVYYCVKGYNWNRFDYWGQGT LVTVSSGEGK (SEQ ID NO:8)Attorney Docket No.07039-2338WO1 / 2024-299 Framework Region 1 of VH domain: EVQLLESGGGLVQPGGSLRLSC (SEQ ID NO:4) CDR1 of VH domain: AASGFTFSSYAMS (SEQ ID NO:1) Framework Region 2 of VH domain: WVRQAPGKGLEHVS (SEQ ID NO:5) CDR2 of VH domain: AISPNGATTY (SEQ ID NO:2) Framework Region 3 of VH domain: YADSVKGRFTISRDNSKNTLYLQMSSLRPEDTAVYYCVK (SEQ ID NO:6) CDR3 of VH domain: GYNWNRFDY (SEQ ID NO:3) Framework Region 4 of VH domain: WGQGTLVTVSSGEGK (SEQ ID NO:7) VH domain:Framework Region 1 of VH domain: ESKASEVQLLESGGGLVQPGRSLRLSC (SEQ ID NO:20) CDR1 of VH domain: AASGFTFDDYAMH (SEQ ID NO:17) Framework Region 2 of VH domain: WVRQAPGKGLEWVS (SEQ ID NO:21) CDR2 of VH domain: GISWNSGSIG (SEQ ID NO:18)Attorney Docket No.07039-2338WO1 / 2024-299 Framework Region 3 of VH domain: YADSVKGRFTISRDNAKNSLYLQMNSLRAEDTALYYCAK (SEQ ID NO:22) CDR3 of VH domain: DILYEWELPTFDY (SEQ ID NO:19) Framework Region 4 of VH domain: WGQGTLVTVSS (SEQ ID NO:23) VH domain: ESKASEVQLVQSGAEVKKPGASVKVSCKVSGYTLTELSMHWVRQAPGKGLEWMGFramework Region 1 of VH domain: ESKASEVQLVQSGAEVKKPGASVKVSC (SEQ ID NO:36) CDR1 of VH domain: KVSGYTLTELSMH (SEQ ID NO:33) Framework Region 2 of VH domain: WVRQAPGKGLEWMG (SEQ ID NO:37) CDR2 of VH domain: GFDPEDGETI (SEQ ID NO:34) Framework Region 3 of VH domain: YAQKFQGRVTMTEDTSTDTAYMELSSLRSEDTAVYYCAT (SEQ ID NO:38) CDR3 of VH domain: AVEWELLSFDY (SEQ ID NO:35) Framework Region 4 of VH domain: WGQGTLVTVSS (SEQ ID NO:39)Attorney Docket No.07039-2338WO1 / 2024-299 VH domain:Framework Region 1 of VH domain: ESKASQVQLQESGPGLVRPSETLSLTC (SEQ ID NO:52) CDR1 of VH domain: TVSGASIISSSYFWG (SEQ ID NO:49) Framework Region 2 of VH domain: WIRQTPGKGLEWIG (SEQ ID NO:53) CDR2 of VH domain: SFYYSGNID (SEQ ID NO:50) Framework Region 3 of VH domain: YNPSLKSRGTISADTSKNQLSLKLTSVTAADTAVYYCAR (SEQ ID NO:54) CDR3 of VH domain: EGGHDAFDI (SEQ ID NO:51) Framework Region 4 of VH domain: WGQGTLVTVSS (SEQ ID NO:55) Exemplary VL domains VL domain:Framework Region 1 of VL domain: ESKASDIQMTQSPDSLAVSLGERATINC (SEQ ID NO:12)Attorney Docket No.07039-2338WO1 / 2024-299 CDR1 of VL domain: KSSQSVLYSSNNKNYLA (SEQ ID NO:9) Framework Region 2 of VL domain: WYQQKPGQPPKLLI (SEQ ID NO:13)Framework Region 3 of VL domain: GVPDRFSGSIDSSSNSASLTISGLKTEDEADYYC (SEQ ID NO:30)Attorney Docket No.07039-2338WO1 / 2024-299 CDR3 of VL domain: QSYDSSNVV (SEQ ID NO:27) Framework Region 4 of VL domain: FGGGTKLTVLGEGK (SEQ ID NO:31)Framework Region 1 of VL domain: QSVLTQPPSVSAAPGQKVTISC (SEQ ID NO:60)Attorney Docket No.07039-2338WO1 / 2024-299 CDR1 of VL domain: SGSSSNIGNNYVS (SEQ ID NO:57) Framework Region 2 of VL domain: WYQQLPGTAPKLLI (SEQ ID NO:61) CDR2 of VL domain: YDNNKRPS (SEQ ID NO:58) Framework Region 3 of VL domain: GIPDRFSGSKSGTSATLGITGLQTGDEADYYC (SEQ ID NO:62) CDR3 of VL domain: GTWDSSLGAYV (SEQ ID NO:59) Framework Region 4 of VL domain: FGTGTKVTVLGEGK (SEQ ID NO:63) Example 4: Nucleic Acids Encoding Exemplary CS1-Binding Molecules This Example provides the nucleic acid sequences encoding the indicated chains / domains. Nucleic acid sequences encoding exemplary VH domains GAGGTACAATTGCTGGAGTCAGGCGGTGGACTGGTTCAACCGGGCGGGTCAC TGCGCTTGAGCTGCGCTGCATCAGGCTTCACCTTTTCAAGTTACGCGATGTCC TGGGTACGACAAGCCCCTGGGAAGGGCCTGGAGCATGTCAGCGCCATCTCTC CGAATGGCGCAACTACCTATTATGCCGATAGCGTGAAAGGCCGCTTCACAAT CTCACGAGACAACAGCAAAAACACCCTCTACCTCCAGATGAGTTCTCTCAGG CCGGAGGATACAGCAGTGTATTACTGTGTCAAAGGATACAATTGGAATCGAT TCGACTACTGGGGTCAAGGAACACTTGTCACTGTGTCAAGCGGGGAGGGTAA A (SEQ ID NO:73)Attorney Docket No.07039-2338WO1 / 2024-299 Nucleic acid sequences encoding exemplary VL domains GAGTCCAAGGCTTCAGACATACAAATGACGCAAAGCCCTGATAGCTTGGCTG TAAGTTTGGGCGAGAGAGCCACCATTAACTGTAAGTCCAGCCAGTCAGTCCT GTACTCCAGTAATAATAAAAATTATCTTGCATGGTATCAACAAAAACCTGGTC AGCCCCCAAAGCTGCTGATCTACTGGGCAAGTACGCGCGAGTCTGGCGTACC AGACCGGTTCACAGGCTCTGGCTCCGGGACTGATTTCACACTGACGATCTCCT CTTTGCAAGCTGAGGATGTCGCGGTATATTACTGCCAGCAGTACTATAGTTCA TGGACTTTTGGTCAGGGCACGAAGTTGGATATTAAA (SEQ ID NO:74) Example 5: Exemplary scFv Structures This Example provides structures of exemplary scFv’s. An exemplary linker amino acid sequence such as a linker amino acid sequence set forth in Example 6 can be used to link the heavy chain variable domain and the light chain variable domain together to form a scFv. Structures of exemplary scFv’s are shown. Exemplary scFv structure: Heavy Chain Variable Domain / Region + Linker + Light Chain Variable Domain / Region Exemplary scFv structure: Light Chain Variable Domain / Region + Linker + Heavy Chain Variable Domain / Region Example 6: Exemplary Linkers This Example provides exemplary linker amino acid sequences, and nucleic acid sequences encoding such linkers, that can be used to link a heavy chain variable domain and a light chain variable domain together to form a scFv. These linker sequences also can be used to create CARs and cell engagers. Linker sequences SSGSGS (SEQ ID NO:75) GGGGSGGGGSGGGGS (SEQ ID NO:76) SSGGGGSGGGGSSGGGS (SEQ ID NO:77) GSTSGSGKPGSGEGSTKG (SEQ ID NO:78)Attorney Docket No.07039-2338WO1 / 2024-299 AAA (SEQ ID NO:79) Nucleic acid sequence encoding a linker sequence set forth in SEQ ID NO:75 TCCTCAGGTAGTGGTTCA (SEQ ID NO:80) Nucleic acid sequence encoding a linker sequence set forth in SEQ ID NO:76 GGCGGTGGGGGGTCAGGTGGCGGCGGGAGCGGGGGAGGAGGCTCC (SEQ ID NO:81) Nucleic acid sequence encoding a linker sequence set forth in SEQ ID NO:77 TCTAGCGGAGGCGGCGGATCTGGCGGAGGGGGATCTAGTGGCGGAGGCTCT (SEQ ID NO:82) Nucleic acid sequence encoding a linker sequence set forth in SEQ ID NO:78 GGCTCCACTAGCGGTTCCGGCAAACCTGGCAGCGGAGAAGGCAGCACCAAA GGG (SEQ ID NO:83) Nucleic acid sequence encoding a linker sequence set forth in SEQ ID NO:79 GCGGCCGCA (SEQ ID NO:84) Example 7: Exemplary anti-CS1 Binding Molecules This Example provides the amino acid sequences of exemplary binding molecules (e.g., scFvs) having the ability to bind a CS1 polypeptide. The linkers of each also are provided and delineated. Anti-CS1 clone #1 (also referred to as K271) EVQLLESGGGLVQPGGSLRLSCAASGFTFSSYAMSWVRQAPGKGLEHVSAISPNGAT TYYADSVKGRFTISRDNSKNTLYLQMSSLRPEDTAVYYCVKGYNWNRFDYWGQGT LVTVSSGEGKSSGSGSESKASDIQMTQSPDSLAVSLGERATINCKSSQSVLYSSNN KNYLAWYQQKPGQPPKLLIYWASTRESGVPDRFTGSGSGTDFTLTISSLQAEDVA VYYCQQYYSSWTFGQGTKLDIK (SEQ ID NO:85) Anti-CS1 clone #2 (also referred to as K272) ESKASDIQMTQSPDSLAVSLGERATINCKSSQSVLYSSNNKNYLAWYQQKPGQPP KLLIYWASTRESGVPDRFTGSGSGTDFTLTISSLQAEDVAVYYCQQYYSSWTFGQAttorney Docket No.07039-2338WO1 / 2024-299 GTKLDIKSSGSGSEVQLLESGGGLVQPGGSLRLSCAASGFTFSSYAMSWVRQAPGKG LEHVSAISPNGATTYYADSVKGRFTISRDNSKNTLYLQMSSLRPEDTAVYYCVKGYN WNRFDYWGQGTLVTVSSGEGK (SEQ ID NO:86) Anti-CS1 clone #3 (also referred to as K273) ESKASEVQLLESGGGLVQPGRSLRLSCAASGFTFDDYAMHWVRQAPGKGLEWV SGISWNSGSIGYADSVKGRFTISRDNAKNSLYLQMNSLRAEDTALYYCAKDILYE WELPTFDYWGQGTLVTVSSSSGSGSNFMLTQPHSVSESPGKTVTISCTRSSGSIAS NYVQWYQQRPGSAPTTVIYEDNQRPSGVPDRFSGSIDSSSNSASLTISGLKTEDEA DYYCQSYDSSNVVFGGGTKLTVLGEGK (SEQ ID NO:87) Anti-CS1 clone #4 (also referred to as K274) NFMLTQPHSVSESPGKTVTISCTRSSGSIASNYVQWYQQRPGSAPTTVIYEDNQRP SGVPDRFSGSIDSSSNSASLTISGLKTEDEADYYCQSYDSSNVVFGGGTKLTVLGE GKSSGSGSESKASEVQLLESGGGLVQPGRSLRLSCAASGFTFDDYAMHWVRQAP GKGLEWVSGISWNSGSIGYADSVKGRFTISRDNAKNSLYLQMNSLRAEDTALYY CAKDILYEWELPTFDYWGQGTLVTVSS (SEQ ID NO:88) Anti-CS1 clone #5 (also referred to as K275) ESKASEVQLVQSGAEVKKPGASVKVSCKVSGYTLTELSMHWVRQAPGKGLEW MGGFDPEDGETIYAQKFQGRVTMTEDTSTDTAYMELSSLRSEDTAVYYCATAVE WELLSFDYWGQGTLVTVSSSSGSGSSYELTQPPSVSVAPGQTARITCSGDALPKK YAYWYQQKSGQAPVLVIYEDSKRPSGIPERFSGSSSGTMATLTISGAQVEDEADY YCYSTDSSGRGVFGGGTKLTVLGEGK (SEQ ID NO:89) Anti-CS1 clone #6 (also referred to as K276) SYELTQPPSVSVAPGQTARITCSGDALPKKYAYWYQQKSGQAPVLVIYEDSKRPS GIPERFSGSSSGTMATLTISGAQVEDEADYYCYSTDSSGRGVFGGGTKLTVLGEG KSSGSGSESKASEVQLVQSGAEVKKPGASVKVSCKVSGYTLTELSMHWVRQAP GKGLEWMGGFDPEDGETIYAQKFQGRVTMTEDTSTDTAYMELSSLRSEDTAVY YCATAVEWELLSFDYWGQGTLVTVSS (SEQ ID NO:90)Attorney Docket No.07039-2338WO1 / 2024-299 Anti-CS1 clone #7 (also referred to as K277) ESKASQVQLQESGPGLVRPSETLSLTCTVSGASIISSSYFWGWIRQTPGKGLEWIG SFYYSGNIDYNPSLKSRGTISADTSKNQLSLKLTSVTAADTAVYYCAREGGHDAF DIWGQGTLVTVSSSSGSGSQSVLTQPPSVSAAPGQKVTISCSGSSSNIGNNYVSWY QQLPGTAPKLLIYDNNKRPSGIPDRFSGSKSGTSATLGITGLQTGDEADYYCGTW DSSLGAYVFGTGTKVTVLGEGK (SEQ ID NO:91) Example 8: Nucleic Acids Encoding Exemplary CS1-Binding Molecules This Example provides the nucleic acid sequences encoding Clones #1 - #7. Nucleic acid encoding anti-CS1 clone #1 (also referred to as K271) GAGGTACAATTGCTGGAGTCAGGCGGTGGACTGGTTCAACCGGGCGGGTCAC TGCGCTTGAGCTGCGCTGCATCAGGCTTCACCTTTTCAAGTTACGCGATGTCC TGGGTACGACAAGCCCCTGGGAAGGGCCTGGAGCATGTCAGCGCCATCTCTC CGAATGGCGCAACTACCTATTATGCCGATAGCGTGAAAGGCCGCTTCACAAT CTCACGAGACAACAGCAAAAACACCCTCTACCTCCAGATGAGTTCTCTCAGG CCGGAGGATACAGCAGTGTATTACTGTGTCAAAGGATACAATTGGAATCGAT TCGACTACTGGGGTCAAGGAACACTTGTCACTGTGTCAAGCGGGGAGGGTAA ATCCTCAGGTAGTGGTTCAGAGTCCAAGGCTTCAGACATACAAATGACGCAA AGCCCTGATAGCTTGGCTGTAAGTTTGGGCGAGAGAGCCACCATTAACTGTA AGTCCAGCCAGTCAGTCCTGTACTCCAGTAATAATAAAAATTATCTTGCATGG TATCAACAAAAACCTGGTCAGCCCCCAAAGCTGCTGATCTACTGGGCAAGTA CGCGCGAGTCTGGCGTACCAGACCGGTTCACAGGCTCTGGCTCCGGGACTGA TTTCACACTGACGATCTCCTCTTTGCAAGCTGAGGATGTCGCGGTATATTACT GCCAGCAGTACTATAGTTCATGGACTTTTGGTCAGGGCACGAAGTTGGATATT AAA (SEQ ID NO:92) Nucleic acid encoding anti-CS1 clone #2 (also referred to as K272) GAAAGCAAGGCGAGTGATATTCAGATGACGCAATCCCCCGACAGCCTTGCTG TTTCTCTGGGAGAACGCGCGACTATCAACTGTAAGAGCTCCCAATCAGTGCTT TACTCTTCCAACAATAAAAATTATCTCGCATGGTATCAGCAGAAGCCGGGAC AACCACCGAAGCTCCTCATTTATTGGGCAAGCACTCGGGAATCTGGTGTTCCA GACAGATTCACTGGATCTGGTTCCGGCACCGACTTTACACTGACAATAAGTAAttorney Docket No.07039-2338WO1 / 2024-299 GTCTCCAAGCGGAGGATGTTGCAGTGTATTACTGTCAACAATATTATAGTTCA TGGACATTCGGACAGGGAACCAAGCTCGACATTAAGTCATCCGGGTCAGGGT CCGAAGTTCAGCTCCTCGAATCCGGAGGGGGACTGGTGCAGCCCGGAGGGTC ATTGCGGTTGAGTTGCGCGGCGTCTGGATTCACTTTCAGTTCCTACGCTATGA GCTGGGTCAGGCAAGCTCCGGGTAAAGGGCTGGAGCATGTCAGTGCTATTAG TCCCAACGGAGCAACGACTTATTACGCAGATTCCGTAAAGGGTCGATTTACC ATCTCCCGGGATAACTCAAAAAATACCCTTTACCTCCAAATGAGTTCCCTCAG ACCTGAGGATACAGCGGTTTATTATTGCGTTAAAGGGTACAACTGGAACCGC TTCGACTACTGGGGACAGGGTACTTTGGTCACTGTTAGCTCTGGGGAAGGGA AA (SEQ ID NO:93) Nucleic acid encoding anti-CS1 clone #3 (also referred to as K273) GAAAGCAAGGCGTCAGAAGTACAGCTCCTTGAGAGCGGCGGTGGACTCGTCC AACCGGGGCGATCCTTGCGACTCAGTTGCGCGGCTAGCGGTTTCACTTTCGAT GACTACGCCATGCACTGGGTGCGACAAGCACCCGGAAAAGGCCTTGAATGGG TGTCCGGAATTTCTTGGAACAGTGGGAGCATAGGATACGCCGATAGCGTAAA AGGCAGGTTTACTATAAGTCGGGATAACGCCAAAAATTCATTGTACCTTCAA ATGAATTCTCTTCGCGCAGAAGACACGGCTTTGTATTATTGTGCCAAAGACAT TCTCTACGAGTGGGAGCTTCCAACATTCGACTACTGGGGCCAAGGCACCCTC GTCACAGTATCTTCAAGTTCCGGTTCTGGTTCCAATTTTATGCTGACTCAACC GCATTCTGTTAGCGAATCTCCTGGAAAAACAGTCACCATTTCTTGTACCCGCA GCTCCGGCTCAATCGCCTCAAATTACGTGCAATGGTATCAGCAAAGACCGGG ATCTGCACCTACGACAGTCATTTACGAGGACAACCAGCGACCGTCCGGTGTA CCCGATAGGTTCTCCGGCTCCATTGACTCTTCTAGCAACTCAGCGTCTCTGAC CATTTCCGGACTTAAAACAGAGGACGAGGCAGATTACTATTGCCAATCCTAT GACTCAAGTAACGTTGTGTTCGGAGGGGGTACCAAATTGACAGTATTGGGTG AAGGGAAA (SEQ ID NO:94) Nucleic acid encoding anti-CS1 clone #4 (also referred to as K274) GAAAGCAAGGCGTCAGAAGTACAGCTCCTTGAGAGCGGCGGTGGACTCGTCC AACCGGGGCGATCCTTGCGACTCAGTTGCGCGGCTAGCGGTTTCACTTTCGAT GACTACGCCATGCACTGGGTGCGACAAGCACCCGGAAAAGGCCTTGAATGGG TGTCCGGAATTTCTTGGAACAGTGGGAGCATAGGATACGCCGATAGCGTAAAAttorney Docket No.07039-2338WO1 / 2024-299 AGGCAGGTTTACTATAAGTCGGGATAACGCCAAAAATTCATTGTACCTTCAA ATGAATTCTCTTCGCGCAGAAGACACGGCTTTGTATTATTGTGCCAAAGACAT TCTCTACGAGTGGGAGCTTCCAACATTCGACTACTGGGGCCAAGGCACCCTC GTCACAGTATCTTCAAGTTCCGGTTCTGGTTCCAATTTTATGCTGACTCAACC GCATTCTGTTAGCGAATCTCCTGGAAAAACAGTCACCATTTCTTGTACCCGCA GCTCCGGCTCAATCGCCTCAAATTACGTGCAATGGTATCAGCAAAGACCGGG ATCTGCACCTACGACAGTCATTTACGAGGACAACCAGCGACCGTCCGGTGTA CCCGATAGGTTCTCCGGCTCCATTGACTCTTCTAGCAACTCAGCGTCTCTGAC CATTTCCGGACTTAAAACAGAGGACGAGGCAGATTACTATTGCCAATCCTAT GACTCAAGTAACGTTGTGTTCGGAGGGGGTACCAAATTGACAGTATTGGGTG AAGGGAAA (SEQ ID NO:95) Nucleic acid encoding anti-CS1 clone #5 (also referred to as K275) GAATCAAAGGCGTCAGAGGTTCAGCTGGTACAGAGTGGGGCCGAGGTGAAG AAACCAGGGGCATCCGTGAAAGTATCTTGCAAAGTAAGCGGCTATACGCTGA CTGAATTGTCCATGCATTGGGTACGACAGGCTCCTGGCAAAGGATTGGAATG GATGGGCGGTTTTGATCCTGAGGACGGTGAGACAATATATGCACAAAAATTC CAAGGGAGAGTGACGATGACGGAGGATACATCTACCGATACAGCTTACATGG AGCTTTCCTCCCTGAGGAGTGAGGATACAGCAGTATATTATTGCGCAACAGC AGTAGAATGGGAATTGCTGTCCTTTGATTATTGGGGACAAGGTACTCTTGTTA CCGTCAGCTCATCCAGCGGTAGCGGCTCCTCCTACGAACTGACTCAGCCACCA TCAGTCTCTGTGGCGCCCGGACAGACCGCCCGGATTACTTGCTCAGGCGACG CTCTGCCGAAAAAATACGCATATTGGTATCAACAGAAATCTGGTCAGGCTCC CGTCCTGGTAATTTACGAGGACAGTAAACGGCCTTCAGGCATTCCTGAAAGG TTCTCAGGTAGCAGTTCAGGGACCATGGCAACCTTGACTATTTCTGGAGCCCA GGTAGAGGATGAGGCAGATTATTATTGCTACTCCACTGACAGTTCAGGACGA GGAGTCTTTGGGGGAGGAACAAAATTGACCGTCCTCGGTGAAGGAAAA (SEQ ID NO:96) Nucleic acid encoding anti-CS1 clone #6 (also referred to as K276) TCCTACGAGTTGACACAGCCGCCAAGCGTGAGCGTCGCTCCCGGACAAACTG CGAGAATAACCTGTTCAGGCGATGCCTTGCCAAAAAAATATGCCTATTGGTA CCAACAGAAAAGTGGACAAGCTCCAGTCCTTGTAATTTATGAAGATAGCAAGAttorney Docket No.07039-2338WO1 / 2024-299 CGCCCATCAGGGATACCGGAAAGATTTTCCGGTTCTAGCAGTGGGACTATGG CGACTTTGACGATATCAGGGGCGCAGGTGGAAGATGAGGCGGACTATTATTG CTACTCCACTGATAGCAGTGGTCGGGGGGTTTTCGGAGGTGGAACGAAACTT ACCGTCCTGGGTGAAGGCAAATCATCAGGCTCTGGGTCTGAAAGTAAGGCAT CCGAGGTGCAGTTGGTTCAGTCCGGCGCGGAAGTAAAGAAACCGGGCGCGA GCGTGAAAGTCAGCTGCAAAGTGTCTGGTTACACGCTCACGGAGCTGTCCAT GCACTGGGTTCGGCAAGCCCCAGGTAAGGGTCTTGAGTGGATGGGAGGGTTT GATCCTGAGGACGGCGAGACCATCTATGCGCAAAAATTCCAGGGTAGAGTTA CAATGACAGAAGATACTTCAACCGACACGGCTTACATGGAACTCTCATCCTT GCGGAGCGAAGACACCGCAGTCTATTACTGCGCCACCGCAGTAGAGTGGGAG CTTCTCAGCTTCGATTATTGGGGCCAGGGTACCTTGGTGACAGTGTCATCA (SEQ ID NO:97) Nucleic acid encoding anti-CS1 clone #7 (also referred to as K277) GAATCAAAAGCGTCCCAGGTACAACTGCAAGAAAGTGGCCCTGGCCTTGTTC GACCTAGCGAAACACTCAGTCTGACTTGTACCGTTTCCGGCGCATCTATCATT TCAAGTAGTTATTTCTGGGGGTGGATAAGACAGACCCCAGGGAAGGGTCTTG AATGGATCGGTTCCTTTTATTACAGTGGGAACATAGATTACAACCCCAGTTTG AAGTCAAGGGGTACAATCTCTGCAGATACCTCAAAAAACCAATTGAGCCTGA AGCTTACATCTGTGACCGCCGCAGACACCGCCGTGTATTATTGTGCAAGAGA GGGCGGGCATGATGCCTTCGATATATGGGGTCAAGGCACTCTGGTAACCGTA TCCTCTAGCTCAGGATCCGGATCCCAATCCGTTCTGACACAACCTCCTTCAGT TTCTGCTGCACCAGGTCAAAAAGTAACAATTAGTTGTAGCGGATCTAGCTCA AACATAGGCAATAACTACGTTAGCTGGTACCAACAGCTTCCAGGTACCGCAC CTAAACTGTTGATTTACGACAATAATAAAAGGCCTAGCGGCATTCCCGACAG ATTCTCTGGTAGCAAGAGCGGGACTTCTGCGACTCTCGGTATCACTGGACTTC AAACGGGCGATGAAGCGGATTACTACTGCGGGACCTGGGACAGTAGTTTGGG AGCATATGTGTTCGGTACGGGTACGAAGGTGACTGTACTGGGTGAAGGAAAA (SEQ ID NO:98) Example 9: Exemplary CAR Structures This Example provides structures of exemplary CARs. An exemplary linker amino acid sequence such as a linker amino acid sequence set forth in Example 6 orAttorney Docket No.07039-2338WO1 / 2024-299 Example 11 can be used to link a sdAb or a scFv to a transmembrane domain. Structures of exemplary CARs are shown. Exemplary CAR structures: Signal Peptide + sdAb + (Linker / Hinge)m+ Transmembrane Domain + (Intracellular Signaling Domain)nm = 0, 1, 2, or 3 n = 1, 2, 3, 4, or 5 with or without a linker located between consecutive intracellular signaling domains Signal Peptide + sdAb + Linker + Hinge + Transmembrane Domain + Intracellular Signaling Domain + Intracellular Signaling Domain + Linker + Intracellular Signaling Domain Signal Peptide + sdAb + Linker + Hinge + Transmembrane Domain + Intracellular Signaling Domain + Linker + Intracellular Signaling Domain Signal Peptide + sdAb + Hinge + Transmembrane Domain + Intracellular Signaling Domain + Intracellular Signaling Domain + Linker + Intracellular Signaling Domain Signal Peptide + sdAb + Hinge + Transmembrane Domain + Intracellular Signaling Domain + Intracellular Signaling Domain + Intracellular Signaling Domain Signal Peptide + sdAb + Linker + Transmembrane Domain + Intracellular Signaling Domain + Intracellular Signaling Domain + Intracellular Signaling Domain Signal Peptide + scFv + (Linker / Hinge)m+ Transmembrane Domain + (Intracellular Signaling Domain)nm = 0, 1, 2, or 3 n = 1, 2, 3, 4, or 5 with or without a linker located between consecutive intracellular signaling domainsAttorney Docket No.07039-2338WO1 / 2024-299 Signal Peptide + scFv + Linker + Hinge + Transmembrane Domain + Intracellular Signaling Domain + Intracellular Signaling Domain + Linker + Intracellular Signaling Domain Signal Peptide + scFv + Linker + Hinge + Transmembrane Domain + Intracellular Signaling Domain + Linker + Intracellular Signaling Domain Signal Peptide + scFv + Hinge + Transmembrane Domain + Intracellular Signaling Domain + Intracellular Signaling Domain + Linker + Intracellular Signaling Domain Signal Peptide + scFv + Hinge + Transmembrane Domain + Intracellular Signaling Domain + Intracellular Signaling Domain + Intracellular Signaling Domain Signal Peptide + scFv + Linker + Transmembrane Domain + Intracellular Signaling Domain + Intracellular Signaling Domain + Intracellular Signaling Domain Example 10: Exemplary Signal Peptides This Example provides the amino acid sequences of exemplary signal peptides, and nucleic acid sequences encoding such signal peptides, that can be used to design a CAR.Exemplary CD8 alpha (CD8 ) signal peptideMALPVTALLLPLALLLHAARP (SEQ ID NO:99)Nucleic acid sequence encoding a CD8 signal peptide set forth in SEQ ID NO:99ATGGCCTTACCAGTGACCGCCTTGCTCCTGCCGCTGGCCTTGCTGCTCCACGC CGCCAGGCCG (SEQ ID NO:100) Exemplary human IGKV1-39-derived signal peptide: MDMRVPAQLLGLLLLWLRGARC (SEQ ID NO:101)Attorney Docket No.07039-2338WO1 / 2024-299 Nucleic acid sequence encoding a human IGKV1-39-derived signal peptide set forth in SEQ ID NO:101 ATGGATATGAGGGTCCCCGCACAATTGCTCGGTCTCCTTCTGCTTTGGCTCCG GGGCGCGCGGTGC (SEQ ID NO:102) Exemplary human IGKV1-16-derived signal peptide: MDMRVLAQLLGLLLLCFPGARC (SEQ ID NO:103) Exemplary human IGKV3-11-derived signal peptide: MEAPAQLLFLLLLWLPDTTG (SEQ ID NO:104) Exemplary human IGKV4-1-derived signal peptide: MVLQTQVFISLLLWISGAYG (SEQ ID NO:105) Exemplary human IGKV6-21-derived signal peptide: MLPSQLIGFLLLWVPASRG (SEQ ID NO:106) Exemplary human IGKV1-33-derived signal peptide: MDMRVPAQLLGLLLLWLSGARC (SEQ ID NO:107) Exemplary human IGKV1-33-derived signal peptide: MDMRVPAQLLGLLLLWLSGARC (SEQ ID NO:108) Exemplary human GMCSF-derived signal peptide: MWLQSLLLLGTVACSIS (SEQ ID NO:109) Example 11: Exemplary Hinges This Example provides the amino acid sequences of exemplary hinges, and nucleic acid sequences encoding such hinges, that can be used to design a CAR.Exemplary CD8 hingeTTTPAPRPPTPAPTIASQPLSLRPEACRPAAGGAVHTRGLDFACD (SEQ ID NO:110)Attorney Docket No.07039-2338WO1 / 2024-299 Exemplary human IgG1-derived hinge: EPKSCDKTHTCPPCP (SEQ ID NO:111) Exemplary human IgG2-derived hinge: DKTHTCPPCPAPPVA (SEQ ID NO:112) Exemplary human IgG4-derived hinges: ESKYGPPCPPCP (SEQ ID NO:113) ESKYGPPCPSCP (SEQ ID NO:114) Exemplary human CD28-derived hinges: IEVMYPPPYLDNERSNGTIIHVKGKHLCPSPLFPGPSKP (SEQ ID NO:115) TTTPAPRPPTPAPTIASQPLSLRPEACRPAAGGAVHTRGLDFACDIY (SEQ ID NO:116) TTTPAPRPPTPAPTIASQPLSLRPEACRPAAGGAVHTRGLDFACD (SEQ ID NO:117)Nucleic acid sequence encoding a CD8 hinge set forth in SEQ ID NO:110ACCACGACGCCAGCGCCGCGACCACCAACACCGGCGCCCACCATCGCGTCGC AGCCCCTGTCCCTGCGCCCAGAGGCGTGCCGGCCAGCGGCGGGGGGCGCAGT GCACACGAGGGGGCTGGACTTCGCCTGTGAT (SEQ ID NO:118) Example 12: Exemplary Transmembrane Domains This Example provides the amino acid sequences of exemplary transmembrane domains, and nucleic acid sequences encoding such transmembrane domains, that can be used to design a CAR.Exemplary CD8 transmembrane domainIYIWAPLAGTCGVLLLSLVITLYC (SEQ ID NO:119) IYIWAPLAGTCGVLLLSLVIT (SEQ ID NO:120) IWAPLAGTCGVLLLSLVITLYC (SEQ ID NO:121) IWAPLAGTCGVLLLSLVIT (SEQ ID NO:122)Attorney Docket No.07039-2338WO1 / 2024-299Exemplary human CD3 transmembrane domain:LCYLLDGILFIYGVILTALFL (SEQ ID NO:123) Exemplary human CD4 transmembrane domain: MALIVLGGVAGLLLFIGLGIFF (SEQ ID NO:124) Exemplary human CD28 transmembrane domain: FWVLVVVGGVLACYSLLVTVAFIIFWV (SEQ ID NO:125) Exemplary human CD278 transmembrane domain: FWLPIGCAAFVVVCILGCILI (SEQ ID NO:126)Nucleic acid encoding a CD8 transmembrane domain set forth in SEQ ID NO:119ATCTACATCTGGGCGCCCTTGGCCGGGACTTGTGGGGTCCTTCTCCTGTCACT GGTTATCACCCTTTACTGC (SEQ ID NO:127) Example 13: Exemplary Intracellular Signaling Domains This Example provides the amino acid sequences of exemplary intracellular signaling domains, and nucleic acid sequences encoding such intracellular signaling domains, that can be used to design a CAR. 4-1BB signaling domains KRGRKKLLYIFKQPFMRPVQTTQEEDGCSCRFPEEEEGGCEL (SEQ ID NO:128) KRGRKKLLYIFKQPFMRPVQTTQEEDGCSCRFPEEEE (SEQ ID NO:129)Exemplary CD3 zeta ( ) signaling domainsRVKFSRSADAPAYKQGQNQLYNELNLGRREEYDVLDKRRGRDPEMGGKPRRKN PQEGLYNELQKDKMAEAYSEIGMKGERRRGKGHDGLYQGLSTATKDTYDALH MQALPPR (SEQ ID NO:130) RVKFSRSADAPAYQQGQNQLYNELNLGRREEYDVLDKRRGRDPEMGGKPQRRK NPQEGLYNELQKDKMAEAYSEIGMKGERRRGKGHDGLYQGLSTATKDTYDAL HMQALPPR (SEQ ID NO:131)Attorney Docket No.07039-2338WO1 / 2024-299 Exemplary human CD28 intracellular signaling domain: RSKRSRLLHSDYMNMTPRRPGPTRKHYQPYAPPRDFAAYRS (SEQ ID NO:132) Exemplary human OX40 (CD134) intracellular signaling domain: ALYLLRRDQRLPPDAHKPPGGGSFRTPIQEEQADAHSTLAKI (SEQ ID NO:133) Exemplary human CD278 intracellular signaling domain: CWLTKKKYSSSVHDPNGEYMFMRAVNTAKKSRLTDVTL (SEQ ID NO:134) Exemplary human DAP10 intracellular signaling domain: LCARPRRSPAQEDGKVYINMPGRG (SEQ ID NO:135) Exemplary human DAP12 intracellular signaling domain: YFLGRLVPRGRGAAEAATRKQRITETESPYQELQGQRSDVYSDLNTQRPYYK (SEQ ID NO:136) Exemplary human CD27 intracellular signaling domain: QRRKYRSNKGESPVEPAEPCHYSCPREEEGSTIPIQEDYRKPEPACSP (SEQ ID NO:137) Nucleic acid encoding a 4-1BB signaling domain set forth in SEQ ID NO:128 AAACGGGGCAGAAAGAAACTCCTGTATATATTCAAACAACCATTTATGAGAC CAGTACAAACTACTCAAGAGGAAGATGGCTGTAGCTGCCGATTTCCAGAAGA AGAAGAAGGAGGATGTGAACTG (SEQ ID NO:138)Nucleic acid encoding a CD3 signaling domain set forth in SEQ ID NO:130AGAGTGAAGTTCAGCAGGAGCGCAGACGCCCCCGCGTACAAGCAGGGCCAG AACCAGCTCTATAACGAGCTCAATCTAGGACGAAGAGAGGAGTACGATGTTT TGGACAAGAGACGTGGCCGGGACCCTGAGATGGGGGGAAAGCCGAGAAGGA AGAACCCTCAGGAAGGCCTGTACAATGAACTGCAGAAAGATAAGATGGCGG AGGCCTACAGTGAGATTGGGATGAAAGGCGAGCGCCGGAGGGGCAAGGGGC ACGATGGCCTTTACCAGGGTCTCAGTACAGCCACCAAGGACACCTACGACGC CCTTCACATGCAGGCCCTGCCCCCTCGC (SEQ ID NO:139)Attorney Docket No.07039-2338WO1 / 2024-299 Example 14: Exemplary CARs Having the Ability to Bind a CS1 Polypeptide This Example provides amino acid sequences of CARs designed to bind a CS1 polypeptide and nucleic acid sequences encoding such CARs. The various components of each CAR (e.g., domains and linkers) are provided and delineated. CAR designed using CDRs of any one of Clones #1-7:CD8 Signal Peptide + CS1 binding molecule of Example 3 or Example 7 +Hinge + CD8 Transmembrane Domain +1BB Intracellular Signaling +CD3 Intracellular Signaling DomainExemplary anti-CS1 CAR: MALPVTALLLPLALLLHAARPEVQLLESGGGLVQPGGSLRLSCAASGFTFSSYAM SWVRQAPGKGLEHVSAISPNGATTYYADSVKGRFTISRDNSKNTLYLQMSSLRPE DTAVYYCVKGYNWNRFDYWGQGTLVTVSSGEGKSSGSGSESKASDIQMTQSPD SLAVSLGERATINCKSSQSVLYSSNNKNYLAWYQQKPGQPPKLLIYWASTRESG VPDRFTGSGSGTDFTLTISSLQAEDVAVYYCQQYYSSWTFGQGTKLDIKTTTPAP RPPTPAPTIASQPLSLRPEACRPAAGGAVHTRGLDFACDIYIWAPLAGTCGVLLLS LVITLYCKRGRKKLLYIFKQPFMRPVQTTQEEDGCSCRFPEEEEGGCELRVKFSRS ADAPAYKQGQNQLYNELNLGRREEYDVLDKRRGRDPEMGGKPRRKNPQEGLY NELQKDKMAEAYSEIGMKGERRRGKGHDGLYQGLSTATKDTYDALHMQALPP R (SEQ ID NO:140) Nucleic acid sequence encoding a anti-CS1 CAR set forth in SEQ ID NO:140 atggccttaccagtgaccgccttgctcctgccgctggccttgctgctccacgccgccaggccgGAGGTACAATTGC TGGAGTCAGGCGGTGGACTGGTTCAACCGGGCGGGTCACTGCGCTTGAGCTG CGCTGCATCAGGCTTCACCTTTTCAAGTTACGCGATGTCCTGGGTACGACAAG CCCCTGGGAAGGGCCTGGAGCATGTCAGCGCCATCTCTCCGAATGGCGCAAC TACCTATTATGCCGATAGCGTGAAAGGCCGCTTCACAATCTCACGAGACAAC AGCAAAAACACCCTCTACCTCCAGATGAGTTCTCTCAGGCCGGAGGATACAG CAGTGTATTACTGTGTCAAAGGATACAATTGGAATCGATTCGACTACTGGGGT CAAGGAACACTTGTCACTGTGTCAAGCGGGGAGGGTAAATCCTCAGGTAGTGAttorney Docket No.07039-2338WO1 / 2024-299 GTTCAGAGTCCAAGGCTTCAGACATACAAATGACGCAAAGCCCTGATAGCTT GGCTGTAAGTTTGGGCGAGAGAGCCACCATTAACTGTAAGTCCAGCCAGTCA GTCCTGTACTCCAGTAATAATAAAAATTATCTTGCATGGTATCAACAAAAACC TGGTCAGCCCCCAAAGCTGCTGATCTACTGGGCAAGTACGCGCGAGTCTGGC GTACCAGACCGGTTCACAGGCTCTGGCTCCGGGACTGATTTCACACTGACGAT CTCCTCTTTGCAAGCTGAGGATGTCGCGGTATATTACTGCCAGCAGTACTATA GTTCATGGACTTTTGGTCAGGGCACGAAGTTGGATATTAAAaccacgacgccagcgcc gcgaccaccaacaccggcgcccaccatcgcgtcgcagcccctgtccctgcgcccagaggcgtgccggccagcggcggggg gcgcagtgcacacgagggggctggacttcgcctgtgatatctacatctgggcgcccttggccgggacttgtggggtccttctcct gtcactggttatcaccctttactgcaaacggggcagaaagaaactcctgtatatattcaaacaaccatttatgagaccagtacaaac tactcaagaggaagatggctgtagctgccgatttccagaagaagaagaaggaggatgtgaactgagagtgaagttcagcagga gcgcagacgcccccgcgtacaagcagggccagaaccagctctataacgagctcaatctaggacgaagagaggagtacgatgt tttggacaagagacgtggccgggaccctgagatggggggaaagccgagaaggaagaaccctcaggaaggcctgtacaatga actgcagaaagataagatggcggaggcctacagtgagattgggatgaaaggcgagcgccggaggggcaaggggcacgatg gcctttaccagggtctcagtacagccaccaaggacacctacgacgcccttcacatgcaggccctgccccctcgc (SEQ ID NO:141) Example 15: Exemplary CARs Having the Ability to Bind a BCMA Polypeptide This Example provides amino acid sequences of CARs designed to bind a BCMA polypeptide and nucleic acid sequences encoding such CARs. The various components of each CAR (e.g., domains and linkers) are provided and delineated. CAR designed to bind a BCMA polypeptide:CD8 Signal Peptide + CS1 binding molecule of Example 3 or Example 7 + CD8Hinge + CD8 Transmembrane Domain + 4-1BB Intracellular Signaling Domain +CD3 Intracellular Signaling DomainExemplary anti-BCMA CAR: MALPVTALLLPLALLLHAARPDIVLTQSPPSLAMSLGKRATISCRASESVTILGSH LIHWYQQKPGQPPTLLIQLASNVQTGVPARFSGSGSRTDFTLTIDPVEEDDVAVY YCLQSRTIPRTFGGGTKLEIKGSTSGSGKPGSGEGSTKGQIQLVQSGPELKKPGETAttorney Docket No.07039-2338WO1 / 2024-299 VKISCKASGYTFTDYSINWVKRAPGKGLKWMGWINTETREPAYAYDFRGRFAFS LETSASTAYLQINNLKYEDTATYFCALDYSYAMDYWGQGTSVTVSSTTTPAPRP PTPAPTIASQPLSLRPEACRPAAGGAVHTRGLDFACDIYIWAPLAGTCGVLLLSLV ITLYCKRGRKKLLYIFKQPFMRPVQTTQEEDGCSCRFPEEEEGGCELRVKFSRSAD APAYKQGQNQLYNELNLGRREEYDVLDKRRGRDPEMGGKPRRKNPQEGLYNEL QKDKMAEAYSEIGMKGERRRGKGHDGLYQGLSTATKDTYDALHMQALPPR (SEQ ID NO:142) Nucleic acid sequence encoding a anti-BCMA CAR set forth in SEQ ID NO:142 atggccttaccagtgaccgccttgctcctgccgctggccttgctgctccacgccgccaggccggacattgtgctcactcagtcac ctcccagcctggccatgagcctgggaaaaagggccaccatctcctgtagagccagtgagtccgtcacaatcttggggagccatc ttattcactggtatcagcagaagcccgggcagcctccaacccttcttattcagctcgcgtcaaacgtccagacgggtgtacctgcc agattttctggtagcgggtcccgcactgattttacactgaccatagatccagtggaagaagacgatgtggccgtgtattattgtctgc agagcagaacgattcctcgcacatttggtgggggtactaagctggagattaagggaagcacgtccggctcagggaagccggg ctccggcgagggaagcacgaaggggcaaattcagctggtccagagcggacctgagctgaaaaaacccggcgagactgttaa gatcagttgtaaagcatctggctataccttcaccgactacagcataaattgggtgaaacgggcccctggaaagggcctcaaatgg atgggttggatcaataccgaaactagggagcctgcttatgcatatgacttccgcgggagattcgccttttcactcgagacatctgcc tctactgcttacctccaaataaacaacctcaagtatgaagatacagccacttacttttgcgccctcgactatagttacgccatggact actggggacagggaacctccgttaccgtcagttccaccacgacgccagcgccgcgaccaccaacaccggcgcccaccatcg cgtcgcagcccctgtccctgcgcccagaggcgtgccggccagcggcggggggcgcagtgcacacgagggggctggacttc gcctgtgatatctacatctgggcgcccttggccgggacttgtggggtccttctcctgtcactggttatcaccctttactgcaaacggg gcagaaagaaactcctgtatatattcaaacaaccatttatgagaccagtacaaactactcaagaggaagatggctgtagctgccg atttccagaagaagaagaaggaggatgtgaactgagagtgaagttcagcaggagcgcagacgcccccgcgtacaagcaggg ccagaaccagctctataacgagctcaatctaggacgaagagaggagtacgatgttttggacaagagacgtggccgggaccctg agatggggggaaagccgagaaggaagaaccctcaggaaggcctgtacaatgaactgcagaaagataagatggcggaggcct acagtgagattgggatgaaaggcgagcgccggaggggcaaggggcacgatggcctttaccagggtctcagtacagccacca aggacacctacgacgcccttcacatgcaggccctgccccctcgctaa (SEQ ID NO:143) Example 16: Exemplary Antigen Binding Domains Having the Ability to Bind a T Cell This Example provides the amino acid sequences of exemplary antigen binding domains that can be used to design cell engagers that bind to T cells.Attorney Docket No.07039-2338WO1 / 2024-299 Exemplary anti-human CD3 scFv (clone OKT3): VH domain: QVQLVQSGGGVVQPGRSLRLSCKASGYTFTRYTMHWVRQAPGKGLEWIGYINP SRGYTNYNQKVKDRFTISRDNSKNTAFLQMDSLRPEDTGVYFCARYYDDHYCL DYWGQGTPVTVSS (SEQ ID NO:144) VL domain: DIQMTQSPSSLSASVGDRVTITCSASSSVSYMNWYQQTPGKAPKRWIYDTSKLAS GVPSRFSGSGSGTDYTFTISSLQPEDIATYYCQQWSSNPFTFGQGTKLQITR (SEQ ID NO:145) Exemplary anti-human CD3 scFv (clone UCHT1): VH domain: EVQLQQSGPELVKPGASMKISCKASGYSFTGYTMNWVKQSHGKNLEWMGLINP YKGVSTYNQKFKDKATLTVDKSSSTAYMELLSLTSEDSAVYYCARSGYYGDSD WYFDVWGQGTTLTVFS (SEQ ID NO:146) VL domain: MDIQMTQTTSSLSASLGDRVTISCRASQDIRNYLNWYQQKPDGTVKLLIYYTSRL HSGVPSKFSGSGSGTDYSLTISNLEQEDIATYFCQQGNTLPWTFAGGTKLEIK (SEQ ID NO:147) Example 17: Exemplary Antigen Binding Domains Having the Ability to Bind a NK Cell This Example provides the amino acid sequences of exemplary antigen binding domains that can be used to design cell engagers that bind to NK cells. Exemplary anti-human CD16a scFv: VH domain: EVQLVESGGGVVRPGGSLRLSCAASGFTFDDYGMSWVRQAPGKGLEWVSGINW NGGSTGYADSVKGRFTISRDNAKNSLYLQMNSLRAEDTAVYYCARGRSLLFDY WGQGTLVTVSR (SEQ ID NO:148)Attorney Docket No.07039-2338WO1 / 2024-299 VL domain: SSELTQDPAVSVALGQTVRITCQGDSLRSYYASWYQQKPGQAPVLVIYGKNNRP SGIPDRFSGSSSGNTASLTITGAQAEDEADYYCNSRDSSGNHVVFGGGTKLTVG (SEQ ID NO:149) Exemplary anti-human NKG2A scFv: VH domain: QVQLVQSGAEVKKPGASVKVSCKASGYTFTSYWMNWVRQAPGQGLEWMGRID PYDSETHYAQKLQGRVTMTTDTSTSTAYMELRSLRSDDTAVYYCARGGYDFDV GTLYWFFDVWGQGTTVTVSS (SEQ ID NO:150) VL domain: DIQMTQSPSSLSASVGDRVTITCRASENIYSYLAWYQQKPGKAPKLLIYNAKTLA EGVPSRFSGSGSGTDFTLTISSLQPEDFATYYCQHHYGTPRTFGGGTKVEIK (SEQ ID NO:151) Exemplary anti-human NKG2A scFv: VH domain: EVQLVESGGGLVKPGGSLRLSCAASGFTFSSYAMSWVRQAPGKGLEWVSEISS GGSYTYYADSVKGRFTISRDNAKNSLYLQMNSLRAEDTAVYYCARHGDYPRFF DVWGQGTTVTVSS (SEQ ID NO:152) VL domain: EIVLTQSPATLSLSPGERATLSCSASSSVSSYIYWYQQKPGQAPRLLIYLTSNLASG IPARFSGSGSGTDFTLTISSLEPEDFAVYYCQQWSGNPYTFGQGTKLEIK (SEQ ID NO:153) Exemplary anti-human NKG2D scFv: VH domain: QVQLVESGGGLVKPGGSLRLSCAASGFTFSSYGMHWVRQAPGKGLEWVAFIRY DGSNKYYADSVKGRFTISRDNSKNTLYLQMNSLRAEDTAVYYCAKDRGLGDGT YFDYWGQGTTVTVSS (SEQ ID NO:154)Attorney Docket No.07039-2338WO1 / 2024-299 VL domain: QSALTQPASVSGSPGQSITISCSGSSSNIGNNAVNWYQQLPGKAPKLLIYYDDLLP S GVSDRFSGSKSGTSAFLAISGLQSEDEADYYCAAWDDSLNGPVFGGGTKLTVL (SEQ ID NO:155) Exemplary anti-human NKp30 scFv: VH domain: QVQLVQSGAEVKKPGASVKVSCKASGHTFTSYFMHWVRQAPGQGLEWMGIINP SDDYANYAQKFQGRVTMTRDTSTSTVYMELSSLRSEDTAVYYCATAIFDYWGQ GTLVTVSS (SEQ ID NO:156) alternative VH domain: QVQLVQSGAEVKKPGASVKVSCKASGHTFTSYFMHWVRQAPGQGLEWMGIINP SDDYANYAQKFQGRVTMTRDTSTSTVYMELSSLRSEDTAVYYCATAIFDYWGQ GTPVTVSS (SEQ ID NO:157) VL domain: DIQMTQSPSSLSASVGDRVTITCRASQSISSYLNWYQQKPGKAPKLLIYAASSLQS GVPSRFSGSGSGTDFTLTISSLQPEDFATYYCQQSYSTPLTFGGGTKVEIK (SEQ ID NO:158) Exemplary anti-human NKp46 scFv VH domain: EIQLQQSGAELVKPGASVKLSCTASGFNIKDTYFHWVKQRPEQGLEWIGRIDPAN GNTKYDPKFHDKATIIADISSNTAYLQFSSLTSEDTAVYYCAANRYGYWGQGTT LTVSS (SEQ ID NO:159) VL domain: DIVMTQAAPSIPVTPGESVSISCRSSKSLLYINGNTHLFWFLQRPGQSPQLLIYRMS NLASGVPDRFSGSGSGTAFTLRISRVEAEDVGVYYCMQHLEYPFTFGSGTKLEIK (SEQ ID NO:160)Attorney Docket No.07039-2338WO1 / 2024-299 Exemplary anti-human NKp46 scFv VH domain: QVQLQQSGPELVKPGASVKMSCKASGYTFTDYVINWGKQRSGQGLEWIGEIYPG SGTNYYNEKFKAKATLTADKSSNIAYMQLSSLTSEDSAVYFCARRGRYGLYAM DYWGQGTSVTVSS (SEQ ID NO:161) VL domain: DIQMTQTTSSLSASLGDRVTISCRASQDISNYLNWYQQKPDGTVKLLIYYTSRLHS GVPSRFSGSGSGTDYSLTINNLEQEDIATYFCQQGNTRPWTFGGGTKLEIK (SEQ ID NO:162) Exemplary anti-human CD16a VH domain: EVQLVESGGGLVQPGGSLRLSCAASGFTFSNYGMSWVRQAPGKGLEWIGSIYYS GSTNYNPSLKSLVTISRDNSKNTLYLQMNSLRAEDTATYYCARESIDYWGQGTL VTVSS (SEQ ID NO:163) Example 18: Generation of CS1-specific CAR+T cells T cells are obtained from a human. Nucleic acid designed to express one or more CARs having the ability to bind to a CS1 polypeptide provided herein is introduced into the T cells by transduction (e.g., viral transduction using a retroviral vector such as a lentiviral vector) or transfection such that the T cells express the CAR(s) having the ability to bind to a CS1 polypeptide. Example 19: Generation of CS1+BCMA+dual-specific CAR+T cells T cells are obtained from a human. Nucleic acid designed to express one or more CARs having the ability to bind to a CS1 polypeptide provided herein and nucleic acid designed to express one or more CARs having the ability to bind to a BCMA polypeptide are introduced into the T cells by transduction (e.g., viral transduction using a retroviral vector such as a lentiviral vector) or transfection such that the T cells express the CAR(s) having the ability to bind to a CS1 polypeptide and express the CAR(s) having the ability to bind to a BCMA polypeptide.Attorney Docket No.07039-2338WO1 / 2024-299 Example 20: Treating a CS1+Cancer Cells (e.g., T cells) designed to express one or more CARs having the ability to bind to a CS1 polypeptide are administered to a human identified as having a CS1+multiple myeloma. The cells (e.g., T cells) engineered to express one or more binders having the ability to bind to a CS1 polypeptide are administered using intravenous injection. After the administration of cells (e.g., T cells) engineered to express one or more binders having the ability to bind to a CS1 polypeptide, the number of cancer cells (e.g., CS1+cancer cells) within the human is reduced. After the administration of the cells (e.g., T cells) engineered to express one or more binders having the ability to bind to a CS1 polypeptide, the size of one or more tumors (e.g., tumors having one or more CS1+cancer cells) within the human is reduced. Example 21: Treating a CS1+Cancer Cells (e.g., T cells) designed to express one or more CARs having the ability to bind to a CS1 polypeptide and to express one or more CARs having the ability to bind to a BCMA polypeptide are administered to a human identified as having a CS1+multiple myeloma. The cells (e.g., T cells) engineered to express one or more binders having the ability to bind to a CS1 polypeptide and to express one or more CARs having the ability to bind to a BCMA polypeptide are administered using intravenous injection. After the administration of cells (e.g., T cells) engineered to express one or more binders having the ability to bind to a CS1 polypeptide and to express one or more CARs having the ability to bind to a BCMA polypeptide, the number of cancer cells (e.g., CS1+cancer cells) within the human is reduced. After the administration of the cells (e.g., T cells) engineered to express one or more binders having the ability to bind to a CS1 polypeptide and to express one or more CARs having the ability to bind to a BCMA polypeptide, the size of one or more tumors (e.g., tumors having one or more CS1+cancer cells) within the human is reduced. Example 22: Treating a CS1+Cancer T cells are obtained from a human identified as having a CS1+multiple myeloma. Nucleic acid designed to express one or more CARs having the ability to bind to a CS1 polypeptide provided herein is introduced into the T cells by transduction (e.g., viralAttorney Docket No.07039-2338WO1 / 2024-299 transduction using a retroviral vector such as a lentiviral vector) or transfection such that the T cells express the CAR(s) having the ability to bind to a CS1 polypeptide. The T cells engineered to express one or more CARs having the ability to bind to a CS1 polypeptide are administered back into the human using, for example, intravenous injection. After the administration of the cells (e.g., T cells) engineered to express a one or more CARs having the ability to bind to a CS1 polypeptide, the number of cancer cells (e.g., CS1+cancer cells) within the human is reduced. After the administration of the cells (e.g., T cells) engineered to express a one or more CARs having the ability to bind to a CS1 polypeptide, the size of one or more tumors (e.g., tumors having one or more CS1+cancer cells) within the human is reduced. Example 23: Treating a CS1+Cancer T cells are obtained from a human identified as having a CS1+multiple myeloma. Nucleic acid designed to express one or more CARs having the ability to bind to a CS1 polypeptide provided herein and nucleic acid designed to express one or more CARs having the ability to bind to a BCMA polypeptide are introduced into the T cells by transduction (e.g., viral transduction using a retroviral vector such as a lentiviral vector) or transfection such that the T cells express the CAR(s) having the ability to bind to a CS1 polypeptide and express the CAR(s) having the ability to bind to a BCMA polypeptide. The T cells engineered to express one or more CARs having the ability to bind to a CS1 polypeptide and to express one or more CARs having the ability to bind to a BCMA polypeptide are administered back into the human using, for example, intravenous injection. After the administration of the cells (e.g., T cells) engineered to express a one or more CARs having the ability to bind to a CS1 polypeptide and to express one or more CARs having the ability to bind to a BCMA polypeptide, the number of cancer cells (e.g., CS1+cancer cells) within the human is reduced. After the administration of the cells (e.g., T cells) engineered to express a one or more CARs having the ability to bind to a CS1 polypeptide and to express one or more CARs having the ability to bind to a BCMA polypeptide, the size of one or more tumors (e.g., tumors having one or more CS1+cancer cells) within the human is reduced.Attorney Docket No.07039-2338WO1 / 2024-299 Example 24: Exemplary Embodiments Embodiment 1. A binding molecule comprising: (i) a heavy chain variable domain or region comprising the amino acid sequences set forth in SEQ ID NO:1 (or SEQ ID NO:1 with one, two, or three amino acid additions, deletions, or substitutions), SEQ ID NO:2 (or SEQ ID NO:2 with one, two, or three amino acid additions, deletions, or substitutions), and SEQ ID NO:3 (or SEQ ID NO:3 with one, two, or three amino acid additions, deletions, or substitutions), and a light chain variable domain or region comprising the amino acid sequences set forth in SEQ ID NO:9 (or SEQ ID NO:9 with one, two, or three amino acid additions, deletions, or substitutions), SEQ ID NO:10 (or SEQ ID NO:10 with one, two, or three amino acid additions, deletions, or substitutions), and SEQ ID NO:11 (or SEQ ID NO:11 with one, two, or three amino acid additions, deletions, or substitutions); (ii) a heavy chain variable domain or region comprising the amino acid sequences set forth in SEQ ID NO:17 (or SEQ ID NO:17 with one, two, or three amino acid additions, deletions, or substitutions), SEQ ID NO:18 (or SEQ ID NO:18 with one, two, or three amino acid additions, deletions, or substitutions), and SEQ ID NO:19 (or SEQ ID NO:19 with one, two, or three amino acid additions, deletions, or substitutions), and a light chain variable domain or region comprising the amino acid sequences set forth in SEQ ID NO:25 (or SEQ ID NO:25 with one, two, or three amino acid additions, deletions, or substitutions), SEQ ID NO:26 (or SEQ ID NO:26 with one, two, or three amino acid additions, deletions, or substitutions), and SEQ ID NO:27 (or SEQ ID NO:27 with one, two, or three amino acid additions, deletions, or substitutions); (iii) a heavy chain variable domain or region comprising the amino acid sequences set forth in SEQ ID NO:33 (or SEQ ID NO:33 with one, two, or three amino acid additions, deletions, or substitutions), SEQ ID NO:34 (or SEQ ID NO:34 with one, two, or three amino acid additions, deletions, or substitutions), and SEQ ID NO:35 (or SEQ ID NO:35 with one, two, or three amino acid additions, deletions, or substitutions), and a light chain variable domain or region comprising the amino acid sequences set forth in SEQ ID NO:41 (or SEQ ID NO:41 with one, two, or three amino acid additions, deletions, or substitutions), SEQ ID NO:42 (or SEQ ID NO:42 with one, two, or threeAttorney Docket No.07039-2338WO1 / 2024-299 amino acid additions, deletions, or substitutions), and SEQ ID NO:43 (or SEQ ID NO:43 with one, two, or three amino acid additions, deletions, or substitutions); or (iv) a heavy chain variable domain or region comprising the amino acid sequences set forth in SEQ ID NO:49 (or SEQ ID NO:49 with one, two, or three amino acid additions, deletions, or substitutions), SEQ ID NO:50 (or SEQ ID NO:50 with one, two, or three amino acid additions, deletions, or substitutions), and SEQ ID NO:51 (or SEQ ID NO:51 with one, two, or three amino acid additions, deletions, or substitutions), and a light chain variable domain or region comprising the amino acid sequences set forth in SEQ ID NO:57 (or SEQ ID NO:57 with one, two, or three amino acid additions, deletions, or substitutions), SEQ ID NO:58 (or SEQ ID NO:58 with one, two, or three amino acid additions, deletions, or substitutions), and SEQ ID NO:59 (or SEQ ID NO:59 with one, two, or three amino acid additions, deletions, or substitutions). Embodiment 2. The binding molecule of claim 1, wherein said binding molecule comprises the ability to bind to a polypeptide sequence set forth in any one of SEQ ID NOs:65-66. Embodiment 3. The binding molecule of any one of claims 1-2, wherein said binding molecule comprises said (i). Embodiment 4. The binding molecule of claim 3, wherein said heavy chain variable domain comprises an amino acid sequence having at least 90 percent identity to the amino acid sequence set forth in SEQ ID NO:8, and wherein said light chain variable region comprises an amino acid sequence having at least 90 percent identify to the amino acid sequence set forth in SEQ ID NO:16. Embodiment 5. The binding molecule of any one of claims 1-2, wherein said binding molecule comprises said (ii). Embodiment 6. The binding molecule of claim 3, wherein said heavy chain variable domain comprises an amino acid sequence having at least 90 percent identity to the amino acid sequence set forth in SEQ ID NO:24, and wherein said light chain variableAttorney Docket No.07039-2338WO1 / 2024-299 region comprises an amino acid sequence having at least 90 percent identify to the amino acid sequence set forth in SEQ ID NO:32. Embodiment 7. The binding molecule of any one of claims 1-2, wherein said binding molecule comprises said (iii). Embodiment 8. The binding molecule of claim 7, wherein said heavy chain variable domain comprises an amino acid sequence having at least 90 percent identity to the amino acid sequence set forth in SEQ ID NO:40, and wherein said light chain variable region comprises an amino acid sequence having at least 90 percent identify to the amino acid sequence set forth in SEQ ID NO:48. Embodiment 9. The binding molecule of any one of claims 1-2, wherein said binding molecule comprises said (iv). Embodiment 10. The binding molecule of claim 9, wherein said heavy chain variable domain comprises an amino acid sequence having at least 90 percent identity to the amino acid sequence set forth in SEQ ID NO:56, and wherein said light chain variable region comprises an amino acid sequence having at least 90 percent identify to the amino acid sequence set forth in SEQ ID NO:64. Embodiment 11. The binding molecule of any one of claims 1-10, wherein said binding molecule is a monoclonal antibody. Embodiment 12. The binding molecule of any one of claims 1-11, wherein said binding molecule is an scFv antibody. Embodiment 13. A chimeric antigen receptor (CAR) comprising an antigen binding domain, a hinge, a transmembrane domain, and one or more signaling domains, wherein said antigen binding domain comprises a binding molecule of any one of claims 1-12.Attorney Docket No.07039-2338WO1 / 2024-299 Embodiment 14. The CAR of claim 13, wherein said antigen binding domain comprises a scFv having the ability to bind to a CS1 polypeptide. Embodiment 15. The CAR of any one of claims 13-14, wherein said hinge comprises a hinge set forth in any one of SEQ ID NOs:110-117. Embodiment 16. The CAR of any one of claims 13-14, wherein said hinge is aCD8 hinge.Embodiment 17. The CAR of any one of claims 13-16, wherein said transmembrane domain comprises a transmembrane domain set forth in any one of SEQ ID NOs:119-126. Embodiment 18. The CAR of any one of claims 13-16, wherein said transmembranedomain is a CD8 transmembrane domain.Embodiment 19. The CAR of any one of claims 13-18, wherein said CAR comprises one or more signaling domains set forth in any one of SEQ ID NOs:128-137. Embodiment 20. The CAR of any one of claims 13-18, wherein said CAR comprisesa 4-1BB intracellular signaling domain and a CD3 intracellular signaling domain.Embodiment 21. A cell comprising a CAR of any one of claims 13-20. Embodiment 22. The cell of claim 21, wherein said cell is a T cell, a stem cell, or an NK cell. Embodiment 23. The cell of any one of claims 21-22, wherein said cell further comprises a second CAR. Embodiment 24. The cell of claim 23, said second CAR comprising an antigen binding domain, a hinge, a transmembrane domain, and one or more signaling domains,Attorney Docket No.07039-2338WO1 / 2024-299 wherein said antigen binding domain comprises a scFv having the ability to bind to a B- cell maturation antigen (BCMA) polypeptide. Embodiment 25. The cell of claim 24, wherein said scFv comprises: a heavy chain variable domain comprising the amino acid sequences set forth in SEQ ID NO:67, SEQ ID NO:68, and SEQ ID NO:69, and a light chain variable domain or region comprising the amino acid sequences set forth in SEQ ID NO:70, SEQ ID NO:71, and SEQ ID NO:72. Embodiment 26. The cell of any one of claims 23-25, wherein said second CAR is an activation-inducible CAR. Embodiment 27. The cell of any one of claims 23-25, wherein said second CAR is an expression-inducible CAR. Embodiment 28. A cell engager comprising a first antigen binding domain, a linker, and a second antigen binding domain, wherein said first antigen binding domain comprises a binding molecule of any one of claims 1-12. Embodiment 29. The cell engager of claim 28, wherein said first antigen binding domain comprises a scFv having the ability to bind to a CS1 polypeptide. Embodiment 30. The cell engager of any one of claims 28-29, wherein said linker comprises a linker set forth in any one of SEQ ID NOs:75-79 or SEQ ID NOs:110-117. Embodiment 31. The cell engager of any one of claims 28-30, wherein said second antigen binding domain binds to a polypeptide expressed on the surface of T cells. Embodiment 32. The cell engager of claim 31, wherein said polypeptide expressed on the surface of T cells is a CD3 polypeptide.Attorney Docket No.07039-2338WO1 / 2024-299 Embodiment 33. The cell engager of claim 31, wherein said second antigen binding domain is an antigen binding domain set forth in Example 16. Embodiment 34. The cell engager of any one of claims 28-30, wherein said second antigen binding domain binds to a polypeptide expressed on the surface of NK cells. Embodiment 35. The cell engager of claim 34, wherein said polypeptide expressed on the surface of NK cells is a CD16a, NKG2A, NKG2D, NKp30, NKp44, or NKp46 polypeptide. Embodiment 36. The cell engager of claim 34, wherein said second antigen binding domain is an antigen binding domain set forth in Example 17. Embodiment 37. A nucleic acid comprising a nucleic acid sequence encoding at least part of a binding molecule of any one of claims 1-12. Embodiment 38. The nucleic acid of claim 37, wherein said nucleic acid sequence encodes said heavy chain variable domain or region of said (i) of claim 1. Embodiment 39. The nucleic acid of claim 37, wherein said nucleic acid sequence encodes said light chain variable domain or region of said (i) of claim 1. The nucleic acid of claim 37, wherein said nucleic acid sequence chain variable domain or region of said (ii) of claim 1.Embodiment 41. The nucleic acid of claim 37, wherein said nucleic acid sequence encodes said light chain variable domain or region of said (ii) of claim 1. Embodiment 42. The nucleic acid of claim 37, wherein said nucleic acid sequence encodes said heavy chain variable domain or region of said (iii) of claim 1.Attorney Docket No.07039-2338WO1 / 2024-299 Embodiment 43. The nucleic acid of claim 37, wherein said nucleic acid sequence encodes said light chain variable domain or region of said (iii) of claim 1. Embodiment 44. The nucleic acid of claim 37, wherein said nucleic acid sequence encodes said heavy chain variable domain or region of said (iv) of claim 1. Embodiment 45. The nucleic acid of claim 37, wherein said nucleic acid sequence encodes said light chain variable domain or region of said (iv) of claim 1. Embodiment 46. The nucleic acid of any one of claims 37-45, wherein said nucleic acid is a viral vector. Embodiment 47. A nucleic acid comprising a nucleic acid sequence encoding a CAR of any one of claims 13-20 or a cell engager of any one of claims 28-36. Embodiment 48. The nucleic acid of claim 42, wherein said nucleic acid is a viral vector. Embodiment 49. A host cell comprising a nucleic acid of any one of claims 37-48. Embodiment 50. A host cell that expresses a CAR of any one of claims 13-20 or a cell engager of any one of claims 28-36. Embodiment 51. The host cell of any one of claims 49-50, wherein said host cell is a T cell, stem cell, or NK cell. Embodiment 52. An antibody-drug conjugate (ADC) comprising an antigen binding domain covalently linked to a drug, wherein said antigen binding domain comprises a binding molecule of any one of claims 1-12. Embodiment 53. The ADC of claim 52, wherein said binding molecule has the ability to bind to a CS1 polypeptide.Attorney Docket No.07039-2338WO1 / 2024-299 Embodiment 54. The ADC of any one of claims 52-53, wherein said drug is selected from the group consisting of an auristatin, a mertansine, a pyrrolobenzodiazepine (PBD) dimer, ozogamicin, calicheamicin, deruxtecan, vedotin, and tesirine. Embodiment 55. A composition comprising a binding molecule of any one of claims 1-12. Embodiment 56. A composition comprising a cell engager of any one of claims 28- 36. Embodiment 57. A composition comprising a cell of any one of claims 21-27 or 49- 51. Embodiment 58. A composition comprising an ADC of any one of claims 52-54. Embodiment 59. A method of treating a mammal having cancer, wherein said method comprises administering, to said mammal, a composition of any one of claims 55- 58. Embodiment 60. The method of claim 59, wherein said mammal is a human. Embodiment 61. The method of any one of claims 59-60, wherein said cancer is a CS1+cancer. Embodiment 62. The method of any one of claims 59-61, wherein said cancer is selected from the group consisting of a multiple myeloma and a myelofibrosis. Embodiment 63. The method of any one of claims 59-62, wherein the number of cancer cells within said mammal is reduced following said administering step.Attorney Docket No.07039-2338WO1 / 2024-299A method for binding a binding molecule to a CS1 polypeptide, wherein said method comprises contacting said CS1 polypeptide with a binding molecule of any one of claims 1-12. Embodiment 65. The method of claim 64, wherein said contacting is performed in vitro. Embodiment 66. The method of claim 64, wherein said contacting is performed in vivo. Embodiment 67. The method of claim 66, wherein said contacting is performed within a mammal by administering said binding molecule to said mammal. Embodiment 68. The method of claim 67, wherein said mammal is a human. Embodiment 69. A method for binding a binding molecule to a CS1 polypeptide, wherein said method comprises contacting said CS1 polypeptide with a CAR of any one of claims 13-20, a cell engager of any one of claims 28-36, or an ADC of any one of claims 52-54. Embodiment 70. The method of claim 69, wherein said contacting is performed in vitro. Embodiment 71. The method of claim 69, wherein said contacting is performed in vivo. Embodiment 72. The method of claim 71, wherein said contacting is performed within a mammal by administering said CAR, said cell engager, or said ADC to said mammal. Embodiment 73. The method of claim 72, wherein said mammal is a human.Attorney Docket No.07039-2338WO1 / 2024-299 OTHER EMBODIMENTS It is to be understood that while the invention has been described in conjunction with the detailed description thereof, the foregoing description is intended to illustrate and not limit the scope of the invention, which is defined by the scope of the appended claims. Other aspects, advantages, and modifications are within the scope of the following claims.

Claims

Attorney Docket No.07039-2338WO1 / 2024-299 WHAT IS CLAIMED IS:

1. A binding molecule comprising: (i) a heavy chain variable domain or region comprising the amino acid sequences set forth in SEQ ID NO:1 (or SEQ ID NO:1 with one, two, or three amino acid additions, deletions, or substitutions), SEQ ID NO:2 (or SEQ ID NO:2 with one, two, or three amino acid additions, deletions, or substitutions), and SEQ ID NO:3 (or SEQ ID NO:3 with one, two, or three amino acid additions, deletions, or substitutions), and a light chain variable domain or region comprising the amino acid sequences set forth in SEQ ID NO:9 (or SEQ ID NO:9 with one, two, or three amino acid additions, deletions, or substitutions), SEQ ID NO:10 (or SEQ ID NO:10 with one, two, or three amino acid additions, deletions, or substitutions), and SEQ ID NO:11 (or SEQ ID NO:11 with one, two, or three amino acid additions, deletions, or substitutions); (ii) a heavy chain variable domain or region comprising the amino acid sequences set forth in SEQ ID NO:17 (or SEQ ID NO:17 with one, two, or three amino acid additions, deletions, or substitutions), SEQ ID NO:18 (or SEQ ID NO:18 with one, two, or three amino acid additions, deletions, or substitutions), and SEQ ID NO:19 (or SEQ ID NO:19 with one, two, or three amino acid additions, deletions, or substitutions), and a light chain variable domain or region comprising the amino acid sequences set forth in SEQ ID NO:25 (or SEQ ID NO:25 with one, two, or three amino acid additions, deletions, or substitutions), SEQ ID NO:26 (or SEQ ID NO:26 with one, two, or three amino acid additions, deletions, or substitutions), and SEQ ID NO:27 (or SEQ ID NO:27 with one, two, or three amino acid additions, deletions, or substitutions); (iii) a heavy chain variable domain or region comprising the amino acid sequences set forth in SEQ ID NO:33 (or SEQ ID NO:33 with one, two, or three amino acid additions, deletions, or substitutions), SEQ ID NO:34 (or SEQ ID NO:34 with one, two, or three amino acid additions, deletions, or substitutions), and SEQ ID NO:35 (or SEQ ID NO:35 with one, two, or three amino acid additions, deletions, or substitutions), and a light chain variable domain or region comprising the amino acid sequences set forth in SEQ ID NO:41 (or SEQ ID NO:41 with one, two, or three amino acid additions, deletions, or substitutions), SEQ IDAttorney Docket No.07039-2338WO1 / 2024-299 NO:42 (or SEQ ID NO:42 with one, two, or three amino acid additions, deletions, or substitutions), and SEQ ID NO:43 (or SEQ ID NO:43 with one, two, or three amino acid additions, deletions, or substitutions); or (iv) a heavy chain variable domain or region comprising the amino acid sequences set forth in SEQ ID NO:49 (or SEQ ID NO:49 with one, two, or three amino acid additions, deletions, or substitutions), SEQ ID NO:50 (or SEQ ID NO:50 with one, two, or three amino acid additions, deletions, or substitutions), and SEQ ID NO:51 (or SEQ ID NO:51 with one, two, or three amino acid additions, deletions, or substitutions), and a light chain variable domain or region comprising the amino acid sequences set forth in SEQ ID NO:57 (or SEQ ID NO:57 with one, two, or three amino acid additions, deletions, or substitutions), SEQ ID NO:58 (or SEQ ID NO:58 with one, two, or three amino acid additions, deletions, or substitutions), and SEQ ID NO:59 (or SEQ ID NO:59 with one, two, or three amino acid additions, deletions, or substitutions).

2. The binding molecule of claim 1, wherein said binding molecule comprises the ability to bind to a polypeptide sequence set forth in any one of SEQ ID NOs:65-66.

3. The binding molecule of any one of claims 1-2, wherein said binding molecule comprises said (i).

4. The binding molecule of claim 3, and wherein said heavy chain variable domain comprises an amino acid sequence having at least 90 percent identity to the amino acid sequence set forth in SEQ ID NO:8, and wherein said light chain variable region comprises an amino acid sequence having at least 90 percent identify to the amino acid sequence set forth in SEQ ID NO:

16.

4. The binding molecule of any one of claims 1-2, wherein said binding molecule comprises said (ii), and wherein said heavy chain variable domain comprises an amino acid sequence having at least 90 percent identity to the amino acid sequence set forth in SEQ IDAttorney Docket No.07039-2338WO1 / 2024-299 NO:24, and wherein said light chain variable region comprises an amino acid sequence having at least 90 percent identify to the amino acid sequence set forth in SEQ ID NO:

32.

5. The binding molecule of any one of claims 1-2, wherein said binding molecule comprises said (iii), and wherein said heavy chain variable domain comprises an amino acid sequence having at least 90 percent identity to the amino acid sequence set forth in SEQ ID NO:40, and wherein said light chain variable region comprises an amino acid sequence having at least 90 percent identify to the amino acid sequence set forth in SEQ ID NO:

48.

6. The binding molecule of any one of claims 1-2, wherein said binding molecule comprises said (iv), and wherein said heavy chain variable domain comprises an amino acid sequence having at least 90 percent identity to the amino acid sequence set forth in SEQ ID NO:56, and wherein said light chain variable region comprises an amino acid sequence having at least 90 percent identify to the amino acid sequence set forth in SEQ ID NO:

64.

7. The binding molecule of any one of claims 1-6, wherein said binding molecule is a monoclonal antibody.

8. The binding molecule of any one of claims 1-6, wherein said binding molecule is an scFv antibody.

9. A chimeric antigen receptor (CAR) comprising an antigen binding domain, a hinge, a transmembrane domain, and one or more signaling domains, wherein said antigen binding domain comprises a binding molecule of any one of claims 1-8.

10. The CAR of claim 9, wherein said antigen binding domain comprises a scFv having the ability to bind to a CS1 polypeptide.

11. The CAR of any one of claims 9-10, wherein said hinge comprises a hinge set forth in any one of SEQ ID NOs:110-117.Attorney Docket No.07039-2338WO1 / 2024-29912. The CAR of any one of claims 9-10, wherein said hinge is a CD8 hinge.

13. The CAR of any one of claims 9-10, wherein said transmembrane domain comprises a transmembrane domain set forth in any one of SEQ ID NOs:119-126.

14. The CAR of any one of claims 9-10, wherein said transmembrane domain is a CD8transmembrane domain.

15. The CAR of any one of claims 9-10, wherein said CAR comprises one or more signaling domains set forth in any one of SEQ ID NOs:128-137.

16. The CAR of any one of claims 9-10, wherein said CAR comprises a 4-1BBintracellular signaling domain and a CD3 intracellular signaling domain.

17. A cell comprising a CAR of any one of claims 9-16.

18. The cell of claim 17, wherein said cell is a T cell, a stem cell, or an NK cell.

19. The cell of claim 17, wherein said cell further comprises a second CAR.

20. The cell of claim 19, said second CAR comprising an antigen binding domain, a hinge, a transmembrane domain, and one or more signaling domains, wherein said antigen binding domain comprises a scFv having the ability to bind to a B-cell maturation antigen (BCMA) polypeptide.

21. The cell of claim 20, wherein said scFv comprises: a heavy chain variable domain comprising the amino acid sequences set forth in SEQ ID NO:67, SEQ ID NO:68, and SEQ ID NO:69, and a light chain variable domain or regionAttorney Docket No.07039-2338WO1 / 2024-299 comprising the amino acid sequences set forth in SEQ ID NO:70, SEQ ID NO:71, and SEQ ID NO:

72.

22. The cell of any one of claims 19-21, wherein said second CAR is an activation- inducible CAR.

23. The cell of any one of claims 19-21, wherein said second CAR is an expression- inducible CAR.

24. A cell engager comprising a first antigen binding domain, a linker, and a second antigen binding domain, wherein said first antigen binding domain comprises a binding molecule of any one of claims 1-8.

25. The cell engager of claim 24, wherein said first antigen binding domain comprises a scFv having the ability to bind to a CS1 polypeptide.

26. The cell engager of claim 24, wherein said linker comprises a linker set forth in any one of SEQ ID NOs:75-79 or SEQ ID NOs:110-117.

27. The cell engager of any one of claims 24-25, wherein said second antigen binding domain binds to a polypeptide expressed on the surface of T cells.

28. The cell engager of claim 27, wherein said polypeptide expressed on the surface of T cells is a CD3 polypeptide.

29. The cell engager of claim 27, wherein said second antigen binding domain is an antigen binding domain set forth in Example 16.

30. The cell engager of any one of claims 24-25, wherein said second antigen binding domain binds to a polypeptide expressed on the surface of NK cells.Attorney Docket No.07039-2338WO1 / 2024-299 31. The cell engager of claim 30, wherein said polypeptide expressed on the surface of NK cells is a CD16a, NKG2A, NKG2D, NKp30, NKp44, or NKp46 polypeptide.

32. The cell engager of claim 30, wherein said second antigen binding domain is an antigen binding domain set forth in Example 17.

33. A nucleic acid comprising a nucleic acid sequence encoding at least part of a binding molecule of any one of claims 1-8.

34. The nucleic acid of claim 33, wherein said nucleic acid is a viral vector.

35. A nucleic acid comprising a nucleic acid sequence encoding a CAR of any one of claims 9-16 or a cell engager of any one of claims 24-32.

36. The nucleic acid of claim 35, wherein said nucleic acid is a viral vector.

37. A host cell comprising a nucleic acid of any one of claims 33-36.

38. A host cell that expresses a CAR of any one of claims 9-16 or a cell engager of any one of claims 24-32.

39. The host cell of any one of claims 37-38, wherein said host cell is a T cell, stem cell, or NK cell.

40. An antibody-drug conjugate (ADC) comprising an antigen binding domain covalently linked to a drug, wherein said antigen binding domain comprises a binding molecule of any one of claims 1-8.Attorney Docket No.07039-2338WO1 / 2024-299 41. The ADC of claim 40, wherein said binding molecule has the ability to bind to a CS1 polypeptide.

42. The ADC of any one of claims 40-41, wherein said drug is selected from the group consisting of an auristatin, a mertansine, a pyrrolobenzodiazepine (PBD) dimer, ozogamicin, calicheamicin, deruxtecan, vedotin, and tesirine.

43. A composition comprising a binding molecule of any one of claims 1-8, a cell engager of any one of claims 24-32, a cell of any one of claims 17-23 or 37-39, or an ADC of any one of claims 40-42.

44. A method of treating a mammal having cancer, wherein said method comprises administering, to said mammal, a composition of claim 43.

45. The method of claim 44, wherein said mammal is a human.

46. The method of any one of claims 44-45, wherein said cancer is a CS1+cancer.

47. The method of any one of claims 44-45, wherein said cancer is selected from the group consisting of a multiple myeloma and a myelofibrosis.

48. The method of any one of claims 44-45, wherein the number of cancer cells within said mammal is reduced following said administering step.

49. A method for binding a binding molecule to a CS1 polypeptide, wherein said method comprises contacting said CS1 polypeptide with a binding molecule of any one of claims 1-8.

50. The method of claim 49, wherein said contacting is performed in vitro.

51. The method of claim 49, wherein said contacting is performed in vivo.Attorney Docket No.07039-2338WO1 / 2024-299 52. The method of claim 51, wherein said contacting is performed within a mammal by administering said binding molecule to said mammal.

53. The method of claim 52, wherein said mammal is a human.

54. A method for binding a binding molecule to a CS1 polypeptide, wherein said method comprises contacting said CS1 polypeptide with a CAR of any one of claims 9-16, a cell engager of any one of claims 24-32, or an ADC of any one of claims 40-42.

55. The method of claim 54, wherein said contacting is performed in vitro.

56. The method of claim 54, wherein said contacting is performed in vivo.

57. The method of claim 56, wherein said contacting is performed within a mammal by administering said CAR, said cell engager, or said ADC to said mammal.

58. The method of claim 56, wherein said mammal is a human.

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