Molecules that bind to claudin 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 claudin 18 isoform 2 (CLDN18.2) polypeptide. For example, this document provides binders (e.g., antibody domains, antigen binding fragments, antibodies, CARs, cell engagers, and ADCs) that bind to a CLDN18.2 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., colorectal cancer).

Description

Attorney Docket No.07039-2318WO1 / 2024-074 MOLECULES THAT BIND TO CLAUDIN POLYPEPTIDES CROSS-REFERENCETORELATEDAPPLICATIONSThis application claims the benefit of U.S. Patent Application Serial No. 63 / 672,550,filed on July 17, 2024, and claims the benefit of U.S. Patent Application Serial No.63 / 708,804, filed on October 18, 2024. The disclosure of the prior applications 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 “07039-2318WO1_SL.xml.” The XML file, created on July 7, 2025, is 901,724 bytes in size. The material in the XML file is hereby incorporated by reference in its entirety. TECHNICALFIELDThis 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 claudin 18 isoform 2 (CLDN18.2) polypeptide. For example, this document provides binders (e.g., antibody domains, antigen binding fragments, antibodies, CARs, cell engagers, and ADCs) that bind to a CLDN18.2 polypeptide. This document also provides methods and materials for using such binders to treat cancer (e.g., colorectal cancer). BACKGROUND Adoptive cell therapy using T cells containing chimeric antigen receptors (CARs) that target CD19 (CD19-directed CART (CART19) cell therapy) has revolutionized the treatment of malignancies such as B cell malignancy. Activity of CART cell therapy against solidtumors remains limited. See, e.g., Sakemura et al., Leukemia & Lymphoma, 62:2052–2063(2021); Rodriguez-Garcia et al., Front. Immunol., 11:548227 (2020); Jain et al., Blood,134:2885–2885 (2019); and Sakemura et al., Blood, 139:3708–3721 (2022).Attorney Docket No.07039-2318WO1 / 2024-074 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 CLDN18.2 polypeptide. For example, this document provides binders (e.g., antibody domains, antigen binding fragments, antibodies, CARs, cell engagers, and ADCs) that bind to a CLDN18.2 polypeptide and methods and materials for using one or more such binders to treat a mammal (e.g., a human) having cancer (e.g., colorectal cancer). 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 CLDN18.2 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 CLDN18.2 polypeptide as set forth in any one of SEQ ID NOs:69-71 (see, e.g., Example 17). 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, or SEQ ID NOs:17-19) 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 CLDN18.2+cells (e.g., CLDN18.2+cancer cells), can be engineered into an antibody structure that includes an Fc region to create antibodies having the ability to target CLDN18.2+cells (e.g., CLDN18.2+cancer cells) and induce antibody-dependent cell- mediated cytotoxicity (ADCC) against the targeted CLDN18.2+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 CLDN18.2+cells (e.g., CLDN18.2+cancer cells) 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 CLDN18.2+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.07039-2318WO1 / 2024-074 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., CLDN18.2+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 CLDN18.2 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 CLDN18.2 polypeptide. Such cells (e.g., CLDN18.2-specific CAR+T cells or NK cells) can be used to treat cancer (e.g., colorectal cancer). 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 CLDN18.2 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 CLDN18.2 polypeptide to treat cancer (e.g., colorectal cancer). 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., colorectal cancer). For example, a mammal (e.g., a human) having cancer (e.g., a CLDN18.2+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 CLDN18.2 polypeptide. For example, a binder (e.g., an antibody domain, anAttorney Docket No.07039-2318WO1 / 2024-074 antigen binding fragment, an antibody, a cell engager, or an ADC) provided herein can be 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 CLDN18.2+cells (e.g., CLDN18.2+cancer cells). Having the ability to detect the presence or absence of a CLDN18.2 polypeptide (e.g., CLDN18.2+cancer cells) can allow clinicians, health professionals, and patients to make better decisions about possible treatment options. For example, detection of CLDN18.2+cancer cells within a mammal can allow clinicians, health professionals, and patients to select an appropriate anti-cancer treatment that targets the CLDN18.2+cancer cells. Such treatments that target the CLDN18.2+cancer cells can include administration of an anti- CLDN18.2 antibody such as zolbetuximab and / or one or more of the binders described herein having the ability to bind to a CLDN18.2 polypeptide and / or administration of one or more cells (e.g., CLDN18.2-specific CAR+T cells or NK cells) designed to express a binder described herein. In general, one aspect of this document features single-domain antibodies each comprising: (i) a heavy chain variable domain 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); (ii) a heavy chain variable domain 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); (iii) a heavy chain variable domain 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); (iv) a heavy chain variable domain comprising the amino acid sequences set forth in SEQ ID NO:155 (or SEQ ID NO:155 with one, two, or three amino acid additions, deletions, or substitutions), SEQ IDAttorney Docket No.07039-2318WO1 / 2024-074 NO:156 (or SEQ ID NO:156 with one, two, or three amino acid additions, deletions, or substitutions), and SEQ ID NO:157 (or SEQ ID NO:157 with one, two, or three amino acid additions, deletions, or substitutions); (v) a heavy chain variable domain comprising the amino acid sequences set forth in SEQ ID NO:163 (or SEQ ID NO:163 with one, two, or three amino acid additions, deletions, or substitutions), SEQ ID NO:164 (or SEQ ID NO:164 with one, two, or three amino acid additions, deletions, or substitutions), and SEQ ID NO:165 (or SEQ ID NO:165 with one, two, or three amino acid additions, deletions, or substitutions); (vi) a heavy chain variable domain comprising the amino acid sequences set forth in SEQ ID NO:171 (or SEQ ID NO:171 with one, two, or three amino acid additions, deletions, or substitutions), SEQ ID NO:172 (or SEQ ID NO:172 with one, two, or three amino acid additions, deletions, or substitutions), and SEQ ID NO:173 (or SEQ ID NO:173 with one, two, or three amino acid additions, deletions, or substitutions); (vii) a heavy chain variable domain comprising the amino acid sequences set forth in SEQ ID NO:179 (or SEQ ID NO:179 with one, two, or three amino acid additions, deletions, or substitutions), SEQ ID NO:180 (or SEQ ID NO:180 with one, two, or three amino acid additions, deletions, or substitutions), and SEQ ID NO:181 (or SEQ ID NO:181 with one, two, or three amino acid additions, deletions, or substitutions); (viii) a heavy chain variable domain comprising the amino acid sequences set forth in SEQ ID NO:186 (or SEQ ID NO:186 with one, two, or three amino acid additions, deletions, or substitutions), SEQ ID NO:187 (or SEQ ID NO:187 with one, two, or three amino acid additions, deletions, or substitutions), and SEQ ID NO:188 (or SEQ ID NO:188 with one, two, or three amino acid additions, deletions, or substitutions); (ix) a heavy chain variable domain comprising the amino acid sequences set forth in SEQ ID NO:194 (or SEQ ID NO:194 with one, two, or three amino acid additions, deletions, or substitutions), SEQ ID NO:195 (or SEQ ID NO:195 with one, two, or three amino acid additions, deletions, or substitutions), and SEQ ID NO:196 (or SEQ ID NO:196 with one, two, or three amino acid additions, deletions, or substitutions); (x) a heavy chain variable domain comprising the amino acid sequences set forth in SEQ ID NO:202 (or SEQ ID NO:202 with one, two, or three amino acid additions, deletions, or substitutions), SEQ ID NO:203 (or SEQ ID NO:203 with one, two, or three amino acid additions, deletions, or substitutions), and SEQ ID NO:204 (or SEQ ID NO:204 with one, two, or three amino acidAttorney Docket No.07039-2318WO1 / 2024-074 additions, deletions, or substitutions); (xi) a heavy chain variable domain comprising the amino acid sequences set forth in SEQ ID NO:210 (or SEQ ID NO:210 with one, two, or three amino acid additions, deletions, or substitutions), SEQ ID NO:211 (or SEQ ID NO:211 with one, two, or three amino acid additions, deletions, or substitutions), and SEQ ID NO:212 (or SEQ ID NO:212 with one, two, or three amino acid additions, deletions, or substitutions); (xii) a heavy chain variable domain comprising the amino acid sequences set forth in SEQ ID NO:218 (or SEQ ID NO:218 with one, two, or three amino acid additions, deletions, or substitutions), SEQ ID NO:219 (or SEQ ID NO:219 with one, two, or three amino acid additions, deletions, or substitutions), and SEQ ID NO:220 (or SEQ ID NO:220 with one, two, or three amino acid additions, deletions, or substitutions); (xiii) a heavy chain variable domain comprising the amino acid sequences set forth in SEQ ID NO:226 (or SEQ ID NO:226 with one, two, or three amino acid additions, deletions, or substitutions), SEQ ID NO:227 (or SEQ ID NO:227 with one, two, or three amino acid additions, deletions, or substitutions), and SEQ ID NO:228 (or SEQ ID NO:228 with one, two, or three amino acid additions, deletions, or substitutions); (xiv) a heavy chain variable domain comprising the amino acid sequences set forth in SEQ ID NO:234 (or SEQ ID NO:234 with one, two, or three amino acid additions, deletions, or substitutions), SEQ ID NO:235 (or SEQ ID NO:235 with one, two, or three amino acid additions, deletions, or substitutions), and SEQ ID NO:236 (or SEQ ID NO:236 with one, two, or three amino acid additions, deletions, or substitutions); or (xv) a heavy chain variable domain comprising the amino acid sequences set forth in SEQ ID NO:242 (or SEQ ID NO:242 with one, two, or three amino acid additions, deletions, or substitutions), SEQ ID NO:243 (or SEQ ID NO:243_ with one, two, or three amino acid additions, deletions, or substitutions), and SEQ ID NO:244 (or SEQ ID NO:244 with one, two, or three amino acid additions, deletions, or substitutions). The single- domain antibody can have the ability to bind to a polypeptide sequence set forth in any one of SEQ ID NOs: 69-71. The single-domain antibody can include the heavy chain variable domain of (i). The heavy chain variable domain can include an amino acid sequence having at least 90 percent identity to the amino acid sequence set forth in SEQ ID NO:8. The single- domain antibody can include the heavy chain variable domain of (ii). The heavy chain variable domain can include an amino acid sequence having at least 90 percent identity to theAttorney Docket No.07039-2318WO1 / 2024-074 amino acid sequence set forth in SEQ ID NO:16. The single-domain antibody can include the heavy chain variable domain of (iii). The heavy chain variable domain can include an amino acid sequence having at least 90 percent identity to the amino acid sequence set forth in SEQ ID NO:24. The single-domain antibody can include the heavy chain variable domain of (iv). The heavy chain variable domain can include an amino acid sequence having at least 90 percent identity to the amino acid sequence set forth in SEQ ID NO:162. The single-domain antibody can include the heavy chain variable domain of (v). The heavy chain variable domain can include an amino acid sequence having at least 90 percent identity to the amino acid sequence set forth in SEQ ID NO:170. The single-domain antibody can include the heavy chain variable domain of (vi). The heavy chain variable domain can include an amino acid sequence having at least 90 percent identity to the amino acid sequence set forth in SEQ ID NO:178. The single-domain antibody can include the heavy chain variable domain of (vii). The heavy chain variable domain can include an amino acid sequence having at least 90 percent identity to the amino acid sequence set forth in SEQ ID NO:274. The single-domain antibody can include the heavy chain variable domain of (viii). The heavy chain variable domain can include an amino acid sequence having at least 90 percent identity to the amino acid sequence set forth in SEQ ID NO:193. The single-domain antibody can include the heavy chain variable domain of (ix). The heavy chain variable domain can include an amino acid sequence having at least 90 percent identity to the amino acid sequence set forth in SEQ ID NO:201. The single-domain antibody can include the heavy chain variable domain of said (x). The heavy chain variable domain can include an amino acid sequence having at least 90 percent identity to the amino acid sequence set forth in SEQ ID NO:209. The single-domain antibody can include the heavy chain variable domain of (xi). The heavy chain variable domain can include an amino acid sequence having at least 90 percent identity to the amino acid sequence set forth in SEQ ID NO:217. The single-domain antibody can include the heavy chain variable domain of (xii). The heavy chain variable domain can include an amino acid sequence having at least 90 percent identity to the amino acid sequence set forth in SEQ ID NO:225. The single-domain antibody can include the heavy chain variable domain of (xiii). The heavy chain variable domain can include an amino acid sequence having at least 90 percent identity to the amino acid sequence set forth in SEQ ID NO:233. The single-Attorney Docket No.07039-2318WO1 / 2024-074 domain antibody can include the heavy chain variable domain of (xiv). The heavy chain variable domain can include an amino acid sequence having at least 90 percent identity to the amino acid sequence set forth in SEQ ID NO:241. The single-domain antibody can include the heavy chain variable domain of (xv). The heavy chain variable domain can include an amino acid sequence having at least 90 percent identity to the amino acid sequence set forth in SEQ ID NO:249. In another aspect, this document features single chain variable fragments (scFvs) each comprising: (i) a heavy chain variable domain or region comprising the amino acid sequences set forth in SEQ ID NO:250 (or SEQ ID NO:250 with one, two, or three amino acid additions, deletions, or substitutions), SEQ ID NO:251 (or SEQ ID NO:251 with one, two, or three amino acid additions, deletions, or substitutions), and SEQ ID NO:252 (or SEQ ID NO:252 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:258 (or SEQ ID NO:258 with one, two, or three amino acid additions, deletions, or substitutions), SEQ ID NO:259 (or SEQ ID NO:259 with one, two, or three amino acid additions, deletions, or substitutions), and SEQ ID NO:260 (or SEQ ID NO:260 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:266 (or SEQ ID NO:266 with one, two, or three amino acid additions, deletions, or substitutions), SEQ ID NO:267 (or SEQ ID NO:267 with one, two, or three amino acid additions, deletions, or substitutions), and SEQ ID NO:268 (or SEQ ID NO:268 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:258 (or SEQ ID NO:258 with one, two, or three amino acid additions, deletions, or substitutions), SEQ ID NO:259 (or SEQ ID NO:259 with one, two, or three amino acid additions, deletions, or substitutions), and SEQ ID NO:260 (or SEQ ID NO:260 with one, two, or three amino acid additions, deletions, or substitutions); or (iii) a heavy chain variable domain or region comprising the amino acid sequences set forth in SEQ ID NO:282 (or SEQ ID NO:282 with one, two, or three amino acid additions, deletions, or substitutions), SEQ ID NO:283 (or SEQ ID NO:283 with one, two, or three amino acid additions, deletions, or substitutions), and SEQ ID NO:284 (or SEQAttorney Docket No.07039-2318WO1 / 2024-074 ID NO:284 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:290 (or SEQ ID NO:290 with one, two, or three amino acid additions, deletions, or substitutions), SEQ ID NO:291 (or SEQ ID NO:291 with one, two, or three amino acid additions, deletions, or substitutions), and SEQ ID NO:292 (or SEQ ID NO:292 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: 69- 71. The binding molecule can include (i), where the 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:257, and where the 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:265. The binding molecule can include (ii), where the 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:273, and where the 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:265. The binding molecule can include (iii), where the 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:289, and where the 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:297. In another aspect, this document features CARs that include an antigen binding domain, a hinge, a transmembrane domain, and one or more signaling domains, wherein the antigen binding domain comprises a single-domain antibody including (i) a heavy chain variable domain 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); (ii) a heavy chain variable domain 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 aminoAttorney Docket No.07039-2318WO1 / 2024-074 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); or (iii) a heavy chain variable domain 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). The single-domain antibody can have the ability to bind to a polypeptide sequence set forth in any one of SEQ ID NOs: 69-71. The single-domain antibody can include the heavy chain variable domain of (i). The heavy chain variable domain can include an amino acid sequence having at least 90 percent identity to the amino acid sequence set forth in SEQ ID NO:8. The single-domain antibody can include the heavy chain variable domain of (ii). The heavy chain variable domain can include an amino acid sequence having at least 90 percent identity to the amino acid sequence set forth in SEQ ID NO:16. The single-domain antibody can include the heavy chain variable domain of (iii). The heavy chain variable domain can include an amino acid sequence having at least 90 percent identity to the amino acid sequence set forth in SEQ ID NO:24. The single-domain antibody can have the ability to bind to a CLDN18.2 polypeptide. The hinge can be a hinge set forth in any one ofSEQ ID NOs:94-101. The hinge can be a CD8 hinge. The transmembrane domain can be atransmembrane domain set forth in any one of SEQ ID NOs:102-109. The transmembranedomain can be a CD8 transmembrane domain. The CAR can include one or more signalingdomains set forth in any one of SEQ ID NOs:110-119. The CAR can include a 4-1BBintracellular signaling domain and a CD3 intracellular signaling domain.In another aspect, this document features cells that express a CAR including an antigen binding domain, a hinge, a transmembrane domain, and one or more signaling domains, wherein the antigen binding domain comprises a single-domain antibody including (i) a heavy chain variable domain 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); (ii) a heavy chain variable domainAttorney Docket No.07039-2318WO1 / 2024-074 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); or (iii) a heavy chain variable domain 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). The single-domain antibody can have the ability to bind to a polypeptide sequence set forth in any one of SEQ ID NOs: 69-71. The single-domain antibody can include the heavy chain variable domain of (i). The heavy chain variable domain can include an amino acid sequence having at least 90 percent identity to the amino acid sequence set forth in SEQ ID NO:8. The single-domain antibody can include the heavy chain variable domain of (ii). The heavy chain variable domain can include an amino acid sequence having at least 90 percent identity to the amino acid sequence set forth in SEQ ID NO:16. The single-domain antibody can include the heavy chain variable domain of (iii). The heavy chain variable domain can include an amino acid sequence having at least 90 percent identity to the amino acid sequence set forth in SEQ ID NO:24. The cell can be a T cell, a stem cell, or an NK cell. The cell 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, wherein the antigen binding domain comprises a scFv having the ability to bind to a fibroblast activation protein (FAP) polypeptide. The scFv can include: (i) a heavy chain variable domain comprising the amino acid sequences set forth in SEQ ID NO:57, SEQ ID NO:58, and SEQ ID NO:59, and a light chain variable domain or region comprising the amino acid sequences set forth in SEQ ID NO:60, SEQ ID NO:61, and SEQ ID NO:62; or (ii) a heavy chain variable domain comprising the amino acid sequences set forth in SEQ ID NO:63, SEQ ID NO:64, and SEQ ID NO:65, and a light chain variable domain or region comprising the amino acid sequences set forth in SEQ ID NO:66, SEQ ID NO:67, and SEQ ID NO:68. The second CAR can be an activation-inducible CAR. The second CAR can be an expression-inducible CAR.Attorney Docket No.07039-2318WO1 / 2024-074 In another aspect, this document features cell engagers including a first antigen binding domain, a linker, and a second antigen binding domain, wherein the first antigen binding domain comprises a single-domain antibody including (i) a heavy chain variable domain 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); (ii) a heavy chain variable domain 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); or (iii) a heavy chain variable domain 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). The single-domain antibody can have the ability to bind to a polypeptide sequence set forth in any one of SEQ ID NOs: 69-71. The single-domain antibody can include the heavy chain variable domain of (i). The heavy chain variable domain can include an amino acid sequence having at least 90 percent identity to the amino acid sequence set forth in SEQ ID NO:8. The single-domain antibody can include the heavy chain variable domain of (ii). The heavy chain variable domain can include an amino acid sequence having at least 90 percent identity to the amino acid sequence set forth in SEQ ID NO:16. The single-domain antibody can include the heavy chain variable domain of (iii). The heavy chain variable domain can include an amino acid sequence having at least 90 percent identity to the amino acid sequence set forth in SEQ ID NO:24. The first antigen binding domain can include a scFv having the ability to bind to a CLDN18.2 polypeptide. The linker can be a linker set forth in any one of SEQ ID NOs:83-86 or SEQ ID NOs:94-101. 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 secondAttorney Docket No.07039-2318WO1 / 2024-074 antigen binding domain can be an antigen binding domain set forth in Example 15. The second antigen binding domain can bind 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 16. In another aspect, this document features nucleic acids including a nucleic acid sequence encoding a single-domain antibody including (i) a heavy chain variable domain 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); (ii) a heavy chain variable domain 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); or (iii) a heavy chain variable domain 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). The single-domain antibody can have the ability to bind to a polypeptide sequence set forth in any one of SEQ ID NOs: 69-71. The single-domain antibody can include the heavy chain variable domain of (i). The heavy chain variable domain can include an amino acid sequence having at least 90 percent identity to the amino acid sequence set forth in SEQ ID NO:8. The single-domain antibody can include the heavy chain variable domain of (ii). The heavy chain variable domain can include an amino acid sequence having at least 90 percent identity to the amino acid sequence set forth in SEQ ID NO:16. The single-domain antibody can include the heavy chain variable domain of (iii). The heavy chain variable domain can include an amino acid sequence having at least 90 percent identity to the amino acid sequence set forth in SEQ ID NO:24. The nucleic acid sequence can encode (i).Attorney Docket No.07039-2318WO1 / 2024-074 The nucleic acid sequence can encode (ii). The nucleic acid sequence can encode (iii). The nucleic acid can be a viral vector. In another aspect, this document features nucleic acids including a nucleic acid sequence encoding a including an antigen binding domain, a hinge, a transmembrane domain, and one or more signaling domains, wherein the antigen binding domain comprises a single-domain antibody including (i) a heavy chain variable domain 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); (ii) a heavy chain variable domain 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); or (iii) a heavy chain variable domain 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). or a cell engager including a first antigen binding domain, a linker, and a second antigen binding domain, wherein the first antigen binding domain comprises a single-domain antibody including (i) a heavy chain variable domain 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); (ii) a heavy chain variable domain 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, orAttorney Docket No.07039-2318WO1 / 2024-074 substitutions); or (iii) a heavy chain variable domain 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). The single-domain antibody can have the ability to bind to a polypeptide sequence set forth in any one of SEQ ID NOs: 69-71. The single-domain antibody can include the heavy chain variable domain of (i). The heavy chain variable domain can include an amino acid sequence having at least 90 percent identity to the amino acid sequence set forth in SEQ ID NO:8. The single-domain antibody can include the heavy chain variable domain of (ii). The heavy chain variable domain can include an amino acid sequence having at least 90 percent identity to the amino acid sequence set forth in SEQ ID NO:16. The single-domain antibody can include the heavy chain variable domain of (iii). The heavy chain variable domain can include an amino acid sequence having at least 90 percent identity to the amino acid sequence set forth in SEQ ID NO:24. The nucleic acid can be a viral vector. In another aspect, this document features host cells including a nucleic acid including a nucleic acid sequence encoding a CAR including an antigen binding domain, a hinge, a transmembrane domain, and one or more signaling domains, wherein the antigen binding domain comprises a single-domain antibody including (i) a heavy chain variable domain 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); (ii) a heavy chain variable domain 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); or (iii) a heavy chain variable domain 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 (orAttorney Docket No.07039-2318WO1 / 2024-074 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). The single-domain antibody can have the ability to bind to a polypeptide sequence set forth in any one of SEQ ID NOs: 69-71. The single-domain antibody can include the heavy chain variable domain of (i). The heavy chain variable domain can include an amino acid sequence having at least 90 percent identity to the amino acid sequence set forth in SEQ ID NO:8. The single-domain antibody can include the heavy chain variable domain of (ii). The heavy chain variable domain can include an amino acid sequence having at least 90 percent identity to the amino acid sequence set forth in SEQ ID NO:16. The single-domain antibody can include the heavy chain variable domain of (iii). The heavy chain variable domain can include an amino acid sequence having at least 90 percent identity to the amino acid sequence set forth in SEQ ID NO:24. The host cell can be a T cell, stem cell, or NK cell. In another aspect, this document features host cells including a cell engager including a first antigen binding domain, a linker, and a second antigen binding domain, wherein the first antigen binding domain comprises a single-domain antibody including (i) a heavy chain variable domain 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); (ii) a heavy chain variable domain 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); or (iii) a heavy chain variable domain 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). The single-domain antibody can have the ability to bind to a polypeptideAttorney Docket No.07039-2318WO1 / 2024-074 sequence set forth in any one of SEQ ID NOs: 69-71. The single-domain antibody can include the heavy chain variable domain of (i). The heavy chain variable domain can include an amino acid sequence having at least 90 percent identity to the amino acid sequence set forth in SEQ ID NO:8. The single-domain antibody can include the heavy chain variable domain of (ii). The heavy chain variable domain can include an amino acid sequence having at least 90 percent identity to the amino acid sequence set forth in SEQ ID NO:16. The single-domain antibody can include the heavy chain variable domain of (iii). The heavy chain variable domain can include an amino acid sequence having at least 90 percent identity to the amino acid sequence set forth in SEQ ID NO:24. The host cell can be a T cell, stem cell, or NK cell. In another aspect, this document features host cells that expresses a CAR including an antigen binding domain, a hinge, a transmembrane domain, and one or more signaling domains, wherein the antigen binding domain comprises a single-domain antibody including (i) a heavy chain variable domain 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); (ii) a heavy chain variable domain 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); or (iii) a heavy chain variable domain 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) or a cell engager including a first antigen binding domain, a linker, and a second antigen binding domain, wherein the first antigen binding domain comprises a single-domain antibody including (i) a heavy chain variable domain comprising the amino acid sequences set forth in SEQ ID NO:1 (or SEQ IDAttorney Docket No.07039-2318WO1 / 2024-074 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); (ii) a heavy chain variable domain 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); or (iii) a heavy chain variable domain 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). The single-domain antibody can have the ability to bind to a polypeptide sequence set forth in any one of SEQ ID NOs: 69-71. The single-domain antibody can include the heavy chain variable domain of (i). The heavy chain variable domain can include an amino acid sequence having at least 90 percent identity to the amino acid sequence set forth in SEQ ID NO:8. The single-domain antibody can include the heavy chain variable domain of (ii). The heavy chain variable domain can include an amino acid sequence having at least 90 percent identity to the amino acid sequence set forth in SEQ ID NO:16. The single-domain antibody can include the heavy chain variable domain of (iii). The heavy chain variable domain can include an amino acid sequence having at least 90 percent identity to the amino acid sequence set forth in SEQ ID NO:24. The host cell can be a T cell, stem cell, or NK cell. In another aspect, this document features ADCs including an antigen binding domain covalently linked to a drug, wherein the antigen binding domain comprises a single-domain antibody including (i) a heavy chain variable domain 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); (ii) a heavy chain variableAttorney Docket No.07039-2318WO1 / 2024-074 domain 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); or (iii) a heavy chain variable domain 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). The single-domain antibody can have the ability to bind to a polypeptide sequence set forth in any one of SEQ ID NOs: 69-71. The single-domain antibody can include the heavy chain variable domain of (i). The heavy chain variable domain can include an amino acid sequence having at least 90 percent identity to the amino acid sequence set forth in SEQ ID NO:8. The single-domain antibody can include the heavy chain variable domain of (ii). The heavy chain variable domain can include an amino acid sequence having at least 90 percent identity to the amino acid sequence set forth in SEQ ID NO:16. The single-domain antibody can include the heavy chain variable domain of (iii). The heavy chain variable domain can include an amino acid sequence having at least 90 percent identity to the amino acid sequence set forth in SEQ ID NO:24. The single-domain antibody can have the ability to bind to a CLDN18.2 polypeptide. The drug can be an auristatin, a mertansine, or a pyrrolobenzodiazepine (PBD) dimers. In another aspect, this document features compositions including a single-domain antibody, a cell engager including the single-domain antibody, a cell including a nucleic acid including a nucleic acid sequence encoding a CAR including the single-domain antibody, a cell that expresses a CAR including the single-domain antibody, and / or an ADC, including the single-domain antibody covalently linked to a drug, wherein the single-domain antibody includes (i) a heavy chain variable domain 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); (ii) a heavy chain variable domainAttorney Docket No.07039-2318WO1 / 2024-074 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); or (iii) a heavy chain variable domain 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). The single-domain antibody can have the ability to bind to a polypeptide sequence set forth in any one of SEQ ID NOs: 69-71. The single-domain antibody can include the heavy chain variable domain of (i). The heavy chain variable domain can include an amino acid sequence having at least 90 percent identity to the amino acid sequence set forth in SEQ ID NO:8. The single-domain antibody can include the heavy chain variable domain of (ii). The heavy chain variable domain can include an amino acid sequence having at least 90 percent identity to the amino acid sequence set forth in SEQ ID NO:16. The single-domain antibody can include the heavy chain variable domain of (iii). The heavy chain variable domain can include an amino acid sequence having at least 90 percent identity to the amino acid sequence set forth in SEQ ID NO:24. In another aspect, this document features methods for treating a mammal having cancer. The methods can include, or consist essentially of, administering, to the mammal, a composition including a single-domain antibody, a cell engager including the single-domain antibody, a cell including a nucleic acid including a nucleic acid sequence encoding a CAR including the single-domain antibody, a cell that expresses a CAR including the single- domain antibody, and / or an ADC including the single-domain antibody covalently linked to a drug, wherein the single-domain antibody includes (i) a heavy chain variable domain 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, orAttorney Docket No.07039-2318WO1 / 2024-074 substitutions); (ii) a heavy chain variable domain 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); or (iii) a heavy chain variable domain 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). The single-domain antibody can have the ability to bind to a polypeptide sequence set forth in any one of SEQ ID NOs: 69-71. The single-domain antibody can include the heavy chain variable domain of (i). The heavy chain variable domain can include an amino acid sequence having at least 90 percent identity to the amino acid sequence set forth in SEQ ID NO:8. The single-domain antibody can include the heavy chain variable domain of (ii). The heavy chain variable domain can include an amino acid sequence having at least 90 percent identity to the amino acid sequence set forth in SEQ ID NO:16. The single-domain antibody can include the heavy chain variable domain of (iii). The heavy chain variable domain can include an amino acid sequence having at least 90 percent identity to the amino acid sequence set forth in SEQ ID NO:24. The mammal can be a human. The cancer can be a CLDN18.2+cancer. The cancer can be a colorectal cancer, a colon cancer, a gastric cancer, a gastrointestinal cancer, or a pancreatic cancer. The number of cancer cells within the mammal can be reduced following the administering step. In another aspect, this document features methods for binding a binding molecule to a CLDN18.2 polypeptide. The methods can include, or consist essentially of, contacting the CLDN18.2 polypeptide with a single-domain antibody including (i) a heavy chain variable domain 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); (ii) a heavy chain variable domain comprising the amino acid sequences setAttorney Docket No.07039-2318WO1 / 2024-074 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); or (iii) a heavy chain variable domain 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). The single-domain antibody can have the ability to bind to a polypeptide sequence set forth in any one of SEQ ID NOs: 69-71. The single-domain antibody can include the heavy chain variable domain of (i). The heavy chain variable domain can include an amino acid sequence having at least 90 percent identity to the amino acid sequence set forth in SEQ ID NO:8. The single-domain antibody can include the heavy chain variable domain of (ii). The heavy chain variable domain can include an amino acid sequence having at least 90 percent identity to the amino acid sequence set forth in SEQ ID NO:16. The single-domain antibody can include the heavy chain variable domain of (iii). The heavy chain variable domain can include an amino acid sequence having at least 90 percent identity to theamino acid sequence set forth in SEQ ID NO:24. The contacting can be performed in vitro.The contacting can be performed in vivo. The contacting can be performed within a mammalby administering the antibody or the antigen binding fragment to the mammal. The mammal can be a human. In another aspect, this document features methods for binding a binding molecule to a CLDN18.2 polypeptide. The methods can include, or consist essentially of, contacting the CLDN18.2 polypeptide with a CAR including a single-domain antibody, a cell engager including the single-domain antibody, and / or an ADC including the single-domain antibody covalently linked to a drug, wherein the single-domain antibody includes (i) a heavy chain variable domain 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,Attorney Docket No.07039-2318WO1 / 2024-074 or substitutions); (ii) a heavy chain variable domain 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); or (iii) a heavy chain variable domain 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). The single-domain antibody can have the ability to bind to a polypeptide sequence set forth in any one of SEQ ID NOs: 69-71. The single-domain antibody can include the heavy chain variable domain of (i). The heavy chain variable domain can include an amino acid sequence having at least 90 percent identity to the amino acid sequence set forth in SEQ ID NO:8. The single-domain antibody can include the heavy chain variable domain of (ii). The heavy chain variable domain can include an amino acid sequence having at least 90 percent identity to the amino acid sequence set forth in SEQ ID NO:16. The single-domain antibody can include the heavy chain variable domain of (iii). The heavy chain variable domain can include an amino acid sequence having at least 90 percent identity to theamino acid sequence set forth in SEQ ID NO:24. The contacting can be performed in vitro.The contacting can be performed in vivo. The contacting can be performed within a mammalby administering the CAR, the cell engager, and / or the ADC to the 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.Attorney Docket No.07039-2318WO1 / 2024-074 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 Figure1. Schematic of exemplary Hu8e5-BBz and GC-182-BBz CARs. Figure 2. Claudin18.2 positive and negative patient tumors and patient derived tumor xenograft (PDTX) mouse models. Immunohistochemistry staining of colon cancer tumor tissues identified tumors expressing Claudin18.2. Staining showed Claudin18.2 protein expression on the cell membrane. Figures 3A-3B. Generating colorectal cancer cells stably expressing Claudin 18.1 or Claudin 18.2. Colorectal cancer cell lines LS411N and SNU-C2B were transduced with lentivirus encoding a HA-tagged Claudin 18.1 polypeptide (Claudin18.1-HA) or Claudin18.2-HA. Figure 3A) Expression of transduced genes was validated by immunoblotting of the HA tag. Figure 3B) Claudin18.2 expression was confirmed by flow cytometry using a PE conjugated anti-Cldn18.2 antibody (anti-Claudin18.2-PE). Figures 4A-4C. hu8e5-BBz and GC-182-BBz CAR+T cells effectively eliminated colorectal cancer cells. Figure 4A) CAR expression in hu8e5-BBz and GC-182-BBz CAR+T Cells was validated by flow cytometry using goat anti-mouse-APC (GAM). CART cells were co-cultured with 10,000 LS411N cells (Luc+WT, Luc+18.1-HA, or Luc+18.2-HA; Figure 4B) or 10,000 SNU-C2B cells (Luc+WT, Luc+18.1-HA, or Luc+18.2-HA; Figure 4C) at different effector-to-target ratios (E:T). CART-mediated cytotoxicity was assessed by luciferase luminescence at 24, 48, and 72 hours. Figure 5. Generating dual-targeting Claudin 18.2-FAP CART cells. Dual-targeting CART cells were transduced with hu8e5-BBz-CAR or GC-182-BBz-CAR and FAP-CAR. CAR expression was validated by flow cytometry. CART cells were incubated with soluble Claudin18.2-VLP-GFP, to detect Claudin18.2 targeting CARs, and FAP-Fc (followed by goat anti-human Fc-APC), to detect FAP-CAR. Figure 6. Dual-targeting Claudin18.2-FAP CART cells effectively eliminated colorectal cancer cells and fibroblasts. Single- and dual-targeting CART cells wereAttorney Docket No.07039-2318WO1 / 2024-074 cocultured at different E:T ratios with WT SNU-C2B Luc+cells, Claudin18.1-HA SNU-C2B Luc+, Claudin18.2-HA SNU-C2B Luc+cells, or Nalm6 Luc+cells as negative control (10,000 cells). CART-mediated cytotoxicity was assessed by luciferase luminescence at 24, 48, and 72 hours. Figure 7. Single and dual-targeting CART cell proliferation was assessed by coculturing CART cells with media, PMA / ionomycin, SNU-C2B WT, SNU-C2B Claudin18.1, SNU-C2B Claudin18.2, WI-38, or mixed SNU-C2B Claudin18.2-WI-38 cells at a 1:1 ratio (5K:5K cells). Cells were cultured for a total of 5 days, with media feeding on day 3. Absolute numbers of CD3+cells were quantified using flow cytometry. Figure 8. Schematic of exemplary Claudin 18.2 nanobody-based CARs. High affinity Claudin18.2 nanobodies (VHH antibodies) were identified by phage display screening. VHH sequences of Claudin18.2 nanobodies were used as the variable region (instead of theconventional scFv) to generate CARs containing a CD8 hinge, CD28 transmembranedomain, 41BB intracellular signal domain, and CD3 intracellular signal domain.Figures 9A-9B. Nanobody-based CART cells were generated by transduction of T cells with lentiviral vectors encoding a KGHH18-1-BBz CAR, a KGHH18-2-BBz CAR, a KGHH18-3-BBz CAR, a KGHH18-4-BBz CAR, a KGHH18-5-BBz CAR, a KGHH18-6- BBz CAR, or a KGHH18-7-BBz CAR. Figure 9A) CAR expression was validated by flow cytometry using goat anti-humanized-VHH-APC. Figure 9B) CART cells and Luc+WT, Luc+18.1-HA, or Luc+18.2-HA SNU-C2B cells (10,000 cells) were cocultured at different E:T ratios and CART-mediated cytotoxicity was assessed by luciferase luminescence at 24, 48, and 72 hours. Figure 10. KGHH18-3-BBz, KGHH18-5-BBz, and KGHH18-7-BBz CART cells had higher affinity for Luc+Claudin18.2+cells. Nanobody-based CART cells KGHH18-3- BBz-CAR, KGHH18-5-BBz-CAR, and KGHH18-7-BBz-CAR effectively eliminated Luc+SNU-C2B Claudin18.2+colorectal cancer cells, with higher specificity than the other anti- CLDN18.2 clones. The rest of the CART cells had higher cytotoxic effects towards WT and Claudin18.1 SNU-C2B colorectal cancer cells. Figure 11. Nanobody-based CART cell proliferation. Nanobody-based CART cell proliferation was assessed by coculturing CART cells with media, phorbol 12-myristate 13-Attorney Docket No.07039-2318WO1 / 2024-074 acetate (PMA) / ionomycin, SNU-C2B WT, SNU-C2B Claudin18.1, or SNU-C2B Claudin18.2 colorectal cancer cells at a 1:1 ratio (100K:100K cells). Cells were cultured for 5 days, with media feeding on day 3. Absolute numbers of CD3+cells were quantified using flow cytometry. Figure 12. Nanobody CART cells exhibited higher specificity for CLDN18.2+cells compared to scFv CART Cells. Figure 13. Schematics of an exemplary Claudin 18.2 nanobody-based cell engager (top) and an exemplary Claudin 18.2 scFv-based cell engager (bottom). Figures 14A-14B. Anti-tumor assessment of Claudin18.2 CART cells in vitro. Figure14A) Expression of Claudin18.2 CARs in CART cells was confirmed by flow cytometry using rabbit-anti-VHH-APC for nanobody based CART cells (KGHH) and goat-anti-mouse- APC for scFv based CARs (KGSV). Figure 14B) Claudin18.2-CART cell cytotoxicity against Luc+WT, Claudin18.1, and Claudin18.2 SNU-C2B cancer cells. Different E:T ratios were cultured for 48 hours. Cytotoxicity was assessed by bioluminescence of residual live cells. Figures 15A-15E. VHH-based Claudin18.2-CART cells exhibited higher antigen specificity than scFv-based Claudin18.2-CART cells. Figure 15A) Expression of CARs in CART cells was confirmed by flow cytometry using rabbit-anti-VHH-APC for nanobody based CART cells (KGHH) and goat-anti-mouse-APC for scFv based CARs.2x106WT, Claudin18.1, or Claudin18.2 SNU-C2B cancer cells were implanted subcutaneously in NSG mice and allowed to engraft. Intravenous infusion of 5x106control untransduced T cells, Claudin18.2-VHH-BBz CART cells, or Claudin18.2-scFv CART cells was administered upon tumor engraftment. Figure 15B) Tumor volume was determined via caliper measurement. Figure 15C) CART cell expansion was assessed 14- and 27-days post-CART infusion by flow cytometry staining for human CD3+cells in peripheral blood. Figure 15D) Mouse weight was measured as a readout of wellness. Figure 15E) Kaplan-Meier survival curves. Figure 16A-16F. VHH-based Claudin18.2-CART cells exhibited sustained anti-tumor activity in tumor-rechallenged mice. Figure 16A) CAR expression in CART cells was confirmed by flow cytometry using rabbit-anti-VHH-APC for nanobody based CART cellsAttorney Docket No.07039-2318WO1 / 2024-074 (KGHH) and goat-anti-mouse-APC for scFv based CARs.1x106Claudin18.2 SNU-C2B cancer cells were implanted subcutaneously in NSG mice and allowed to engraft. Intravenous infusion of 1x105control untransduced T cells, KGHH18-5-BBz CART cells, or Hu8e-BBz CART cells was administered upon tumor engraftment. Figure 16B) Tumor volume was determined via caliper measurement.140 days post-KGHH18-5-BBz CART infusion, mice were rechallenged with 1x106Claudin18.2 SNU-C2B cancer cells implanted subcutaneously. A new group of mice treated with untransduced T cells was included as control. Figure 16C) Tumor growth was monitored via caliper measurement. Figure 16D) Mouse weight was measured as a readout of wellness. Figure 16E) Kaplan-Meier survival curves. Figure 16F) CART cell expansion was assessed at multiple timepoints post-CART infusion by flow cytometry staining for human CD3+cells in peripheral blood. Figures 17A-17E. The anti-tumor activity of KGHH18-5-BBz effectively eliminated large tumors. Figure 17A) Expression of CARs in CART cells was confirmed by flow cytometry using rabbit-anti-VHH-APC for nanobody based CART cells (KGHH).1x106Claudin18.2 SNU-C2B cancer cells were implanted subcutaneously in NSG mice and allowed to engraft. Intravenous infusion of 5x105control untransduced T cells, KGHH18-5- BBz CART cells, KGHH18-12-BBz CART cells, or KGHH18-15-BBz CART cells was administered upon tumor engraftment. Figure 17B) Tumor volume was monitored via caliper measurement. Figure 17C) CART cell expansion was assessed 17- and 24- days post-CART infusion by flow cytometry staining for human CD3+cells in peripheral blood. Figure 17D) Mouse weight was measured as a readout of wellness. Figure 17E) Kaplan-Meier survival curves. 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 CLDN18.2 polypeptide (e.g., a human CLDN18.2 polypeptide). A binder provided herein can be any appropriate binder including an antigen binding domain having the ability to bind to a CLDN18.2 polypeptide. For example, this document provides antibody domains, antigen binding fragments, antibodies, CARs, cell engagers, and ADCs that bind (e.g., specificallyAttorney Docket No.07039-2318WO1 / 2024-074 bind) to a polypeptide comprising, consisting essentially of, or consisting of the amino acid set forth in any one of SEQ ID NOs: 69-71 (see, e.g., Example 17). In some cases, a binder provided herein can have the ability to bind to a CLDN18.2 polypeptide and can lack the ability to bind to other members of the claudin family (e.g., a CLDN1 polypeptide, a CLDN2 polypeptide, a CLDN3 polypeptide, a CLDN4 polypeptide, a CLDN5 polypeptide, a CLDN6 polypeptide, a CLDN7 polypeptide, a CLDN8 polypeptide, a CLDN9 polypeptide, a CLDN10 polypeptide, a CLDN11 polypeptide, a CLDN12 polypeptide, a CLDN13 polypeptide, a CLDN14 polypeptide, a CLDN15 polypeptide, a CLDN16 polypeptide, a CLDN17 polypeptide, a CLDN18.1 polypeptide, a CLDN19 polypeptide, a CLDN20 polypeptide, a CLDN21 polypeptide, a CLDN22 polypeptide, and a CLDN23 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 have the ability to bind to a human CLDN18.2 polypeptide and can lack the ability to bind to one or more other human CLDN polypeptides (e.g., a human CLDN1 polypeptide, a human CLDN2 polypeptide, a human CLDN3 polypeptide, a human CLDN4 polypeptide, a human CLDN5 polypeptide, a human CLDN6 polypeptide, a human CLDN7 polypeptide, a human CLDN8 polypeptide, a human CLDN9 polypeptide, a human CLDN10 polypeptide, a human CLDN11 polypeptide, a human CLDN12 polypeptide, a human CLDN13 polypeptide, a human CLDN14 polypeptide, a human CLDN15 polypeptide, a human CLDN16 polypeptide, a human CLDN17 polypeptide, a human CLDN18.1 polypeptide, a human CLDN19 polypeptide, a human CLDN20 polypeptide, a human CLDN21 polypeptide, a human CLDN22 polypeptide, and a human CLDN23 polypeptide). 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 63) 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 providedAttorney Docket No.07039-2318WO1 / 2024-074 herein can include the CDRs as described herein (e.g., as described in Table 63) 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 63) 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 63) 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 63) 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 63) and can be configured as a 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), 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 differentantibodies (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 domainscan 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 domainAttorney Docket No.07039-2318WO1 / 2024-074 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). 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 havean 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 6. An antibody provided herein can include the CDRs as described herein (e.g., as described in Table 63) 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 63) 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 63) and can be configured as a scFv antibody. An anti-CLDN18.2 antibody domain, anti-CLDN18.2 antigen binding fragment, or anti-CLDN18.2 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-CLDN18.2 antibody domain) can be a VH domain. In some cases, an antibody domain provided herein (e.g., an anti-CLDN18.2 antibody domain) can be a sdAb (a nanobody). In some cases, an antigen binding fragment provided herein (e.g., an anti-CLDN18.2 antibody fragment) can be a Fab. In some cases, an antibody provided herein (e.g., an anti-CLDN18.2 antibody) can beAttorney Docket No.07039-2318WO1 / 2024-074 a scFv antibody. In some cases, an antibody provided herein (e.g., an anti-CLDN18.2 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 binding 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 CLDN18.2 polypeptide (e.g., a human CLDN18.2 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 CLDN18.2 polypeptide (e.g., a human CLDN18.2 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, or SEQ ID NOs:17-19). For example, an antigen binding domain of a CAR targeting a CLDN18.2 polypeptide can be designed to include a VH 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:25-27 and 33-35 or SEQ ID NOs:41-43 and 49-51). For example, an antigen binding domain of a CAR targeting a CLDN18.2 polypeptide can be designed to include a VH domain described herein or a scFv antibody described herein. In some cases, a CAR provided herein can be designed to have a structure set forth in Example 8. In some cases, a CAR provided herein can be designed to have a structure shown in Figure 1A and / or Figure 8A. 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 peptide that can be used to make a CAR described herein include without limitation,human CD8 -derived signal peptides, human IGKV1-39-derived signal peptides, humanAttorney Docket No.07039-2318WO1 / 2024-074 IGKV1-16-derived signal peptides, human IGKV3-11-derived signal peptides, human IGKV4-1-derived signal peptides, human IGKV6-21-derived signal peptides, and human IGKV1-33-derived signal peptides. 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 9 (e.g., a signal peptide that comprises, consists of, or consisting of the amino acid set forth in SEQ ID NO: 87). 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 9 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 signal peptide that comprises, consists essentially of, or consists of one of the amino acid sequences set forth in Example 9 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. In some cases, a hinge region can be located between an antigen-binding domain and a transmembrane domain of a CAR. In some cases, a hinge region can provide a CAR with increased flexibility for the antigen-binding domain. For example, a hinge region can reduce spatial limitations of an antigen-binding domain of a CAR and its target antigen (e.g., to increase binding between an antigen-binding domain of a CAR and its target antigen). Examples of hinges that can beused to make a CAR described herein include, without limitation, CD8 -derived hinges, IgG-derived hinges, and CD28-derived 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 3 to about 75 (e.g., from about 3 to about 65, from about 3 to about 50, from about 5 to about 75, from about 10 to about 75, from about 5 to about 50, from about 10 to about 50, from about 10 to about 40, or from about 10 to about 30) 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 canAttorney Docket No.07039-2318WO1 / 2024-074 be designed to include a hinge that comprises, consists essentially of, or consists of one of the amino acid sequences set forth in Example 7 or Example 10. 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 7 or Example 10 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 7 or 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 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. A transmembrane domain can be located between an antigen-binding domain and a signaling domain of a CAR and / or located between a hinge and a signaling domain of a CAR. In some cases, a transmembrane domain can provide structural stability for the CAR. For example, a transmembrane domain can include a structure (e.g., a hydrophobic alpha helix structure) that can span a cell membrane and can anchor the CAR to the plasma membrane. Examples of transmembrane domains that can be used to make a CAR describedherein include, without limitation, CD3 transmembrane domains, CD4 transmembranedomains, CD8 transmembrane domains, CD28 transmembrane domains, 4-1BBtransmembrane domains, CD8 (e.g., a CD8 ) transmembrane domains, CD28transmembrane domains, CD16 transmembrane domains, and erythropoietin receptorAttorney Docket No.07039-2318WO1 / 2024-074 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 11. 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 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 transmembrane domain that comprises, consists essentially of, or consists of one of the amino acid sequences set forth in 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 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. 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. In some cases, a signaling domain of a CAR can be an intracellular signaling domain normally found within T cells or NK cells. 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 beused to make a CAR described herein include, without limitation, CD3 intracellularAttorney Docket No.07039-2318WO1 / 2024-074 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 signalingdomains, DAP12 intracellular signaling domains, BB signaling domains, 28 signalingdomains, CD2 signaling domains, Toll-like receptor (TLR) signaling domains (e.g., TLR3 or TLR4 signaling domains), FceRly intracellular signaling domains, CD122 intracellular signaling domains, CD132 intracellular signaling domains, CD70 intracellular signaling domains, cytokine receptor intracellular signaling domains, and CD40 intracellular signaling domains. In some cases, a CAR described herein can be designed to be a first-generationCAR having a CD3 intracellular signaling domain. In some cases, a CAR described hereincan be designed to be a second-generation CAR having a CD28 intracellular signalingdomain followed by a CD3 intracellular signaling domain. In some cases, a CAR describedherein 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 4-1BB intracellular signaling domain followed by (c) aCD3 intracellular signaling domain. In some cases, a CAR provided herein can be designedto 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 12. 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 12 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 domain 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 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, provided that that intracellular signaling domain has at least some activity to activate intracellular signaling.Attorney Docket No.07039-2318WO1 / 2024-074 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 CLDN18.2 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 a hinge such as a hinge / linker set forth in Example 7 or Example 10 (e.g., aCD8 hinge such as a CD8 hinge that comprises, consists of, or consisting of the aminoacid set forth in SEQ ID NO: 94), followed by a transmembrane domain such as atransmembrane domain set forth in Example 11 (e.g., a CD8 transmembrane domain such asa CD8 transmembrane domain that comprises, consists of, or consisting of the amino acidset forth in SEQ ID NO:102), followed by one or more intracellular signaling domains such as one or more intracellular signaling domain set forth in Example 12 (e.g., a human 4-1BBintracellular signaling domain followed by a human CD3 intracellular signaling domain).For example, a CAR targeting a CLDN18.2 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:94, followed by SEQ ID NO:102, followed by SEQ ID NO:110, followed by SEQ ID NO:112. In some cases, a CAR targeting a CLDN18.2 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 a hinge such as a hinge / linker set forth in Example 7 or Example 10(e.g., a CD8 hinge such as a CD8 hinge that comprises, consists of, or consisting of theamino acid set forth in SEQ ID NO:94), followed by a transmembrane domain such as atransmembrane domain set forth in Example 11 (e.g., a CD8 transmembrane domain such asa transmembrane domain set forth in Example 11 (e.g., a CD8 transmembrane domain suchas a CD8 transmembrane domain that comprises, consists of, or consisting of the aminoacid set forth in SEQ ID NO:102), followed by one or more intracellular signaling domains such as one or more intracellular signaling domain set forth in Example 12 (e.g., a human 4-1BB intracellular signaling domain followed by a human CD3 intracellular signalingAttorney Docket No.07039-2318WO1 / 2024-074 domain). For example, a CAR targeting a CLDN18.2 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:94, followed by SEQ ID NO:102, followed by SEQ ID NO:110, followed by SEQ ID NO:112. In some cases, a CAR targeting a CLDN18.2 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 a hinge such as a hinge / linker set forth in Example 7 or Example 10(e.g., a CD8 hinge such as a CD8 hinge that comprises, consists of, or consisting of theamino acid set forth in SEQ ID NO:94), followed by a transmembrane domain such as atransmembrane domain set forth in Example 11 (e.g., a CD8 transmembrane domain such asa transmembrane domain set forth in Example 11 (e.g., a CD8 transmembrane domain suchas a CD8 transmembrane domain that comprises, consists of, or consisting of the aminoacid set forth in SEQ ID NO: 102), followed by one or more intracellular signaling domains such as one or more intracellular signaling domain set forth in Example 12 (e.g., a human 4-1BB intracellular signaling domain followed by a human CD3 intracellular signalingdomain). For example, a CAR targeting a CLDN18.2 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:94, followed by SEQ ID NO:102, followed by SEQ ID NO:110, followed by SEQ ID NO:112. 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 CLDN18.2 polypeptide (e.g., a human CLDN18.2 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 CLDN18.2+cell (e.g., a CLDN18.2+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 13. InAttorney Docket No.07039-2318WO1 / 2024-074 some cases, the anti-CD3 scFv depicted in Figure 13 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 CLDN18.2 polypeptide (e.g., a human CLDN18.2 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 domain having the ability to bind to a CLDN18.2 polypeptide (e.g., a human CLDN18.2 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 CLDN18.2 polypeptide (e.g., a human CLDN18.2 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 CLDN18.2 polypeptide (e.g., a human CLDN18.2 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, or SEQ ID NOs:17-19). In some cases, an antigen binding domain of a cell engager targeting a CLDN18.2 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 CLDN18.2 polypeptide (e.g., a human CLDN18.2 polypeptide) can be used as an antigen binding domain of a cell engager that targets CLDN18.2+cells.Attorney Docket No.07039-2318WO1 / 2024-074 As described herein, a cell engager can be designed to include at least one antigen binding domain having the ability to bind to a CLDN18.2 polypeptide (e.g., a human CLDN18.2 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 CLDN18.2+cell and a T cell, the cell engager can include an antigen binding domain having the ability to bind to a CLDN18.2 polypeptide (e.g., a human CLDN18.2 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 domains 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-CD4 scFv, andi-CD4 VH domains, anti-CD8 scFv, andi-CD8 VH domains, anti-CD16 scFv, andi-CD16 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 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 15. 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 15 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 15 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,Attorney Docket No.07039-2318WO1 / 2024-074 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 CLDN18.2+cell and an NK cell, the cell engager can include an antigen binding domain having the ability to bind to a CLDN18.2 polypeptide (e.g., a human CLDN18.2 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, without 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 thesurface of an NK cell (e.g., CD16, NKG2A, NKG2D, or NKp46) are described in McCall etal. (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 ofAttorney Docket No.07039-2318WO1 / 2024-074 one or more 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 (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 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 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 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 an NK cell. 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 7. 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:83) linker. In some cases, a hinge of a CAR described herein can be used as a linker to make a cell engager describedAttorney Docket No.07039-2318WO1 / 2024-074 herein. For example, any one of the sequences set forth in Example 10 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 7 or Example 10. 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 7 or Example 10 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 7 or 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 cell engager (e.g., a BiTE) targeting a CLDN18.2 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 a hinge such as a hinge / linker set forth in Example 7 or Example 10, 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 CLDN18.2 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 a hinge such as a hinge / linker set forth in Example 7 or Example 10, 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 CLDN18.2 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 a hinge such as a hinge / linker set forth in Example 7 or Example 10, 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 CLDN18.2 polypeptide can be designed to include a heavy chain variable domain comprising SEQ IDAttorney Docket No.07039-2318WO1 / 2024-074 NO:1, SEQ ID NO:2, and SEQ ID NO:3, followed by a linker such as a hinge / linker set forth in Example 7 or Example 10, 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 CLDN18.2 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 a linker such as a hinge / linker set forth in Example 7 or Example 10, 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 CLDN18.2 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 a linker such as a hinge / linker set forth in Example 7 or Example 10, 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 CLDN18.2 polypeptide (e.g., a human CLDN18.2 polypeptide) can include 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). An example of such an antigen binding domain having these CDRs and the ability to bind to a CLDN18.2 polypeptide (e.g., a human CLDN18.2Attorney Docket No.07039-2318WO1 / 2024-074 polypeptide) includes, without limitation, the VH domain set forth in SEQ ID NO:8 (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 CLDN18.2 polypeptide (e.g., a human CLDN18.2 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 in 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 CLDN18.2 polypeptide (e.g., a human CLDN18.2 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 chainAttorney Docket No.07039-2318WO1 / 2024-074 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 CLDN18.2 polypeptide (e.g., a human CLDN18.2 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 CLDN18.2 polypeptide (e.g., a human CLDN18.2 polypeptide) can include a heavy 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). An example of such an antigen binding domain having these CDRs and the ability to bind to a CLDN18.2 polypeptide (e.g., a human CLDN18.2 polypeptide) includes, without limitation, the VH 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 CLDN18.2 polypeptide (e.g., a human CLDN18.2 polypeptide) and a heavy 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:10Attorney Docket No.07039-2318WO1 / 2024-074 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. 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: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 CLDN18.2 polypeptide (e.g., a human CLDN18.2 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:16. 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:16. 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: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 CLDN18.2 polypeptide (e.g., a human CLDN18.2 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:16, provided that the heavy chain variable domain includes the amino acid sequences set forth in SEQ ID NOs:9, 10, and 11. ForAttorney Docket No.07039-2318WO1 / 2024-074 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:16, provided that the heavy chain variable domain includes the amino acid sequences set forth in SEQ ID NOs:9, 10, and 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 CLDN18.2 polypeptide (e.g., a human CLDN18.2 polypeptide) can include 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). An example of such an antigen binding domain having these CDRs and the ability to bind to a CLDN18.2 polypeptide (e.g., a human CLDN18.2 polypeptide) includes, without limitation, the VH domain set forth in SEQ ID NO:24 (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 CLDN18.2 polypeptide (e.g., a human CLDN18.2 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 acid 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,Attorney Docket No.07039-2318WO1 / 2024-074 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 CLDN18.2 polypeptide (e.g., a human CLDN18.2 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:24. 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 CLDN18.2 polypeptide (e.g., a human CLDN18.2 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) having any of the CDRs set forth in Example 3 can be designed to include framework regions as set forth in Example 3 or can be designed to include one or more framework regions from another antibody, antibody fragment, orAttorney Docket No.07039-2318WO1 / 2024-074 antibody domain. For example, a sdAb can be designed to include one set of three CDRs (e.g., CDR1, CDR2, and CDR3) set forth in Example 3 and the framework regions set forth in Example 3. For example, a sdAb can be designed to include one set of three CDRs (e.g., CDR1, CDR2, and CDR3) set forth in Example 3 and the framework regions set forth in Example 3 except that framework region 1 having the amino acid set forth in SEQ ID NO:4 is replaced with a framework region 1 having the amino acid set forth in SEQ ID NO:28 or a framework region 1 having the amino acid set forth in SEQ ID NO:44. 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 CLDN18.2 polypeptide (e.g., a human CLDN18.2 polypeptide) can include 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. 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 acid residues directly following SEQ ID NO:1, provided that the binder maintains its basic ability to bind to a CLDN18.2 polypeptide (e.g., a human CLDN18.2 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. Sequence SEQ ID NO:Attorney Docket No.07039-2318WO1 / 2024-074 VYMGW 882YMGWY 883, 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 CLDN18.2 polypeptide (e.g., a human CLDN18.2 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. Sequence SEQ ID NO:ATIAEGGNTYYADSVK 887As 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 precedingAttorney Docket No.07039-2318WO1 / 2024-074 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 CLDN18.2 polypeptide (e.g., a human CLDN18.2 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. Sequence SEQ ID NO:ADYWYFSDYQ 897In 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 CLDN18.2 polypeptide (e.g., a human CLDN18.2 polypeptide) can include 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: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: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 fiveAttorney Docket No.07039-2318WO1 / 2024-074 amino acid residues directly following SEQ ID NO:9, provided that the binder maintains its basic ability to bind to a CLDN18.2 polypeptide (e.g., a human CLDN18.2 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. Table 4. Exemplary CDR1s that consist essentially of the amino acid sequence set forth in SEQ ID NO:9. Sequence SEQ ID NO:RYDYM 907As 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 CLDN18.2 polypeptide (e.g., a human CLDN18.2 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. Sequence SEQ ID NO:Attorney Docket No.07039-2318WO1 / 2024-074 ATIAYGATTYYADSVK 917VATIAYGATTYYADSV 918, y q 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 residues 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 CLDN18.2 polypeptide (e.g., a human CLDN18.2 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. Sequence SEQ ID NO:Attorney Docket No.07039-2318WO1 / 2024-074 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 CLDN18.2 polypeptide (e.g., a human CLDN18.2 polypeptide) can include 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. 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 basic ability to bind to a CLDN18.2 polypeptide (e.g., a human CLDN18.2 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. Sequence SEQ ID NO:Attorney Docket No.07039-2318WO1 / 2024-074 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 CLDN18.2 polypeptide (e.g., a human CLDN18.2 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. Sequence SEQ ID NO:AAINYGTTTNYADSVK 947As 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 CLDN18.2 polypeptide (e.g., a human CLDN18.2 polypeptide).Attorney Docket No.07039-2318WO1 / 2024-074 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. Sequence SEQ ID NO:VAYRTITGLF 957In some cases, a binder (e.g., a CAR) having the ability to bind to a CLDN18.2 polypeptide (e.g., a human CLDN18.2 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: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, 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: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. In some cases, a binding agent (e.g., a CAR) having the ability to bind to a CLDN18.2 polypeptide (e.g., a human CLDN18.2 polypeptide) can include CDRs that comprise, consist essentially of, or consist of the CDR amino acid sequences set forth in Table 10.Attorney Docket No.07039-2318WO1 / 2024-074 Table 10. Exemplary CDR sequences for a binder that can bind a CLDN18.2 polypeptide. Sequence SEQ ID NOVH domain CDR1 SGYNWH 25. ., d to a CLDN18.2 polypeptide (e.g., a human CLDN18.2 polypeptide) that consists essentially of a CDR amino acid sequence set forth in any one of SEQ ID NOs:25-27 or 33-35 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:25-27 or 33-35), 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:25-27 or 33-35), 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:25-27 or 33-35), provided that the binder retains the ability to bind to a CLDN18.2 polypeptide (e.g., a human CLDN18.2 polypeptide). In some cases, a binder (e.g., a CAR) having the ability to bind to a CLDN18.2 polypeptide (e.g., a human CLDN18.2 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: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, 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: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. In some cases, a binding agent (e.g., a CAR) having the ability to bind to a CLDN18.2 polypeptide (e.g., a humanAttorney Docket No.07039-2318WO1 / 2024-074 CLDN18.2 polypeptide) can include CDRs that comprise, consist essentially of, or consist of the CDR amino acid sequences set forth in Table 11. Table 11. Exemplary CDR sequences for a binder that can bind a CLDN18.2 polypeptide. Sequence SEQ ID NOVH domain CDR1 SYWIN 41a can e nc u e n a n er e.g., a av ng e a y o nd to a CLDN18.2 polypeptide (e.g., a human CLDN18.2 polypeptide) that consists essentially of a CDR amino acid sequence set forth in any one of SEQ ID NOs:41-43 or 49-51 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: 41-43 or 49-51), 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: 41-43 or 49-51), 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: 41-43 or 49-51), provided that the binder retains the ability to bind to a CLDN18.2 polypeptide (e.g., a human CLDN18.2 polypeptide). 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 CLDN18.2 polypeptide (e.g., a human CLDN18.2 polypeptide) can include 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:155, (ii) a CDR2 that comprises, consists essentially of, or consists of the amino acid sequence set forth in SEQ ID NO:156, and (iii) a CDR3 that comprises, consists essentially of, or consists of the amino acid sequence set forth in SEQ ID NO:157. As used herein, a “CDR1 that consists essentially of the amino acid sequence set forth in SEQ ID NO:155” is a CDR1 that has zero, one, or two amino acidAttorney Docket No.07039-2318WO1 / 2024-074 substitutions within SEQ ID NO:155, that has zero, one, two, three, four, or five amino acid residues directly preceding SEQ ID NO:155, and / or that has zero, one, two, three, four, or five amino acid residues directly following SEQ ID NO:155, provided that the binder maintains its basic ability to bind to a CLDN18.2 polypeptide (e.g., a human CLDN18.2 polypeptide). Examples of a CDR1 that consists essentially of the amino acid sequence set forth in SEQ ID NO:155 include, without limitation, those set forth in Table 12. Table 12. Exemplary CDR1s that consist essentially of the amino acid sequence set forth in SEQ ID NO:155. Sequence SEQ ID NO:YANDM 357As used herein, a “CDR2 that consists essentially of the amino acid sequence set forth in SEQ ID NO:156” is a CDR2 that has zero, one, or two amino acid substitutions within SEQ ID NO:156, that has zero, one, two, three, four, or five amino acid residues directly preceding SEQ ID NO:156, and / or that has zero, one, two, three, four, or five amino acid residues directly following SEQ ID NO:156, 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 CLDN18.2 polypeptide (e.g., a human CLDN18.2 polypeptide). Examples of a CDR2 that consists essentially of the amino acid sequence set forth in SEQ ID NO:156 include, without limitation, those set forth in Table 13.Attorney Docket No.07039-2318WO1 / 2024-074 Table 13. Exemplary CDR2s that consist essentially of the amino acid sequence set forth in SEQ ID NO:156. Sequence SEQ ID NO:ARIGFGSNTNYADSVK 367s use ere n, a a cons s s essen a y o e am no ac sequence se forth in SEQ ID NO:157” is a CDR3 that has zero, one, or two amino acid substitutions within SEQ ID NO:157, that has zero, one, two, three, four, or five amino acid residues directly preceding SEQ ID NO:157, and / or that has zero, one, two, three, four, or five amino acid residues directly following SEQ ID NO:157, 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 CLDN18.2 polypeptide (e.g., a human CLDN18.2 polypeptide). Examples of a CDR3 that consists essentially of the amino acid sequence set forth in SEQ ID NO:157 include, without limitation, those set forth in Table 14. Table 14. Exemplary CDR3s that consist essentially of the amino acid sequence set forth in SEQ ID NO:157. Sequence SEQ ID NO:Attorney Docket No.07039-2318WO1 / 2024-074 GPGYALPAHRYWGQ 384PGYALPAHRYWGQG 385an antibody, a CAR, a cell engager, or an ADC) provided herein having the ability to bind to a CLDN18.2 polypeptide (e.g., a human CLDN18.2 polypeptide) can include 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:163, (ii) a CDR2 that comprises, consists essentially of, or consists of the amino acid sequence set forth in SEQ ID NO:164, and (iii) a CDR3 that comprises, consists essentially of, or consists of the amino acid sequence set forth in SEQ ID NO:165. As used herein, a “CDR1 that consists essentially of the amino acid sequence set forth in SEQ ID NO:163” is a CDR1 that has zero, one, or two amino acid substitutions within SEQ ID NO:163, that has zero, one, two, three, four, or five amino acid residues directly preceding SEQ ID NO:163, and / or that has zero, one, two, three, four, or five amino acid residues directly following SEQ ID NO:163, provided that the binder maintains its basic ability to bind to a CLDN18.2 polypeptide (e.g., a human CLDN18.2 polypeptide). Examples of a CDR1 that consists essentially of the amino acid sequence set forth in SEQ ID NO:163 include, without limitation, those set forth in Table 15. Table 15. Exemplary CDR1s that consist essentially of the amino acid sequence set forth in SEQ ID NO:163. Sequence SEQ ID NO:Attorney Docket No.07039-2318WO1 / 2024-074 WYRQA 396Asforth in SEQ ID NO:164” is a CDR2 that has zero, one, or two amino acid substitutions within SEQ ID NO:164, that has zero, one, two, three, four, or five amino acid residues directly preceding SEQ ID NO:164, and / or that has zero, one, two, three, four, or five amino acid residues directly following SEQ ID NO:164, 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 CLDN18.2 polypeptide (e.g., a human CLDN18.2 polypeptide). Examples of a CDR2 that consists essentially of the amino acid sequence set forth in SEQ ID NO:164 include, without limitation, those set forth in Table 16. Table 16. Exemplary CDR2s that consist essentially of the amino acid sequence set forth in SEQ ID NO:164. Sequence SEQ ID NO:AGISPGSNTNYADSVK 397As used herein, a “CDR3 that consists essentially of the amino acid sequence set forth in SEQ ID NO:165” is a CDR3 that has zero, one, or two amino acid substitutions within SEQ ID NO:165, that has zero, one, two, three, four, or five amino acid residues directly preceding SEQ ID NO:165, and / or that has zero, one, two, three, four, or five amino acid residues directly following SEQ ID NO:165, provided that the binder (e.g., the antibody domain, the antigen binding fragment, the antibody, the CAR, the cell engager, or the ADC)Attorney Docket No.07039-2318WO1 / 2024-074 maintains its basic ability to bind to a CLDN18.2 polypeptide (e.g., a human CLDN18.2 polypeptide). Examples of a CDR3 that consists essentially of the amino acid sequence set forth in SEQ ID NO:165 include, without limitation, those set forth in Table 17. Table 17. Exemplary CDR3s that consist essentially of the amino acid sequence set forth in SEQ ID NO:165. Sequence SEQ ID NO:AGDSFYYVRGGRLY 407In 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 CLDN18.2 polypeptide (e.g., a human CLDN18.2 polypeptide) can include 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:171, (ii) a CDR2 that comprises, consists essentially of, or consists of the amino acid sequence set forth in SEQ ID NO:172, and (iii) a CDR3 that comprises, consists essentially of, or consists of the amino acid sequence set forth in SEQ ID NO:173. As used herein, a “CDR1 that consists essentially of the amino acid sequence set forth in SEQ ID NO:171” is a CDR1 that has zero, one, or two amino acid substitutions within SEQ ID NO:171, that has zero, one, two, three, four, or five amino acid residues directly preceding SEQ ID NO:171, and / or that has zero, one, two, three, four, or five amino acid residues directly following SEQ ID NO:171, provided that the binder maintains its basic ability to bind to a CLDN18.2 polypeptide (e.g., a human CLDN18.2Attorney Docket No.07039-2318WO1 / 2024-074 polypeptide). Examples of a CDR1 that consists essentially of the amino acid sequence set forth in SEQ ID NO:171 include, without limitation, those set forth in Table 18. Table 18. Exemplary CDR1s that consist essentially of the amino acid sequence set forth in SEQ ID NO:171. Sequence SEQ ID NO:PAYRM 417As used herein, a CDR2 that consists essentially of the amino acid sequence set forth in SEQ ID NO:172” is a CDR2 that has zero, one, or two amino acid substitutions within SEQ ID NO:172, that has zero, one, two, three, four, or five amino acid residues directly preceding SEQ ID NO:172, and / or that has zero, one, two, three, four, or five amino acid residues directly following SEQ ID NO:172, 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 CLDN18.2 polypeptide (e.g., a human CLDN18.2 polypeptide). Examples of a CDR2 that consists essentially of the amino acid sequence set forth in SEQ ID NO:172 include, without limitation, those set forth in Table 19. Table 19. Exemplary CDR2s that consist essentially of the amino acid sequence set forth in SEQ ID NO:172. Sequence SEQ ID NO:Attorney Docket No.07039-2318WO1 / 2024-074 LVATITFGANTNYADS 429ELVATITFGANTNYAD 430, forth in SEQ ID NO:173” is a CDR3 that has zero, one, or two amino acid substitutions within SEQ ID NO:173, that has zero, one, two, three, four, or five amino acid residues directly preceding SEQ ID NO:173, and / or that has zero, one, two, three, four, or five amino acid residues directly following SEQ ID NO:173, 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 CLDN18.2 polypeptide (e.g., a human CLDN18.2 polypeptide). Examples of a CDR3 that consists essentially of the amino acid sequence set forth in SEQ ID NO:173 include, without limitation, those set forth in Table 20. Table 20. Exemplary CDR3s that consist essentially of the amino acid sequence set forth in SEQ ID NO:173. Sequence SEQ ID NO:Attorney Docket No.07039-2318WO1 / 2024-074 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 CLDN18.2 polypeptide (e.g., a human CLDN18.2 polypeptide) can include 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:179, (ii) a CDR2 that comprises, consists essentially of, or consists of the amino acid sequence set forth in SEQ ID NO:180, and (iii) a CDR3 that comprises, consists essentially of, or consists of the amino acid sequence set forth in SEQ ID NO:181. As used herein, a “CDR1 that consists essentially of the amino acid sequence set forth in SEQ ID NO:179” is a CDR1 that has zero, one, or two amino acid substitutions within SEQ ID NO:179, that has zero, one, two, three, four, or five amino acid residues directly preceding SEQ ID NO:179, and / or that has zero, one, two, three, four, or five amino acid residues directly following SEQ ID NO:179, provided that the binder maintains its basic ability to bind to a CLDN18.2 polypeptide (e.g., a human CLDN18.2 polypeptide). Examples of a CDR1 that consists essentially of the amino acid sequence set forth in SEQ ID NO:179 include, without limitation, those set forth in Table 21. Table 21. Exemplary CDR1s that consist essentially of the amino acid sequence set forth in SEQ ID NO:179. Sequence SEQ ID NO:As used herein, a “CDR2 that consists essentially of the amino acid sequence set forth in SEQ ID NO:180” is a CDR2 that has zero, one, or two amino acid substitutions withinAttorney Docket No.07039-2318WO1 / 2024-074 SEQ ID NO:180, that has zero, one, two, three, four, or five amino acid residues directly preceding SEQ ID NO:180, and / or that has zero, one, two, three, four, or five amino acid residues directly following SEQ ID NO:180, 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 CLDN18.2 polypeptide (e.g., a human CLDN18.2 polypeptide). Examples of a CDR2 that consists essentially of the amino acid sequence set forth in SEQ ID NO:180 include, without limitation, those set forth in Table 22. Table 22. Exemplary CDR2s that consist essentially of the amino acid sequence set forth in SEQ ID NO:180. Sequence SEQ ID NO:AAIDSGTTTNYADSVK 457As used herein, a “CDR3 that consists essentially of the amino acid sequence set forth in SEQ ID NO:181” is a CDR3 that has zero, one, or two amino acid substitutions within SEQ ID NO:181, that has zero, one, two, three, four, or five amino acid residues directly preceding SEQ ID NO:181, and / or that has zero, one, two, three, four, or five amino acid residues directly following SEQ ID NO:181, 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 CLDN18.2 polypeptide (e.g., a human CLDN18.2 polypeptide). Examples of a CDR3 that consists essentially of the amino acid sequence set forth in SEQ ID NO:181 include, without limitation, those set forth in Table 23.Attorney Docket No.07039-2318WO1 / 2024-074 Table 23. Exemplary CDR3s that consist essentially of the amino acid sequence set forth in SEQ ID NO:181. Sequence SEQ ID NO:VGYGPYSYLY 467n some cases, a n er (e.g., an an o y oma n, an an gen n ng ragmen , an antibody, a CAR, a cell engager, or an ADC) provided herein having the ability to bind to a CLDN18.2 polypeptide (e.g., a human CLDN18.2 polypeptide) can include 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:186, (ii) a CDR2 that comprises, consists essentially of, or consists of the amino acid sequence set forth in SEQ ID NO:187, and (iii) a CDR3 that comprises, consists essentially of, or consists of the amino acid sequence set forth in SEQ ID NO:188. As used herein, a “CDR1 that consists essentially of the amino acid sequence set forth in SEQ ID NO:186” is a CDR1 that has zero, one, or two amino acid substitutions within SEQ ID NO:186, that has zero, one, two, three, four, or five amino acid residues directly preceding SEQ ID NO:186, and / or that has zero, one, two, three, four, or five amino acid residues directly following SEQ ID NO:186, provided that the binder maintains its basic ability to bind to a CLDN18.2 polypeptide (e.g., a human CLDN18.2 polypeptide). Examples of a CDR1 that consists essentially of the amino acid sequence set forth in SEQ ID NO:186 include, without limitation, those set forth in Table 24.Attorney Docket No.07039-2318WO1 / 2024-074 Table 24. Exemplary CDR1s that consist essentially of the amino acid sequence set forth in SEQ ID NO:186. Sequence SEQ ID NO:PTRIM 477s use ere n, a a cons s s essen a y o e am no ac sequence se forth in SEQ ID NO:187” is a CDR2 that has zero, one, or two amino acid substitutions within SEQ ID NO:187, that has zero, one, two, three, four, or five amino acid residues directly preceding SEQ ID NO:187, and / or that has zero, one, two, three, four, or five amino acid residues directly following SEQ ID NO:187, 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 CLDN18.2 polypeptide (e.g., a human CLDN18.2 polypeptide). Examples of a CDR2 that consists essentially of the amino acid sequence set forth in SEQ ID NO:187 include, without limitation, those set forth in Table 25. Table 25. Exemplary CDR2s that consist essentially of the amino acid sequence set forth in SEQ ID NO:187. Sequence SEQ ID NO:Attorney Docket No.07039-2318WO1 / 2024-074 LGSTTNYADSVKGRFT 494GSTTNYADSVKGRFTI 495forth in SEQ ID NO:188” is a CDR3 that has zero, one, or two amino acid substitutions within SEQ ID NO:188, that has zero, one, two, three, four, or five amino acid residues directly preceding SEQ ID NO:188, and / or that has zero, one, two, three, four, or five amino acid residues directly following SEQ ID NO:188, 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 CLDN18.2 polypeptide (e.g., a human CLDN18.2 polypeptide). Examples of a CDR3 that consists essentially of the amino acid sequence set forth in SEQ ID NO:188 include, without limitation, those set forth in Table 26. Table 26. Exemplary CDR3s that consist essentially of the amino acid sequence set forth in SEQ ID NO:188. Sequence SEQ ID NO:VRQYSGVVHD 497In 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 CLDN18.2 polypeptide (e.g., a human CLDN18.2 polypeptide) can include 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:194, (ii) a CDR2 that comprises, consistsAttorney Docket No.07039-2318WO1 / 2024-074 essentially of, or consists of the amino acid sequence set forth in SEQ ID NO:195, and (iii) a CDR3 that comprises, consists essentially of, or consists of the amino acid sequence set forth in SEQ ID NO:196. As used herein, a “CDR1 that consists essentially of the amino acid sequence set forth in SEQ ID NO:194” is a CDR1 that has zero, one, or two amino acid substitutions within SEQ ID NO:194, that has zero, one, two, three, four, or five amino acid residues directly preceding SEQ ID NO:194, and / or that has zero, one, two, three, four, or five amino acid residues directly following SEQ ID NO:194, provided that the binder maintains its basic ability to bind to a CLDN18.2 polypeptide (e.g., a human CLDN18.2 polypeptide). Examples of a CDR1 that consists essentially of the amino acid sequence set forth in SEQ ID NO:194 include, without limitation, those set forth in Table 27. Table 27. Exemplary CDR1s that consist essentially of the amino acid sequence set forth in SEQ ID NO:194. Sequence SEQ ID NO:VPKDM 507As used herein, a “CDR2 that consists essentially of the amino acid sequence set forth in SEQ ID NO:195” is a CDR2 that has zero, one, or two amino acid substitutions within SEQ ID NO:195, that has zero, one, two, three, four, or five amino acid residues directly preceding SEQ ID NO:195, and / or that has zero, one, two, three, four, or five amino acid residues directly following SEQ ID NO:195, 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 CLDN18.2 polypeptide (e.g., a human CLDN18.2Attorney Docket No.07039-2318WO1 / 2024-074 polypeptide). Examples of a CDR2 that consists essentially of the amino acid sequence set forth in SEQ ID NO:195 include, without limitation, those set forth in Table 28. Table 28. Exemplary CDR2s that consist essentially of the amino acid sequence set forth in SEQ ID NO:195. Sequence SEQ ID NO:AGITRGSTTYYADSVK 517As used herein, a CDR3 that consists essentially of the amino acid sequence set forth in SEQ ID NO:196” is a CDR3 that has zero, one, or two amino acid substitutions within SEQ ID NO:196, that has zero, one, two, three, four, or five amino acid residues directly preceding SEQ ID NO:196, and / or that has zero, one, two, three, four, or five amino acid residues directly following SEQ ID NO:196, 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 CLDN18.2 polypeptide (e.g., a human CLDN18.2 polypeptide). Examples of a CDR3 that consists essentially of the amino acid sequence set forth in SEQ ID NO:196 include, without limitation, those set forth in Table 29. Table 29. Exemplary CDR3s that consist essentially of the amino acid sequence set forth in SEQ ID NO:196. Sequence SEQ ID NO:Attorney Docket No.07039-2318WO1 / 2024-074 CAAQQHYYAG 529YCAAQQHYYA 530, . ., , , an antibody, a CAR, a cell engager, or an ADC) provided herein having the ability to bind to a CLDN18.2 polypeptide (e.g., a human CLDN18.2 polypeptide) can include 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:202, (ii) a CDR2 that comprises, consists essentially of, or consists of the amino acid sequence set forth in SEQ ID NO:203, and (iii) a CDR3 that comprises, consists essentially of, or consists of the amino acid sequence set forth in SEQ ID NO:204. As used herein, a “CDR1 that consists essentially of the amino acid sequence set forth in SEQ ID NO:202” is a CDR1 that has zero, one, or two amino acid substitutions within SEQ ID NO:202, that has zero, one, two, three, four, or five amino acid residues directly preceding SEQ ID NO:202, and / or that has zero, one, two, three, four, or five amino acid residues directly following SEQ ID NO:202, provided that the binder maintains its basic ability to bind to a CLDN18.2 polypeptide (e.g., a human CLDN18.2 polypeptide). Examples of a CDR1 that consists essentially of the amino acid sequence set forth in SEQ ID NO:202 include, without limitation, those set forth in Table 30. Table 30. Exemplary CDR1s that consist essentially of the amino acid sequence set forth in SEQ ID NO:202. Sequence SEQ ID NO:Attorney Docket No.07039-2318WO1 / 2024-074 GNISL 541RYMGW 542, forth in SEQ ID NO:203” is a CDR2 that has zero, one, or two amino acid substitutions within SEQ ID NO:203, that has zero, one, two, three, four, or five amino acid residues directly preceding SEQ ID NO:203, and / or that has zero, one, two, three, four, or five amino acid residues directly following SEQ ID NO:203, 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 CLDN18.2 polypeptide (e.g., a human CLDN18.2 polypeptide). Examples of a CDR2 that consists essentially of the amino acid sequence set forth in SEQ ID NO:203 include, without limitation, those set forth in Table 31. Table 31. Exemplary CDR2s that consist essentially of the amino acid sequence set forth in SEQ ID NO:203. Sequence SEQ ID NO:ARINN TYYAD VK 47As used herein, a “CDR3 that consists essentially of the amino acid sequence set forth in SEQ ID NO:204” is a CDR3 that has zero, one, or two amino acid substitutions withinAttorney Docket No.07039-2318WO1 / 2024-074 SEQ ID NO:204, that has zero, one, two, three, four, or five amino acid residues directly preceding SEQ ID NO:204, and / or that has zero, one, two, three, four, or five amino acid residues directly following SEQ ID NO:204, 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 CLDN18.2 polypeptide (e.g., a human CLDN18.2 polypeptide). Examples of a CDR3 that consists essentially of the amino acid sequence set forth in SEQ ID NO:204 include, without limitation, those set forth in Table 32. Table 32. Exemplary CDR3s that consist essentially of the amino acid sequence set forth in SEQ ID NO:204. Sequence SEQ ID NO:VLTNAYWSLW 557In 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 CLDN18.2 polypeptide (e.g., a human CLDN18.2 polypeptide) can include 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:210, (ii) a CDR2 that comprises, consists essentially of, or consists of the amino acid sequence set forth in SEQ ID NO:211, and (iii) a CDR3 that comprises, consists essentially of, or consists of the amino acid sequence set forth in SEQ ID NO:212. As used herein, a “CDR1 that consists essentially of the amino acid sequence set forth in SEQ ID NO:210” is a CDR1 that has zero, one, or two amino acid substitutions within SEQ ID NO:210, that has zero, one, two, three, four, or five amino acidAttorney Docket No.07039-2318WO1 / 2024-074 residues directly preceding SEQ ID NO:210, and / or that has zero, one, two, three, four, or five amino acid residues directly following SEQ ID NO:210, provided that the binder maintains its basic ability to bind to a CLDN18.2 polypeptide (e.g., a human CLDN18.2 polypeptide). Examples of a CDR1 that consists essentially of the amino acid sequence set forth in SEQ ID NO:210 include, without limitation, those set forth in Table 33. Table 33. Exemplary CDR1s that consist essentially of the amino acid sequence set forth in SEQ ID NO:210. Sequence SEQ ID NO:SYYGM 567As used herein, a “CDR2 that consists essentially of the amino acid sequence set forth in SEQ ID NO:211” is a CDR2 that has zero, one, or two amino acid substitutions within SEQ ID NO:211, that has zero, one, two, three, four, or five amino acid residues directly preceding SEQ ID NO:211, and / or that has zero, one, two, three, four, or five amino acid residues directly following SEQ ID NO:211, 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 CLDN18.2 polypeptide (e.g., a human CLDN18.2 polypeptide). Examples of a CDR2 that consists essentially of the amino acid sequence set forth in SEQ ID NO:211 include, without limitation, those set forth in Table 34.Attorney Docket No.07039-2318WO1 / 2024-074 Table 34. Exemplary CDR2s that consist essentially of the amino acid sequence set forth in SEQ ID NO:211. Sequence SEQ ID NO:ATITRGGITYYADSVK 577s use ere n, a a cons s s essen a y o e am no ac sequence se forth in SEQ ID NO:212” is a CDR3 that has zero, one, or two amino acid substitutions within SEQ ID NO:212, that has zero, one, two, three, four, or five amino acid residues directly preceding SEQ ID NO:212, and / or that has zero, one, two, three, four, or five amino acid residues directly following SEQ ID NO:212, 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 CLDN18.2 polypeptide (e.g., a human CLDN18.2 polypeptide). Examples of a CDR3 that consists essentially of the amino acid sequence set forth in SEQ ID NO:212 include, without limitation, those set forth in Table 35. Table 35. Exemplary CDR3s that consist essentially of the amino acid sequence set forth in SEQ ID NO:212. Sequence SEQ ID NO:Attorney Docket No.07039-2318WO1 / 2024-074 DYGYHKYWGQ 594YGYHKYWGQG 595an antibody, a CAR, a cell engager, or an ADC) provided herein having the ability to bind to a CLDN18.2 polypeptide (e.g., a human CLDN18.2 polypeptide) can include 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:218, (ii) a CDR2 that comprises, consists essentially of, or consists of the amino acid sequence set forth in SEQ ID NO:219, and (iii) a CDR3 that comprises, consists essentially of, or consists of the amino acid sequence set forth in SEQ ID NO:220. As used herein, a “CDR1 that consists essentially of the amino acid sequence set forth in SEQ ID NO:218” is a CDR1 that has zero, one, or two amino acid substitutions within SEQ ID NO:218, that has zero, one, two, three, four, or five amino acid residues directly preceding SEQ ID NO:218, and / or that has zero, one, two, three, four, or five amino acid residues directly following SEQ ID NO:218, provided that the binder maintains its basic ability to bind to a CLDN18.2 polypeptide (e.g., a human CLDN18.2 polypeptide). Examples of a CDR1 that consists essentially of the amino acid sequence set forth in SEQ ID NO:218 include, without limitation, those set forth in Table 36. Table 36. Exemplary CDR1s that consist essentially of the amino acid sequence set forth in SEQ ID NO:218. Sequence SEQ ID NO:Attorney Docket No.07039-2318WO1 / 2024-074 WYRQA 606Asforth in SEQ ID NO:219” is a CDR2 that has zero, one, or two amino acid substitutions within SEQ ID NO:219, that has zero, one, two, three, four, or five amino acid residues directly preceding SEQ ID NO:219, and / or that has zero, one, two, three, four, or five amino acid residues directly following SEQ ID NO:219, 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 CLDN18.2 polypeptide (e.g., a human CLDN18.2 polypeptide). Examples of a CDR2 that consists essentially of the amino acid sequence set forth in SEQ ID NO:219 include, without limitation, those set forth in Table 37. Table 37. Exemplary CDR2s that consist essentially of the amino acid sequence set forth in SEQ ID NO:219. Sequence SEQ ID NO:ARINYGTTTYYADSVK 607As used herein, a “CDR3 that consists essentially of the amino acid sequence set forth in SEQ ID NO:220” is a CDR3 that has zero, one, or two amino acid substitutions within SEQ ID NO:220, that has zero, one, two, three, four, or five amino acid residues directly preceding SEQ ID NO:220, and / or that has zero, one, two, three, four, or five amino acid residues directly following SEQ ID NO:220, provided that the binder (e.g., the antibody domain, the antigen binding fragment, the antibody, the CAR, the cell engager, or the ADC)Attorney Docket No.07039-2318WO1 / 2024-074 maintains its basic ability to bind to a CLDN18.2 polypeptide (e.g., a human CLDN18.2 polypeptide). Examples of a CDR3 that consists essentially of the amino acid sequence set forth in SEQ ID NO:220 include, without limitation, those set forth in Table 38. Table 38. Exemplary CDR3s that consist essentially of the amino acid sequence set forth in SEQ ID NO:220. Sequence SEQ ID NO:VYSFFAGAHG 617In 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 CLDN18.2 polypeptide (e.g., a human CLDN18.2 polypeptide) can include 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:226, (ii) a CDR2 that comprises, consists essentially of, or consists of the amino acid sequence set forth in SEQ ID NO:227, and (iii) a CDR3 that comprises, consists essentially of, or consists of the amino acid sequence set forth in SEQ ID NO:228. As used herein, a “CDR1 that consists essentially of the amino acid sequence set forth in SEQ ID NO:226” is a CDR1 that has zero, one, or two amino acid substitutions within SEQ ID NO:226, that has zero, one, two, three, four, or five amino acid residues directly preceding SEQ ID NO:226, and / or that has zero, one, two, three, four, or five amino acid residues directly following SEQ ID NO:226, provided that the binder maintains its basic ability to bind to a CLDN18.2 polypeptide (e.g., a human CLDN18.2Attorney Docket No.07039-2318WO1 / 2024-074 polypeptide). Examples of a CDR1 that consists essentially of the amino acid sequence set forth in SEQ ID NO:226 include, without limitation, those set forth in Table 39. Table 39. Exemplary CDR1s that consist essentially of the amino acid sequence set forth in SEQ ID NO:226. Sequence SEQ ID NO:PPYAM 627As used herein, a CDR2 that consists essentially of the amino acid sequence set forth in SEQ ID NO:227” is a CDR2 that has zero, one, or two amino acid substitutions within SEQ ID NO:227, that has zero, one, two, three, four, or five amino acid residues directly preceding SEQ ID NO:227, and / or that has zero, one, two, three, four, or five amino acid residues directly following SEQ ID NO:227, 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 CLDN18.2 polypeptide (e.g., a human CLDN18.2 polypeptide). Examples of a CDR2 that consists essentially of the amino acid sequence set forth in SEQ ID NO:227 include, without limitation, those set forth in Table 40. Table 40. Exemplary CDR2s that consist essentially of the amino acid sequence set forth in SEQ ID NO:227. Sequence SEQ ID NO:Attorney Docket No.07039-2318WO1 / 2024-074 LVAAITYGGITNYADS 639ELVAAITYGGITNYAD 640, forth in SEQ ID NO:228” is a CDR3 that has zero, one, or two amino acid substitutions within SEQ ID NO:228, that has zero, one, two, three, four, or five amino acid residues directly preceding SEQ ID NO:228, and / or that has zero, one, two, three, four, or five amino acid residues directly following SEQ ID NO:228, 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 CLDN18.2 polypeptide (e.g., a human CLDN18.2 polypeptide). Examples of a CDR3 that consists essentially of the amino acid sequence set forth in SEQ ID NO:228 include, without limitation, those set forth in Table 41. Table 41. Exemplary CDR3s that consist essentially of the amino acid sequence set forth in SEQ ID NO:228. Sequence SEQ ID NO:Attorney Docket No.07039-2318WO1 / 2024-074 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 CLDN18.2 polypeptide (e.g., a human CLDN18.2 polypeptide) can include 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:234, (ii) a CDR2 that comprises, consists essentially of, or consists of the amino acid sequence set forth in SEQ ID NO:235, and (iii) a CDR3 that comprises, consists essentially of, or consists of the amino acid sequence set forth in SEQ ID NO:236. As used herein, a “CDR1 that consists essentially of the amino acid sequence set forth in SEQ ID NO:234” is a CDR1 that has zero, one, or two amino acid substitutions within SEQ ID NO:234, that has zero, one, two, three, four, or five amino acid residues directly preceding SEQ ID NO:234, and / or that has zero, one, two, three, four, or five amino acid residues directly following SEQ ID NO:234, provided that the binder maintains its basic ability to bind to a CLDN18.2 polypeptide (e.g., a human CLDN18.2 polypeptide). Examples of a CDR1 that consists essentially of the amino acid sequence set forth in SEQ ID NO:234 include, without limitation, those set forth in Table 42. Table 42. Exemplary CDR1s that consist essentially of the amino acid sequence set forth in SEQ ID NO:234. Sequence SEQ ID NO:As used herein, a “CDR2 that consists essentially of the amino acid sequence set forth in SEQ ID NO:235” is a CDR2 that has zero, one, or two amino acid substitutions withinAttorney Docket No.07039-2318WO1 / 2024-074 SEQ ID NO:235, that has zero, one, two, three, four, or five amino acid residues directly preceding SEQ ID NO:235, and / or that has zero, one, two, three, four, or five amino acid residues directly following SEQ ID NO:235, 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 CLDN18.2 polypeptide (e.g., a human CLDN18.2 polypeptide). Examples of a CDR2 that consists essentially of the amino acid sequence set forth in SEQ ID NO:235 include, without limitation, those set forth in Table 43. Table 43. Exemplary CDR2s that consist essentially of the amino acid sequence set forth in SEQ ID NO:235. Sequence SEQ ID NO:ARISPGSSTNYADSVK 667As used herein, a “CDR3 that consists essentially of the amino acid sequence set forth in SEQ ID NO:236” is a CDR3 that has zero, one, or two amino acid substitutions within SEQ ID NO:236, that has zero, one, two, three, four, or five amino acid residues directly preceding SEQ ID NO:236, and / or that has zero, one, two, three, four, or five amino acid residues directly following SEQ ID NO:236, 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 CLDN18.2 polypeptide (e.g., a human CLDN18.2 polypeptide). Examples of a CDR3 that consists essentially of the amino acid sequence set forth in SEQ ID NO:236 include, without limitation, those set forth in Table 44.Attorney Docket No.07039-2318WO1 / 2024-074 Table 44. Exemplary CDR3s that consist essentially of the amino acid sequence set forth in SEQ ID NO:236. Sequence SEQ ID NO:VRAGWAYDLV 677n some cases, a n er (e.g., an an o y oma n, an an gen n ng ragmen , an antibody, a CAR, a cell engager, or an ADC) provided herein having the ability to bind to a CLDN18.2 polypeptide (e.g., a human CLDN18.2 polypeptide) can include 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:242, (ii) a CDR2 that comprises, consists essentially of, or consists of the amino acid sequence set forth in SEQ ID NO:243, and (iii) a CDR3 that comprises, consists essentially of, or consists of the amino acid sequence set forth in SEQ ID NO:244. As used herein, a “CDR1 that consists essentially of the amino acid sequence set forth in SEQ ID NO:242” is a CDR1 that has zero, one, or two amino acid substitutions within SEQ ID NO:242, that has zero, one, two, three, four, or five amino acid residues directly preceding SEQ ID NO:242, and / or that has zero, one, two, three, four, or five amino acid residues directly following SEQ ID NO:242, provided that the binder maintains its basic ability to bind to a CLDN18.2 polypeptide (e.g., a human CLDN18.2 polypeptide). Examples of a CDR1 that consists essentially of the amino acid sequence set forth in SEQ ID NO:242 include, without limitation, those set forth in Table 45.Attorney Docket No.07039-2318WO1 / 2024-074 Table 45. Exemplary CDR1s that consist essentially of the amino acid sequence set forth in SEQ ID NO:242. Sequence SEQ ID NO:DGHIM 687s use ere n, a a cons s s essen a y o e am no ac sequence se forth in SEQ ID NO:243” is a CDR2 that has zero, one, or two amino acid substitutions within SEQ ID NO:243, that has zero, one, two, three, four, or five amino acid residues directly preceding SEQ ID NO:243, and / or that has zero, one, two, three, four, or five amino acid residues directly following SEQ ID NO:243, 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 CLDN18.2 polypeptide (e.g., a human CLDN18.2 polypeptide). Examples of a CDR2 that consists essentially of the amino acid sequence set forth in SEQ ID NO:243 include, without limitation, those set forth in Table 46. Table 46. Exemplary CDR2s that consist essentially of the amino acid sequence set forth in SEQ ID NO:243. Sequence SEQ ID NO:Attorney Docket No.07039-2318WO1 / 2024-074 PGAITNYADSVKGRFT 704GAITNYADSVKGRFTI 705forth in SEQ ID NO:244” is a CDR3 that has zero, one, or two amino acid substitutions within SEQ ID NO:244, that has zero, one, two, three, four, or five amino acid residues directly preceding SEQ ID NO:244, and / or that has zero, one, two, three, four, or five amino acid residues directly following SEQ ID NO:244, 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 CLDN18.2 polypeptide (e.g., a human CLDN18.2 polypeptide). Examples of a CDR3 that consists essentially of the amino acid sequence set forth in SEQ ID NO:244 include, without limitation, those set forth in Table 47. Table 47. Exemplary CDR3s that consist essentially of the amino acid sequence set forth in SEQ ID NO:244. Sequence SEQ ID NO:VDASVYYGPFVLYR 707In 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 CLDN18.2 polypeptide (e.g., a human CLDN18.2 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:250, (ii) a CDR2 that comprises, consistsAttorney Docket No.07039-2318WO1 / 2024-074 essentially of, or consists of the amino acid sequence set forth in SEQ ID NO:251, and (iii) a CDR3 that comprises, consists essentially of, or consists of the amino acid sequence set forth in SEQ ID NO:252, 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:258, (ii) a CDR2 that comprises, consists essentially of, or consists of the amino acid sequence set forth in SEQ ID NO:259, and (iii) a CDR3 that comprises, consists essentially of, or consists of the amino acid sequence set forth in SEQ ID NO:260. As used herein, a “CDR1 that consists essentially of the amino acid sequence set forth in SEQ ID NO:250” is a CDR1 that has zero, one, or two amino acid substitutions within SEQ ID NO:250, that has zero, one, two, three, four, or five amino acid residues directly preceding SEQ ID NO:250, and / or that has zero, one, two, three, four, or five amino acid residues directly following SEQ ID NO:250, provided that the binder maintains its basic ability to bind to a CLDN18.2 polypeptide (e.g., a human CLDN18.2 polypeptide). Examples of a CDR1 that consists essentially of the amino acid sequence set forth in SEQ ID NO:250 include, without limitation, those set forth in Table 48. Table 48. Exemplary CDR1s that consist essentially of the amino acid sequence set forth in SEQ ID NO:250. Sequence SEQ ID NO:SSYAI 717As used herein, a “CDR2 that consists essentially of the amino acid sequence set forth in SEQ ID NO:251” is a CDR2 that has zero, one, or two amino acid substitutions within SEQ ID NO:251, that has zero, one, two, three, four, or five amino acid residues directlyAttorney Docket No.07039-2318WO1 / 2024-074 preceding SEQ ID NO:251, and / or that has zero, one, two, three, four, or five amino acid residues directly following SEQ ID NO:251, 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 CLDN18.2 polypeptide (e.g., a human CLDN18.2 polypeptide). Examples of a CDR2 that consists essentially of the amino acid sequence set forth in SEQ ID NO:251 include, without limitation, those set forth in Table 49. Table 49. Exemplary CDR2s that consist essentially of the amino acid sequence set forth in SEQ ID NO:251. Sequence SEQ ID NO:GGIIPIFGTANYAQKFQ 727As used herein, a “CDR3 that consists essentially of the amino acid sequence set forth in SEQ ID NO:252” is a CDR3 that has zero, one, or two amino acid substitutions within SEQ ID NO:252, that has zero, one, two, three, four, or five amino acid residues directly preceding SEQ ID NO:252, and / or that has zero, one, two, three, four, or five amino acid residues directly following SEQ ID NO:252, 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 CLDN18.2 polypeptide (e.g., a human CLDN18.2 polypeptide). Examples of a CDR3 that consists essentially of the amino acid sequence set forth in SEQ ID NO:252 include, without limitation, those set forth in Table 50. Table 50. Exemplary CDR3s that consist essentially of the amino acid sequence set forth in SEQ ID NO:252. Sequence SEQ ID NO:Attorney Docket No.07039-2318WO1 / 2024-074 RATADYVLD 737ARATADYVL 738As used herein, a “CDR1 that consists essentially of the amino acid sequence set forth in SEQ ID NO:258” is a CDR1 that has zero, one, or two amino acid substitutions within SEQ ID NO:258, that has zero, one, two, three, four, or five amino acid residues directly preceding SEQ ID NO:258, and / or that has zero, one, two, three, four, or five amino acid residues directly following SEQ ID NO:258, provided that the binder maintains its basic ability to bind to a CLDN18.2 polypeptide (e.g., a human CLDN18.2 polypeptide). Examples of a CDR1 that consists essentially of the amino acid sequence set forth in SEQ ID NO:258 include, without limitation, those set forth in Table 51. Table 51. Exemplary CDR1s that consist essentially of the amino acid sequence set forth in SEQ ID NO:258. Sequence SEQ ID NO:Attorney Docket No.07039-2318WO1 / 2024-074 As used herein, a “CDR2 that consists essentially of the amino acid sequence set forth in SEQ ID NO:259” is a CDR2 that has zero, one, or two amino acid substitutions within SEQ ID NO:259, that has zero, one, two, three, four, or five amino acid residues directly preceding SEQ ID NO:259, and / or that has zero, one, two, three, four, or five amino acid residues directly following SEQ ID NO:259, 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 CLDN18.2 polypeptide (e.g., a human CLDN18.2 polypeptide). Examples of a CDR2 that consists essentially of the amino acid sequence set forth in SEQ ID NO:259 include, without limitation, those set forth in Table 52. Table 52. Exemplary CDR2s that consist essentially of the amino acid sequence set forth in SEQ ID NO:259. Sequence SEQ ID NO:YGASGRA 757As used herein, a “CDR3 that consists essentially of the amino acid sequence set forth in SEQ ID NO:260” is a CDR3 that has zero, one, or two amino acid substitutions within SEQ ID NO:260, that has zero, one, two, three, four, or five amino acid residues directly preceding SEQ ID NO:260, and / or that has zero, one, two, three, four, or five amino acid residues directly following SEQ ID NO:260, 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 CLDN18.2 polypeptide (e.g., a human CLDN18.2 polypeptide). Examples of a CDR3 that consists essentially of the amino acid sequence set forth in SEQ ID NO:260 include, without limitation, those set forth in Table 53Attorney Docket No.07039-2318WO1 / 2024-074 Table 53. Exemplary CDR3s that consist essentially of the amino acid sequence set forth in SEQ ID NO:260. Sequence SEQ ID NO:CQQYGISP 767n some cases, a n er (e.g., an an o y oma n, an an gen n ng ragmen , an antibody, a CAR, a cell engager, or an ADC) provided herein having the ability to bind to a CLDN18.2 polypeptide (e.g., a human CLDN18.2 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:266, (ii) a CDR2 that comprises, consists essentially of, or consists of the amino acid sequence set forth in SEQ ID NO:267, and (iii) a CDR3 that comprises, consists essentially of, or consists of the amino acid sequence set forth in SEQ ID NO:268, 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:258, (ii) a CDR2 that comprises, consists essentially of, or consists of the amino acid sequence set forth in SEQ ID NO:259, and (iii) a CDR3 that comprises, consists essentially of, or consists of the amino acid sequence set forth in SEQ ID NO:260. As used herein, a “CDR1 that consists essentially of the amino acid sequence set forth in SEQ ID NO:266” is a CDR1 that has zero, one, or two amino acid substitutions within SEQ ID NO:266, that has zero, one, two, three, four, or five amino acid residues directly preceding SEQ ID NO:266, and / or that has zero, one, two, three, four, or five amino acid residues directly following SEQ ID NO:266, provided that the binder maintains its basic ability to bind to a CLDN18.2 polypeptide (e.g., a human CLDN18.2 polypeptide). Examples of a CDR1 that consistsAttorney Docket No.07039-2318WO1 / 2024-074 essentially of the amino acid sequence set forth in SEQ ID NO:266include, without limitation, those set forth in Table 54. Table 54. Exemplary CDR1s that consist essentially of the amino acid sequence set forth in SEQ ID NO:266. Sequence SEQ ID NO:TRYYM 777As used herein, a CDR2 that consists essentially of the amino acid sequence set forth in SEQ ID NO:267” is a CDR2 that has zero, one, or two amino acid substitutions within SEQ ID NO:267, that has zero, one, two, three, four, or five amino acid residues directly preceding SEQ ID NO:267, and / or that has zero, one, two, three, four, or five amino acid residues directly following SEQ ID NO:267, 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 CLDN18.2 polypeptide (e.g., a human CLDN18.2 polypeptide). Examples of a CDR2 that consists essentially of the amino acid sequence set forth in SEQ ID NO:267 include, without limitation, those set forth in Table 55. Table 55. Exemplary CDR2s that consist essentially of the amino acid sequence set forth in SEQ ID NO:267. Sequence SEQ ID NO:Attorney Docket No.07039-2318WO1 / 2024-074 TNPTDGSTSYAQKFQGR 792NPTDGSTSYAQKFQGRL 793, forth in SEQ ID NO:268” is a CDR3 that has zero, one, or two amino acid substitutions within SEQ ID NO:268, that has zero, one, two, three, four, or five amino acid residues directly preceding SEQ ID NO:268, and / or that has zero, one, two, three, four, or five amino acid residues directly following SEQ ID NO:268, 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 CLDN18.2 polypeptide (e.g., a human CLDN18.2 polypeptide). Examples of a CDR3 that consists essentially of the amino acid sequence set forth in SEQ ID NO:268 include, without limitation, those set forth in Table 56. Table 56. Exemplary CDR3s that consist essentially of the amino acid sequence set forth in SEQ ID NO:268. Sequence SEQ ID NO:RGTYYFD 797In 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 CLDN18.2 polypeptide (e.g., a human CLDN18.2 polypeptide) can include (a) a heavy chainAttorney Docket No.07039-2318WO1 / 2024-074 variable domain comprising (i) a CDR1 that comprises, consists essentially of, or consists of the amino acid sequence set forth in SEQ ID NO:282, (ii) a CDR2 that comprises, consists essentially of, or consists of the amino acid sequence set forth in SEQ ID NO:283, and (iii) a CDR3 that comprises, consists essentially of, or consists of the amino acid sequence set forth in SEQ ID NO:284, 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:290, (ii) a CDR2 that comprises, consists essentially of, or consists of the amino acid sequence set forth in SEQ ID NO:291, and (iii) a CDR3 that comprises, consists essentially of, or consists of the amino acid sequence set forth in SEQ ID NO:292. As used herein, a “CDR1 that consists essentially of the amino acid sequence set forth in SEQ ID NO:282” is a CDR1 that has zero, one, or two amino acid substitutions within SEQ ID NO:282, that has zero, one, two, three, four, or five amino acid residues directly preceding SEQ ID NO:282, and / or that has zero, one, two, three, four, or five amino acid residues directly following SEQ ID NO:282, provided that the binder maintains its basic ability to bind to a CLDN18.2 polypeptide (e.g., a human CLDN18.2 polypeptide). Examples of a CDR1 that consists essentially of the amino acid sequence set forth in SEQ ID NO:282 include, without limitation, those set forth in Table 57. Table 57. Exemplary CDR1s that consist essentially of the amino acid sequence set forth in SEQ ID NO:282. Sequence SEQ ID NO:Attorney Docket No.07039-2318WO1 / 2024-074 As used herein, a “CDR2 that consists essentially of the amino acid sequence set forth in SEQ ID NO:283” is a CDR2 that has zero, one, or two amino acid substitutions within SEQ ID NO:283, that has zero, one, two, three, four, or five amino acid residues directly preceding SEQ ID NO:283, and / or that has zero, one, two, three, four, or five amino acid residues directly following SEQ ID NO:283, 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 CLDN18.2 polypeptide (e.g., a human CLDN18.2 polypeptide). Examples of a CDR2 that consists essentially of the amino acid sequence set forth in SEQ ID NO:283 include, without limitation, those set forth in Table 58. Table 58. Exemplary CDR2s that consist essentially of the amino acid sequence set forth in SEQ ID NO:283. Sequence SEQ ID NO:GIINPSGGSTSYAQKFQ 817As used herein, a “CDR3 that consists essentially of the amino acid sequence set forth in SEQ ID NO:284” is a CDR3 that has zero, one, or two amino acid substitutions within SEQ ID NO:284, that has zero, one, two, three, four, or five amino acid residues directly preceding SEQ ID NO:284, and / or that has zero, one, two, three, four, or five amino acid residues directly following SEQ ID NO:284, 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 CLDN18.2 polypeptide (e.g., a human CLDN18.2 polypeptide). Examples of a CDR3 that consists essentially of the amino acid sequence set forth in SEQ ID NO:284 include, without limitation, those set forth in Table 59.Attorney Docket No.07039-2318WO1 / 2024-074 Table 59. Exemplary CDR3s that consist essentially of the amino acid sequence set forth in SEQ ID NO:284. Sequence SEQ ID NO:RDLRLAVADTGGYSYYYGMD 827As used herein, a “CDR1 that consists essentially of the amino acid sequence set forth in SEQ ID NO:290” is a CDR1 that has zero, one, or two amino acid substitutions within SEQ ID NO:290, that has zero, one, two, three, four, or five amino acid residues directly preceding SEQ ID NO:290, and / or that has zero, one, two, three, four, or five amino acid residues directly following SEQ ID NO:290, provided that the binder maintains its basic ability to bind to a CLDN18.2 polypeptide (e.g., a human CLDN18.2 polypeptide). Examples of a CDR1 that consists essentially of the amino acid sequence set forth in SEQ ID NO:290 include, without limitation, those set forth in Table 60. Table 60. Exemplary CDR1s that consist essentially of the amino acid sequence set forth in SEQ ID NO:290. Sequence SEQ ID NO:Attorney Docket No.07039-2318WO1 / 2024-074 IGSKSVHWYQQ 845GSKSVHWYQQK 846forth in SEQ ID NO:291” is a CDR2 that has zero, one, or two amino acid substitutions within SEQ ID NO:291, that has zero, one, two, three, four, or five amino acid residues directly preceding SEQ ID NO:291, and / or that has zero, one, two, three, four, or five amino acid residues directly following SEQ ID NO:291, 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 CLDN18.2 polypeptide (e.g., a human CLDN18.2 polypeptide). Examples of a CDR2 that consists essentially of the amino acid sequence set forth in SEQ ID NO:291 include, without limitation, those set forth in Table 61. Table 61. Exemplary CDR2s that consist essentially of the amino acid sequence set forth in SEQ ID NO:291. Sequence SEQ ID NO:YDDSDRP 847As used herein, a “CDR3 that consists essentially of the amino acid sequence set forth in SEQ ID NO:292” is a CDR3 that has zero, one, or two amino acid substitutions within SEQ ID NO:292, that has zero, one, two, three, four, or five amino acid residues directly preceding SEQ ID NO:292, and / or that has zero, one, two, three, four, or five amino acid residues directly following SEQ ID NO:292, provided that the binder (e.g., the antibody domain, the antigen binding fragment, the antibody, the CAR, the cell engager, or the ADC)Attorney Docket No.07039-2318WO1 / 2024-074 maintains its basic ability to bind to a CLDN18.2 polypeptide (e.g., a human CLDN18.2 polypeptide). Examples of a CDR3 that consists essentially of the amino acid sequence set forth in SEQ ID NO:292 include, without limitation, those set forth in Table 62. Table 62. Exemplary CDR3s that consist essentially of the amino acid sequence set forth in SEQ ID NO:292. Sequence SEQ ID NO:CQVWDNSEG 857In 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 CLDN18.2 polypeptide (e.g., a human CLDN18.2 polypeptide) can include (a) a heavy chain variable domain and / or (b) a light chain variable domain as described elsewhere. See, for example, Qi et al., Nat. Med., 28(6):1189-1198 (2022); and Shah et al., Nat. Med.,29(8):2133-2141 (2023). 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 acid 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 aminoAttorney Docket No.07039-2318WO1 / 2024-074 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 acidencoding 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. 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 CLDN18.2 polypeptide (e.g., a human CLDN18.2 polypeptide) are further described in Table 63.Attorney Docket No.07039-2318WO1 / 2024-074 Table 63. Representative binders having the ability to bind to a CLDN18.2 polypeptide. Clone (binde#1 (sd#2 (sd#3 (sd#4 (sc#5 (sc#6 (sd#7 (sd#8 (sd#9 (sd#10 (s#11 (s#12 (s#13 (s#14 (s#15 (s#16 (sd, , , , , -- -- --Attorney Docket No.07039-2318WO1 / 2024-074#17 (s#18 (s#19 (s#20 (sAttorney Docket No.07039-2318WO1 / 2024-074 Table 64 includes an alternative designation that can be used to refer to each of Clones #1 - #5. Table 64. Alternative nomenclature for Clones #1 - #20. Clone # Alternative names1 KGHH18-3The 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 is a sequence listing of nucleic acid sequences encoding 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, orLactobacillus paracasei. A binder provided herein also can be recombinantly produced in eukaryotic hosts such as yeast (e.g., Pichia pastoris, Saccharomyces cerevisiae, HansenulaAttorney Docket No.07039-2318WO1 / 2024-074 polymorpha, Schizosaccharomyces pombe, Schwanniomyces occidentalis, Kluyveromyceslactis, 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, insectcells, 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 humanembryonic kidney cell line HEK293). See, for example, the Frenzel et al. reference (FrontImmunol., 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 CLDN18.2 polypeptide (e.g., a human CLDN18.2 polypeptide). In some cases, a bispecific binder provided herein can be designed to bind to two different epitopes of the same CLDN18.2 polypeptide (e.g., a human CLDN18.2 polypeptide). In some cases, a bispecific binder provided herein can bind to a CLDN18.2 polypeptide (e.g., a human CLDN18.2 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-producingAttorney Docket No.07039-2318WO1 / 2024-074 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 IgGmolecules. 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 polypeptide such as a fragmentcrystallizable region (Fc region) or an Ig secretion signal. For example, a binder providedherein 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 and polyethylene oxides. 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., covalently or non-covalently) to a water-solubleAttorney Docket No.07039-2318WO1 / 2024-074 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 CLDN18.2 polypeptide (e.g., a human CLDN18.2 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 CLDN18.2 polypeptide (e.g., a human CLDN18.2 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 63 can be used to make an ADC having the ability to bind to a CLDN18.2 polypeptide (e.g., a human CLDN18.2 polypeptide). Examples of drugs that can be used to make an ADC described herein include, without limitation, auristatins (e.g., monomethyl auristatin E (MMAE)), mertansine (DM-1), and pyrrolobenzodiazepine (PBD) dimers. 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 CLDN18.2 polypeptide (e.g., a human CLDN18.2 polypeptide) to form an ADC providedAttorney Docket No.07039-2318WO1 / 2024-074 herein. For example, cleavable or non-cleavable ADC linkers can be used to covalently attach one or more drugs to an antigen binding domain having the ability to bind to a CLDN18.2 polypeptide (e.g., a human CLDN18.2 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 CLDN18.2 polypeptide (e.g., a human CLDN18.2 polypeptide) to form an ADC provided herein include, without limitation, ADC disulfide linkers, ADC hydrazone linkers, ADC peptide linkers, ADC thioether linkers, and ADC PEG-containing 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. 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), VSV-based vectors, and hybrid or chimeric viral vectors. For example, a viral vector having an adenoviral backbone with lentiviral components suchAttorney Docket No.07039-2318WO1 / 2024-074as those described elsewhere (Zheng et al., Nat. Biotech., 18(2): 176-80 (2000); WO98 / 22143; WO 98 / 46778; and WO 00 / 17376) or viral vectors having an adenoviral backbonewith AAV components such as those described elsewhere (Fisher et 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 describedelsewhere (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 inAttorney Docket No.07039-2318WO1 / 2024-074 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., 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 cellsthat 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), Bacillussubtilis, 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 humancells). 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 acidprovided herein into a host cell (see, e.g., Sambrook et al., Molecular Biology: A LaboratoryManual, Cold Spring Harbor Laboratory, NY (1989); Davis et al., Basic Methods inMolecular 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 CLDN18.2 polypeptide).Attorney Docket No.07039-2318WO1 / 2024-074 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 CLDN18.2 polypeptide). 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 CLDN18.2 polypeptide can be dual-specific cells (e.g., can bind to two different polypeptides with at least one being a CLDN18.2 polypeptide (e.g., a human CLDN18.2 polypeptide)). For example, a dual-specific cell provided herein can include a first CAR having the ability to bind to a CLDN18.2 polypeptide and can include a second CAR having the ability to bind to a polypeptide other than a CLDN18.2 polypeptide. In some cases, cells designed to express a CAR having the ability to bind to a CLDN18.2 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 CLDN18.2+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 CLDN18.2 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 CLDN18.2 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 CLDN18.2-specific CARs (e.g., such that the CAR+T cell can bind to a CLDN18.2 polypeptide) and can express one or more binders (e.g., CARs) specific for a polypeptide other than a CLDN18.2 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 CLDN18.2-specific CARsAttorney Docket No.07039-2318WO1 / 2024-074 include, without limitation, fibroblast activation protein (FAP) polypeptides (e.g., FAP-alpha (FAP ) polypeptides).In some cases, a binder (e.g., a CAR) having the ability to bind to a FAP polypeptide (e.g., a human FAP 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: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, consists essentially of, or consists of the amino acid sequence set forth in SEQ ID NO:59, 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:60, (ii) a CDR2 that comprises, consists essentially of, or consists of the amino acid sequence set forth in SEQ ID NO:61, and (iii) a CDR3 that comprises, consists essentially of, or consists of the amino acid sequence set forth in SEQ ID NO:62. In some cases, a binding agent (e.g., a CAR) having the ability to bind to a FAP polypeptide (e.g., a human FAP polypeptide) can include CDRs that comprise, consist essentially of, or consist of the CDR amino acid sequences set forth in Table 65. Table 65. Exemplary CDR sequences for a binder that can bind a FAP polypeptide. Sequence SEQ ID NOVH i DR1 NN IN 7A CDR that can be included in a binder (e.g., a CAR) having the ability to bind to a FAP polypeptide (e.g., a human FAP polypeptide) that consists essentially of a CDR amino acid sequence set forth in any one of SEQ ID NOs:57-62 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:57-62), has zero, one, two, three, four, or five amino acid residuesAttorney Docket No.07039-2318WO1 / 2024-074 preceding the articulated sequence of the sequence identifier (e.g., any one of SEQ ID NOs:57-62), 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:57-62), provided that the binder retains the ability to bind to a FAP polypeptide (e.g., a human FAP polypeptide). In some cases, a binder (e.g., a CAR) having the ability to bind to a FAP polypeptide (e.g., a human FAP 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:63, (ii) a CDR2 that comprises, consists essentially of, or consists of the amino acid sequence set forth in SEQ ID NO:64, and (iii) a CDR3 that comprises, consists essentially of, or consists of the amino acid sequence set forth in SEQ ID NO:65, 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:66, (ii) a CDR2 that comprises, consists essentially of, or consists of the amino acid sequence set forth in SEQ ID NO:67, and (iii) a CDR3 that comprises, consists essentially of, or consists of the amino acid sequence set forth in SEQ ID NO:68. In some cases, a binding agent (e.g., a CAR) having the ability to bind to a FAP polypeptide (e.g., a human FAP polypeptide) can include CDRs that comprise, consist essentially of, or consist of the CDR amino acid sequences set forth in Table 66. Table 66. Exemplary CDR sequences for a binder that can bind a FAP polypeptide. Sequence SEQ ID NOAttorney Docket No.07039-2318WO1 / 2024-074 A CDR that can be included in a binder (e.g., a CAR) having the ability to bind to a FAP polypeptide (e.g., a human FAP polypeptide) that consists essentially of a CDR amino acid sequence set forth in any one of SEQ ID NOs:63-68 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:63-68), 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:63-68), 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:63-68), provided that the binder retains the ability to bind to a FAP polypeptide (e.g., a human FAP polypeptide). When a CAR+T cell is a dual specific CAR+T cell having the ability to bind to a CLDN18.2 polypeptide also having the ability to bind to a polypeptide other than a CLDN18.2 polypeptide (e.g., a FAP polypeptide), the CAR specific for a polypeptide other than the CLDN18.2 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 CLDN18.2 polypeptide (e.g., a FAP 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 CLDN18.2 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 CLDN18.2-specific CARs, can express a CAR specific for a polypeptide other than the CLDN18.2 polypeptide (e.g., a FAP polypeptide), and can express one or more response elements such that the CAR specific for a polypeptide other than the CLDN18.2 polypeptide is only expressed in the cell when the CLDN18.2-specific CAR(s) intracellular signaling domain(s) are activated (e.g., by binding to a CLDN18.2 polypeptide). Examples of systems that can be used to induce a CAR specific for a polypeptide other than the CLDN18.2 polypeptide (e.g., a FAP polypeptide) upon activation of aAttorney Docket No.07039-2318WO1 / 2024-074 CLDN18.2-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 antigen 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 CLDN18.2 polypeptide (e.g., a human CLDN18.2 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, orcombinations thereof as, for example, described elsewhere (Gervasi, et al., Eur. J.Pharmaceutics and Biopharmaceutics, 131:8-24 (2018)). Examples of pharmaceuticallyAttorney Docket No.07039-2318WO1 / 2024-074 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 liquid 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, fromAttorney Docket No.07039-2318WO1 / 2024-074 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 to bind to a CLDN18.2 polypeptide provided herein can be formulated as a dosage form with from about 50,000 anti-CLDN18.2 CAR+cells (e.g., per kg body weight of the mammal to be treated) to about 50,000,000 anti-CLDN18.2 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 aboutAttorney Docket No.07039-2318WO1 / 2024-074 500,000 to about 1,000,000, or from about 750,000 to about 25,000,000 anti-CLDN18.2 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, 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, fromAttorney Docket No.07039-2318WO1 / 2024-074 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 can 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 beAttorney Docket No.07039-2318WO1 / 2024-074 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., colorectal cancer) 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 CLDN18.2+cancer) to reduce or eliminate one or more symptoms of the cancer. Examples of symptoms of a cancer (e.g., colorectal cancer) that can be reduced using a composition comprising one or more binders described herein include, without limitation, a change in bowel habits (e.g., more frequent diarrhea or constipation), rectal bleeding, ongoing discomfort in the belly area (e.g., cramps, gas, and / or pain), and losing weight without trying. 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,Attorney Docket No.07039-2318WO1 / 2024-074 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 CLDN18.2+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 CLDN18.2+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., 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 oneAttorney Docket No.07039-2318WO1 / 2024-074 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 include one or more solid tumors. 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, colorectal cancers, colon cancers, gastric cancers, gastrointestinal cancers, and pancreatic cancers. In some cases, a mammal (e.g., a human) having a CLDN18.2+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 or 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 CLDN18.2 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 ofAttorney Docket No.07039-2318WO1 / 2024-074 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. 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 ofAttorney Docket No.07039-2318WO1 / 2024-074 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 composition 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 treatedAttorney Docket No.07039-2318WO1 / 2024-074 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 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 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 chemotherapeuticAttorney Docket No.07039-2318WO1 / 2024-074 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., a 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, 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 pharmaceuticalAttorney Docket No.07039-2318WO1 / 2024-074 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, and / or surgeries. In cases where one or more binders provided herein (or a nucleic acid, vector, or host cell (e.g., CAR+cells) provided herein) 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). For example, one or more binders provided herein (or a nucleic acid, vector, or host cell (e.g., CAR+cells) provided herein) 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 thepresence or absence of a CLDN18.2 polypeptide (e.g., a human CLDN18.2 polypeptide) invitro, in situ, or in vivo (e.g., in vivo imaging within a mammal such as a human). Forexample, 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 CLDN18.2 polypeptide (e.g., a humanCLDN18.2 polypeptide) within a biological sample in vitro. Examples of biological samplesthat 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 CLDN18.2 polypeptide (e.g., a human CLDN18.2 polypeptide). In some cases, a binder provided herein can be immobilized, e.g., on a support, and retention of a CLDN18.2 polypeptide (e.g., a human CLDN18.2 polypeptide) from a biological sample on the supportAttorney Docket No.07039-2318WO1 / 2024-074 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). 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 CLDN18.2 polypeptide (e.g., a human CLDN18.2 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, acell engager, or an ADC) provided herein include, without limitation, radiolabels such as 131I,111In, 123I, 99mTc, 32P, 33P, 125I, 3H, 14C, and 188Rh, fluorescent labels such as fluorescein andrhodamine, 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 CLDN18.2+Cancer This Example describes the design and characterization of molecules that can bind to a CLDN18.2 polypeptide.Attorney Docket No.07039-2318WO1 / 2024-074 Materials and methods Development of CLDN18.2-specific CART cells A Claudin 18.2-specific single chain variable fragment (scFv) was cloned into a CARconstruct containing 41BB and CD3 signaling domains in a third-generation lentiviralbackbone (Figure 1). 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 CLDN18.2 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 for scFv containing CARs and rabbit anti-humanized VHH Antibody for VH only containing CARs. CART cell cytotoxicity assay Colorectal cancer cells or fibroblasts expressing luciferase and claudin18.1 or claudin18.2 were co-cultured with untransduced T cells or CART cells at different effector:target (E:T) ratios, and CART-mediated cytotoxicity was assessed by luciferase luminescence at 24, 48, and 72 hours. CART cell proliferation assay CART cell proliferation was assessed by coculturing CART cells with media, PMA / Ionomycin, WT colorectal cancer cells, or colorectal cancer cells expressing claudin18.1 or claudin18.2 at a 1:1 ratio (100K:100K cells). Cells were cultured for a total of 5 days, with media feeding on day 3, followed by flow cytometry-based count of CD3+ T cells.Attorney Docket No.07039-2318WO1 / 2024-074 Results Development of colorectal cancer cells stably expressing a CLDN18.2 polypeptide or a CLDN18.1 polypeptide To confirm CLDN18.2 expression in various gastric and colon cancer samples, a panel of patient-derived tumor xenografts (PDTX) and biopsies from colon cancer patients was assessed. Figure 2 shows that colon cancer tumor tissues express Caludin18.2. CLDN18.2 expression was also evaluated in colorectal cancer cell lines LS411N and SNU-C2B were transduced with lentivirus encoding Claudin18.1-HA or Claudin18.2-HA cDNA. Expression of transduced genes was validated by (A)immunoblotting of the HA tag (Figure 3A). Claudin18.2 expression was confirmed by flow cytometry using Anti- Claudin18.2-PE (Figure 3B). hu8e5-BBz and GC-182-BBz CART cells were generated, and CAR expression was validated by flow cytometry (Figure 4A). CART cells and Luc+WT, Luc+18.1-HA, or Luc+18.2-HA LS411N cells (10,000 cells) were cocultured at different E:T ratios and CART- mediated cytotoxicity was assessed by luciferase luminescence at 24, 48, and 72 hours (Figure 4B). CART cells and Luc+WT, Luc+18.1-HA, or Luc+18.2-HA SNU-C2B cells (10,000 cells) were cocultured at different E:T ratios and CART-mediated cytotoxicity was assessed by luciferase luminescence at 24, 48, and 72 hours (Figure 4C). CART cells were generated by lentiviral transduction of hu8e5-BBz or GC-182-BBz and FAP-CAR. Dual targeting CART cells were transduced with hu8e5-BBz or GC-182-BBz and FAP-CAR. CAR expression was validated by flow cytometry (Figure 5). CART cells were incubated with soluble Claudin18.2-VLP-GFP, to detect Claudin18.2 targeting CARs, and FAP-Fc (followed by goat anti-human Fc-APC), to detect FAP CAR. Single and dual targeting CART cells were cocultured at different E:T ratios with WT SNU-C2B Luc+, Claudin18.1-HA SNU-C2B Luc+, or Claudin18.1-HA SNU-C2B Luc+ colorectal cancer cells (10,000 cells). CART-mediated cytotoxicity was assessed by luciferase luminescence at 24, 48, and 72 hours (Figure 6). Single and dual-targeting CART cell proliferation was assessed by coculturing CART cells with media, PMA / Ionomycin, SNU-C2B WT, SNU-C2B Claudin18.1, SNU-C2BAttorney Docket No.07039-2318WO1 / 2024-074 Claudin18.2, WI-38, or mixed SNU-C2B Claudin18.2-WI-38 cells at a 1:1 ratio (5K:5K cells). Cells were cultured for a total of 5 days, with media feeding on day 3, followed by flow cytometry-based count of CD3+ T cells. Results are shown in Figure 7. VH sequences of novel Claudin18.2 antibodies, identified by phage display, wereused as the variable region to generate chimeric-antigen receptors containing a CD8 hinge,CD28 transmembrane domain, 41BB intracellular signal domain, and CD3 intracellularsignal domain. Schematics of exemplary constructs are shown in Figure 8. CART Cells generated using VHH sequences described herein and CAR expression was validated by flow cytometry using rabbit-anti-humanized-VHH-APC (Figure 9A). VHH- based CART cells KGHH18-3-BBz, CAR, KGHH18-5-BBz CAR, and KGHH18-7-BBz CAR effectively killed SNU-C2B Claudin18.2+ colorectal cancer cells, with higher specificity, whereas the rest of the CART cells had higher cytotoxic effects towards WT and Claudin18.1 SNU-C2B colorectal cancer cells (Figure 9B). VHH-based CART cells KGHH18-3-BBz, CAR, KGHH18-5-BBz CAR, and KGHH18-7-BBz CAR effectively killed SNU-C2B Claudin18.2+ colorectal cancer cells (Figure 10). Nanobody-based CART cell proliferation was assessed by coculturing CART cells with media, PMA / Ionomycin, SNU-C2B WT, SNU-C2B Claudin18.1, or SNU-C2B Claudin18.2 colorectal cancer cells at a 1:1 ratio (100K:100K cells). Cells were cultured for a total of 5 days, with media feeding on day 3, followed by flow cytometry-based count of CD3+ T cells. Results are shown in Figure 11. A side by side comparison of scFv and VHH based CART cell cytotoxicity against Luc+SNU-C2B WT, Luc+SNU-C2B Claudin18.1, or Luc+SNU-C2B Claudin18.2 colorectal cancer cells is shown in Figure 12. Example 2: CLDN18.2-Specific CART cells Having Anti-tumor Activity KGHH-BBz CART cells were generated via lentivirus transduction. CAR expression was validated by flow cytometry using rabbit-anti-humanized-VHH-APC and goat-anti- mouse, respectively (Figure 14A). CART cells and Luc+WT, Luc+18.1-HA, or Luc+18.2- HA SNU-C2B cells (10,000 cells) were cocultured at different E:T ratios and CART-Attorney Docket No.07039-2318WO1 / 2024-074 mediated cytotoxicity was assessed by luciferase luminescence after 48 hours and after 72 hours (Figure 14B). KGHH-BBz, hu8e5-BBz, and GC-182-BBz CART cells were generated by lentiviral transduction. CAR expression was validated by flow cytometry using rabbit-anti-humanized-VHH-APC and goat-anti-mouse, respectively (Figure 15A). To assess CART cell efficacy invivo, NSG mice were subcutaneously implanted with 2x106 Luc+ WT, Luc+ 18.1-HA, or Luc+18.2-HA SNU-C2B cells. Tumor burden was monitored using serial caliper measurements (Figure 15B). Upon tumor engraftment, mice were intravenously administered 5x106Claudin18.2-CART cells or 5 x 106untransduced (UTD) control T cells. Peripheral blood samples were collected at multiple timepoints to assess CART cell expansion and persistence by looking for human CD3+cells (Figure 15C). Weight changes were monitored as an indicator of overall health status (Figure 15D). Probability of mouse survival was calculated (Figure 15E). KGHH18-5-BBz and Hu8e5-BBz CART cells were generated by lentiviral transduction. CAR expression was validated by flow cytometry using rabbit-anti-humanized-VHH-APC and goat-anti-mouse respectively (Figure 16A). To assess CART cell efficacy invivo, NSG mice were subcutaneously implanted with 1x106 Luc+ 18.2-HA SNU-C2B cells.Tumor burden was monitored using serial caliper measurements (Figure 16B). At 140 days post-infusion of KGHH18-5-BBz CART cells, long-term surviving mice were rechallenged subcutaneously with 1x106Claudin18.2-expressing SNU-C2B colorectal cancer cells. A separate cohort of naïve mice receiving untransduced T cells served as a control. Tumor growth was monitored over time using caliper measurements (Figure 16C). Body weight was recorded at regular intervals as an indicator of overall health and treatment- associated toxicity (Figure 16D). Survival was analyzed using Kaplan–Meier survival curves (Figure 16E). Peripheral blood samples were collected at defined timepoints following CART cell infusion to evaluate CART cell persistence. Flow cytometry was performed to quantify circulating human CD3+T cells (Figure 16F). To evaluate the therapeutic efficacy of nanobody-based CART cells, 1x106Claudin18.2-expressing SNU-C2B colorectal cancer cells were implanted subcutaneously into NSG mice. Tumors were allowed to establish prior to intravenous administration ofAttorney Docket No.07039-2318WO1 / 2024-074 5x106CART cells. Mice were randomized into four treatment groups receiving either untransduced T cells (control) or CART cells expressing KGHH18-5-BBz, KGHH18-12- BBz, or KGHH18-15-BBz constructs. CAR expression was confirmed prior to infusion by flow cytometry using rabbit-anti-humanized-VHH-APC, which specifically detects the nanobody-based CARs (Figure 17A). Tumor growth was monitored by caliper measurements (Figure 17B). Peripheral blood was collected on Day 17 and Day 24 post-CART cell infusionto assess in vivo expansion and persistence of human T cells. Flow cytometry was performedto quantify the amount of human CD3+T cells in circulation (Figure 17C). Mouse body weight was recorded throughout the study as a surrogate for treatment-associated toxicity and general wellness (Figure 17D). Survival was assessed over time and plotted using Kaplan– Meier survival analysis (Figure 17E). Example 3: Exemplary CLDN18.2-Binding Molecules This Example provides the amino acid sequences of exemplary binders (e.g., sdAbs (also referred to as nanobodies) and scFvs) having the ability to bind a CLDN18.2 polypeptide. The CDRs and framework sequences of each also are provided and delineated. Anti-#1 (also referred to as KGHH18-3) VH domain: QVQLQESGGGLVQAGGSLRLSCAASGYISKYVYMGWYRQAPGKERELVATIAE GGNTYYADSVKGRFTISRDNAKNTVYLQMNSLEPEDTAVYYCAADYWYFSDY QYWGQGTQVTVSS (SEQ ID NO:8) Framework Region 1 of VH domain: QVQLQESGGGLVQAGGSLRLSCAASGYISK (SEQ ID NO:4) CDR1 of VH domain: YVYMG (SEQ ID NO:1) Framework Region 2 of VH domain: WYRQAPGKERELVA (SEQ ID NO:5)Attorney Docket No.07039-2318WO1 / 2024-074 CDR2 of VH domain: TIAEGGNTYYADSVKG (SEQ ID NO:2) Framework Region 3 of VH domain: RFTISRDNAKNTVYLQMNSLEPEDTAVYYCAA (SEQ ID NO:6) CDR3 of VH domain: DYWYFSDYQY (SEQ ID NO:3) Framework Region 4 of VH domain: WGQGTQVTVSS (SEQ ID NO:7) Anti-CLDN18.2 clone #2 (also referred to as KGHH18-5) VH domain: QVQLQESGGGLVQAGGSLRLSCAASGNISRYDYMGWYRQAPGKEREFVATIAYQVQLQESGGGLVQAGGSLRLSCAASGNISR (SEQ ID NO:12) CDR1 of VH domain: YDYMG (SEQ ID NO:9) Framework Region 2 of VH domain: WYRQAPGKEREFVA (SEQ ID NO:13) CDR2 of VH domain: TIAYGATTYYADSVKG (SEQ ID NO:10) Framework Region 3 of VH domain: RFTISRDNAKNTVYLQMNSLKPEDTAVYYCAA (SEQ ID NO:14)Attorney Docket No.07039-2318WO1 / 2024-074 CDR3 of VH domain: RWPGYYSHIY (SEQ ID NO:11) Framework Region 4 of VH domain: WGQGTQVTVSS (SEQ ID NO:15) Anti-CLDN18.2 clone #3 (also referred to as KGHH18-7) VH domain: QVQLQESGGGLVQAGGSLRLSCAASGNISGWPDMGWYRQAPGKEREFVAAINY GTTTNYADSVKGRFTISRDNAKNTVYLQMNSLKPEDTAVYYCAVAYRTITGLFY WGQGTQVTVSS (SEQ ID NO:24) Framework Region 1 of VH domain: QVQLQESGGGLVQAGGSLRLSCAASGNISG (SEQ ID NO:20) CDR1 of VH domain: WPDMG (SEQ ID NO:17) Framework Region 2 of VH domain: WYRQAPGKEREFVA (SEQ ID NO:21) CDR2 of VH domain: AINYGTTTNYADSVKG (SEQ ID NO:18) Framework Region 3 of VH domain: RFTISRDNAKNTVYLQMNSLKPEDTAVYYCAV (SEQ ID NO:22) CDR3 of VH domain: AYRTITGLFY (SEQ ID NO:19) Framework Region 4 of VH domain: WGQGTQVTVSS (SEQ ID NO:23)Attorney Docket No.07039-2318WO1 / 2024-074 Anti-CLDN18.2 clone #4 (also referred to as hu8e5) VH domain VH domain: QVQLQESGPGLVKPSQTLSLTCTVSGGSISSGYNWHWIRQPPGKGLEWIGYIHYT GSTNYNPALRSRVTISVDTSKNQFSLKLSSVTAADTAVYYCARIYNGNSFPYWG QGTTVTV (SEQ ID NO:32) Framework Region 1 of VH domain: QVQLQESGPGLVKPSQTLSLTCTVSGGSIS (SEQ ID NO:28) CDR1 of VH domain: SGYNWH (SEQ ID NO:25) Framework Region 2 of VH domain: WIRQPPGKGLEWIG (SEQ ID NO:29) CDR2 of VH domain: YIHYTGSTNYNPALRS (SEQ ID NO:26) Framework Region 3 of VH domain: RVTISVDTSKNQFSLKLSSVTAADTAVYYCAR (SEQ ID NO:30) CDR3 of VH domain: IYNGNSFPY (SEQ ID NO:27) Framework Region 4 of VH domain: WGQGTTVTV (SEQ ID NO:31) Anti-CLDN18.2 clone #4 (also referred to as hu8e5) VL domain VL domain: DIVMTQSPDSLAVSLGERATINCKSSQSLFNSGNQKNYLTWYQQKPGQPPKLLIYAttorney Docket No.07039-2318WO1 / 2024-074 Framework Region 1 of VL domain: DIVMTQSPDSLAVSLGERATINC (SEQ ID NO:36) CDR1 of VL domain: KSSQSLFNSGNQKNYLT (SEQ ID NO:33) Framework Region 2 of VL domain: WYQQKPGQPPKLLIY (SEQ ID NO:37) CDR2 of VL domain: WASTRES (SEQ ID NO:34) Framework Region 3 of VL domain: GVPDRFSGSGSGTDFTLTISSLQAEDVAVYYC (SEQ ID NO:38) CDR3 of VL domain: QNAYSFPYT (SEQ ID NO:35) Framework Region 4 of VL domain: FGGGTKLEIK (SEQ ID NO:39) Anti-CLDN18.2 clone #5 (also referred to as GC-182) VH domain VH domain: QVQLQQPGAELVRPGASVKLSCKASGYTFTSYWINWVKQRPGQGLEWIGNIYPS DSYTNYNQKFKDKATLTVDKSSSTAYMQLSSPTSEDSAVYYCTRSWRGNSFDY WGQGTTLTVSS (SEQ ID NO:48) Framework Region 1 of VH domain: QVQLQQPGAELVRPGASVKLSCKASGYTFT (SEQ ID NO:44) CDR1 of VH domain: SYWIN (SEQ ID NO:41)Attorney Docket No.07039-2318WO1 / 2024-074 Framework Region 2 of VH domain: WVKQRPGQGLEWIG (SEQ ID NO:45) CDR2 of VH domain: NIYPSDSYTNYNQKFKD (SEQ ID NO:42) Framework Region 3 of VH domain: KATLTVDKSSSTAYMQLSSPTSEDSAVYYCTR (SEQ ID NO:46) CDR3 of VH domain: SWRGNSFDY (SEQ ID NO:43) Framework Region 4 of VH domain: WGQGTTLTVSS (SEQ ID NO:47) Anti-CLDN18.2 clone #5 (also referred to as GC-182) VL domain VL domain: DIVMTQSPSSLTVTAGEKVTMSCKSSQSLLNSGNQKNYLTWYQQKPGQPPKLLIDIVMTQSPSSLTVTAGEKVTMSC (SEQ ID NO:52) CDR1 of VL domain: KSSQSLLNSGNQKNYLT (SEQ ID NO:49) Framework Region 2 of VL domain: WYQQKPGQPPKLLIY (SEQ ID NO:53) CDR2 of VL domain: WASTRES (SEQ ID NO:50)Attorney Docket No.07039-2318WO1 / 2024-074 Framework Region 3 of VL domain: GVPDRFTGSGSGTDFTLTISSVQAEDLAVYYC (SEQ ID NO:54) CDR3 of VL domain: QNDYSYPFT (SEQ ID NO:51) Framework Region 4 of VL domain: FGSGTKLEIK (SEQ ID NO:55) Anti-CLDN18.2 clone #6 (also referred to as KGHH18-1) VH domain: QVQLQESGGGLVQAGGSLRLSCAASGYIFYANDMGWYRQAPGKERELVARIGFQVQLQESGGGLVQAGGSLRLSCAASGYIFY (SEQ ID NO:158) CDR1 of VH domain: ANDMG (SEQ ID NO:155) Framework Region 2 of VH domain: WYRQAPGKERELVA (SEQ ID NO:159) CDR2 of VH domain: RIGFGSNTNYADSVKG (SEQ ID NO:156) Framework Region 3 of VH domain: RFTISRDNAKNTVYLQMNSLKPEDTAVYYCAA (SEQ ID NO:160) CDR3 of VH domain: TDYGPGYALPAHRY (SEQ ID NO:157)Attorney Docket No.07039-2318WO1 / 2024-074 Framework Region 4 of VH domain: WGQGTQVTVSS (SEQ ID NO:161) Anti-CLDN18.2 clone #7 (also referred to as KGHH18-2) VH domain: QVQLQESGGGLVQAGGSLRLSCAASGTISGRFVMGWYRQAPGKEREFVAGISPGQVQLQESGGGLVQAGGSLRLSCAASGTISG (SEQ ID NO:166) CDR1 of VH domain: RFVMG (SEQ ID NO:163) Framework Region 2 of VH domain: WYRQAPGKEREFVA (SEQ ID NO:167) CDR2 of VH domain: GISPGSNTNYADSVKG (SEQ ID NO:164) Framework Region 3 of VH domain: RFTISRDNAKNTVYLQMNSLKPEDTAVYYCAA (SEQ ID NO:168) CDR3 of VH domain: GDSFYYVRGGRLYY (SEQ ID NO:165) Framework Region 4 of VH domain: WGQGTQVTVSS (SEQ ID NO:169)Attorney Docket No.07039-2318WO1 / 2024-074 Anti-CLDN18.2 clone #8 (also referred to as KGHH18-4) VH domain: QVQLQESGGGLVQAGGSLRLSCAASGNIFPAYRMGWYRQAPGKERELVATITFQVQLQESGGGLVQAGGSLRLSCAASGNIFP (SEQ ID NO:174) CDR1 of VH domain: AYRMG (SEQ ID NO:171) Framework Region 2 of VH domain: WYRQAPGKERELVA (SEQ ID NO:175) CDR2 of VH domain: TITFGANTNYADSVKG (SEQ ID NO:172) Framework Region 3 of VH domain: RFTISRDNAKNTVYLQMNSLKPEDTAVYYCAV (SEQ ID NO:176) CDR3 of VH domain: STYYTYTLDY (SEQ ID NO:173) Framework Region 4 of VH domain: WGQGTQVTVSS (SEQ ID NO:177) Anti-CLDN18.2 clone #9 (also referred to as KGHH18-6) VH domain: QVQLQESGGGLVQAGGSLRLSCAASGYISSFYYMGWYRQAPGKEREFVAAIDSAttorney Docket No.07039-2318WO1 / 2024-074 Framework Region 1 of VH domain: QVQLQESGGGLVQAGGSLRLSCAASGYISS (SEQ ID NO:182) CDR1 of VH domain: FYYMG (SEQ ID NO:179) Framework Region 2 of VH domain: WYRQAPGKEREFVA (SEQ ID NO:183) CDR2 of VH domain: AIDSGTTTNYADSVKG (SEQ ID NO:180) Framework Region 3 of VH domain: RFTISRDNAKNTVYLQMNSLKPEDTAVYYCAV (SEQ ID NO:184) CDR3 of VH domain: GYGPYSYLYY (SEQ ID NO:181) Framework Region 4 of VH domain: WGQGTQVTVSS (SEQ ID NO:185) Anti-CLDN18.2 clone #10 (also referred to as KGHH18-8) VH domain: QVQLQESGGGLVQAGGSLRLSCAASGNIFPTRIMGWYRQAPGKEREFVARINLG STTNYADSVKGRFTISRDNAKNTVYLQMNSLKPEDTAVYYCAVRQYSGVVHDY WGQGTQVTVSS (SEQ ID NO:193) Framework Region 1 of VH domain: QVQLQESGGGLVQAGGSLRLSCAASGNIFP (SEQ ID NO:189) CDR1 of VH domain: TRIMG (SEQ ID NO:186)Attorney Docket No.07039-2318WO1 / 2024-074 Framework Region 2 of VH domain: WYRQAPGKEREFVA (SEQ ID NO:190) CDR2 of VH domain: RINLGSTTNYADSVKG (SEQ ID NO:187) Framework Region 3 of VH domain: RFTISRDNAKNTVYLQMNSLKPEDTAVYYCAV (SEQ ID NO:191) CDR3 of VH domain: RQYSGVVHDY (SEQ ID NO:188) Framework Region 4 of VH domain: WGQGTQVTVSS (SEQ ID NO:192) Anti-CLDN18.2 clone #11 (also referred to as KGHH18-9) VH domain: QVQLQESGGGLVQAGGSLRLSCAASGNIFVPKDMGWYRQAPGKERELVAGITRQVQLQESGGGLVQAGGSLRLSCAASGNIFV (SEQ ID NO:197) CDR1 of VH domain: PKDMG (SEQ ID NO:194) Framework Region 2 of VH domain: WYRQAPGKERELVA (SEQ ID NO:198) CDR2 of VH domain: GITRGSTTYYADSVKG (SEQ ID NO:195)Attorney Docket No.07039-2318WO1 / 2024-074 Framework Region 3 of VH domain: RFTISRDNAKNTVYLQMNSLKPEDTAVYYCAA (SEQ ID NO:199) CDR3 of VH domain: QQHYYAGHYY (SEQ ID NO:196) Framework Region 4 of VH domain: WGQGTQVTVSS (SEQ ID NO:200) Anti-CLDN18.2 clone #12 (also referred to as KGHH18-10) VH domain: QVQLQESGGGLVQAGGSLRLSCAASGNISLYRYMGWYRQAPGKEREFVARINNQVQLQESGGGLVQAGGSLRLSCAASGNISL (SEQ ID NO:205) CDR1 of VH domain: YRYMG (SEQ ID NO:202) Framework Region 2 of VH domain: WYRQAPGKEREFVA (SEQ ID NO:206) CDR2 of VH domain: RINNGGSTYYADSVKG (SEQ ID NO:203) Framework Region 3 of VH domain: RFTISRDNAKNTVYLQMNSLKPEDTAVYYCAV (SEQ ID NO:207) CDR3 of VH domain: LTNAYWSLWY (SEQ ID NO:204)Attorney Docket No.07039-2318WO1 / 2024-074 Framework Region 4 of VH domain: WGQGTQVTVSS (SEQ ID NO:208) Anti-CLDN18.2 clone #13 (also referred to as KGHH18-11) VH domain: QVQLQESGGGLVQAGGSLRLSCAASGTISSYYGMGWYRQAPGKEREFVATITRQVQLQESGGGLVQAGGSLRLSCAASGTISS (SEQ ID NO:213) CDR1 of VH domain: YYGMG (SEQ ID NO:210) Framework Region 2 of VH domain: WYRQAPGKEREFVA (SEQ ID NO:214) CDR2 of VH domain: TITRGGITYYADSVKG (SEQ ID NO:211) Framework Region 3 of VH domain: RFTISRDNAKNTVYLQMNSLKPEDTAVYYCAA (SEQ ID NO:215) CDR3 of VH domain: KPTDYGYHKY (SEQ ID NO:212) Framework Region 4 of VH domain: WGQGTQVTVSS (SEQ ID NO:216)Attorney Docket No.07039-2318WO1 / 2024-074 Anti-CLDN18.2 clone #14 (also referred to as KGHH18-12) VH domain: QVQLQESGGGLVQAGGSLRLSCAASGYISPYIQMGWYRQAPGKEREFVARINYQVQLQESGGGLVQAGGSLRLSCAASGYISP (SEQ ID NO:221) CDR1 of VH domain: YIQMG (SEQ ID NO:218) Framework Region 2 of VH domain: WYRQAPGKEREFVA (SEQ ID NO:222) CDR2 of VH domain: RINYGTTTYYADSVKG (SEQ ID NO:219) Framework Region 3 of VH domain: RFTISRDNAKNTVYLQMNSLKPEDTAVYYCAV (SEQ ID NO:223) CDR3 of VH domain: YSFFAGAHGY (SEQ ID NO:220) Framework Region 4 of VH domain: WGQGTQVTVSS (SEQ ID NO:224) Anti-CLDN18.2 clone #15 (also referred to as KGHH18-13) VH domain: QVQLQESGGGLVQAGGSLRLSCAASGSISPPYAMGWYRQAPGKERELVAAITY GGITNYADSVKGRFTISRDNAKNTVYLQMNSLKPEDTAVYYCAAARLYDYYYG DTFPYWGQGTQVTVSS (SEQ ID NO:233)Attorney Docket No.07039-2318WO1 / 2024-074 Framework Region 1 of VH domain: QVQLQESGGGLVQAGGSLRLSCAASGSISP (SEQ ID NO:229) CDR1 of VH domain: PYAMG (SEQ ID NO:226) Framework Region 2 of VH domain: WYRQAPGKERELVA (SEQ ID NO:230) CDR2 of VH domain: AITYGGITNYADSVKG (SEQ ID NO:227) Framework Region 3 of VH domain: RFTISRDNAKNTVYLQMNSLKPEDTAVYYCAA (SEQ ID NO:231) CDR3 of VH domain: ARLYDYYYGDTFPY (SEQ ID NO:228) Framework Region 4 of VH domain: WGQGTQVTVSS (SEQ ID NO:232) Anti-CLDN18.2 clone #16 (also referred to as KGHH18-14) VH domain: QVQLQESGGGLVQAGGSLRLSCAASGSIFLNGPMGWYRQAPGKEREFVARISPGQVQLQESGGGLVQAGGSLRLSCAASGSIFL (SEQ ID NO:237) CDR1 of VH domain: NGPMG (SEQ ID NO:234)Attorney Docket No.07039-2318WO1 / 2024-074 Framework Region 2 of VH domain: WYRQAPGKEREFVA (SEQ ID NO:238) CDR2 of VH domain: RISPGSSTNYADSVKG (SEQ ID NO:235) Framework Region 3 of VH domain: RFTISRDNAKNTVYLQMNSLKPEDTAVYYCAV (SEQ ID NO:239) CDR3 of VH domain: RAGWAYDLVY (SEQ ID NO:236) Framework Region 4 of VH domain: WGQGTQVTVSS (SEQ ID NO:240) Anti-CLDN18.2 clone #17 (also referred to as KGHH18-15) VH domain: QVQLQESGGGLVQAGGSLRLSCAASGNIFDGHIMGWYRQAPGKEREFVARIDPQVQLQESGGGLVQAGGSLRLSCAASGNIFD (SEQ ID NO:245) CDR1 of VH domain: GHIMG (SEQ ID NO:242) Framework Region 2 of VH domain: WYRQAPGKEREFVA (SEQ ID NO:246) CDR2 of VH domain: RIDPGAITNYADSVKG (SEQ ID NO:243)Attorney Docket No.07039-2318WO1 / 2024-074 Framework Region 3 of VH domain: RFTISRDNAKNTVYLQMNSLKPEDTAVYYCAV (SEQ ID NO:247) CDR3 of VH domain: DASVYYGPFVLYRY (SEQ ID NO:244) Framework Region 4 of VH domain: WGQGTQVTVSS (SEQ ID NO:248) Anti-CLDN18.2 clone #18 (also referred to as KGSV18-1) VH domain VH domain: ESKASQVQLVQSGAEVKKPGSSVKVSCKASGGTFSSYAISWVRQAPGQGLEWM GGIIPIFGTANYAQKFQGRVTITADESTSTAYMELSSLRSEDTAVYYCARATADYESKASQVQLVQSGAEVKKPGSSVKVSCKASGGTFS (SEQ ID NO:253) CDR1 of VH domain: SYAIS (SEQ ID NO:250) Framework Region 2 of VH domain: WVRQAPGQGLEWMG (SEQ ID NO:254) CDR2 of VH domain: GIIPIFGTANYAQKFQG (SEQ ID NO:251) Framework Region 3 of VH domain: RVTITADESTSTAYMELSSLRSEDTAVYYCAR (SEQ ID NO:255) CDR3 of VH domain: ATADYVLDY (SEQ ID NO:252)Attorney Docket No.07039-2318WO1 / 2024-074 Framework Region 4 of VH domain: WGQGTLVTVSS (SEQ ID NO:256) Anti-CLDN18.2 clone #18 (also referred to as KGSV18-1) VL domain VL domain: EIVLTQSPGILSLSPGERATLSCRASQRLSISYLAWYQQRPGQAPRLLIYGASGRA TGIPARFSGSGSGTDFTLTISRLEPEDFAVYYCQQYGISPTFGQGTKVKIKEGK (SEQ ID NO:265) Framework Region 1 of VL domain: EIVLTQSPGILSLSPGERATLSC (SEQ ID NO:261) CDR1 of VL domain: RASQRLSISYLA (SEQ ID NO:258) Framework Region 2 of VL domain: WYQQRPGQAPRLLIY (SEQ ID NO:262) CDR2 of VL domain: GASGRAT (SEQ ID NO:259) Framework Region 3 of VL domain: GIPARFSGSGSGTDFTLTISRLEPEDFAVYYC (SEQ ID NO:263) CDR3 of VL domain: QQYGISPT (SEQ ID NO:260) Framework Region 4 of VL domain: FGQGTKVKIKEGK (SEQ ID NO:264)Attorney Docket No.07039-2318WO1 / 2024-074 Anti-CLDN18.2 clone #19 (also referred to as KGSV18-2) VH domain VH domain: ESKASQVQLVQSGAEVKKPGASVKVSCKASGYPFTRYYMHWVRQAPGQGLEW MAMTNPTDGSTSYAQKFQGRLTVTRDTSTSTLYMELSSLRSADTAVYYCARGT YYFDSWGQGTLVTVSS (SEQ ID NO:273) Framework Region 1 of VH domain: ESKASQVQLVQSGAEVKKPGASVKVSCKASGYPFT (SEQ ID NO:269) CDR1 of VH domain: RYYMH (SEQ ID NO:266) Framework Region 2 of VH domain: WVRQAPGQGLEWMA (SEQ ID NO:270) CDR2 of VH domain: MTNPTDGSTSYAQKFQG (SEQ ID NO:267) Framework Region 3 of VH domain: RLTVTRDTSTSTLYMELSSLRSADTAVYYCAR (SEQ ID NO:271) CDR3 of VH domain: GTYYFDS (SEQ ID NO:268) Framework Region 4 of VH domain: WGQGTLVTVSS (SEQ ID NO:272) Anti-CLDN18.2 clone #19 (also referred to as KGSV18-2) VL domain VL domain: EIVLTQSPGILSLSPGERATLSCRASQRLSISYLAWYQQRPGQAPRLLIYGASGRAAttorney Docket No.07039-2318WO1 / 2024-074 Framework Region 1 of VL domain: EIVLTQSPGILSLSPGERATLSC (SEQ ID NO:261) CDR1 of VL domain: RASQRLSISYLA (SEQ ID NO:258) Framework Region 2 of VL domain: WYQQRPGQAPRLLIY (SEQ ID NO:262) CDR2 of VL domain: GASGRAT (SEQ ID NO:259) Framework Region 3 of VL domain: GIPARFSGSGSGTDFTLTISRLEPEDFAVYYC (SEQ ID NO:263) CDR3 of VL domain: QQYGISPT (SEQ ID NO:260) Framework Region 4 of VL domain: FGQGTKVKIKEGK (SEQ ID NO:264) Anti-CLDN18.2 clone #20 (also referred to as KGSV18-3) VH domain VH domain: ESKASEVQLVQSGAEVKKPGASVKVSCKASGYTFTSYYMHWVRQAPGQGLEW MGIINPSGGSTSYAQKFQGRVTMTRDTSTSTVYMELSSLRSEDTAVYYCARDLR LAVADTGGYSYYYGMDVWGQGTLVTVSS (SEQ ID NO:289) Framework Region 1 of VH domain: ESKASEVQLVQSGAEVKKPGASVKVSCKASGYTFT (SEQ ID NO:285) CDR1 of VH domain: SYYMH (SEQ ID NO:282)Attorney Docket No.07039-2318WO1 / 2024-074 Framework Region 2 of VH domain: WVRQAPGQGLEWMG (SEQ ID NO:286) CDR2 of VH domain: IINPSGGSTSYAQKFQG (SEQ ID NO:283) Framework Region 3 of VH domain: RVTMTRDTSTSTVYMELSSLRSEDTAVYYCAR (SEQ ID NO:287) CDR3 of VH domain: DLRLAVADTGGYSYYYGMDV (SEQ ID NO:284) Framework Region 4 of VH domain: WGQGTLVTVSS (SEQ ID NO:288) Anti-CLDN18.2 clone #20 (also referred to as KGSV18-3) VL domain VL domain: QSVLTQPPSVSVAPGQTAKITCGGTNIGSKSVHWYQQKPGQAPVLVVYDDSDRP SGIPERFSGFVSGNTATLTIRRVEAGDEADYYCQVWDNSEGVFGGGTKLTVLGE GK (SEQ ID NO:297) Framework Region 1 of VL domain: QSVLTQPPSVSVAPGQTAKITC (SEQ ID NO:293) CDR1 of VL domain: GGTNIGSKSVH (SEQ ID NO:290) Framework Region 2 of VL domain: WYQQKPGQAPVLVVY (SEQ ID NO:294) CDR2 of VL domain: DDSDRPS (SEQ ID NO:291)Attorney Docket No.07039-2318WO1 / 2024-074 Framework Region 3 of VL domain: GIPERFSGFVSGNTATLTIRRVEAGDEADYYC (SEQ ID NO:295) CDR3 of VL domain: QVWDNSEGV (SEQ ID NO:292) Framework Region 4 of VL domain: FGGGTKLTVLGEGK (SEQ ID NO:297) Example 4: Nucleic Acids Encoding Exemplary CLDN18.2-Binding Molecules This Example provides the nucleic acid sequences encoding anti-CLDN18.2 clone #1, anti-CLDN18.2 clone #2, anti-CLDN18.2 clone #3, anti-CLDN18.2 hu8e5 VH domain, anti- CLDN18.2 hu8e5 VL domain, anti-CLDN18.2 GC-182 VH domain, and anti-CLDN18.2 GC-182 VL domain. Nucleic acid sequence encoding anti-CLDN18.2 clone #1 (KGHH18-3) CAGGTTCAATTGCAGGAGTCTGGCGGTGGACTCGTGCAAGCCGGGGGATCTCTT AGACTCTCCTGTGCAGCCTCTGGGTACATTTCCAAATATGTGTATATGGGGTGGT ATCGGCAGGCACCTGGGAAGGAAAGAGAGTTGGTCGCAACAATAGCAGAAGGG GGCAACACCTACTACGCTGATAGCGTTAAGGGGAGGTTTACTATCAGTAGGGAC AATGCAAAAAATACAGTTTATCTCCAGATGAATAGCCTTGAGCCAGAAGATACA GCAGTTTACTATTGTGCTGCCGACTACTGGTATTTTAGCGATTATCAATATTGGG GGCAGGGTACACAAGTTACAGTTAGCAGC (SEQ ID NO:72) Nucleic acid sequence encoding anti-CLDN18.2 clone #2 (KGHH18-5) CAGGTCCAACTTCAGGAATCTGGAGGAGGGCTTGTGCAGGCAGGAGGAAGTTTG CGACTCTCATGCGCTGCCTCTGGAAATATCTCACGCTATGACTACATGGGTTGGT ATCGACAAGCGCCCGGAAAGGAGAGGGAGTTCGTCGCAACAATTGCCTACGGCG CTACTACCTACTACGCGGATTCCGTTAAAGGCCGGTTTACCATATCCCGGGATAA TGCGAAGAACACAGTATATCTCCAGATGAACTCCCTGAAGCCCGAAGATACCGCAttorney Docket No.07039-2318WO1 / 2024-074 CGTCTACTATTGCGCGGCACGGTGGCCGGGCTATTATTCTCATATTTACTGGGGC CAGGGAACACAAGTGACTGTCAGTAGC (SEQ ID NO:73) Nucleic acid sequence encoding anti-CLDN18.2 clone #3 (KGHH18-7) CAGGTGCAGCTCCAGGAGTCCGGGGGAGGTCTTGTGCAGGCGGGCGGAAGTCTT CGCCTCTCTTGCGCTGCAAGCGGCAATATCTCAGGTTGGCCCGATATGGGTTGGT ATCGCCAGGCCCCTGGTAAAGAGCGGGAATTCGTCGCTGCAATCAACTACGGCA CTACTACGAATTACGCTGATTCCGTGAAAGGACGATTCACCATCAGTCGGGACA ATGCAAAAAATACCGTGTACCTGCAAATGAATAGCTTGAAGCCAGAAGACACCG CTGTATATTATTGCGCCGTTGCTTACCGCACAATTACCGGACTTTTCTACTGGGGC CAAGGGACGCAAGTAACTGTCTCTAGC (SEQ ID NO:74) Nucleic acid sequence encoding an anti-CLDN18.2 hu8e5 VH domain CAGGTGCAACTGCAAGAGAGTGGGCCTGGCCTCGTGAAGCCGAGTCAAACTCTG TCTCTGACTTGCACTGTCAGTGGGGGTTCAATAAGCTCAGGTTACAATTGGCATT GGATTCGACAGCCCCCTGGAAAGGGATTGGAGTGGATCGGATACATACACTATA CAGGATCTACTAACTACAACCCCGCGCTCCGGTCACGAGTCACTATCAGCGTGG ACACCAGCAAGAATCAATTCTCCTTGAAATTGTCTTCTGTAACGGCGGCTGATAC AGCCGTCTATTATTGTGCAAGAATATATAATGGTAACAGCTTCCCTTATTGGGGA CAGGGGACGACAGTAACTGTC (SEQ ID NO:75) Nucleic acid sequence encoding an anti-CLDN18.2 hu8e5 VL domain GATATAGTCATGACTCAATCTCCCGACAGCCTTGCTGTCTCCCTCGGTGAAAGAG CAACAATCAACTGCAAATCTAGTCAATCTCTCTTTAATAGTGGCAACCAGAAGA ATTACCTGACTTGGTACCAACAGAAGCCGGGGCAGCCCCCCAAGCTGTTGATAT ACTGGGCATCTACCCGCGAGAGCGGTGTTCCAGATAGGTTTAGCGGAAGTGGCA GCGGTACAGACTTTACTCTTACTATCAGCTCTCTGCAGGCTGAGGACGTAGCCGT CTACTACTGCCAAAACGCTTACAGTTTCCCATATACCTTTGGAGGTGGCACGAAA CTCGAGATCAAA (SEQ ID NO:76)Attorney Docket No.07039-2318WO1 / 2024-074 Nucleic acid sequence encoding an anti-CLDN18.2 GC-182 VH domain CAGGTTCAACTCCAGCAGCCAGGCGCCGAGCTGGTGAGGCCAGGCGCGTCCGTG AAACTGAGCTGCAAGGCAAGTGGCTACACGTTCACTTCCTACTGGATCAACTGG GTGAAGCAAAGACCTGGCCAAGGACTCGAGTGGATAGGGAATATCTATCCAAGT GATAGCTATACAAATTATAACCAAAAATTTAAGGACAAGGCCACCCTTACGGTG GACAAAAGTAGTTCTACTGCCTACATGCAACTCAGTTCCCCTACTTCAGAGGACT CAGCAGTCTACTACTGCACTCGGTCCTGGAGAGGCAACTCATTTGACTATTGGGG CCAAGGGACGACACTGACCGTCTCTAGT (SEQ ID NO:77) Nucleic acid sequence encoding an anti-CLDN18.2 GC-182 VL domain GATATTGTTATGACTCAAAGCCCGTCATCACTTACGGTTACCGCCGGTGAAAAAG TTACAATGTCATGTAAGTCATCTCAATCTCTCCTGAATTCCGGAAATCAAAAAAA CTACCTTACGTGGTATCAACAAAAACCCGGACAACCACCTAAACTCCTTATATAT TGGGCGTCTACTAGGGAGTCAGGAGTCCCCGATAGGTTCACTGGATCCGGAAGC GGTACAGACTTTACTCTCACTATCTCAAGTGTGCAGGCCGAGGATCTTGCAGTAT ATTATTGTCAAAACGATTATAGTTACCCATTCACATTCGGCTCCGGAACGAAACT CGAGATCAAA (SEQ ID NO:78) Nucleic acid sequence encoding anti-CLDN18.2 clone #6 (KGHH18-1) CAGGTGCAACTGCAAGAATCTGGTGGTGGCCTCGTGCAGGCCGGTGGTTCTTTGA GACTTAGCTGCGCGGCGTCTGGTTATATCTTCTACGCAAATGATATGGGATGGTA TAGACAAGCACCCGGTAAGGAAAGAGAACTGGTTGCTAGAATCGGATTCGGTTC AAACACAAATTATGCGGACTCCGTTAAAGGACGGTTCACGATATCTCGGGACAA TGCAAAAAACACCGTATATCTTCAAATGAATTCCTTGAAGCCTGAGGATACCGCC GTATATTATTGTGCGGCCACCGATTATGGACCCGGTTATGCACTTCCTGCGCATC GCTACTGGGGTCAAGGCACCCAGGTCACCGTGAGTAGC (SEQ ID NO:298) Nucleic acid sequence encoding anti-CLDN18.2 clone #7 (KGHH18-2) CAGGTCCAACTGCAGGAATCTGGGGGAGGTCTGGTTCAAGCCGGGGGTAGTCTG CGATTGTCCTGCGCTGCAAGCGGGACTATTAGCGGTCGGTTCGTCATGGGCTGGT ACCGGCAAGCGCCCGGTAAAGAGCGCGAGTTCGTTGCCGGAATATCACCCGGCAAttorney Docket No.07039-2318WO1 / 2024-074 GTAACACCAACTATGCAGATAGCGTTAAGGGACGCTTCACTATCTCACGGGATA ATGCCAAGAACACCGTGTATCTTCAGATGAACTCACTTAAACCTGAGGACACTG CGGTCTATTATTGTGCCGCCGGGGATAGCTTTTACTATGTCCGAGGAGGCCGACT TTACTACTGGGGACAAGGCACGCAAGTAACAGTTTCCAGC (SEQ ID NO:299) Nucleic acid sequence encoding anti-CLDN18.2 clone #8 (KGHH18-4) CAGGTACAGTTGCAAGAAAGCGGTGGAGGGCTCGTCCAAGCAGGTGGTAGTCTG AGGTTGTCATGCGCAGCATCCGGTAACATTTTTCCGGCTTACCGGATGGGTTGGT ACAGGCAAGCTCCAGGAAAAGAGCGGGAACTCGTCGCGACTATAACATTCGGTG CCAATACCAATTACGCGGATTCTGTCAAGGGAAGGTTTACAATAAGTCGCGATA ACGCGAAAAACACCGTGTACCTCCAGATGAATAGTCTTAAACCGGAAGACACAG CAGTTTATTATTGTGCCGTATCCACCTACTACACCTATACGCTTGACTACTGGGG CCAAGGAACGCAGGTGACAGTTTCAAGC (SEQ ID NO:300) Nucleic acid sequence encoding anti-CLDN18.2 clone #9 (KGHH18-6) CAGGTTCAACTTCAGGAAAGTGGCGGAGGACTCGTTCAGGCAGGTGGTTCTCTG CGACTTTCTTGTGCTGCCAGCGGATATATATCTAGTTTCTATTACATGGGATGGT ACAGACAGGCCCCAGGAAAGGAGAGGGAGTTTGTGGCAGCTATCGATTCTGGGA CAACAACAAATTATGCGGATAGCGTTAAGGGCCGCTTCACAATCTCACGGGACA ATGCAAAGAACACTGTGTATCTTCAGATGAACAGCCTTAAACCCGAAGACACGG CAGTTTACTACTGCGCAGTAGGGTACGGGCCGTATAGTTATCTTTATTATTGGGG GCAGGGTACACAGGTAACTGTGAGCAGC (SEQ ID NO:301) Nucleic acid sequence encoding anti-CLDN18.2 clone #10 (KGHH18-8) CAGGTGCAACTTCAAGAATCTGGCGGTGGGCTGGTTCAGGCAGGTGGTTCACTTC GCCTGTCCTGCGCTGCATCTGGTAATATATTTCCCACTCGGATTATGGGCTGGTA TCGACAGGCCCCTGGGAAAGAACGGGAGTTCGTGGCGAGGATCAACCTCGGTTC AACCACGAACTACGCCGATTCTGTGAAAGGTCGATTCACCATTTCTAGGGATAAT GCAAAAAATACAGTTTACCTCCAAATGAACTCACTTAAACCCGAAGACACCGCA GTGTACTACTGCGCGGTTAGACAATATAGTGGCGTTGTGCATGACTACTGGGGCC AGGGTACACAGGTGACAGTCTCCAGC (SEQ ID NO:302)Attorney Docket No.07039-2318WO1 / 2024-074 Nucleic acid sequence encoding anti-CLDN18.2 clone #11 (KGHH18-9) CAGGTACAGCTCCAGGAATCAGGTGGTGGGTTGGTACAAGCTGGTGGGAGTCTC CGGTTGAGCTGTGCTGCTTCAGGGAACATCTTCGTTCCCAAAGACATGGGCTGGT ACAGGCAAGCTCCCGGAAAAGAACGAGAACTGGTAGCCGGCATTACCAGAGGT TCTACTACTTATTATGCAGATTCTGTCAAGGGGCGCTTTACTATCTCAAGGGATA ATGCCAAAAATACCGTTTATCTTCAGATGAACAGCCTGAAACCGGAGGACACTG CAGTTTATTACTGTGCAGCCCAACAGCACTACTATGCAGGACATTATTATTGGGG ACAGGGAACGCAGGTAACAGTCTCCAGC (SEQ ID NO:303) Nucleic acid sequence encoding anti-CLDN18.2 clone #12 (KGHH18-10) CAGGTTCAGCTTCAGGAATCAGGCGGAGGCTTGGTACAAGCCGGAGGTAGCCTT CGCCTTTCCTGTGCGGCCAGCGGGAATATATCCTTGTATAGGTATATGGGTTGGT ACAGACAAGCGCCGGGCAAAGAGAGAGAGTTCGTGGCACGCATCAATAACGGA GGGTCAACGTACTATGCAGATAGCGTAAAAGGCAGGTTCACCATCAGTAGGGAT AATGCAAAAAACACAGTCTACCTTCAGATGAACTCTCTCAAGCCCGAGGATACC GCAGTCTACTACTGCGCGGTGCTTACCAATGCCTACTGGTCTCTCTGGTACTGGG GACAGGGAACACAAGTGACAGTGAGTAGC (SEQ ID NO:304) Nucleic acid sequence encoding anti-CLDN18.2 clone #13 (KGHH18-11) CAGGTTCAACTGCAGGAATCTGGTGGTGGCCTGGTACAAGCAGGGGGGTCTCTG CGCCTTTCTTGTGCGGCATCTGGAACGATCAGTTCCTATTATGGAATGGGGTGGT ACAGACAAGCACCGGGTAAGGAACGCGAGTTCGTTGCCACTATAACCCGAGGCG GTATCACTTATTATGCGGATTCCGTAAAAGGCAGATTTACCATAAGCAGAGACA ACGCCAAAAATACTGTGTATCTGCAGATGAACTCTTTGAAACCCGAGGATACTG CGGTCTATTATTGTGCAGCGAAACCAACTGATTATGGGTATCACAAATATTGGGG ACAGGGAACTCAAGTTACTGTCAGCAGC (SEQ ID NO:305) Nucleic acid sequence encoding anti-CLDN18.2 clone #14 (KGHH18-12) CAGGTCCAACTTCAAGAAAGTGGGGGTGGCCTGGTACAAGCGGGCGGTAGTCTC CGGCTCTCTTGCGCGGCTAGTGGGTATATATCCCCCTACATCCAGATGGGTTGGT ACCGACAGGCACCCGGAAAAGAGAGGGAGTTCGTGGCGAGGATTAATTATGGGAttorney Docket No.07039-2318WO1 / 2024-074 ACTACTACTTACTATGCGGATAGCGTGAAAGGCAGATTCACCATCAGCCGCGAC AACGCGAAGAACACTGTTTACCTTCAGATGAATAGCTTGAAGCCCGAAGACACC GCTGTGTATTACTGTGCCGTGTACTCCTTCTTTGCCGGCGCACATGGATATTGGG GACAGGGCACCCAGGTGACTGTTAGCAGC (SEQ ID NO:306) Nucleic acid sequence encoding anti-CLDN18.2 clone #15 (KGHH18-13) CAGGTCCAACTTCAAGAGTCTGGAGGAGGTCTTGTACAAGCCGGTGGAAGTCTG AGGCTTAGCTGTGCCGCATCCGGCTCCATTAGTCCCCCGTACGCTATGGGTTGGT ATCGACAAGCGCCTGGAAAGGAAAGGGAATTGGTAGCTGCCATTACTTACGGAG GCATAACCAACTATGCTGACAGTGTCAAGGGCCGGTTTACGATCTCCCGCGACA ATGCTAAAAATACTGTTTACCTCCAAATGAACTCACTTAAGCCCGAAGACACCG CTGTCTACTACTGTGCTGCGGCCCGGCTTTACGATTATTACTACGGCGATACGTTT CCTTACTGGGGTCAGGGGACGCAAGTTACAGTATCCAGC (SEQ ID NO:307) Nucleic acid sequence encoding anti-CLDN18.2 clone #16 (KGHH18-14) CAGGTTCAGCTTCAGGAAAGTGGCGGAGGTCTCGTGCAAGCAGGGGGCTCACTC AGATTGAGTTGCGCTGCCAGCGGTAGTATTTTCCTCAATGGGCCCATGGGGTGGT ATAGACAAGCACCCGGAAAAGAGAGGGAGTTTGTTGCGAGGATCTCACCAGGG AGCAGTACCAACTATGCTGATTCCGTGAAAGGCCGCTTTACAATATCCAGGGAT AATGCTAAAAATACTGTGTATCTTCAGATGAATAGTCTCAAACCCGAAGACACG GCTGTTTACTACTGTGCGGTGCGAGCCGGGTGGGCTTATGATCTTGTCTACTGGG GTCAGGGAACGCAAGTAACCGTTTCAAGC (SEQ ID NO:308) Nucleic acid sequence encoding anti-CLDN18.2 clone #17 (KGHH18-15) CAGGTACAGTTGCAAGAGAGCGGAGGTGGACTTGTCCAAGCTGGTGGATCACTT AGATTGAGTTGTGCTGCAAGCGGCAATATATTCGATGGTCACATTATGGGCTGGT ATCGACAGGCTCCAGGCAAAGAGCGAGAATTCGTTGCAAGAATCGACCCCGGAG CTATCACAAATTACGCAGATTCCGTGAAAGGGCGGTTTACTATCTCTCGGGATAA CGCGAAAAATACTGTCTATCTGCAAATGAACAGTTTGAAGCCTGAGGATACGGC GGTGTACTATTGTGCTGTAGACGCTTCCGTGTATTACGGCCCATTCGTACTCTATC GGTATTGGGGTCAGGGTACGCAGGTGACCGTGAGCAGC (SEQ ID NO:309)Attorney Docket No.07039-2318WO1 / 2024-074 Nucleic acid sequence encoding an anti-CLDN18.2 clone #18 (KGSV18-1) VH domain GAAAGCAAAGCTAGTCAGGTTCAGTTGGTACAATCTGGGGCCGAGGTCAAAAAA CCTGGAAGTAGTGTAAAAGTGAGTTGCAAGGCAAGCGGCGGTACCTTTAGTTCC TATGCGATCTCCTGGGTACGCCAAGCACCTGGACAAGGTTTGGAGTGGATGGGT GGTATCATCCCGATCTTCGGCACCGCTAACTATGCGCAGAAGTTCCAAGGGCGC GTCACGATAACGGCTGATGAATCAACTTCTACAGCCTACATGGAGCTGTCATCAC TGCGATCAGAGGACACAGCTGTGTACTATTGTGCCAGGGCCACGGCTGACTATG TGCTTGATTACTGGGGACAAGGTACGCTCGTCACTGTTTCCTCA (SEQ ID NO:310) Nucleic acid sequence encoding an anti-CLDN18.2 clone #18 (KGSV18-1) VL domain GAAATAGTTTTGACCCAGAGCCCCGGAATACTCTCATTGTCACCGGGCGAAAGA GCGACGTTGAGTTGCCGGGCATCCCAGAGATTGTCTATTTCATATCTCGCCTGGT ATCAACAGCGACCGGGCCAGGCTCCGCGCTTGTTGATATACGGAGCAAGTGGTC GAGCAACAGGCATACCCGCAAGATTTTCAGGCTCAGGCTCCGGGACTGACTTTA CGCTTACGATTAGTCGCCTTGAACCAGAAGACTTTGCCGTATATTATTGTCAGCA ATATGGCATTTCCCCAACATTCGGCCAGGGGACAAAAGTCAAAATTAAAGAAGG TAAG (SEQ ID NO:311) Nucleic acid sequence encoding an anti-CLDN18.2 clone #19 (KGSV18-2) VH domain GAGTCTAAGGCATCACAAGTACAACTCGTTCAGTCTGGCGCCGAGGTCAAAAAA CCTGGGGCTAGTGTAAAAGTAAGCTGTAAAGCAAGCGGATACCCTTTCACCCGG TACTACATGCATTGGGTTCGACAAGCTCCTGGACAGGGTCTGGAATGGATGGCA ATGACCAATCCAACGGATGGTTCCACATCCTACGCGCAAAAATTCCAAGGCAGG CTTACTGTCACTCGAGACACCTCCACTTCTACTCTCTACATGGAGCTTAGTAGCC TTCGCTCTGCCGATACGGCTGTTTACTATTGTGCAAGAGGCACCTATTACTTTGA CTCTTGGGGACAGGGGACCCTCGTAACCGTGTCCTCA (SEQ ID NO:312) Nucleic acid sequence encoding an anti-CLDN18.2 clone #189(KGSV18-2) VL domain GAAATCGTGTTGACTCAATCACCGGGAATACTCTCACTGTCTCCGGGTGAGAGG GCCACGCTTTCCTGTCGAGCAAGTCAGCGGCTGTCCATTAGCTACCTTGCTTGGT ACCAACAGAGGCCTGGGCAAGCTCCGCGACTCTTGATCTATGGCGCGTCTGGTAAttorney Docket No.07039-2318WO1 / 2024-074 GGGCTACCGGCATCCCAGCTAGGTTTAGCGGCTCCGGGTCTGGCACGGATTTTAC GCTTACAATCTCACGCCTGGAACCAGAAGACTTCGCCGTTTATTACTGTCAGCAA TACGGGATTAGTCCCACGTTCGGCCAAGGAACGAAGGTCAAGATTAAAGAAGGA AAG (SEQ ID NO:313) Nucleic acid sequence encoding an anti-CLDN18.2 clone #20 (KGSV18-3) VH domain GAGTCCAAAGCCTCCGAAGTACAGCTTGTGCAAAGCGGAGCCGAAGTGAAAAA ACCAGGTGCTTCTGTCAAAGTGTCCTGCAAGGCAAGTGGATATACTTTTACTTCC TATTATATGCACTGGGTGAGACAAGCCCCTGGACAGGGACTGGAGTGGATGGGC ATTATTAATCCGAGCGGTGGTTCAACTAGCTATGCCCAAAAATTCCAAGGAAGA GTCACCATGACAAGGGATACGAGTACCTCTACTGTTTACATGGAGCTCAGCAGC CTCCGATCTGAGGATACTGCAGTGTACTACTGTGCAAGAGATTTGAGGCTTGCAG TTGCTGACACAGGTGGCTATTCCTACTACTATGGCATGGACGTTTGGGGACAGGG GACGTTGGTGACGGTCAGCTCA (SEQ ID NO:314) Nucleic acid sequence encoding an anti-CLDN18.2 clone #20 (KGSV18-3) VL domain CAGAGTGTTCTGACGCAGCCACCCTCAGTGTCCGTCGCCCCCGGTCAGACTGCCA AAATAACGTGCGGCGGTACTAATATCGGCTCTAAGTCTGTGCATTGGTACCAACA AAAGCCTGGGCAGGCTCCCGTCCTTGTAGTGTACGATGACAGCGACCGACCTAG TGGAATACCGGAGCGATTTTCCGGGTTTGTTTCCGGAAACACGGCGACCCTGACT ATCCGACGGGTCGAAGCCGGTGATGAAGCTGACTATTACTGCCAAGTCTGGGAC AACAGCGAAGGTGTTTTTGGAGGTGGGACAAAGCTCACGGTACTGGGAGAAGGG AAG (SEQ ID NO:315) Example 5: Exemplary scFvs 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 7 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.Attorney Docket No.07039-2318WO1 / 2024-074 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 scFvs Having the Ability to Bind a CLDN18.2 Polypeptide This Example provides structures of exemplary scFv’s having the ability to bind a CLDN18.2 polypeptide. Exemplary hu8e5 scFv VH domain + Linker + VL domain: QVQLQESGPGLVKPSQTLSLTCTVSGGSISSGYNWHWIRQPPGKGLEWIGYIHYTGS TNYNPALRSRVTISVDTSKNQFSLKLSSVTAADTAVYYCARIYNGNSFPYWGQGTTV TVGGGGSGGGGSGGGGSDIVMTQSPDSLAVSLGERATINCKSSQSLFNSGNQKNYLT WYQQKPGQPPKLLIYWASTRESGVPDRFSGSGSGTDFTLTISSLQAEDVAVYYCQNA YSFPYTFGGGTKLEIK (SEQ ID NO:79) Exemplary hu8e5 scFv VL domain + Linker + VH domain: DIVMTQSPDSLAVSLGERATINCKSSQSLFNSGNQKNYLTWYQQKPGQPPKLLIYWA STRESGVPDRFSGSGSGTDFTLTISSLQAEDVAVYYCQNAYSFPYTFGGGTKLEIKGG GGSGGGGSGGGGSQVQLQESGPGLVKPSQTLSLTCTVSGGSISSGYNWHWIRQPPG KGLEWIGYIHYTGSTNYNPALRSRVTISVDTSKNQFSLKLSSVTAADTAVYYCARIY NGNSFPYWGQGTTVTV (SEQ ID NO:80) Exemplary GC-182 scFv VH domain + Linker + VL domain: QVQLQQPGAELVRPGASVKLSCKASGYTFTSYWINWVKQRPGQGLEWIGNIYPSDS YTNYNQKFKDKATLTVDKSSSTAYMQLSSPTSEDSAVYYCTRSWRGNSFDYWGQG TTLTVSSGGGGSGGGGSGGGGSDIVMTQSPSSLTVTAGEKVTMSCKSSQSLLNSGNQAttorney Docket No.07039-2318WO1 / 2024-074 KNYLTWYQQKPGQPPKLLIYWASTRESGVPDRFTGSGSGTDFTLTISSVQAEDLAVY YCQNDYSYPFTFGSGTKLEIK (SEQ ID NO:81) Exemplary GC-182 scFv VL domain + Linker + VH domain: DIVMTQSPSSLTVTAGEKVTMSCKSSQSLLNSGNQKNYLTWYQQKPGQPPKLLIYW ASTRESGVPDRFTGSGSGTDFTLTISSVQAEDLAVYYCQNDYSYPFTFGSGTKLEIKG GGGSGGGGSGGGGSQVQLQQPGAELVRPGASVKLSCKASGYTFTSYWINWVKQRP GQGLEWIGNIYPSDSYTNYNQKFKDKATLTVDKSSSTAYMQLSSPTSEDSAVYYCTR SWRGNSFDYWGQGTTLTVSS (SEQ ID NO:82) Exemplary anti-CLDN18.2 clone #18 (KGSV18-1) scFv VL domain + Linker + VH domain: EIVLTQSPGILSLSPGERATLSCRASQRLSISYLAWYQQRPGQAPRLLIYGASGRATGI PARFSGSGSGTDFTLTISRLEPEDFAVYYCQQYGISPTFGQGTKVKIKEGKSSGSGSES KASQVQLVQSGAEVKKPGSSVKVSCKASGGTFSSYAISWVRQAPGQGLEWMGGIIPI FGTANYAQKFQGRVTITADESTSTAYMELSSLRSEDTAVYYCARATADYVLDYWG QGTLVTVSS (SEQ ID NO:316) Exemplary anti-CLDN18.2 scFv based on clone #18 VH domain + Linker + VL domain: ESKASQVQLVQSGAEVKKPGSSVKVSCKASGGTFSSYAISWVRQAPGQGLEWMGGI IPIFGTANYAQKFQGRVTIT...

Claims

1. Attorney Docket No.07039-2318WO1 / 2024-074 WHAT IS CLAIMED IS:

1. A single-domain antibody comprising:(i) a heavy chain variable domain 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); (ii) a heavy chain variable domain 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); (iii) a heavy chain variable domain 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); (iv) a heavy chain variable domain comprising the amino acid sequences set forth in SEQ ID NO:155 (or SEQ ID NO:155 with one, two, or three amino acid additions, deletions, or substitutions), SEQ ID NO:156 (or SEQ ID NO:156 with one, two, or three amino acid additions, deletions, or substitutions), and SEQ ID NO:157 (or SEQ ID NO:157 with one, two, or three amino acid additions, deletions, or substitutions); (v) a heavy chain variable domain comprising the amino acid sequences set forth in SEQ ID NO:163 (or SEQ ID NO:163 with one, two, or three amino acid additions, deletions, or substitutions), SEQ ID NO:164 (or SEQ ID NO:164 with one, two, or three amino acid additions, deletions, or substitutions), and SEQ ID NO:165 (or SEQ ID NO:165 with one, two, or three amino acid additions, deletions, or substitutions); (vi) a heavy chain variable domain comprising the amino acid sequences set forth in SEQ ID NO:171 (or SEQ ID NO:171 with one, two, or three amino acid additions, deletions, Attorney Docket No.07039-2318WO1 / 2024-074 or substitutions), SEQ ID NO:172 (or SEQ ID NO:172 with one, two, or three amino acid additions, deletions, or substitutions), and SEQ ID NO:173 (or SEQ ID NO:173 with one, two, or three amino acid additions, deletions, or substitutions); (vii) a heavy chain variable domain comprising the amino acid sequences set forth in SEQ ID NO:179 (or SEQ ID NO:179 with one, two, or three amino acid additions, deletions, or substitutions), SEQ ID NO:180 (or SEQ ID NO:180 with one, two, or three amino acid additions, deletions, or substitutions), and SEQ ID NO:181 (or SEQ ID NO:181 with one, two, or three amino acid additions, deletions, or substitutions); (viii) a heavy chain variable domain comprising the amino acid sequences set forth in SEQ ID NO:186 (or SEQ ID NO:186 with one, two, or three amino acid additions, deletions, or substitutions), SEQ ID NO:187 (or SEQ ID NO:187 with one, two, or three amino acid additions, deletions, or substitutions), and SEQ ID NO:188 (or SEQ ID NO:188 with one, two, or three amino acid additions, deletions, or substitutions); (ix) a heavy chain variable domain comprising the amino acid sequences set forth in SEQ ID NO:194 (or SEQ ID NO:194 with one, two, or three amino acid additions, deletions, or substitutions), SEQ ID NO:195 (or SEQ ID NO:195 with one, two, or three amino acid additions, deletions, or substitutions), and SEQ ID NO:196 (or SEQ ID NO:196 with one, two, or three amino acid additions, deletions, or substitutions); (x) a heavy chain variable domain comprising the amino acid sequences set forth in SEQ ID NO:202 (or SEQ ID NO:202 with one, two, or three amino acid additions, deletions, or substitutions), SEQ ID NO:203 (or SEQ ID NO:203 with one, two, or three amino acid additions, deletions, or substitutions), and SEQ ID NO:204 (or SEQ ID NO:204 with one, two, or three amino acid additions, deletions, or substitutions); (xi) a heavy chain variable domain comprising the amino acid sequences set forth in SEQ ID NO:210 (or SEQ ID NO:210 with one, two, or three amino acid additions, deletions, or substitutions), SEQ ID NO:211 (or SEQ ID NO:211 with one, two, or three amino acid additions, deletions, or substitutions), and SEQ ID NO:212 (or SEQ ID NO:212 with one, two, or three amino acid additions, deletions, or substitutions); (xii) a heavy chain variable domain comprising the amino acid sequences set forth in SEQ ID NO:218 (or SEQ ID NO:218 with one, two, or three amino acid additions, deletions, Attorney Docket No.07039-2318WO1 / 2024-074 or substitutions), SEQ ID NO:219 (or SEQ ID NO:219 with one, two, or three amino acid additions, deletions, or substitutions), and SEQ ID NO:220 (or SEQ ID NO:220 with one, two, or three amino acid additions, deletions, or substitutions); (xiii) a heavy chain variable domain comprising the amino acid sequences set forth in SEQ ID NO:226 (or SEQ ID NO:226 with one, two, or three amino acid additions, deletions, or substitutions), SEQ ID NO:227 (or SEQ ID NO:227 with one, two, or three amino acid additions, deletions, or substitutions), and SEQ ID NO:228 (or SEQ ID NO:228 with one, two, or three amino acid additions, deletions, or substitutions); (xiv) a heavy chain variable domain comprising the amino acid sequences set forth in SEQ ID NO:234 (or SEQ ID NO:234 with one, two, or three amino acid additions, deletions, or substitutions), SEQ ID NO:235 (or SEQ ID NO:235 with one, two, or three amino acid additions, deletions, or substitutions), and SEQ ID NO:236 (or SEQ ID NO:236 with one, two, or three amino acid additions, deletions, or substitutions); or (xv) a heavy chain variable domain comprising the amino acid sequences set forth in SEQ ID NO:242 (or SEQ ID NO:242 with one, two, or three amino acid additions, deletions, or substitutions), SEQ ID NO:243 (or SEQ ID NO:243_ with one, two, or three amino acid additions, deletions, or substitutions), and SEQ ID NO:244 (or SEQ ID NO:244 with one, two, or three amino acid additions, deletions, or substitutions).

2. The single-domain antibody of claim 1, wherein said single-domain antibodycomprises the ability to bind to a polypeptide sequence set forth in any one of SEQ ID NOs: 69-71.

3. The single-domain antibody of any one of claims 1-2, wherein said single-domainantibody comprises said heavy chain variable domain of said (i), 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.

4. The single-domain antibody of any one of claims 1-2, wherein said single-domainantibody comprises said heavy chain variable domain of said (ii), and wherein said heavy Attorney Docket No.07039-2318WO1 / 2024-074 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:16.

5. The single-domain antibody of any one of claims 1-2, wherein said single-domainantibody comprises said heavy chain variable domain of 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:24.

6. The single-domain antibody of any one of claims 1-2, wherein said single-domainantibody comprises said heavy chain variable domain of 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:162.

7. The single-domain antibody of any one of claims 1-2, wherein said single-domainantibody comprises said heavy chain variable domain of said (v), 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:170.

8. The single-domain antibody of any one of claims 1-2, wherein said single-domainantibody comprises said heavy chain variable domain of said (vi), 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:178.

9. The single-domain antibody of any one of claims 1-2, wherein said single-domainantibody comprises said heavy chain variable domain of said (vii), 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:

274.

10. The single-domain antibody of any one of claims 1-2, wherein said single-domain antibody comprises said heavy chain variable domain of said (viii), and wherein said heavy Attorney Docket No.07039-2318WO1 / 2024-074 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:

193.

11. The single-domain antibody of any one of claims 1-2, wherein said single-domain antibody comprises said heavy chain variable domain of said (ix), 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:

201.

12. The single-domain antibody of any one of claims 1-2, wherein said single-domain antibody comprises said heavy chain variable domain of said (x), 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:

209.

13. The single-domain antibody of any one of claims 1-2, wherein said single-domain antibody comprises said heavy chain variable domain of said (xi), 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:

217.

14. The single-domain antibody of any one of claims 1-2, wherein said single-domain antibody comprises said heavy chain variable domain of said (xii), 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:

225.

15. The single-domain antibody of any one of claims 1-2, wherein said single-domain antibody comprises said heavy chain variable domain of said (xiii), 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:

233.

16. The single-domain antibody of any one of claims 1-2, wherein said single-domain antibody comprises said heavy chain variable domain of said (xiv), and wherein said heavy Attorney Docket No.07039-2318WO1 / 2024-074 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:

241.

17. The single-domain antibody of any one of claims 1-2, wherein said single-domain antibody comprises said heavy chain variable domain of said (xv), 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:

249.

18. A single chain variable fragment (scFv) antibody comprising: (i) a heavy chain variable domain or region comprising the amino acid sequences set forth in SEQ ID NO:250 (or SEQ ID NO:250 with one, two, or three amino acid additions, deletions, or substitutions), SEQ ID NO:251 (or SEQ ID NO:251 with one, two, or three amino acid additions, deletions, or substitutions), and SEQ ID NO:252 (or SEQ ID NO:252 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:258 (or SEQ ID NO:258 with one, two, or three amino acid additions, deletions, or substitutions), SEQ ID NO:259 (or SEQ ID NO:259 with one, two, or three amino acid additions, deletions, or substitutions), and SEQ ID NO:260 (or SEQ ID NO:260 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:266 (or SEQ ID NO:266 with one, two, or three amino acid additions, deletions, or substitutions), SEQ ID NO:267 (or SEQ ID NO:267 with one, two, or three amino acid additions, deletions, or substitutions), and SEQ ID NO:268 (or SEQ ID NO:268 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:258 (or SEQ ID NO:258 with one, two, or three amino acid additions, deletions, or substitutions), SEQ ID NO:259 (or SEQ ID NO:259 with one, two, or three amino acid additions, deletions, or substitutions), and SEQ ID NO:260 (or SEQ ID NO:260 with one, two, or three amino acid additions, deletions, or substitutions); or Attorney Docket No.07039-2318WO1 / 2024-074 (iii) a heavy chain variable domain or region comprising the amino acid sequences set forth in SEQ ID NO:282 (or SEQ ID NO:282 with one, two, or three amino acid additions, deletions, or substitutions), SEQ ID NO:283 (or SEQ ID NO:283 with one, two, or three amino acid additions, deletions, or substitutions), and SEQ ID NO:284 (or SEQ ID NO:284 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:290 (or SEQ ID NO:290 with one, two, or three amino acid additions, deletions, or substitutions), SEQ ID NO:291 (or SEQ ID NO:291 with one, two, or three amino acid additions, deletions, or substitutions), and SEQ ID NO:292 (or SEQ ID NO:292 with one, two, or three amino acid additions, deletions, or substitutions).

19. The binding molecule of claim 18, wherein said binding molecule comprises the ability to bind to a polypeptide sequence set forth in any one of SEQ ID NOs: 69-71.

20. The binding molecule of any one of claims 18-19, wherein said binding molecule comprises said (i), 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:257, 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:

265.

21. The binding molecule of any one of claims 18-19, wherein said binding molecule comprises said (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:273, 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:

265.

22. The binding molecule of any one of claims 18-19, wherein said binding molecule comprises said (iii), 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 Attorney Docket No.07039-2318WO1 / 2024-074 NO:289, 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:

297.

23. 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 single-domain antibody of any one of claims 1-17 or a scFv antibody of any one of claims 18-22.

24. The CAR of claim 23, wherein said antigen binding domain has the ability to bind to a claudin 18 isoform 2 (CLDN18.2) polypeptide.

25. The CAR of any one of claims 23-24, wherein said hinge comprises a hinge set forth in any one of SEQ ID NOs:94-101.

26. The CAR of any one of claims 23-24, wherein said hinge is a CD8 hinge.

27. The CAR of any one of claims 23-24, wherein said transmembrane domain comprises a transmembrane domain set forth in any one of SEQ ID NOs:102-109.

28. The CAR of any one of claims 23-24, wherein said transmembrane domain is a CD8 transmembrane domain.

29. The CAR of any one of claims 23-24, wherein said CAR comprises one or more signaling domains set forth in any one of SEQ ID NOs:110-119.

30. The CAR of any one of claims 23-24, wherein said CAR comprises a 4-1BBintracellular signaling domain and a CD3 intracellular signaling domain.

31. A cell comprising a CAR of any one of claims 23-30. Attorney Docket No.07039-2318WO1 / 2024-074 32. The cell of claim 31, wherein said cell is a T cell, a stem cell, or an NK cell.

33. The cell of any one of claims 31-32, wherein said cell further comprises a second CAR.

34. The cell of claim 33, 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 fibroblast activation protein (FAP) polypeptide.

35. The cell of claim 34, wherein said scFv comprises: (i) a heavy chain variable domain comprising the amino acid sequences set forth in SEQ ID NO:57, SEQ ID NO:58, and SEQ ID NO:59, and a light chain variable domain or region comprising the amino acid sequences set forth in SEQ ID NO:60, SEQ ID NO:61, and SEQ ID NO:62; or (ii) a heavy chain variable domain comprising the amino acid sequences set forth in SEQ ID NO:63, SEQ ID NO:64, and SEQ ID NO:65, and a light chain variable domain or region comprising the amino acid sequences set forth in SEQ ID NO:66, SEQ ID NO:67, and SEQ ID NO:

68.

36. The cell of any one of claims 34-35, wherein said second CAR is an activation- inducible CAR.

37. The cell of any one of claims 34-35, wherein said second CAR is an expression- inducible CAR.

38. 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 single- domain antibody of any one of claims 1-17 or a scFv antibody of any one of claims 18-22. Attorney Docket No.07039-2318WO1 / 2024-074 39. The cell engager of claim 38, wherein said first antigen binding domain comprises a scFv having the ability to bind to a CLDN18.2 polypeptide.

40. The cell engager of any one of claims 38-39, wherein said linker comprises a linker set forth in any one of SEQ ID NOs:83-86 or SEQ ID NOs:94-101.

41. The cell engager of any one of claims 38-39, wherein said second antigen binding domain binds to a polypeptide expressed on the surface of T cells.

42. The cell engager of claim 41, wherein said polypeptide expressed on the surface of T cells is a CD3 polypeptide.

43. The cell engager of claim 41, wherein said second antigen binding domain is an antigen binding domain set forth in Example 15.

44. The cell engager of any one of claims 38-39, wherein said second antigen binding domain binds to a polypeptide expressed on the surface of NK cells.

45. The cell engager of claim 44, wherein said polypeptide expressed on the surface of NK cells is a CD16a, NKG2A, NKG2D, NKp30, NKp44, or NKp46 polypeptide.

46. The cell engager of claim 44, wherein said second antigen binding domain is an antigen binding domain set forth in Example 16.

47. A nucleic acid comprising a nucleic acid sequence encoding a single-domain antibody of any one of claims 1-17.

48. The nucleic acid of claim 47, wherein said nucleic acid is a viral vector. Attorney Docket No.07039-2318WO1 / 2024-074 49. A nucleic acid comprising a nucleic acid sequence encoding a CAR of any one of claims 23-30 or a cell engager of any one of claims 38-46.

50. The nucleic acid of claim 49, wherein said nucleic acid is a viral vector.

51. A host cell comprising a nucleic acid of any one of claims 47-48.

52. A host cell that expresses a CAR of any one of claims 23-30 or a cell engager of any one of claims 38-46.

53. The host cell of any one of claims 51-52, wherein said host cell is a T cell, stem cell, or NK cell.

54. An antibody-drug conjugate (ADC) comprising an antigen binding domain covalently linked to a drug, wherein said antigen binding domain comprises a single-domain antibody of any one of claims 1-17 or a scFv antibody of any one of claims 18-22.

55. The ADC of claim 54, wherein said drug is selected from the group consisting of an auristatin, a mertansine, or pyrrolobenzodiazepine (PBD) dimers.

56. A composition comprising a single-domain antibody of any one of claims 1-17 or a scFv antibody of any one of claims 18-22.

57. A composition comprising a cell engager of any one of claims 38-46, a cell of any one of claims 31-37 or 52-53, or an ADC of any one of claims 54-55.

58. A method of treating a mammal having cancer, wherein said method comprises administering, to said mammal, a composition of claim 57.

59. The method of claim 58, wherein said mammal is a human. Attorney Docket No.07039-2318WO1 / 2024-074 60. The method of any one of claims 58-59, wherein said cancer is a CLDN18.2+cancer.

61. The method of any one of claims 58-59, wherein said cancer is selected from the group consisting of a colorectal cancer, a colon cancer, a gastric cancer, a gastrointestinal cancer, and a pancreatic cancer.

62. The method of any one of claims 58-61, wherein the number of cancer cells within said mammal is reduced following said administering step.

63. A method for binding a binding molecule to a CLDN18.2 polypeptide, wherein said method comprises contacting said CLDN18.2 polypeptide with a single-domain antibody of any one of claims 1-17 or a scFv antibody of any one of claims 18-22.

64. The method of claim 63, wherein said contacting is performed in vitro.

65. The method of claim 63, wherein said contacting is performed in vivo.

66. A method for binding a binding molecule to a CLDN18.2 polypeptide, wherein said method comprises contacting said CLDN18.2 polypeptide with a CAR of any one of claims 23-30, a cell engager of any one of claims 38-46, or an ADC of any one of claims 87-98.

67. The method of claim 66, wherein said contacting is performed in vitro.

68. The method of claim 66, wherein said contacting is performed in vivo.

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