Abstract: Non-genetically engineered mammalian cells modified by sortase-mediated conjugation of an agent thereto are provided. Methods of conjugating agents to non-genetically engineered mammalian cells using sortase are provided. Methods of using the cells, e.g., for diagnostic and/or therapeutic purposes, are provided.

Abstract: Provided herein are conjugate molecules comprising an antibody or antibody fragment capable of binding polyclonal immnunoglobulins within a subject. Such conjugates are useful for recruiting immune cells of the subject to one or more cell types that are targeted by the conjugate. Also provided herein are compositions comprising the conjugates, including pharmaceutical compositions that may be administered to a subject, for such a purpose as to treat or prevent a disease.

Abstract: Provided herein are methods for producing site specific PEG modifications to single domain antibodies (e.g., VHHs). Methods for producing site-specifically conjugated bivalent single domain antibodies (e.g., VHHs) are also provided. Methods for labeling (e.g., with a fluorophore or radionuclide) site-specifically PEGylated single domain antibodies and site-specifically conjugated bivalent single domain antibodies are also provided.

Abstract: Provided herein are methods for producing site specific PEG modifications to single domain antibodies (e.g., VHHs). Methods for producing site-specifically conjugated bivalent single domain antibodies (e.g., VHHs) are also provided. Methods for labeling (e.g., with a fluorophore or radionuclide) site-specifically PEGylated single domain antibodies and site-specifically conjugated bivalent single domain antibodies are also provided.

Abstract: Methods for the in vitro production of enucleated red blood cells and the enucleated red blood cells thus prepared are provided. Such enucleated red blood cells may express a sortaggable surface protein, which allows for surface modification in the presence of a sortase. Also described herein are surface modified enucleated red blood cells, e.g., conjugated with an agent of interest such as a peptide, a detectable label, or a chemotherapeutic agent, and uses thereof in delivering the agent to a subject.

Abstract: Described herein are engineered ligand that binds a cell surface receptor (e.g., GPCR), with improved affinity, potency, and specificity. By conjugating a sub-optimal ligand for a cell surface receptor (e.g., GPCR) to a targeting molecule that binds an epitope (natural or exogenous epitope) in the extracellular portion of the cell surface receptor (e.g., GPCR), the affinity, potency, and/or specificity of the sub-optimal ligand is enhanced.

Abstract: The present invention, in some aspects, provides methods, reagents, compositions, and kits for the radiolabeling of proteins, for example, of proteins useful for positron emission tomography (PET) or single-photon emission computed tomography (SPECT) (e.g., for diagnostic and therapeutic applications), using sortase-mediated transpeptidation reactions. Some aspects of this invention provide methods for the conjugation of an agent, for example, a radioactive agent or molecule to diagnostic or therapeutic peptides or proteins. Compositions comprising sortagged, radiolabeled proteins as well as reagents for generating radiolabeled proteins are also provided. Kits comprising reagents useful for the generation of radiolabeled proteins are provided, as are precursor proteins that comprise a sortase recognition motif.

Abstract: Methods for developing disease-related nanobodies and related products and kits are provided. The disease-specific proteins are extracellular matrix (ECM) proteins, domains or epitopes that are associated with various aspects of disease and are not present, or are present in very low quantities, in non-diseased individuals. Highly effective nanobodies capable of specifically binding to these ECM protein epitopes useful in in vivo imaging assays, the detection, diagnosis and treatment of diseases as well as monitoring therapeutic progress in a patient with a disease are provided herein.

Abstract: Provided herein are compositions comprising VHH conjugates and their uses in treating diseases.

Abstract: Methods for developing disease-related nanobodies and related products and kits are provided. The disease-specific proteins are extracellular matrix (ECM) proteins, domains or epitopes that are associated with various aspects of disease and are not present, or are present in very low quantities, in non-diseased individuals. Highly effective nanobodies capable of specifically binding to these ECM protein epitopes useful in in vivo imaging assays, the detection, diagnosis and treatment of diseases as well as monitoring therapeutic progress in a patient with a disease are provided herein.

Abstract: Non-genetically engineered mammalian cells modified by sortase-mediated conjugation of an agent thereto are provided. Methods of conjugating agents to non-genetically engineered mammalian cells using sortase are provided. Methods of using the cells, e.g., for diagnostic and/or therapeutic purposes, are provided.

Abstract: Provided herein are engineered cells that comprising a chimeric antigen receptor comprising an extracellular target-binding moiety and an intracellular signaling domain; and secrets a heavy-chain antibody (VHH) or a VHH fusion protein. Methods of using the engineered cell to treat a disease (e.g., cancer or autoimmune disease) are also provided.

Abstract: Methods for the in vitro production of enucleated red blood cells and the enucleated red blood cells thus prepared are provided. Such enucleated red blood cells may express a sortaggable surface protein, which allows for surface modification in the presence of a sortase. Also described herein are surface modified enucleated red blood cells, e.g., conjugated with an agent of interest such as a peptide, a detectable label, or a chemotherapeutic agent, and uses thereof in delivering the agent to a subject.

Abstract: Screening assays and methods of performing such assays are provided. In certain examples, the assays and methods may be designed to determine whether or not two or more species can associate with each other. In some examples, the assays and methods may be used to determine if a known antigen binds to an unknown monoclonal antibody.

Abstract: Screening assays and methods of performing such assays are provided. In certain examples, the assays and methods may be designed to determine whether or not two or more species can associate with each other. In some examples, the assays and methods may be used to determine if a known antigen binds to an unknown monoclonal antibody.

Abstract: Methods and reagents for the installation of click chemistry handles on target proteins are provided, as well as modified proteins comprising click chemistry handles. Further, chimeric proteins, for example, bi-specific antibodies, that comprise two proteins conjugated via click chemistry, as well as methods for their generation and use are disclosed herein.

Abstract: The present invention, in some aspects, provides methods, reagents, compositions, and kits for the radiolabeling of proteins, for example, of proteins useful for positron emission tomography (PET) or single-photon emission computed tomography (SPECT) (e.g., for diagnostic and therapeutic applications), using sortase-mediated transpeptidation reactions. Some aspects of this invention provide methods for the conjugation of an agent, for example, a radioactive agent or molecule to diagnostic or therapeutic peptides or proteins. Compositions comprising sortagged, radiolabeled proteins as well as reagents for generating radiolabeled proteins are also provided. Kits comprising reagents useful for the generation of radiolabeled proteins are provided, as are precursor proteins that comprise a sortase recognition motif.

Abstract: Described herein are engineered ligand that binds a cell surface receptor (e.g., GPCR), with improved affinity, potency, and specificity. By conjugating a sub-optimal ligand for a cell surface receptor (e.g., GPCR) to a targeting molecule that binds an epitope (natural or exogenous epitope) in the extracellular portion of the cell surface receptor (e.g., GPCR), the affinity, potency, and/or specificity of the sub-optimal ligand is enhanced.

Abstract: Multi-step methods for the in vitro production of enucleated red blood cells and the enucleated red blood cells thus prepared are provided. Such enucleated red blood cells may express fusion proteins comprising an antigen binding protein which allows the red blood cell to bind a toxin or an antigen of a pathogen. Also described herein are methods for neutralizing a toxin or pathogen in a subject by administering enucleated red blood cells that express any of the fusion proteins provided herein.

Abstract: Methods for the in vitro production of enucleated red blood cells and the enucleated red blood cells thus prepared are provided. Such enucleated red blood cells may express a sortaggable surface protein, which allows for surface modification in the presence of a sortase. Also described herein are surface modified enucleated red blood cells, e.g., conjugated with an agent of interest such as a peptide, a detectable label, or a chemotherapeutic agent, and uses thereof in delivering the agent to a subject.