Abstract: High affinity PD-1 mimic polypeptides are provided, which (i) comprise at least one amino acid change relative to a wild-type PD-1 protein; and (ii) have an increased affinity for PD-L1 relative to the wild-type protein. Compositions and methods are provided for modulating the activity of immune cells in a mammal by administering a therapeutic dose of a pharmaceutical composition comprising a high affinity PD-1 mimic polypeptide, which blocks the physiological binding interaction between PD-1 and its ligand PD-L1 and/or PD-L2.

Abstract: High affinity PD-1 mimic polypeptides are provided, which (i) comprise at least one amino acid change relative to a wild-type PD-1 protein; and (ii) have an increased affinity for PD-L1 relative to the wild-type protein. Compositions and methods are provided for modulating the activity of immune cells in a mammal by administering a therapeutic dose of a pharmaceutical composition comprising a high affinity PD-1 mimic polypeptide, which blocks the physiological binding interaction between PD-1 and its ligand PD-L1 and/or PD-L2.

Abstract: Anti-SIRP? antibodies, including multi-specific anti-SIRP? antibodies, are provided, as are related compositions and methods. The antibodies of the disclosure bind to SIRP? and can block the interaction of CD47 on one cell with SIRP? on a phagocytic cell. The subject anti-SIRP? antibodies find use in various therapeutic methods. Embodiments of the disclosure include isolated antibodies and derivatives and fragments thereof, pharmaceutical formulations comprising one or more of the anti-SIRP? antibodies; and cell lines that produce the antibodies. Also provided are amino acid sequences of exemplary anti-SIRP? antibodies.

Abstract: The present invention provides a clinically applicable method of stem cell transplantation that facilitates engraftment and reconstitutes immunocompetence of the recipient without requiring radiotherapy or chemotherapy, and without development of GVHD or graft rejection. Aspects of the present invention are based on the discovery that the depletion of the endogenous stem cell niche facilitates efficient engraftment of stem cells into that niche. In particular, the present invention combines the use of selective ablation of endogenous stem cells with a combination of antibodies specific for CD117, and agents that modulate immunoregulatory signaling pathways, e.g. agonists of immune costimulatory molecules, in combination with the administration to the recipient of exogenous stem cells, resulting in efficient, long-term engraftment, even in immunocompetent recipients.

Abstract: Methods and compositions are provided for inducing phagocytosis of a target cell, treating an individual having cancer, treating an individual having an intracellular pathogen infection (e.g., a chronic infection), and/or reducing the number of inflicted cells (e.g., cancer cells, cells infected with an intracellular pathogen, etc.) in an individual. Methods and compositions are also provided for predicting whether an individual is resistant (or susceptible) to treatment with an anti-CD47/SIRPA agent. In some cases, the subject methods and compositions include an anti-MHC Class I/LILRB1 agent. In some cases, the subject methods and compositions include an anti-MHC Class I/LILRB1 agent and an anti-CD47/SIRPA agent (e.g., co-administration of an anti-MHC Class I/LILRB1 agent and an anti-CD47/SIRPA agent). Kits are also provided for practicing the methods of the disclosure.

Abstract: The present invention provides a clinically applicable method of stem cell transplantation that facilitates engraftment and reconstitutes immunocompetence of the recipient without requiring radiotherapy or chemotherapy, and without development of GVHD or graft rejection. Aspects of the present invention are based on the discovery that the depletion of the endogenous stem cell niche facilitates efficient engraftment of stem cells into that niche. In particular, the present invention combines the use of selective ablation of endogenous stem cells with a combination of antibodies specific for CD117, and agents that modulate immunoregulatory signaling pathways, e.g. agonists of immune costimulatory molecules, in combination with the administration to the recipient of exogenous stem cells, resulting in efficient, long-term engraftment, even in immunocompetent recipients.

Abstract: Provided herein are SIRP-gamma, SIRP-beta or SIRP-beta2 decoy polypeptides for immunotherapy and/or treatment of cancer, anemia, transplant, asthma, allergy, auto-immune disease, and viral infection.

Abstract: High affinity SIRP-? reagent are provided, which (i) comprise at least one amino acid change relative to the wild-type protein; and (ii) have an increased affinity for CD47 relative to the wild-type protein. Compositions and methods are provided for modulating phagocytosis in a mammal by administering a therapeutic dose of a pharmaceutical composition comprising a high affinity SIRP? reagent, which blocks the physiological binding interaction between SIRP? and its ligand CD47.

Abstract: High affinity SIRP-? reagent are provided, which (i) comprise at least one amino acid change relative to the wild-type protein; and (ii) have an increased affinity for CD47 relative to the wild-type protein. Compositions and methods are provided for modulating phagocytosis in a mammal by administering a therapeutic dose of a pharmaceutical composition comprising a high affinity SIRP? reagent, which blocks the physiological binding interaction between SIRP? and its ligand CD47.

Abstract: Provided herein are several methods for selecting agents that bind to transmembrane receptors in a conformationally-selective way. In some embodiments, the method may comprise producing: a transmembrane receptor in an active conformation; and said transmembrane receptor in an inactive conformation and using cell sorting to select, from a population of cells comprising a library of cell surface-tethered extracellular capture agents, cells that are specifically bound to either the transmembrane receptor in its active conformation or the transmembrane receptor in its inactive conformation, but not both. In other embodiments, the method may comprise: contacting a GPCR with a population of cells that comprise a library of surface-tethered extracellular proteins; labeling the cell population with a conformationally-specific binding agent, e.g., a G-protein or mimetic thereof; and using cell sorting to select from the cell population cells that bind to the agent.

Abstract: Methods and compositions are provided for inducing phagocytosis of a target cell, treating an individual having cancer, treating an individual having an intracellular pathogen infection (e.g., a chronic infection), and/or reducing the number of inflicted cells (e.g., cancer cells, cells infected with an intracellular pathogen, etc.) in an individual. Methods and compositions are also provided for predicting whether an individual is resistant (or susceptible) to treatment with an anti-CD47/SIRPA agent. In some cases, the subject methods and compositions include an anti-MHC Class I/LILRB1 agent. In some cases, the subject methods and compositions include an anti-MHC Class I/LILRB1 agent and an anti-CD47/SIRPA agent (e.g., co-administration of an anti-MHC Class I/LILRB1 agent and an anti-CD47/SIRPA agent). Kits are also provided for practicing the methods of the disclosure.

Abstract: Cell loss by apoptosis is a common feature in certain conditions, including cancer. Dying tumor cells induce immune tolerance within the tumor microenvironment largely through highly conserved homeostatic clearance programs that are designed to restore tissue homeostasis and contribute to the formation of an immunosuppressive niche. The translocation of phosphatidylserine (PS) on cellular membranes, during the initial phases of apoptosis, functions as a recognition and removal signal that limits the immunogenicity of cell death. To remove inhibitory signals in the homeostatic clearance pathway a fusion protein comprising a phosphatidylserine binding domain and an immunostimulatory domain can restore immune responses to dead tumor cells in antigen cross presentation assays and promotes recruitment and retention of tumor antigen specific immune effector cells into tumors.

Abstract: High affinity PD-1 mimic polypeptides are provided, which (i) comprise at least one amino acid change relative to a wild-type PD-1 protein; and (ii) have an increased affinity for PD-L1 relative to the wild-type protein. Compositions and methods are provided for modulating the activity of immune cells in a mammal by administering a therapeutic dose of a pharmaceutical composition comprising a high affinity PD-1 mimic polypeptide, which blocks the physiological binding interaction between PD-1 and its ligand PD-L1 and/or PD-L2.

Abstract: Methods and compositions are provided for inducing phagocytosis of a target cell, treating an individual having cancer, treating an individual having an intracellular pathogen infection (e.g., a chronic infection), and/or reducing the number of inflicted cells (e.g., cancer cells, cells infected with an intracellular pathogen, etc.) in an individual. Methods and compositions are also provided for predicting whether an individual is resistant (or susceptible) to treatment with an anti-CD47/SIRPA agent. In some cases, the subject methods and compositions include an anti-MHC Class I/LILRB1 agent. In some cases, the subject methods and compositions include an anti-MHC Class I/LILRB1 agent and an anti-CD47/SIRPA agent (e.g., co-administration of an anti-MHC Class I/LILRB1 agent and an anti-CD47/SIRPA agent). Kits are also provided for practicing the methods of the disclosure.

Abstract: Methods and compositions are provided for displaying a protein of interest (POI) on the surface of a eukaryotic cell by fusing the POI to a signal polypeptide, a stalk polypeptide, and a surface anchor polypeptide to generate a surface accessible fusion protein. Nucleic acids are provided that include nucleotide sequences encoding a signal polypeptide, a stalk polypeptide, and a surface anchor polypeptide. In some cases, a subject nucleic acid includes and insertion site for the insertion of a POI. In some cases, a subject nucleic acid includes a nucleotide sequence that encodes a POI. In some cases a stalk polypeptide is a synthetic stalk polypeptide and various example synthetic stalk polypeptides are disclosed. In some cases, a surface anchor polypeptide is a glycosylphosphatidylinisotol (GPI) anchor domain, which can be synthetic. Kits are also provided for practicing the subject methods.

Abstract: High affinity PD-1 mimic polypeptides are provided, which (i) comprise at least one amino acid change relative to a wild-type PD-1 protein; and (ii) have an increased affinity for PD-L1 relative to the wild-type protein. Compositions and methods are provided for modulating the activity of immune cells in a mammal by administering a therapeutic dose of a pharmaceutical composition comprising a high affinity PD-1 mimic polypeptide, which blocks the physiological binding interaction between PD-1 and its ligand PD-L1 and/or PD-L2.

Abstract: Anti-SIRP? antibodies, including multi-specific anti-SIRP? antibodies, are provided, as are related compositions and methods. The antibodies of the disclosure bind to SIRP? and can block the interaction of CD47 on one cell with SIRP? on a phagocytic cell. Antibodies that are bispecific for SIRP? and a second antigen are termed Bi-specific Macrophage Enhancing (BiME) antibodies and have emergent properties. The subject anti-SIRP? antibodies find use in various therapeutic methods. Embodiments of the disclosure include isolated antibodies and derivatives and fragments thereof, pharmaceutical formulations comprising one or more of the anti-SIRP? antibodies; and cell lines that produce the antibodies. Also provided are amino acid sequences of exemplary anti-SIRP? antibodies.

Abstract: Provided herein are SIRP-gamma, SIRP-beta or SIRP-beta2 decoy polypeptides for immunotherapy and/or treatment of cancer, anemia, transplant, asthma, allergy, auto-immune disease, and viral infection.

Abstract: Provided herein are SIRP-gamma, SIRP-beta or SIRP-beta2 decoy polypeptides for immunotherapy and/or treatment of cancer, anemia, transplant, asthma, allergy, auto-immune disease, and viral infection.

Abstract: Anti-SIRP? antibodies, including multi-specific anti-SIRP? antibodies, are provided, as are related compositions and methods. The antibodies of the disclosure bind to SIRP? and can block the interaction of CD47 on one cell with SIRP? on a phagocytic cell. The subject anti-SIRP? antibodies find use in various therapeutic methods. Embodiments of the disclosure include isolated antibodies and derivatives and fragments thereof, pharmaceutical formulations comprising one or more of the anti-SIRP? antibodies; and cell lines that produce the antibodies. Also provided are amino acid sequences of exemplary anti-SIRP? antibodies.