Abstract: Novel structural forms of T cell costimulatory molecules are described. These structural forms comprise a novel structural domain or have a structural domain deleted or added. The structural forms correspond to naturally-occurring alternatively spliced forms of T cell costimulatory molecules or variants thereof which can be produced by standard recombinant DNA techniques. In one embodiment, the T cell costimulatory molecule of the invention contains a novel cytoplasmic domain. In another embodiment, the T cell costimulatory molecule of the invention contains a novel signal peptide domain or has an immunoglobulin variable region-like domain deleted. The novel structural forms of T cell costimulatory molecules can be used to identify agents which stimulate the expression of alternative forms of costimulatory molecules and to identify components of the signal transduction pathway which results in costimulation of T cells.

Abstract: The invention provides isolated nucleic acids molecules, designated PD-L2 nucleic acid molecules, which encode novel B7-related molecules which are ligands for PD-1. The invention also provides antisense nucleic acid molecules, recombinant expression vectors containing PD-L2 nucleic acid molecules, host cells into which the expression vectors have been introduced, and nonhuman transgenic animals in which a PD-L2 gene has been introduced or disrupted. The invention further provides isolated PD-L2 polypeptides, fusion proteins, antigenic peptides and anti-PD-L2 antibodies. The invention still further provides methods for promoting or inhibiting the interaction between PD-L2 and PD-1. The invention further provides methods of identifying compounds that upmodulate T cell activation in the presence of a PD-1-mediated signal. Diagnostic and treatment methods utilizing compositions of the invention are also provided.

Abstract: Structural forms of T cell costimulatory polypeptides are described. These forms comprise an alternative structural domain (i.e., a structural domain having an amino acid sequence which differs from a known amino acid sequence) or have a structural domain deleted or added. The structural forms correspond to naturally-occurring alternatively spliced forms of T cell costimulatory polypeptides or variants thereof which can be produced by standard recombinant DNA techniques. In one embodiment, the T cell costimulatory polypeptide of the invention contains an alternative cytoplasmic domain. In another embodiment, the T cell costimulatory polypeptide of the invention contains an alternative signal peptide domain or has an immunoglobulin variable region-like domain deleted.

Abstract: Novel structural forms of T cell costimulatory molecules are described. These structural forms comprise a novel structural domain or have a structural domain deleted or added. The structural forms correspond to naturally-occurring alternatively spliced forms of T cell costimulatory molecules or variants thereof which can be produced by standard recombinant DNA techniques. In one embodiment, the T cell costimulatory molecule of the invention contains a novel cytoplasmic domain. In another embodiment, the T cell costimulatory molecule of the invention contains a novel signal peptide domain or has an immunoglobulin variable region-like domain deleted. The novel structural forms of T cell costimulatory molecules can be used to identify agents which stimulate the expression of alternative forms of costimulatory molecules and to identify components of the signal transduction pathway which results in costimulation of T cells.

Abstract: Disclosed are methods for identifying an agent that modulates an immune response. One such method comprises screening for agents which inhibit the interaction between a PD-1 ligand and a PD-1 polypeptide, and determining whether the agents inhibit the interaction between a PD-1 ligand and a B7 polypeptide, to identify an agent that inhibits PD-1 ligand and PD-1 polypeptide interaction, while not inhibiting the interaction between a PD-1 ligand and a B7 polypeptide, as an agent that modulates an immune response. Another such method comprises screening for agents which inhibit the interaction between a PD-1 ligand and a B7 polypeptide, and determining whether the agents inhibit the interaction between a PD-1 ligand and a PD-1 polypeptide, to identify an agent that inhibits the PD-1 ligand and B7 polypeptide interaction, which does not inhibit the interaction between a PD-1 ligand and a PD-1 polypeptide, as an agent that modulates the immune response.

Abstract: Novel structural forms of T cell costimulatory molecules are described. These structural forms comprise a novel structural domain or have a structural domain deleted or added. The structural forms correspond to naturally-occurring alternatively spliced forms of T cell costimulatory molecules or variants thereof which can be produced by standard recombinant DNA techniques. In one embodiment, the T cell costimulatory molecule of the invention contains a novel cytoplasmic domain. In another embodiment, the T cell costimulatory molecule of the invention contains a novel signal peptide domain or has an immunoglobulin variable region-like domain deleted. The novel structural forms of T cell costimulatory molecules can be used to identify agents which stimulate the expression of alternative forms of costimulatory molecules and to identify components of the signal transduction pathway which results in costimulation of T cells.

Abstract: Novel structural forms of T cell costimulatory molecules are described. These structural forms comprise a novel structural domain or have a structural domain deleted or added. The structural forms correspond to naturally-occurring alternatively spliced forms of T cell costimulatory molecules or variants thereof which can be produced by standard recombinant DNA techniques. In one embodiment, the T cell costimulatory molecule of the invention contains a novel cytoplasmic domain. In another embodiment, the T cell costimulatory molecule of the invention contains a novel signal peptide domain or has an immunoglobulin variable region-like domain deleted. The novel structural forms of T cell costimulatory molecules can be used to identify agents which stimulate the expression of alternative forms of costimulatory molecules and to identify components of the signal transduction pathway which results in costimulation of T cells.

Abstract: The invention provides isolated nucleic acids molecules, designated PD-L2 nucleic acid molecules, which encode novel B7-related molecules which are ligands for PD-1. The invention also provides antisense nucleic acid molecules, recombinant expression vectors containing PD-L2 nucleic acid molecules, host cells into which the expression vectors have been introduced, and nonhuman transgenic animals in which a PD-L2 gene has been introduced or disrupted. The invention further provides isolated PD-L2 polypeptides, fusion proteins, antigenic peptides and anti-PD-L2 antibodies. The invention still further provides methods for promoting or inhibiting the interaction between PD-L2 and PD-1. Diagnostic and treatment methods utilizing compositions of the invention are also provided.

Abstract: Novel structural forms of T cell costimulatory molecules are described. These structural forms comprise a novel structural domain or have a structural domain deleted or added. The structural forms correspond to naturally-occurring alternatively spliced forms of T cell costimulatory molecules or variants thereof which can be produced by standard recombinant DNA techniques. In one embodiment, the T cell costimulatory molecule of the invention contains a novel cytoplasmic domain. In another embodiment, the T cell costimulatory molecule of the invention contains a novel signal peptide domain or has an immunoglobulin variable region-like domain deleted. The novel structural forms of T cell costimulatory molecules can be used to identify agents which stimulate the expression of alternative forms of costimulatory molecules and to identify components of the signal transduction pathway which results in costimulation of T cells.

Abstract: Nucleic acids encoding B7-1 and B7-2 molecules which bind CD28 or CTLA4 are described. These structural forms correspond to naturally-occurring alternatively spliced forms comprising cytoplasmic and signal peptide domains of T cell costimulatory molecules or variants thereof which can be produced by standard recombinant DNA techniques. These T cell costimulatory molecules can be used to identify agents which stimulate the express of alternative forms of costimulatory molecules and to identify components of the signal transduction pathway which results in costimulation of T cells.

Abstract: Structural forms of T cell costimulatory B7-1 and B7-2 molecules are described. These structural forms comprise a structural domain or have a structural domain deleted or added. The structural forms correspond to naturally-occurring alternatively spliced forms of T cell costimulatory molecules or variants thereof which can be produced by standard recombinant DNA techniques. In one embodiment, the T cell costimulatory molecule of the invention contains a cytoplasmic domain. In another embodiment, the T cell costimulatory molecule of the invention contains a signal peptide domain or has an immunoglobulin variable region-like domain deleted. The structural forms of T cell costimulatory molecules can be used to identify agents which stimulate the expression of alternative forms of costimulatory molecules and to identify components of the signal transduction pathway which results in costimulation of T cells.