Methods of reducing T cell-mediated immune responses with multimeric P-selectin and/or E-selectin compounds
Multimeric compounds that bind to P-Selectin Glycoprotein 1 (PSGL-1) on the surface of T cells or natural killer (NK) cells can be used to induce T cell or NK cell depletion and/or to induce T cell or NK cell apoptosis. The multimeric compounds and methods of the invention can be used to control unwanted T cell- or NK cell-mediated immune responses in conditions such as inflammatory diseases, autoimmune diseases, transplant rejection, and allergic diseases.
1. A method of delaying the onset of or reducing a T cell-mediated immune response in an individual, the method comprising: selecting an individual diagnosed as having or as being at risk of acquiring a condition characterized by an excessive or unwanted T cell-mediated immune response; and administering to the individual an anti-Fc antibody, and a multimeric compound that binds to at least two P-Selectin Glycoprotein Ligand 1 (PSGL-1) proteins on the surface of a T cell, wherein the multimeric compound comprises two polypeptide chains, each of the polypeptide chains comprising (i) a binding domain that binds to PSGL-1, wherein the binding domain comprises a P-Selectin extracellular domain or a PSGL-1-binding fragment thereof; or wherein the binding domain comprises an E-Selectin extracellular domain or a PSGL-1-binding fragment thereof, and (ii) a heterologous amino acid sequence, wherein the heterologous amino acid sequence comprises an immunoglobulin heavy chain constant region, and wherein the polypeptide chains are linked via the heterologous amino acid sequence to form the multimeric compound, wherein the binding of the multimeric compound to the at least two PSGL-1 proteins on the surface of the T cell induces a signal transduction pathway that results in the death of the T cell, thereby delaying the onset of or reducing a T cell-mediated immune response in the individual.
2. The method of claim 1 , wherein the multimeric compound is a homo-multimeric compound.
3. The method of claim 1 , wherein the multimeric compound is a hetero-multimeric compound.
4. The method of claim 1 , wherein the polypeptide chains are covalently linked via the heterologous amino acid sequence to form the multimeric compound.
5. The method of claim 4 , wherein the covalent linkage is a disulfide linkage.
6. The method of claim 1 , comprising selecting an individual diagnosed as having an inflammatory disease.
7. The method of claim 1 , comprising selecting an individual diagnosed as having an autoimmune disease.
8. The method of claim 1 , comprising selecting an individual that has received or is expected to receive an allogeneic or xenogeneic transplant.
9. The method of claim 1 , comprising selecting an individual diagnosed as having an allergic disease.
10. The method of claim 1 , comprising selecting an individual diagnosed as having a T cell cancer.
11. The method of claim 1 , wherein the T cell is an activated T cell.
12. The method of claim 1 , wherein the method comprises determining the percentage of apoptosis of T cells in a first biological sample taken from the individual before the administration of the multimeric compound and comparing to the percentage of apoptosis of T cells in a second biological sample taken from the individual after the administration of the multimeric compound.
13. The method of claim 1 , wherein the administration results in the depletion of at least 10% of activated T cells in the individual.
14. A method of inducing the death of a T cell or a natural killer (NK) cell, the method comprising: providing a T cell or NK cell expressing PSGL-1 on its cell surface; and contacting the T cell or NK cell with an anti-Fc antibody, and a multimeric compound that binds to at least two PSGL-1 proteins on the surface of the T cell or NK cell, wherein the multimeric compound comprises two polypeptide chains, each of the polypeptide chains comprising (i) a binding domain that binds to PSGL-1, wherein the binding domain comprises a P-Selectin extracellular domain or a PSGL-1-binding fragment thereof; or wherein the binding domain comprises an E-Selectin extracellular domain or a PSGL-1-binding fragment thereof, and (ii) a heterologous amino acid sequence, wherein the heterologous amino acid sequence comprises an immunoglobulin heavy chain constant region, and wherein the polypeptide chains are linked via the heterologous amino acid sequence to form the multimeric compound, wherein the binding of the multimeric compound to the at least two PSGL-1 proteins on the surface of the T cell or NK cell induces a signal transduction pathway that results in the death of the T cell or NK cell.
15. The method of claim 14 , wherein the multimeric compound is a homo-multimeric compound.
16. The method of claim 14 , wherein the multimeric compound is a hetero-multimeric compound.
17. The method of claim 14 , wherein the polypeptide chains are covalently linked via the heterologous amino acid sequence to form the multimeric compound.
18. The method of claim 17 , wherein the covalent linkage is a disulfide linkage.
19. The method of claim 14 , comprising inducing the death of an activated T cell.
20. The method of claim 14 , wherein the method comprises determining the percentage of apoptosis of the T cell or NK cell after the contacting with the multimeric compound.