Tim-3 ligands and methods thereof

Abstract

The invention relates to isolated polypeptides and nucleic acids encoding polypeptides which comprise a tim-3 IgV domain and a tim-3 intracellular domain, wherein the polypeptides do not comprise a tim-3 mucin domain or a tim-3 transmembrane domain. In addition, the invention relates to methods of modulating immune responses in a subject, comprising administering to the subject a therapeutically effective amount of an agent that modulates tim-3 activity. Immune responses include, but are not limited to, immune tolerance, transplantation tolerance, Th1 responses and Th2 responses.

We claim: 
     
         1 . A method of identifying an agent that modulates binding between a tim-3 polypeptide and a galectin-9 polypeptide, the method comprising:
 (a) contacting the tim-3 polypeptide and the galectin-9 polypeptide in the presence of a test agent; and   (b) determining the effect of the test agent on the binding of the tim-3 polypeptide and the galectin-9 polypeptide;   thereby identifying an agent that modulates the binding between a tim-3 polypeptide and a galectin-9 polypeptide.   
     
     
         2 . The method of  claim 1 , wherein step (b) comprises comparing formation of a tim-3/galectin-9 complex in the presence of the test agent with formation of a tim-3/galectin-9 complex in the absence of the test agent. 
     
     
         3 . The method of  claim 1 , wherein the test agent is a small molecule compound, an antibody or a polypeptide. 
     
     
         4 . The method of  claim 1 , wherein the test agent increases binding between the tim-3 and galectin-9 polypeptides. 
     
     
         5 . The method of  claim 1 , wherein the test agent decreases binding between the tim-3 and galectin-9 polypeptides. 
     
     
         6 . The method of  claim 1 , wherein the tim-3 polypeptide or the galectin-9 polypeptide or both are expressed in a cell. 
     
     
         7 . The method of  claim 2 , wherein comparing formation of the a tim-3/galectin-9 complex comprises detecting expression of a reporter gene, wherein the expression of the reporter gene is dependent on the formation of the tim-3/galectin-9 complex. 
     
     
         8 . The method of  claim 1 , wherein the galectin-9 polypeptide comprises
 (i) amino acids 1-323 of SEQ ID NO: 10; or   (ii) amino acids 1-355 of SEQ ID NO: 19.   
     
     
         9 . The method of  claim 1 , wherein the tim-3 polypeptide comprises amino acids 30-128 of SEQ ID NO: 13. 
     
     
         10 . A method of identifying an agent that modulates an immune response, the method comprising
 (a) contacting the tim-3 polypeptide and the galectin-9 polypeptide in the presence of a test agent; and   (b) determining the effect of the test agent on the binding of the tim-3 polypeptide and the galectin-9 polypeptide;   thereby identifying an agent that modulates an immune response.   
     
     
         11 . The method of  claim 10 , wherein step (b) comprises comparing formation of a tim-3/galectin-9 complex in the presence of the test agent with formation of a tim-3/galectin-9 complex in the absence of the test agent. 
     
     
         12 . The method of  claim 11 , wherein comparing formation of the a tim-3/galectin-9 complex comprises detecting expression of a reporter gene, wherein the expression of the reporter gene is dependent on the formation of the tim-3/galectin-9 complex. 
     
     
         13 . The method of  claim 10 , wherein the immune response is a Th1 immune response. 
     
     
         14 . The method of  claim 10 , wherein the immune response is a Th2 immune response. 
     
     
         15 . An assay comprising:
 (a) combining a tim-3 polypeptide, a galectin-9 polypeptide, and a test agent under conditions where the tim-3 and galectin-9 polypeptides interact to form a tim-3/galectin-9 complex in the absence of the test agent; and   (b) measuring a parameter of tim-3/galectin-9 complex formation in the presence of the test agent;   wherein a change in the parameter of tim-3/galectin-9 complex formation in the presence of the test agent relative to tim-3/galectin-9 complex formation in the absence of the test agent is indicative that the test agent inhibits or potentiates tim-3/galectin-9 complex formation.   
     
     
         16 . The assay of  claim 15 , wherein the parameter of tim-3/galectin-9 complex formation is assembly or stability of tim-3/galectin-9 complex formation. 
     
     
         17 . The assay of  claim 15 , wherein the test agent is a small molecule compound, an antibody or a polypeptide. 
     
     
         18 . The assay of  claim 15 , wherein the tim-3 polypeptide or the galectin-9 polypeptide or both are expressed in a cell. 
     
     
         19 . The assay of  claim 15 , wherein the galectin-9 polypeptide comprises
 (iii) amino acids 1-323 of SEQ ID NO: 10; or   (iv) amino acids 1-355 of SEQ ID NO: 19.   
     
     
         20 . The assay of  claim 15 , wherein the tim-3 polypeptide comprises amino acids 30-128 of SEQ ID NO: 13.