Cytokine-Like Proteins

Abstract

A full-length cDNA corresponding to an EST (AA418955), which does not show any homology to other proteins in the database but has a weak homology to G-CSF, has been successfully isolated by synthesizing primers based on the EST sequence, and effecting PCR-cloning from a human fetal spleen library. Sequencing of the thus-isolated cDNA and analysis of its structure revealed that the cDNA has typical characteristics of a factor belonging to the IL-6/G-CSF/MGF family. It is also found out that the culture supernatant of said sequence-transfected CHO cells shows a proliferation supporting activity towards bone marrow cells in the coexistence of kit ligand.

1 . A compound that promotes an activity of a polypeptide consisting of the sequence of SEQ ID NO:1. 
     
     
         2 . The compound of  claim 1 , wherein the activity is supporting proliferation of bone marrow cells in the presence of the kit ligand. 
     
     
         3 . A pharmaceutical composition comprising the compound of  claim 1  as an active ingredient. 
     
     
         4 . The compound of  claim 1 , wherein the compound is obtained by a method comprising:
 contacting a mammalian bone marrow cell with a polypeptide comprising the sequence of SEQ ID NO:1 and a kit ligand, in the presence of a test compound;   detecting proliferation of the bone marrow cell; and   selecting the test compound if it promotes the proliferation of the bone marrow cell in comparison with a bone marrow cell cultured in the absence of the test compound.   
     
     
         5 . The compound of  claim 4 , wherein the bone marrow cell is Lin negative, Sca-1 positive, c-kit positive, and CD34 positive. 
     
     
         6 . A compound that inhibits an activity of a polypeptide consisting of the sequence of SEQ ID NO:1. 
     
     
         7 . The compound of  claim 6 , wherein the activity is supporting proliferation of bone marrow cells in the presence of the kit ligand. 
     
     
         8 . A pharmaceutical composition comprising the compound of  claim 6  as an active ingredient. 
     
     
         9 . The compound of  claim 6 , wherein the compound is obtained by a method comprising:
 contacting a mammalian bone marrow cell with a polypeptide comprising the sequence of SEQ ID NO:1 and a kit ligand, in the presence of a test compound;   detecting proliferation of the bone marrow cell; and   selecting the test compound if it inhibits the proliferation of the bone marrow cell in comparison with a bone marrow cell cultured in the absence of the test compound.   
     
     
         10 . The compound of  claim 9 , wherein the bone marrow cell is Lin negative, Sca-1 positive, c-kit positive, and CD34 positive. 
     
     
         11 . A compound that specifically binds to a polypeptide consisting of the sequence of SEQ ID NO:1. 
     
     
         12 . A pharmaceutical composition comprising the compound of  claim 11  as an active ingredient. 
     
     
         13 . The compound of  claim 11 , wherein the compound is obtained by a method comprising:
 contacting a test compound with a polypeptide comprising the sequence of SEQ ID NO:1;   determining whether the test compound binds to the polypeptide; and   selecting the test compound if it binds to the polypeptide.