Methods for using the obese gene and its gene product to identify hematopoietic progenitor cells

Abstract

The present invention relates to methods for using various forms of a novel receptor expressed by hematopoietic and endothelial cells. An additional variant form of this receptor has been detected in brain cells and shown to bind to the obese gene product, leptin. Therefore, leptin may be used to stimulate the growth and development of receptor-positive hematopoietic and endothelial cells in vitro and in vivo. In addition, this receptor is selectively expressed in hematopoietic progenitor cells with long-term repopulating potential. Thus, agents that specifically bind to this receptor may be used to identify and isolate progenitor cells for a variety of clinical applications.

1 - 26 . (canceled)  
     
     
         27 . A method for identifying hematopoietic progenitor cells in a cell mixture, comprising contacting the cell mixture with an agent that binds to Hu-B1.219 protein and selecting the cells bound to the agent.  
     
     
         28 . The method of  claim 27  in which the agent is an antibody or a fragment thereof.  
     
     
         29 . The method of  claim 27  in which the agent is leptin or a fragment thereof.  
     
     
         30 . A method for detecting hematopoietic progenitor cells in a cell mixture, comprising: 
 (a) contacting an RNA extracted from the cell mixture with a nucleic acid probe capable of specifically hybridizing to at least a portion of a coding strand of a cDNA of SEQ ID NO: 1; and    (b) detecting hybridization between the probe and the RNA.    
     
     
         31 . A method for identifying hematopoietic progenitor cells in a tissue, comprising: 
 (a) contacting a tissue with a nucleic acid probe capable of specifically hybridizing to at least a portion of a coding strand of a cDNA of SEQ ID NO: 1    (b) detecting hybridization between the probe and the RNA of the tissue.    
     
     
         32 . A method for detecting cancer, comprising: 
 (a) contacting a bodily fluid with a specific binding agent for Hu-B1.219 protein; and    (b) detecting the presence Hu-B1.219 in the fluid.