Anti-pleiotrophin antibodies and methods of use thereof

Abstract

The present invention concerns antibodies that neutralize at least one biological activity of pleiotrophin. The antibodies can inhibit cancer cell growth and angiogenesis in vitro or in vivo. The present invention provides for methods of inhibiting cancer cell growth or angiogenesis in a subject comprising administering to said subject an effective amount of the antibodies described herein. The present invention also provides for methods of making the neutralizing antibodies described herein.

1 - 38 . (canceled) 
     
     
         39 . A monoclonal antibody or antigen-binding fragment thereof that binds to a type III epitope of pleiotrophin (PTN) and neutralizes at least one biological activity of PTN. 
     
     
         40 . The antibody or antigen-binding fragment thereof according to  claim 39  comprising any one of the following:
 (a) an antibody or antigen-binding fragment thereof that binds to an epitope, which is substantially the same as an epitope of the monoclonal antibody or antigen-binding fragment thereof produced by a hybridoma cell line selected from the group consisting of 4B2, 10, 17, 24, 25, 26, 27, 31, 41, 50, 60, 87, 3-4A, and 3-11FA; 
 (b) a monoclonal antibody or antigen-binding fragment thereof produced by a hybridoma cell line selected from the group consisting of 4B2, 10, 17, 24, 25, 26, 27, 31, 41, 50, 60, 87, 3-4A, and 3-11F; or 
 (c) an antibody that competitively inhibits binding of a PTN polypeptide to the monoclonal antibody or antigen-binding fragment thereof produced by a hybridoma cell line selected from the group consisting of 4B2, 10, 17, 24, 25, 26, 27, 31, 41, 50, 60, 87, 3-4A, and 3-11FA, 
 wherein the antibody or antigen-binding fragment comprises: (i) a light chain CDR1, (ii) a light chain CDR2, (iii) a light chain CDR3, (iv) a heavy chain CDR1, (v) a heavy chain CDR2, and (vi) a heavy chain CDR3. 
 
     
     
         41 . The antibody or antigen-binding fragment thereof according to  claim 39 , wherein said biological activity is selected from the group consisting of: receptor binding activities, signaling transduction activities, and cellular responses induced by PTN. 
     
     
         42 . The antibody or antigen-binding fragment thereof according to  claim 39 , wherein said antibody inhibits cancer cell growth. 
     
     
         43 . The antibody or antigen-binding fragment thereof according to  claim 39 , wherein said antibody inhibits cancer cell proliferation. 
     
     
         44 . The antibody or antigen-binding fragment thereof according to  claim 39 , wherein said antibody inhibits metastasis of cancer cells. 
     
     
         45 . The antibody or antigen-binding fragment thereof according to  claim 39 , wherein said antibody inhibits angiogenesis induced by cancer cells. 
     
     
         46 . The antibody or antigen-binding fragment thereof according to  claim 39 , wherein said antibody is selected from the group consisting of a chimeric antibody, a humanized antibody, and a fully human antibody. 
     
     
         47 . The antibody or antigen-binding fragment thereof according to  claim 39 , wherein said antigen-binding fragment is selected from the group consisting of Fab fragment, (Fab′) 2  Fragment, and a Fv fragment. 
     
     
         48 . The antibody or antigen-binding fragment thereof of  claim 39 , wherein the antibody is conjugated to a cytotoxic agent. 
     
     
         49 . The antibody or antigen-binding fragment thereof according to  claim 39 , wherein said antibody binds to a PTN epitope at a binding affinity of at least 10 6 M −1 . 
     
     
         50 . A pharmaceutical composition comprising the antibody according to  claim 39  and a pharmaceutical carrier. 
     
     
         51 . An isolated monoclonal antibody produced by the method comprising:
 1) selecting a host animal;   2) immunizing said host animal with a fusion protein comprising a pleiotrophin protein connected with a known T-cell epitope derived from a different protein;   3) isolating a lymphoid cell from said host animal;   4) fusing said lymphoid cell to a myeloma cell, so that a hybrid cell is created;   5) cultivating said hybrid cell; and   6) isolating a monoclonal antibody against said pleiotrophin protein produced by said hybrid cell.   
     
     
         52 . A method of neutralizing at least one biological activity of PTN in a subject in need thereof comprising administering to said subject an effective amount of an antibody or antigen-binding fragment thereof according to  claim 39 . 
     
     
         53 . A polynucleotide molecule comprising a nucleotide sequence selected from SEQ ID NOs: 4 and 9.