Pharmaceutical composition for treatment and prevention of cancers

Abstract

The present invention relates to a pharmaceutical composition for treatment and/or prevention of cancer, which comprises, as an active ingredient, an antibody or fragment thereof having an immunological reactivity with a CAPRIN-1 protein or a fragment thereof comprising 7 or more consecutive amino acids.

1 . A method of preparing an antibody, comprising:
 administering a CAPRIN-1 protein, which has an amino acid sequence shown in any one of even-numbered SEQ ID NOs: 2 to 30, or a polypeptide fragment thereof, to a mammal to be immunized, and   purifying the resultant antibodies to obtain the antibody that specifically binds the CAPRIN-1 protein or a polypeptide fragment thereof expressed on the cell surface of a cancer and has an antitumor activity.   
     
     
         2 . The method according to  claim 1 , wherein the antitumor activity is an antibody-dependent cell-mediated cytotoxicity (ADCC) activity of the antibody. 
     
     
         3 . The method according to  claim 1 , wherein the antibody is a monoclonal antibody or polyclonal antibody. 
     
     
         4 . The method according to  claim 1 , wherein the antibody is a human antibody, a humanized antibody, a chimeric antibody, a single-chain antibody, or a bispecific antibody. 
     
     
         5 . The method according to  claim 1 , further comprising separating spleen cells from the immunized mammal and fusing the separated spleen cells with mammalian myeloma cells to obtain a hybridoma producing the antibody. 
     
     
         6 . The method according to  claim 5 , further comprising cloning DNA encoding an antibody from the hybridoma to obtain a clone for the antibody, incorporating the clone into a vector, and introducing the vector into a host cell to produce a recombinant antibody. 
     
     
         7 . The method according to  claim 6 , wherein the cloned DNA comprises DNA encoding a heavy chain variable region and a light chain variable region of the antibody. 
     
     
         8 . The method according to  claim 1 , further comprising preparing an antigen-binding fragment from the antibody, wherein the fragment specifically binds the CAPRIN-1 protein or polypeptide fragment thereof expressed on the cell surface of a cancer and has an antitumor activity.