Anti-ilt7 antibody

Abstract

An antibody binding to IPC was obtained by using an animal cell in which a cell membrane protein associatable with ILT7 was co-expressed as an immunogen. The antibody of the invention has a high specificity which allows immunological distinction between other ILT family molecules and ILT7. The anti-ILT7 antibody of the invention bound to IPC and inhibited the activity thereof. With the anti-ILT7 antibody of the invention, the IPC activity can be inhibited and an interferon-related disease can be treated or prevented. ILT7 expression is maintained even in IPC in the presence of IFNα. Therefore, an inhibitory action of IPC activity by the anti-ILT7 antibody can be expected even in an autoimmune disease patient with an increased production of IFNα.

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         5 . A monoclonal antibody which binds to an extracellular domain of human ILT7 or a fragment comprising its antigen binding region wherein the monoclonal antibody comprises a mature sequence of an amino acid sequence selected from any of the following combinations (a) to (c) as the heavy chain variable region and the light chain variable region:
 a) a heavy chain variable region of SEQ ID NO: 39 and a light chain variable region of SEQ ID NO: 41;   b) a heavy chain variable region of SEQ ID NO: 43 and a light chain variable region of SEQ ID NO: 45; and   c) a heavy chain variable region of SEQ ID NO: 47 and a light chain variable region of SEQ ID NO: 49.   
     
     
         6 . A polynucleotide encoding the monoclonal antibody or the fragment comprising its antigen binding region according to  claim 5 . 
     
     
         7 . A vector comprising a polynucleotide encoding the monoclonal antibody or the fragment comprising its antigen binding region according to  claim 5 . 
     
     
         8 . A transformed cell retaining the vector according to  claim 7  in an expressible manner. 
     
     
         9 . A method for producing the monoclonal antibody or the fragment comprising its antigen binding region according to  claim 5 , comprising the steps of: culturing a transformed cell; and recovering the monoclonal antibody or the fragment comprising its antigen binding region from the culture. 
     
     
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         13 . A method for producing a cell which produces a monoclonal antibody which binds to an extracellular domain of human ILT7, comprising the following steps of:
 (1) administering to an immune animal a cell which expresses a exogenous protein comprising an extracellular domain of human ILT7 and a exogenous molecule which associates with human ILT7; and   (2) selecting an antibody producing cell which produces an antibody which binds to human ILT7 from the antibody producing cell of the immune animal.   
     
     
         14 . The method according to  claim 13 , wherein the molecule which associates with human ILT7 is a cell membrane protein. 
     
     
         15 . The method according to  claim 14 , wherein the cell membrane protein is Fc receptor γ-chain. 
     
     
         16 . The method according to  claim 15 , wherein the cell expressing human ILT7 and the molecule which associates with human ILT7 is a cell retaining the following (a) and (b) in an expressible manner:
 (a) an exogenous polynucleotide encoding an amino acid sequence comprising an extracellular domain of human ILT7; and   (b) an exogenous polynucleotide encoding Fc receptor γ-chain.   
     
     
         17 . The method according to  claim 16 , wherein the cell is an animal cell. 
     
     
         18 . The method according to  claim 17 , wherein the cell is a human-derived cell. 
     
     
         19 . The method according to  claim 18 , wherein the human-derived cell is a 293T cell. 
     
     
         20 . The method according to  claim 13 , additionally comprising a step of cloning the antibody producing cell obtained by the method according to  claim 13 . 
     
     
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